AN11012 Using the TEA1703 to reduce standby power Rev. 1 — 30 March 2011 Application note

Document information Info Content Keywords SMPS, TEA1703, TEA1738, TEA1753, standby power Abstract TEA1703 is a low power standby controller IC intended for use in SMPS applications that require an extremely low no-load standby power. The TEA1703 includes detection circuitry for output voltage, output power and also switching detection circuitry. The TEA1703 integrates a switched mode optocoupler driver which makes it possible to drive an optocoupler with a high peak current, while keeping the required power low. (NXP Semiconductors patent) NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

Revision history Rev Date Description v.1 20110330 first issue

Contact information For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: [email protected]

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 2 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

1. Introduction

The number of electronic products used today in private homes and offices is constantly increasing. Most products, such as: audio equipment, TVs, digital cable receivers, DVD/Blu ray recorders, , printers, etc. consume a considerable amounts of electrical power while on standby (when they are not in use but are still connected to the mains supply). This not only is a waste of energy and money but also has a large impact on the environment. Today, many products required to run in Standby mode have to comply with requirements on energy consumption like the 2.0 APS requirements.

The TEA1703 is a low power standby controller IC intended to be used in SMPS applications that require an extreme low no-load standby power. The TEA1703 includes detection circuitry for output voltage, output power and also switching detection circuitry. The TEA1703 integrates a switched mode optocoupler driver, which makes it possible to drive an optocoupler with a high peak current, while keeping the required power low. (NXP Semiconductors patent). using the TEA1703, the standby power consumption of a SMPS is reduced to 30 mW or less.

Remark: Unless otherwise stated all values given in this application note are typical values.

2. Scope and set-up of this application note

2.1 Scope This application note describes the functionality of the TEA1703 standby controller and the operation in combination with the TEA1738 and TEA1753 SMPS controllers. Detailed application information is given on interfacing and performance optimization.

2.2 General setup of the application note The setup of this document is made in such a way, that a section or paragraph on a selected subject can be read as a stand-alone explanation with a minimum of cross references to other document parts or the data sheet.

2.3 Related documents and tools This application note gives no in depth application information on the TEA1738 or TEA1753 SMPS controller. Application notes, data sheets, user manuals and design tools can be found on the product pages for the TEA1703, TEA1738 and TEA1753 at http://www.nxp.com.

3. TEA1703 features

• SMPS standby controller IC enabling very low power standby operation • Large input voltage range from 5 V up to 30 V • Very low supply current of 30 μA • Switched mode optocoupler driver output (NXP Semiconductors patent) • Ease of application

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 3 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

4. Pin description

Table 1. Pin description Symbol Pin Description VCC 1 supply voltage; the supply voltage ranges from 5 V to 30 V. The supply current is 30 μA GND 2 ground connection OPTO 3 optocoupler driver; open-drain output with integrated diode to pin VCC. A coil in series with the optocoupler is used to achieve a high current transfer ratio. Alternatively, a instead of a coil can be used. n.c. 4, 5 not connected SWDET 6 switch detect input; when the SMPS is not switching and the input current is below the Ith(SWDET) threshold of 1.2 μA, this pin disables the TEA1703. The SWDET input can be used to prevent a reset of the latch protection via the VINSENSE of the SMPS. This is the case with the TEA1753. The SWDET pin can be connected to VCC via a resistor when the functionality is not necessary. The input is clamped at 1 Vd, 0.74 V at 1.2 μA. PSENSE 7 power sense input; the optocoupler pulses are enabled when the voltage on PSENSE drops below 0.5 V. This level is reached at a certain output power level and can be adjusted using an external filtering network connected to pin PSENSE. Pin PSENSE has a hysteresis of 15 mV. The input impedance is approximately 100 MΩ. VSENSE 8 voltage sense input; the optocoupler pulses are disabled when VSENSE drops below 1.22 V. This level is reached when the output voltage drops to a certain level. This level can be adjusted using a resistor divider network from the converter output to pin VSENSE. In Standby mode, the output voltage varies between the nominal output voltage (i.e. the output voltage obtained during normal operation) and the minimum output voltage adjusted which can be as low as 5 V. Pin VSENSE has no hysteresis but below 1.22 V and the internal current source of 0.9 μA from VCC is switched off. The current provides a small hysteresis across the VSENSE resistor to ground. The input impedance (below 1.22 V) is approximately 100 MΩ.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 4 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

5. Application diagram

Figure 1 shows the TEA1703 connections in a typical application.

R1 C3

47 Ω 220 pF

fly 1 Vout fly 2 D1 C1 C2 STMS20M100ST 680 μF 680 μF 19.5 V 25 V 25 V 3.34 A

GND

D2 1 BAS21

R2 R4 U2-1 330 kΩ 4.7 MΩ 2

C4 R3 R5 C5 L1 47 nF 220 kΩ 360 kΩ 100 pF 10 mH

U1 VSENSE VCC 8 1 PSENSE GND 7 2 R6 SWDET TEA1703 OPTO 6 3 2.2 MΩ n.c. n.c. 5 4

019aab497

Fig 1. TEA1703 connections in a typical application

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 5 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

6. TEA1703 description and calculation

This section describes the TEA1703 functions and operation in a typical application.

6.1 General description The TEA1703 is a standby controller IC that reduces the standby power of a switched mode . Standby mode operation information is obtained by sensing the output voltage and the output power of the SMPS. The output voltage is measured at pin VSENSE of the TEA1703 via the resistor divider R4 and R5 as shown in Figure 1. The output power is measured at the flyback winding of the via D2 and a low-pass filter made by R2, R3 and C4 as shown in Figure 1.

The principle of output power measuring is based on SMPS converters where the output power at low load increases with frequency, e.g. in a discontinuous conduction mode flyback converter which has a fixed primary peak current during low load operation.

