Main Applications and Selection of Gate Driver Optocouplers Application Note 1335

Introduction Advantages of Using Optocouplers as Gate Drivers for IGBT/MOSFET IGBTs are now commonly used as switching components in • Low system solution cost both inverter and converter circuits used in power control • High reliability and long life and motor drive applications. A typical power control and • Variable speed/frequency capability motor drive system, as shown in Figure 1, requires isolation • Ease and simplicity of design between the high voltage devices (IGBT/MOSFET) and • Small size and footprint area the low voltage devices (micro-controller). In addition to • Low power dissipation meeting the severe requirements for the isolation function, • Safe optical isolation (galvanic isolation) Avago Technologies’ optocouplers provide customized • Regulatory and safety agency approvals functionality such as direct gate drive for IGBTs or power . This application note focuses on the use of Avago Technologies’ Gate Drive Optocouplers.

+HV

GATE GATE GATE CURRENT DRIVE DRIVE DRIVE SENSE U+ V+ W+ A

3-PHASE OUTPUT

VOLTAGE GATE GATE GATE SENSE DRIVE DRIVE DRIVE C U- V- W- B

CURRENT SENSE -HV U+, U-, V+, V-, W+, W- A, B, C ANALOG ISOLATION MICRO- MOTOR SPEED POSITION CONTROLLER

Figure 1. Isolation Circuits for Power Control – System Overview

6315-01 AN 1335 Block Diagrams of Main Applications of Gate Drive Optocouplers

GATE GATE GATE DRIVER DRIVER DRIVER

M

GATE GATE GATE DRIVER DRIVER DRIVER

Figure 2. VVVF Inverter (PWM)

6315-02 AN 1335 GATE DRIVER GATE GATE GATE DRIVER DRIVER DRIVER

M

GATE GATE GATE DRIVER DRIVER DRIVER

Figure 3. VVVF Inverter (PAM)

6315-03 AN 1335

GATE GATE GATE DRIVER DRIVER DRIVER

GATE GATE GATE DRIVER DRIVER DRIVER

Figure 4. CVCF Inverter (UPS)

2 6315-04 AN 1335 GATE GATE DRIVER DRIVER

GATE GATE DRIVER DRIVER

Figure 5. Low Power CVCF Inverter (UPS)

6315-05 AN 1335

GATE GATE DRIVER DRIVER

M

GATE GATE GATE DRIVER DRIVER DRIVER

Figure 6. DC Servo

6315-06 AN 1335

MM

GATE DRIVER

Figure 7. Switched Reluctance Drive

3 6315-07 AN 1335 M LOAD IRON POT

+ DC – GATE DRIVER

GATE Figure 8. DC Chopper DRIVER

6315-08 AN 1335

Figure 9. Induction Cooker

GATE DRIVER LOAD IRON POT

GATE DRIVER

Figure 10. Series Resonant Induction Cooker 6315-09 AN 1335

GATE GATE DRIVER DRIVER

GATE GATE DRIVER DRIVER 6315-10 AN 1335

Figure 11. Welder

4 6315-11 AN 1335 Calculation of Minimum Output Current (IOL) to Drive IGBT / MOSFET The key requirement for any IGBT/ The gate capacitance of the MOSFET gate drive optocoupler is IGBT / MOSFET determines how for it to supply the Minimum Output much current is required from the Current (IOL) needed to the driver for basic switching: IGBT/MOSFET to the low-impedance state. A common misunderstanding in selecting a gate drive optocoupler VB Cgc V X C is looking at the Maximum Peak 1 τ = t B GC V = sw i (τ)•dτ I IG1 = Output Currents [IOH(PEAK)/IOL(PEAK)] C(GE) • g g1 tsw Cge τ = 0 in the Absolute Maximum Rating Ig = Ig1 + Ig2 Section of the data sheet. Though Maximum Peak Output Currents are 1 VC(GE) X CGE no less important, they are meant VC(GE) = • Ig • tsw IG2 = C I tsw to define the maximum permissible ge g2 operational condition that could Cge result in the destruction of the where, device, if exceeded. Cgc - gate-to-collector To determine the suitability of a gate Cge - gate-to-emitter capacitor drive optocoupler, it is necessary VC(GE) - Voltage across gate-to-emitter capacitor to look at the Minimum Output Ig - total gate current flows into gate VB Currents (IOH / IOL) of the gate V - V - V I - gate currentCC EE flows OL into C Cgc g1 R = gc V X C drive optocoupler in the Electrical g 1 I τ = t B GC V I - gate = currentOLPEAK flowssw intoi (τ)•d C τ I IG1 = Specifications Section of the data C(GE)g2 • g ge g1 tsw Cge τ = 0 sheet. Particularly important, the VB - bus voltage Ig = Ig1 + Ig2 I needs to be specified at the OL tsw - switching time condition when VO is low, that is 1 VC(GE) X CGE when the gate drive optocoupler is VC(GE) = • Ig • tsw IG2 = Figure 11. IGBTC / MOSFET Parasitic Capacitances (Cge and Cgc) tsw at the charging state. This is because ge Ig2 under this condition the load Cge draws the highest output current. A gate , Rg , must be selected Avago Technologies specifies OLI such that the maximum peak at VO = VCC – 10 V. Similarly for output current rating, IOL(PEAK), is IOH, it is important to specify the not exceeded, condition when VO is high, that is when the gate drive optocoupler is discharging. Avago Technologies VCC - VEE - VOL specifies I at V = V + 10 V. Rg = OH O EE IOLPEAK

This Minimum Output Current where, (I ) required to switch IGBT/ OL V - Positive supply voltage of gate drive optocoupler MOSFET to the low-impedance CC state can be easily calculated using VEE - Negative supply voltage of gate drive optocoupler the gate capacitance charging VOL - Low level output voltage of gate drive optocoupler equations. Gate capacitance of IOL(PEAK) - Maximum peak output current of gate6315-11.EQUA drive optocoupler AN 1335 IGBT /MOSFET can be obtained from the data sheet. After calculating the Minimum Output Current required to drive the IGBT/ MOSFET, the suitable gate drive optocouplers can be selected from Avago Technologies’ Gate Drive Optocoupler Selection Guide.

