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ManualsBrandsBROADCOM ManualsOptoelectronics & DisplaysGate-Drive-Optocoupler With High Integration Level DIP 8

Design and Applications of

HCPL-3020 and HCPL-0302

Gate Drive Optocouplers

Application Note 5004

Introduction

The HCPL-3020 (DIP-8) and HCPL-0302 (SO-8) con-

sist of GaAsP LED optically coupled to an integrated

circuit with a power output stage. The current rating,

combined with the high common mode rejection

(CMR), fast switching and latch-up performance

uniquely qualify these optocouplers to be the ideal

choices in low power inverter gate drive applications.

The high operating voltage ranges of the HCPL-3020

and HCPL-0302 output stages provide the drive volt-

ages required by MOS-gated devices like IGBTs or

MOSFETs. The voltage and current provided by these

optocouplers make it suitable for driving IGBTs with

rating up to 1200V/20A.

The HCPL-3020 and HCPL-0302 represent one of the

cheapest solutions to drive MOS-gated devices in

safe, efficient, reliable and cost–effective manner.

Besides its ease of implementation, the HCPL-3020

and HCPL-0302 also excel in power consumption.

HCPL-3020 and HCPL-0302 will please all designers

in the motor control or inverter arena as the following

features demonstrate:

• Low power consumption: Low supply current of

3mA, which allows powering HCPL-3020 and HCPL-

0302 using bootstrap technique. This eliminates

the need of an isolated power supply or dc-to-dc

converter and a smaller V

capacitor can be used.

This not only reduces the printed circuit board

space but also total system cost.

• External gate resistor connection: Designer can

control the gate signal flow, and have an option to

slow down the device commutation, therefore

reducing the amount of Electro-Magnetic Interfer-

ence (EMI) compared to intelligent power module

(IPM) solution.

• Low level output voltage, V

: The V

of HCPL-

3020 and HCPL-0302 is specified at 1.0V maximum.

This low voltage possibly eliminates the need of

negative gate drive for many applications.

• Low external part–count: by integrating the gate

driver and isolation function in one package, the

final HCPL-3020 and HCPL-0302 implementation

reveals an obvious gain in component reduction

compared to other competing technologies, such

as transformer and high voltage integrated circuit.

Figure 1. Recommended LED Drive and Application Circuit for HCPL-3020 and HCPL-0302.

Summary of content (5 pages)

PAGE 1
Design and Applications of HCPL-3020 and HCPL-0302 Gate Drive Optocouplers Application Note 5004 Introduction The HCPL-3020 (DIP-8) and HCPL-0302 (SO-8) consist of GaAsP LED optically coupled to an integrated circuit with a power output stage. The current rating, combined with the high common mode rejection (CMR), fast switching and latch-up performance uniquely qualify these optocouplers to be the ideal choices in low power inverter gate drive applications.
PAGE 2
Bootstrap Power Supply Circuit Figure 2 shows a bootstrapped power supply circuit. This circuit includes a bootstrap circuit for providing output power to the HCPL-3020 or HCPL-0302 gate drive optocouplers, thereby eliminating the need for isolated power supplies or dc-to-dc converters. It can be modified to suit other Avago Technologies’ gate drive optocouplers and current/voltage sensing isolation amplifiers.
PAGE 3
Therefore, as the gate-to-emitter voltage approaching zero, the effect of anti-parallel diode becomes less significant. Consequently, turn-off delay time is reduced, but improvement switching times and dv/dt immunity is only incremental. B. PNP Turn-Off Speed Improvement Circuit One of the most popular arrangements to improve turn-off speed is the pnp turn-off speed improvement circuit illustrated in Figure 4.
PAGE 4
Common Mode Transient Immunity In motor drives and inverters, there are large voltage transient generated by switching of the transistors. Common Mode Transient Immunity of gate drive optocouplers is the key attribute that allow the transmit of accurate information across the isolation barrier. All Avago Technologies’ gate drive optocouplers rely on two key technical strengths to achieve high Common Mode Transient Immunity.
PAGE 5
Conclusion Avago Technologies’ HCPL-3020 and HCPL-0302 enables designers to meet stringent requirements of high Common Mode Rejection (CMR), wide operating temperature range and fast switching in low power inverter gate drive applications, specially targeting at low power industrial inverters and inverter controlled consumer appliances. Low ICC supply current also allows the use of smaller VCC capacitor, and use bootstrap technique eliminating costly isolated power supply.