The block diagram (Figure 2) shows the VSENSE and PSENSE inputs and the corresponding comparators. A SWDET input is added to disable Standby mode detection e.g. when a latched protection is active. When pins VSENSE, PSENSE and SWDET have the correct levels, the 28 kHz oscillator is enabled. The oscillator drives the MOSFET at the OPTO pin with an on-time of 1.4 μS (4 % duty cycle). Pin OPTO drives the optocoupler via a coil and disables the SMPS.

0.9 μA

REFERENCE 1 8 VCC AND VOLTAGE SENSE VSENSE SUPPLY 1.22 V

POWER SENSE 2 0.5 V 7 GND PSENSE

3 SWITCH 1.2 μA 6 OPTO DETECT SWDET OSCILLATOR 4 5 n.c. n.c.

019aab498

Fig 2. Block diagram

6.2 Standby mode operation The Standby mode operation signals are shown in Figure 3. In Standby mode the optocoupler pulses generated by the TEA1703 disable the SMPS and consequently the output voltage drops. When the voltage at pin VSENSE reaches 1.22 V, the 0.9 μA current source is switched off and VSENSE drops below 1.22 V. The small hysteresis prevents fast on/off switching of the VSENSE comparator.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 6 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

As the output of the VSENSE comparator is low, the optocoupler pulses are disabled and the SMPS can restart. When the output capacitors are charged and the voltage on PSENSE drops below 0.5 V, optocoupler pulses are generated again on the first SWDET pulse. In a typical application the SMPS restarts every couple of minutes. This considerably reduces the standby power consumption.

019aab499

Fig 3. Standby mode operation

6.3 Normal operation The transition to normal operation is shown in Figure 4. When, during Standby mode operation, a load higher than the Standby mode power threshold is connected, the SMPS switches to normal operation. In the example of Figure 4, a load slightly above the standby power threshold is connected. VSENSE drops faster than during Standby mode operation. When VSENSE reaches 1.22 V, the SMPS starts-up and remains active, as PSENSE does not drop below the 0.5 V PSENSE comparator level.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 7 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

019aab500

Fig 4. Normal operation

6.4 PSENSE At pin PSENSE the actual output power of the SMPS is measured. Pin PSENSE should be connected to the secondary winding via a low pass filter (see Figure 1). The power level at pin PSENSE is compared to an internal reference of 0.5 V. Pin PSENSE disables the SMPS when the output power drops below a predefined level. The adjustment of the Standby mode power threshold depends on the power control behavior of the SMPS. The adjustment procedure for the TEA1738 is given in Section 7.7.1.

The adjustment procedure for the TEA1753 is given in Section 8.7.1.

6.5 VSENSE At pin VSENSE the divided output voltage is compared to an internal reference voltage of 1.22 V. See the block diagram of Figure 2. When the comparator level is reached, an internal current source of 0.9 μA from VCC to pin VSENSE is switched off and VSENSE further drops below the comparator level. The hysteresis prevents fast on/off switching of the comparator. Pin VSENSE enables the SMPS when the output voltage drops below a predefined level. The adjustment procedure for the TEA1738 is given in Section 7.7.2.

The adjustment procedure for the TEA1753 is given in Section 8.7.2.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 8 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

6.6 SWDET A SMPS enters latched protection mode when an over voltage, over temperature or output short circuit situation occurs. If a protection is triggered, the SMPS stops switching and enters the off state. When the reason of the protection is removed, removing the mains resets the latched protection. A reset is triggered via the VCC supply (TEA1738) or via the VINSENSE (TEA1753).

When pin SWDET is connected to the secondary transformer winding, as shown in Figure 1, the SWDET input can be used to prevent a reset of the latch protection via the VINSENSE of the SMPS. Without this precaution the latch protection of the TEA1753 is reset, as VINSENSE is forced low in Standby mode.

When the latch protection is not reset via VINSENSE but for instance via the VCC pin of the TEA1738, pin SWDET can be connected to the VCC of the TEA1703 via a 2.2 MΩ resistor. A VCC clamp (ZD2) as shown in Figure 5 is required.

Pin SWDET is a current controlled input. A current above the Ith(SWDET) level of 1.2 μA enables the Standby mode via the optocoupler when VSENSE ≥ 1.22 V and PSENSE ≤ 0.5 V. Place the current limiting resistor (R31 in Figure 5, R50 in Figure 13) at pin SWDET.

A current below the Ith(SWDET) level of 1.2 μA prevents switching from normal operation to the Standby mode.

6.7 Optocoupler To minimize the Standby power consumption it is necessary to keep all currents in a SMPS application as low as possible. A high current transfer ratio type at low input currents is recommended for the optocoupler such as the B/C version of the LTV-356T or IS357.

To maintain the high current transfer ratio of the optocoupler, the optocoupler diode is driven with a high current and low duty cycle. The average current and consequently, the power consumption, is still low. The optocoupler drive is most effective when a coil in series is used. The coil is magnetized during the short on-time of 1.4 μS and demagnetized during a longer time via the internal diode from the OPTO pin to the VCC pin. The use of a coil is much more efficient than the use of a series resistor where most of the energy is lost in the resistor.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 9 of 36 xxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx x xxxxxxxxxxxxxx xxxxxxxxxx xxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxx xxxxx xxxxxx xx xxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxx xxxxxxx xxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxx xxxxxx xx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxx xxxxx x x . Typical TEA1703an 7. NXP Semiconductors Application note Rev. 1 — 30 March 2011 10 of 36 10of B.V. ©NXP 2011.reserved. rights All Rev. 2011 1—30March disclaimers. legal to subject is document this in provided information All note Application AN11012

INLET F1 1 L R26 C18 3.15 A 220 pF 250 V 47 Ω

RM10 3 N Lp = 650 μH T1 2 fly1 R13 R14 Vout LF1 43 kΩ 43 kΩ 3 fly2 D5 STMS20M100ST 1 BD1 C9 C13 C14 19.5 V