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6315-11.EQUA AN 1335 Other Key Parameters in Selecting a Gate Selection Guideline for IGBT Class and AC Drive Optocoupler Motor Rating Other key parameters in selecting Different sizes of IGBT need different a gate driver optocoupler are gate drive optocouplers with propagation delay and common different output driving currents. mode rejection ratio. For typical Tables 1 and 2 below list basic motor control applications, high selection guides based on operating speed gate drive optocouplers line voltage, IGBT ratings, AC motor with propagation delays, tPLH, power ratings, and the appropriate tPHL ≤ 0.8 µs and common mode gate drive optocouplers. rejection ratio, CMR ≥ 10 kV /µs @ VCM = 1000 V are recommended. References Avago Technologies’ gate drive 1. Khan, J. N. “Optocouplers for optocouplers meet all these basic Variable Speed Motor Control requirements. Electronics in Consumer Home Appliances.” Avago Technologies’ Publication Number 5980-1297 (5/00).

Table 1. Gate Drive Optocouplers Selection Guide for 220 Vac Operating Motor

IGBT IGBT AC Motor Rating VCES (V ) IC (A) kW HP Recommended Gate Drive Optocouplers 15 0.4 0.5 HCPL-0314/ 3140/J314/314J, HCPL-3150/ 315J 20 1.5 2 HCPL-0314/ 3140/J314/314J, HCPL-3150/ 315J 30 2.2 3 HCPL-0314/ 3140/J314/314J, HCPL-3150/ 315J 50 3.7 5 HCPL-0314/ 3140/J314/314J, HCPL-3150/ 315J 600 V 75 7.5 10 HCPL-0314/ 3140 /J314/ 314J, HCPL-3150/ 315J 100 11 15 HCPL-3120/J312, HCNW3120, HCPL-316J 150 15 20 HCPL-3120/J312, HCNW3120, HCPL-316J 200 22 30 HCPL-3120/J312, HCNW3120, HCPL-316J 300 30 40 HCPL-3120/J312, HCNW3120, HCPL-316J 400 45 60 Gate Drive Optocoupler + Buffer 600 55 75 Gate Drive Optocoupler + Buffer

Note: The actual application depends on ventilation, power dissipation, heat sinking and other applications conditions. VCES - Collector-Emitter Breakdown Voltage IC - Collector Current

6 Table 2. Gate Drive Optocouplers Selection Guide for 440 Vac Operating Motor

IGBT IGBT AC Motor Rating VCES (V ) IC (A) kW HP Recommended Gate Drive Optocouplers 15 1.5 2 HCPL-0314/ 3140/ J314/ 314J, HCPL-3150 /315J 20 2.2 3 HCPL-0314/ 3140/ J314/ 314J, HCPL-3150 /315J 30 3.7 5 HCPL-0314/ 3140/ J314/ 314J, HCPL-3150 /315J 50 7.5 10 HCPL-3120/ J312, HCNW3120, HCPL-316J 75 11 15 HCPL-3120/ J312, HCNW3120, HCPL-316J 1200 V 100 15 20 HCPL-3120/ J312, HCNW3120, HCPL-316J 150 22 30 Gate Drive Optocoupler + Buffer 200 37 50 Gate Drive Optocoupler + Buffer 300 55 75 Gate Drive Optocoupler + Buffer 400 75 100 Gate Drive Optocoupler + Buffer 600 110 150 Gate Drive Optocoupler + Buffer

Note: The actual application depends on ventilation, power dissipation, heat sinking and other applications conditions. VCES - Collector-Emitter Breakdown Voltage IC - Collector Current

FEATURES GATE DRIVE UVLO HCPL-316J OPTOCOUPLER DESAT +BUFFER

HCPL-3150 HCPL-3120 GATE DRIVE UVLO HCPL-315J** HCPL-J312 OPTOCOUPLER HCNW3120 +BUFFER

HCPL-0314 HCPL-3140 NO HCPL-J314 GATE DRIVE UVLO HCPL-314J** OPTOCOUPLER DESAT COMING! +BUFFER HCPL-3020

0 15 30 50 75 100 150 200 600 V Ic(A) IGBT 0 0.4 2.2 3.7 7.5 11 15 22 MOTOR RATING (kW)

1200 V 0 15 20 30 50 75 100 IGBT Ic(A)

0 1.5 2.2 3.7 7.5 11 15 MOTOR RATING (kW)

* ESTIMATION, ACTUAL APPLICATION DEPENDS ON VENTILATION, HEAT SINKING AND OTHER APPLICATION CONDITIONS. ** INDICATE DUAL CHANNEL DEVICE.

Figure 13. Driving Capability of Gate Drive Optocouplers 6315-13 AN 1335

7 For product information and a complete list of distributors, please go to our web site: www.avagotech.com

Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies, Pte. in the United States and other countries. Data subject to change. Copyright © 2006-2010 Avago Technologies Pte. All rights reserved. Obsoletes 5988-8560EN 5988-9009EN May 12, 2010