R1 KBP206G d TEA1738application LF2 680 μF 680 μF 3. 34 A 750 kΩ - + CX1 2200 pF 25 V 25 V 0.33 μF 630 V R2 C1 C2 750 kΩ R12 120 μF 3300 pF GND 10 MΩ 400 V 1 kV R10 R11 R3 D2 750 kΩ C3 10 MΩ 10 MΩ D7 F SA2M C19 0.22 μF n.m. BAS21 R4 R9 240 kΩ 750 kΩ D6 D3 R16 R28 BAS21 C20 D1 FF 1N4148W 10 Ω 330 kΩ 47 nF 1N4148 1 R23 C15 R21 35.7 kΩ R15 100 nF 330 Ω R5 ZD2 ZD1 1 % R29 R32 U4-1 R34 U1 1 MΩ BZX383-B18 BZX84-B24 4.7 Ω R30 0 Ω 4.7 MΩ n.m. VINSENSE ISENSE C12 220kΩ 5 4 100 pF 2 4 PROTECT DRIVER Q1 6 3 2SK3569 Q1 TEA1738 C8 2N7002 U4-2 CTRL GND U3-1 LTV-817B 68 pF 1 C21 RT1 7 2 R33 L2 R35 R17 R22 100 pF 3 TTC95204 C5 VCC 360 kΩ 10 mH n.m. OPTIMER 1 kΩ n.m. 1 nF 8 1 Using the TEA1703 toreduce standbypower F Q3 C4 F BC848C C10 2 C17 U2 100 nF VSENSE VCC R6 8 1 1 nF 39 kΩ R7 4 C7 0.22 μF R8 C6 R19 PSENSE GND 8.06 kΩ U3-2 0.1 μF 7 2 2.2 MΩ 0.22 μF 0.18 Ω LTV-817B 50 V R18 R27 R31 TEA1703 C16 SWDET OPTO F R25 6 3 3 33 kΩ 1.5 MΩ 2.2 MΩ 10 kΩ n.c. n.c. FFFF F F F 10 nF 5 4 D4 L1 BAS21W 6.8 μH R26 C18 4 U5 1.5 MΩ 22 nF C11 AP431SR 4.7 μF 5 R24 50 V F F 5.23 kΩ 1 %

BC1 CY1 470 nF

F 019aab501 AN11012

Fig 5. Typical TEA1703 and TEA1738 application NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

7.1 General description and typical application Figure 5 shows a typical application of the TEA1738 low cost SMPS controller and the TEA1703 Standby controller. During Standby operation, optocoupler U4 forces VINSENSE (pin 5 of the TEA1738) low via transistor Q3. The SMPS stops switching when the voltage on VINSENSE drops below 0.72 V.

7.2 Interfacing To reduce standby power consumption, the AP431 reference (U4 in Figure 5) and the resistor divider R23 and R24 are switched off in standby by means of Q1. This reduces the standby power by 5 mW to 10 mW. The values of R26, R27 and C18 are not critical. R26 and R27 reduce the maximum gate voltage and C18 creates a switch off delay. See the switching signals in Figure 6. Until the output voltage reaches the minimum value, the power consumption is minimal.

Alternatively R26 and R27 can be increased to reduce the standby power consumption. This, however, reduces the accuracy of the output voltage because of the spread on the reference input current of the AP431.

019aab502

Fig 6. AP431SR voltage reference on/off switching

The standby information for the SMPS is obtained via optocoupler U4. The collector of the optocoupler is not connected directly to pin VINSENSE but via transistor Q3. This is necessary to comply with dark current requirements. Dark currents up to 10 μA can be managed.

Remark: Dark current is the current that can flow through the output phototransistor when it is turned off.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 11 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

Zener diode ZD2 forms a VCC clamp at 18.5 V in Standby mode. This level is just below the TEA1738’s minimum start-up voltage of 18.6 V. Without the Zener clamp the TEA1738 enters a repetitive restart mode where it consumes considerably more power. The Zener clamp furthermore facilitates a fast restart of the SMPS, as the VCC voltage only has to be charged from 18.5 V to 20.6 V.

During start-up VCC temporarily drops to 17 V and consequently the Zener current and base current for Q3 is insufficient to pull VVINSENSE to ground. A bleeder resistor of 1 MΩ in parallel with the Zener diode ZD2 makes VCC drops down to 13 V possible.

7.3 General performance The no-load standby power at 230 V (AC) of the SMPS shown in Figure 5 is 39 mW. In Standby mode, the output voltage varies between 19.9 V and 12.6 V. The standby power threshold is 470 mW and the power-up time from standby to maximum load 160 ms.

7.4 Standby mode power consumption The 39 mW Standby mode power consumption at 230 V (AC) is dissipated in:

• X-cap, bridge rectifier and elcap, 2.5 mW • Start-up resistors R1 – R4, 32.5 mW • VINSENSE resistors R9 to R12, 3.4 mW

• VCC of the TEA1738, less than 0.5 mW

• VCC of the TEA1703, less than 0.5 mW

The start-up resistors are responsible for a substantial part of the Standby mode power consumption. The resistors are chosen such that the start-up time at 115 V (AC) remains below 3 s. The Standby mode power consumption and start-up times for different resistor values are shown in Table 2.

Table 2. Standby mode power dissipation and start-up times for different start-up resistors Capacitance is 4.7 μF + 100 nF. R1 + R2 = R3+ R8 Standby power Start-up time 230 V (AC) 90 V (AC) 115 V (AC) 1MΩ 55 mW 2.54 s 1.65 s 1.2 MΩ 47mW 3s 2s 1.5 MΩ 39 mW 4 s 2.6 s 1.8 MΩ 34 mW 5.2 s 3.2 s 2MΩ 29 mW 6.7 s 4.2 s A further reduction of the Standby mode power is possible when the startup resistors are replaced by a charge MOSFET with active X-cap discharge. See Section 9, the VCC charge MOSFET with active X-cap discharge.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 12 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

7.5 Power-up behavior When a load is connected during Standby mode, the TEA1738 has to start-up before it can deliver full power. The start-up time (i.e. the time necessary to deliver full power) depends on the time to charge the VCC capacitor. The charge time depends on the mains voltage, the value of the VCC capacitance C11, and the value of the start-up resistors R1 to R4. To minimize the start-up time the VCC voltage in Standby mode is clamped at 18.5 V.

This considerably reduces the start-up time. Using the given component values and a load current of 3.3 A, the start-up time at 90 V (AC) is 858 ms. At 230 V (AC) it is 160 ms.

See the power-up behavior shown in Figure 7a and Figure 7b.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 13 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

019aab503

a. Power-up at 90 V (AC)

019aab504

b. Power-up at 230 V (AC) Fig 7. Power-up behavior

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 14 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

7.6 Power-down behavior Figure 8 shows the power-down behavior. When the load is disconnected, or when the load drops below the Standby mode power threshold, the voltage at pin PSENSE drops below 0.5 V. On the first SWDET pulse optocoupler pulses are generated, VINSENSE is forced low and the SMPS is forced into Standby mode.

Using the TEA1738 the SWDET functionality is not necessary as the VCC clamp prevents a reset of the latch protection. Alternatively pin SWDET can be connected to pin VCC via a high-ohmic resistor of 2.2 MΩ.

Remark: The latched protection of the TEA1738 is reset when the voltage VCC drops below 5 V

019aab505

Fig 8. Power-down behavior

7.7 Adjustments Using the component values shown in Figure 5, the power level to enter Standby mode is 470 mW and the minimum output voltage level at which the optocoupler is disabled 12.6 V. These levels can be adjusted separately. Preferably the power level is adjusted first.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 15 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

7.7.1 Standby mode power threshold level adjustment The power level to enter the Standby mode can be adjusted using the low-pass filter connected to pin PSENSE.

Before adjustment, the correct Standby mode power level should be chosen.

A good choice is a power level slightly lower than the minimum power level of the application during normal operation. For example, at a minimum power level of 300 mW, R30 should be ≥ 430 kΩ. See the curves of Figure 9. The slight difference between 115 V (AC) and 230 V (AC) is caused by the overshoot of the Ipeak detector. The higher Ipeak at 230 V (AC) results in a lower switching frequency and lower PSENSE voltage.

Capacitor C20 in parallel to R30 in Figure 5 reduces the ripple at PSENSE. The ripple at PSENSE around the comparator level of 500 mV should be less than the hysteresis of 15 mV.

019aab506 1200 Output power to standby (mW)

800

400 (1)

(2)

0 0 200 400 600 800 1000 R30 (kΩ)

(1) 230 V (AC). (2) 115 V (AC). Fig 9. Output power to Standby mode versus R30

7.7.2 Minimum output voltage adjustment In Standby mode, the output voltage varies between two levels. The maximum level is the output voltage of the SMPS during normal operation. The minimum level is the output voltage reached in Standby mode before the SMPS restarts. See Figure 10 where the output voltage variation is shown in Standby mode for a 20 mA load at 115 V (AC) and 230 V (AC). At a higher load the SMPS switches to normal operation.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 16 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

019aab507

a. 115 V (AC)

019aab508

b. 230 V (AC) Fig 10. Output voltage variation at 20 mA in Standby mode

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 17 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

The minimum output voltage depends on the load in Standby mode. When the output load is zero the minimum output voltage is equal to the set voltage. The set voltage is the output voltage set with the resistor divider at pin VSENSE. See Figure 5.

When the output is loaded in Standby mode, the output voltage decreases below the set voltage until the SMPS restarts. In that case the minimum output voltage is lower than the set voltage. When the application of Figure 5 is loaded with 20 mA in Standby mode, the difference between the set voltage and minimum output voltage is 6 V at 115 V (AC). See Figure 10a. At 230 V (AC), the difference is less and about 2.1 V. At 230 V (AC) the charge current for the VCC capacitor is higher and consequently the start-up time shorter.

7.7.2.1 Adjustment procedure at standby no-load

• Determine the minimum output voltage Vmin. For minimum standby power the minimum output voltage should be as low as possible but above 5 V. At no load there is hardly any difference between Vmin and the set voltage Vset −6 • Resistor R33 = 1.22 / (((Vmin − 1.22) / R32) + 1e ). Alternatively the value for R33 for can be found in Figure 11. The curve is valid for R32 = 4.7 MΩ

019aab509 16 Set voltage (V) 12

8

4

0 250 350 450 550 650 750 R33 (kΩ)

R32 = 4.7 MΩ. Fig 11. Set voltage versus R33

7.7.2.2 Adjustment procedure at low standby loads At low loads up to the Standby mode power threshold level, the minimum output voltage is lower than the set voltage. See Figure 10 for an output load of 20 mA. To guarantee a minimum output voltage is it necessary to adjust to a higher voltage (i.e. to the set voltage as shown in Figure 11). The adjustment procedure is as follows:

• Make R32 = 4.7 MΩ and R33 = 360 kΩ. Now the set voltage sufficiently high; 12.6 V • Apply the minimum mains voltage, e.g. 115 V (AC) • Apply the maximum Standby mode load. At this load level the SMPS should not enter normal operation. If not done already, it is important to first carry out the standby power threshold level adjustment as described in Section 7.7.1

• Measure VOPTO, VDRIVER and VOUT using an oscilloscope as shown in Figure 10

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 18 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

• Determine the new set voltage when the minimum output voltage is not appropriate. For minimum standby power the minimum output voltage should be as low as possible but above 5 V. The difference, however, is slight −6 • Resistor R33 = 1.22 / (((Vset − 1.22) / R32) + 1e ). Alternatively, the value for R33 for can be found in Figure 11. The curve is valid for R32 = 4.7 MΩ

7.7.3 Choosing the right coil When the set voltage is low, the voltage across the coil and the current through the optocoupler might become too low to force VVINSENSE low and to disable the SMPS. In this situation a lower self-inductance is an option.

Be careful not to exceed the maximum peak current of the optocoupler and keep in mind that a large peak current effects the life cycle of the optocoupler and the standby power consumption. Peak currents above 10 mA already have impact on the life cycle of the optocoupler. The coil of 10 mH used in Figure 5 is a compromise between the maximum peak current of 2.5 mA and the minimum drive current of 0.655 mA for the optocoupler. The coil current and optocoupler pulses for the minimum and maximum output voltage of 5 V and 20 V are shown in Figure 12.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 19 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

019aab510

a. Behavior at VOUT = 20 V

019aab511

b. Behavior at VOUT = 5 V Fig 12. Coil current and optocoupler pulses

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 20 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

The peak value of the coil current is calculated using:

10× ()δ V – V × I = CC f (1) peak ------× fosc L

where:

Ipeak (mA) = peak coil current

VCC (V) = supply voltage of the TEA1703; equal to VOUT

Vf (V) = forward voltage of the optocoupler; 1.2 V δ (%) = duty cycle of the optocoupler pulse; 4 %

fosc (Hz) = oscillator frequency, 28 kHz L (H) = inductance of coil L2 in Figure 5, 10 mH

8. Typical application TEA1703 with the TEA1753

See Figure 13 on page 22 and Figure 14 on page 23 for a detailed overview of the typical application.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 21 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

F1

LF1 R1 LF2 BD1 L1 D1 BC1 mains - + L2 CX1 A inlet 9 7 R2 R18 C1 C2 C3 R6 R5 12 1 C8 R19 D3 R6B R5A B

Q9 C5 switch signal D2 R31 Q1 R42 R9 R8 D4 R43 Q8

Q2 R14 R13 C9

R12 R11 R16 R16A

C6 R10 C10 R15

R22 C R17

switch signal D

R7 C4 D5 C23 R45 R23A D23A

E C13 C14

R23 HVS VOSENSE FBDRIVER FBSENSE

U1 HV PFCTIMER VCC 14 15 9 13 10 16 1 PFCSENSE FBAUX 11 4 TEA1753 FBCTRL PFCDRIVER 3 F 12 R27 PFCAUX PFCCOMP 8 7 256 R3 GND LATCH

R28 R29 VINSENSE R26 R25 C17

Q10 C25 4 RT2 C24 C22 R4 C21 C20 C19 C18 U2A-1 NTC

3 OPTIONAL

019aab987

Fig 13. Typical circuit diagram of the TEA1703 with the TEA1753 (part 1)

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 22 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

T1 U3 D30 A 11 VCC 2 8 3 n.c. 5 n.c. 4 C30 TEA1791 6 n.c. GND B 2 7 n.c. 1 41 DRIVER SRSENSE

R30 R32

Q4

Vout+ 7, 8 R33 C31 L4 D50 R53 C L3 R51 1 C27 C29 D R57 U2A-2 5 C52 C28 C51 R52 R54 2 6 9, 10 E Vout- U5 CY1 BC2 VSENSE V 8 1 CC PSENSE GND 7 2 TEA1703 R50 SWDET OPTO 6 3 n.c. n.c. 5 4 F

R34 R37

U2-2 1 Q7 4 R35 R24

C15 U2-1 2 C34

C16 3 C35 R36

U4

R38

D52 R55

C53 R56

019aab988

Fig 14. Typical circuit diagram of the TEA1703 with the TEA1753 (part 2)

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 23 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

8.1 General description typical application Figure 13 and Figure 14 show a typical application of the TEA1753 low cost SMPS controller and the TEA1703 standby controller. During standby operation, optocoupler U2A forces VINSENSE (pin 7 of the TEA1753) low. The SMPS stops switching when the voltage on VINSENSE drops below 0.35 V (DC).

8.2 Interfacing To reduce standby power consumption, the TL431 reference (U4 in Figure 13 and Figure 14) and the resistor divider R37 and R38 are switched off in standby by means of Q7. This reduces the standby power with 5 mW to 10 mW. The values of R55, R56 and C53 are important in relation with components R51, R52 and C51, this relationship is explained in more detail in Section 8.7.1. Resistors R55 and R56 reduce the maximum gate voltage and C53 creates a switch off delay.

Alternatively, R37 and R38 can be increased to reduce the standby power consumption. This, however, reduces the accuracy of the output voltage because of the spread on the reference input current of the TL431.

line VCC (pin 1)

R1 C13

R45

R2 R3

D1001A D1001B neutral

4 R1000 gate Q8 and Q9 U2A-1 R1001 LTV-817B (optional) 3 VINSENSE (pin 7) Q11 D1000 BC547 R4 C20 C21 R8

019aab513

Fig 15. The proposed VSENSE circuit for minimizing the influence of the dark current

The standby information for the SMPS is obtained via optocoupler U2A. The collector of the optocoupler is not compensated for dark current. The brownout voltage can be influenced if there is no compensation for dark current. Figure 15 shows an alternative circuit diagram that compensates dark currents up to 10 μA. The red colored components in Figure 15 have to be added and components R42 and R43 can be removed in Figure 13 and Figure 14. Diode D1001A and D1001B are available in one package.

Remark: Dark current is the current flowing through the output of the phototransistor when it is turned off.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 24 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

8.3 General performance The no load standby power at 230 V (AC) of the SMPS shown in Figure 13 and Figure 14 is 32 mW. In standby, the output voltage varies between 19.5 V and 12.6 V. The standby output power threshold is 190 mW. This corresponds to an output current of approximately 10 mA. The worst-case power-up time from standby to maximum output current is 600 ms (with C13 = 47 μF).

8.4 Standby power consumption The 32 mW standby power at 230 V (AC) is dissipated in:

• X-cap, bridge rectifier and elcap; 2.5 mW • VINSENSE resistors R1, R2, R3 and R4; 17 mW • Power losses TEA1753; 5.3 mW

• VCC of the TEA1703, less than 0.5 mW • Recharging the output voltage; 7 mW

The VINSENSE resistors are responsible for a substantial part of the standby power consumption.

8.5 Power-up behavior When a load is connected in standby, the TEA1753 has to start-up before it can deliver full power. The start-up time (i.e. the time necessary to deliver full power) depends on the time to charge the VCC capacitor. The charge time depends on the value of the VCC capacitance C13. The start-up time is approximately 580 ms if C13 is 47 μF; see Figure 16.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 25 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

CH1

CH2

CH3

CH4

019aab514

(1) CH1: Io = 5 A per division.

(2) CH2: TEA1753 VVINSENSE = 1 V per division.

(3) CH3: TEA1753 VVCC = 10 V per division.

(4) CH4: TEA1753 VO = 10 V per division. Fig 16. Power-up behavior

8.6 Power-down behavior Figure 17 shows the power-down behavior. An extra current is driven through optocoupler U2 when the output current is minimized (during load-step).

The gate drive pulses of the flyback are now disabled for some time, see Figure 17. New FBRIVER pulses are generated when Q7 switches off because of the discharged capacitor C53, which results in a SWDET pulse detection at the TEA1703. The first SWDET activates the OPTO output and forces the VINSENSE of the TEA1753 to drop until the SMPS is forced into standby.

The TEA1753 does not generate new FBDRIVER pulses if it is forced into a latched protection, see Figure 18 (system is forced into OVP by shorting the optocoupler). Therefore the TEA1703 doesn’t activate the OPTO output in such circumstances (no SWDET signal is detected during a latched protection).

Reset of the latched protection is possible by briefly removing the line voltage.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 26 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

CH1

CH2

CH3

CH4

019aab515

(1) CH1: Io = 5 A per division.

(2) CH2: TEA1753 VVINSENSE = 1 V per division.

(3) CH3: TEA1753 VFBDRIVER = 10 V per division.

(4) CH4: TEA1703 VOPTO = 10 V per division. Fig 17. Power-down behavior when load is removed

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 27 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

CH1

CH4

CH3

CH2

019aab516

Io =55mA

(1) CH1: VLATCH = 1 V per division.

(2) CH2: VO = 10 V per division.

(3) CH3: VOPTO = 10 V per division.

(4) CH4: VFBDRIVER = 10 V per division. Fig 18. Power-down behavior when system is forced into a latched protection (OVP)

8.7 Adjustments Using the component values of Figure 13 and Figure 14, the power level to enter standby is 190 mW and the minimum output voltage level at which the optocoupler is disabled 12.6 V. These levels can be adjusted separately. Preferably, adjusted the power level first.

8.7.1 Standby power threshold level adjustment The power level to enter the standby mode can be adjusted within a certain range. Defining the values for these components depends mainly on the required minimum current value at which the system goes into standby and the speed of the selected feedback loop.

Using the circuit diagram (Figure 13 and Figure 14) a capacitance value for C51 between the 27 nF and 100 nF is allowed, assuming that C51 is always equal to or slightly larger than C53.

The value of R52 determines the minimum current value at which the system enters standby. A higher resistance value for R52 results in a lower standby level current within a certain range. Using a resistance value higher than this range can easily be recognized, because it hardly has any impact on further reducing the standby current level.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 28 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

The value of R52 can be found when a constant output current load is applied just above the required minimum current. The voltage across the PSENSE pin should be just above the Vth(PSENSE) level, so keep it just above 0.5 V (DC).

8.7.2 Standby behavior during small load currents In standby, the output voltage varies between two levels. The maximum level is the output voltage of the SMPS during normal operation. The minimum level is the output voltage reached in Standby mode before the SMPS restarts. Figure 19 shows the output voltage variation in Standby mode at an output currents of 9 mA and 4.5 mA. The SMPS changes from Standby mode into normal operation above an output current of approximately 9 mA.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 29 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

CH1

CH2

CH4

CH3

019aab517

a. IO =9mA.

CH1

CH2

CH4

CH3

019aab518

b. IO =4.5mA

(1) CH1: TEA1753 VCC = 10 V per division.

(2) CH2: VO = 10 V per division.

(3) CH3: TEA1753 VFBDRIVER = 10 V per division.

(4) CH4: TEA1703 VOPTO = 10 V per division. Fig 19. Output voltage variation in Standby mode at 9 mA and 4.5 mA

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 30 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

The minimum output voltage depends on the load current in Standby mode but should always be kept above the 5 V (DC). The minimum output voltage is set using the resistor divider at pin VSENSE. The minimum output voltage is almost equal to the set voltage if the output current is zero, but it drops slightly if the output is loaded with a small current. Selecting a slightly higher minimum output voltage can compensate this effect.

8.7.2.1 Adjustment minimum VO in standby mode (output not loaded)

• Determine the minimum output voltage Vmin. For minimum standby power the minimum output voltage should be as low as possible but above 5 V. At no-load there is hardly any difference between Vmin and the set voltage Vset. −6 • Resistor R54 = 1.22 / (((Vmin − 1.22) / R53) + 1e ). Alternatively the value for R54 can be found in Figure 20. The curve is valid for R53 = 4.7 MΩ

019aab519 16

Set voltage (V)

12

8

4

0 250 350 450 550 650 750 R54 (kΩ)

R53=4.7MΩ Fig 20. Set voltage versus R54

8.7.3 Choosing the right coil When the set voltage is low, the voltage across the coil and the current through the optocoupler might become too low to force VINSENSE low and to disable the SMPS. In this situation, a lower self-inductance is an option. Be careful not to exceed the maximum peak current of the optocoupler and keep in mind that a large peak current effects the life cycle of the optocoupler and the standby power consumption.

Remark: Peak currents above 10 mA already have impact on the life cycle of the optocoupler.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 31 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

9. VCC charge MOSFET with active X-cap discharge

Figure 21 shows a proposal for a VCC charge MOSFET using active X-cap discharge. The main advantages compared to the typical application shown in Figure 5 are:

• The VCC capacitor of the TEA1738 is charged using an increased charge current. Using the values shown in Figure 21, the start-up time and power-up time is reduced to 0.25 s at 115 V (AC) and 0.2 s at 230 V (AC). • In standby mode, the charge MOSFET M1 is disabled. This reduces the no-load standby power to approximately 10 mW • When the mains supply voltage is disconnected, the X-cap Cx is actively discharged

The current source M1 only conducts when the mains is disconnected and during start-up of the SMPS. In all other situations, M1 is switched off to save power. In Standby mode, a low bias current maintains the loop formed by M1, U2, Q1 and the TEA1738 VCC is controlled at 0.5 V. During power-up, VCC is quickly charged by M1 and the output voltage is available within 0.25 s (depending on the load and mains voltage). R1 sets the current source charge current. The values shown in Figure 21 give an average charge current of approximately 700 μA, (the maximum clamp current on pin VCC). The maximum dark current allowed is 1.5 μA.

Table 3 gives an overview of operating modes, the MOSFET M1 gate voltage and VVINSENSE.

Table 3. Overview of operating modes, MOSFET M1 gate voltage and VVINSENSE

SMPS operating modes M1 gate voltage VVINSENSE (V) typical Start-up high[1][3] ≥ 0.94 Running (normal operation) low[2] ≥ 0.72 Standby high[4] ≤ 0.72 Running in latched protection high[1] ≥ 0.72 AC mains supply disconnected while running high[1][3] ≥ 0.72 AC mains supply disconnected during latched high[1][3] ≥ 0.72 protection

[1] Gate voltage approximately 10 V higher than TEA1738 VCC.

[2] Gate voltage equal to the TEA1738 VCC. [3] Initial value.

[4] Gate voltage approximately 3.5 V higher than TEA1738 VCC.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 32 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

N

Cx 220 nF

L

C2 D5 D6 100 pF 1N4005 1N4005

R6 R2 R5 22 kΩ 47 MΩ 47 MΩ charge MOSFET D9 mains disconnect high M1 BSS127 1N4148 C12 R7 C1 D8 R1 1 nF flyback running low 10 MΩ 10 nF BZX84C10L 10 kΩ D11 standby low TEA1738 VCC 1N4148 TEA1703 VCC

U2 PC817C L1 10 mH TEA1703 VOPTO Vctrl R13 R4 Vbus Q1 30 MΩ 620 kΩ Q4 TEA1738 VINSENSE BC847C BC847C D10 R8 Q2 Q3 C8 BC847C BC847C 220 nF 1N4148 1 MΩ D7 C11 R3 R10 R12 1N4148 10 nF 300 kΩ 300 kΩ 240 kΩ

GND PRIMARY 019aab720

Fig 21. VCC charge MOSFET with active X-cap discharge

10. TEA1703 with LED indicator

Figure 22 shows the TEA1703 with an optional LED indicator D3. The LED is normally ON when the output power exceeds the standby power threshold.

The flyback pulses at Fly1 switch on Q1 via D4 and the RC network formed by C8, R12 and R13. Q1 switches on the output voltage feedback control via the AP431SR and, via D5 and R7, the indicator LED.

When the output power demand is less than the standby power threshold, the optocoupler pulses disable the SMPS and switch off Q1. In this situation, the optocoupler pulses drive the LED indicator with a lower drive current at a lower intensity.

The LED indicator D3 has three SMPS states: ON, OFF and standby.

A small disadvantage of the indicator LED is the lower drive voltage for coil L1. In Standby mode, when the output voltage drops, the drive current for the optocoupler may become too small. In this situation, a lower value for L1 is an option, see Section 7.7.3.

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 33 of 36 xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx x x x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xx xx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxx x x xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxx NXP Semiconductors Application note Rev. 1 — 30 March 2011 34 of 36 34of B.V. ©NXP 2011.reserved. rights All Rev. 2011 1—30March disclaimers. legal to subject is document this in provided information All note Application AN11012

R1 C3

47 Ω 220 pF

fly1 Vout fly2 D1 STMS20M100ST C1 C2 680 μF 680 μF 19.5 V 25 V 25 V 3.34 A

GND

LED D2 R9 D3 R8 BAS21 35.7 kΩ 330 kΩ 1% 1 R2 R4 330 kΩ 4.7 MΩ 1 U2-1 U3-1 2 2 C4 R3 R5 C5 L1 R7 C5 C6 47 nF 220 kΩ 360 kΩ 100 pF 10 mH 10 kΩ 100 nF 1 nF Using the TEA1703 toreduce standbypower

C7 R10 U1 VSENSE VCC 8 1 10 nF 10 kΩ D5 PSENSE GND BAS21 U4 7 2 AP431SR R6 SWDET TEA1703 OPTO 6 3 R11 2.2 MΩ n.c. n.c. 5.23 kΩ 5 4 1%

D4 BAS21 R12 Q1 2N7002 1.5 MΩ AN11012 C8 R13 22 nF 1.5 MΩ

019aab521

Fig 22. TEA1703 with LED indicator NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

11. Legal information

11.1 Definitions design. It is customer’s sole responsibility to determine whether the NXP Semiconductors product is suitable and fit for the customer’s applications and products planned, as well as for the planned application and use of Draft — The document is a draft version only. The content is still under customer’s third party customer(s). Customers should provide appropriate internal review and subject to formal approval, which may result in design and operating safeguards to minimize the risks associated with their modifications or additions. NXP Semiconductors does not give any applications and products. representations or warranties as to the accuracy or completeness of information included herein and shall have no liability for the consequences of NXP Semiconductors does not accept any liability related to any default, use of such information. damage, costs or problem which is based on any weakness or default in the customer’s applications or products, or the application or use by customer’s third party customer(s). Customer is responsible for doing all necessary 11.2 Disclaimers testing for the customer’s applications and products using NXP Semiconductors products in order to avoid a default of the applications and the products or of the application or use by customer’s third party Limited warranty and liability — Information in this document is believed to customer(s). NXP does not accept any liability in this respect. be accurate and reliable. However, NXP Semiconductors does not give any representations or warranties, expressed or implied, as to the accuracy or Export control — This document as well as the item(s) described herein completeness of such information and shall have no liability for the may be subject to export control regulations. Export might require a prior consequences of use of such information. authorization from national authorities. In no event shall NXP Semiconductors be liable for any indirect, incidental, Evaluation products — This product is provided on an “as is” and “with all punitive, special or consequential damages (including - without limitation - lost faults” basis for evaluation purposes only. NXP Semiconductors, its affiliates profits, lost savings, business interruption, costs related to the removal or and their suppliers expressly disclaim all warranties, whether express, implied replacement of any products or rework charges) whether or not such or statutory, including but not limited to the implied warranties of damages are based on tort (including negligence), warranty, breach of non-infringement, merchantability and fitness for a particular purpose. The contract or any other legal theory. entire risk as to the quality, or arising out of the use or performance, of this Notwithstanding any damages that customer might incur for any reason product remains with customer. whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards In no event shall NXP Semiconductors, its affiliates or their suppliers be liable customer for the products described herein shall be limited in accordance to customer for any special, indirect, consequential, punitive or incidental with the Terms and conditions of commercial sale of NXP Semiconductors. damages (including without limitation damages for loss of business, business Right to make changes — NXP Semiconductors reserves the right to make interruption, loss of use, loss of data or information, and the like) arising out changes to information published in this document, including without the use of or inability to use the product, whether or not based on tort limitation specifications and product descriptions, at any time and without (including negligence), strict liability, breach of contract, breach of warranty or notice. This document supersedes and replaces all information supplied prior any other theory, even if advised of the possibility of such damages. to the publication hereof. Notwithstanding any damages that customer might incur for any reason whatsoever (including without limitation, all damages referenced above and Suitability for use — NXP Semiconductors products are not designed, all direct or general damages), the entire liability of NXP Semiconductors, its authorized or warranted to be suitable for use in life support, life-critical or affiliates and their suppliers and customer’s exclusive remedy for all of the safety-critical systems or equipment, nor in applications where failure or foregoing shall be limited to actual damages incurred by customer based on malfunction of an NXP Semiconductors product can reasonably be expected reasonable reliance up to the greater of the amount actually paid by customer to result in personal injury, death or severe property or environmental for the product or five dollars (US$5.00). The foregoing limitations, exclusions damage. NXP Semiconductors accepts no liability for inclusion and/or use of and disclaimers shall apply to the maximum extent permitted by applicable NXP Semiconductors products in such equipment or applications and law, even if any remedy fails of its essential purpose. therefore such inclusion and/or use is at the customer’s own risk. Applications — Applications that are described herein for any of these products are for illustrative purposes only. NXP Semiconductors makes no 11.3 Trademarks representation or warranty that such applications will be suitable for the specified use without further testing or modification. Notice: All referenced brands, product names, service names and trademarks are the property of their respective owners. Customers are responsible for the design and operation of their applications and products using NXP Semiconductors products, and NXP Semiconductors GreenChip — is a trademark of NXP B.V. accepts no liability for any assistance with applications or customer product

AN11012 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved. Application note Rev. 1 — 30 March 2011 35 of 36 NXP Semiconductors AN11012 Using the TEA1703 to reduce standby power

12. Contents

1 Introduction ...... 3 10 TEA1703 with LED indicator ...... 33 2 Scope and set-up of this application note. . . . 3 11 Legal information ...... 35 2.1 Scope ...... 3 11.1 Definitions ...... 35 2.2 General setup of the application note...... 3 11.2 Disclaimers ...... 35 2.3 Related documents and tools ...... 3 11.3 Trademarks ...... 35 3 TEA1703 features...... 3 12 Contents...... 36 4 Pin description...... 4 5 Application diagram ...... 5 6 TEA1703 description and calculation ...... 6 6.1 General description ...... 6 6.2 Standby mode operation...... 6 6.3 Normal operation ...... 7 6.4 PSENSE ...... 8 6.5 VSENSE ...... 8 6.6 SWDET...... 9 6.7 Optocoupler ...... 9 7 Typical TEA1703 and TEA1738 application . . 10 7.1 General description and typical application . . 11 7.2 Interfacing...... 11 7.3 General performance ...... 12 7.4 Standby mode power consumption...... 12 7.5 Power-up behavior ...... 13 7.6 Power-down behavior...... 15 7.7 Adjustments ...... 15 7.7.1 Standby mode power threshold level adjustment ...... 16 7.7.2 Minimum output voltage adjustment...... 16 7.7.2.1 Adjustment procedure at standby no-load . . . 18 7.7.2.2 Adjustment procedure at low standby loads. . 18 7.7.3 Choosing the right coil ...... 19 8 Typical application TEA1703 with the TEA1753 ...... 21 8.1 General description typical application ...... 24 8.2 Interfacing...... 24 8.3 General performance ...... 25 8.4 Standby power consumption...... 25 8.5 Power-up behavior ...... 25 8.6 Power-down behavior...... 26 8.7 Adjustments ...... 28 8.7.1 Standby power threshold level adjustment . . . 28 8.7.2 Standby behavior during small load currents . 29 8.7.2.1 Adjustment minimum VO in standby mode (output not loaded) ...... 31 8.7.3 Choosing the right coil ...... 31 9 VCC charge MOSFET with active X-cap discharge ...... 32

Please be aware that important notices concerning this document and the product(s) described herein, have been included in section ‘Legal information’.

© NXP B.V. 2011. All rights reserved. For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: [email protected] Date of release: 30 March 2011 Document identifier: AN11012