ACPL-38JT 데이터 시트보기 (PDF) - Avago Technologies

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ACPL-38JT

Automotive Gate Drive Optocoupler with R2Coupler™ Isolation, 2.5 Amp Output Current, Integrated Desaturation (VCE) Detection and Fault Status Feedback

Avago Technologies 

Product Overview Description

The ACPL-38JT (shown in Figure 1) is a highly integrated

power control device that incorporates all the necessary

components for a complete, isolated IGBT gate drive

circuit with fault protection and feedback into one SO-16

package. TTL input logic levels allow direct interface with

a microcontroller, and an optically isolated power output

stage drives IGBTs with power ratings of up to 150 A and

1200 V. A high speed internal optical link minimizes the

propagation delays between the microcontroller and

the IGBT while allowing the two systems to operate at

very large common mode voltage differences that are

common in industrial motor drives and other power

switching applications. An output IC provides local pro-

tection for the IGBT to prevent damage during overcur-

rents, and a second optical link provides a fully isolated

fault status feedback signal for the microcontroller. A built

in “watchdog” circuit monitors the power stage supply

voltage to prevent IGBT caused by insufficient gate drive

voltages. This integrated IGBT gate driver is designed to

increase the performance and reliability of a motor drive

without the cost, size, and complexity of a discrete design.

Two light emitting diodes and two integrated circuits

housed in the same SO-16 package provide the input

control circuitry, the output power stage, and two

optical channels. The input Buffer IC is designed on a

bipolar process, while the output Detector IC is designed

manufactured on a high voltage BiCMOS/Power DMOS

process. The forward optical signal path, as indicated by

LED1, transmits the gate control signal. The return optical

signal path, as indicated by LED2, transmits the fault

status feedback signal. Both optical channels are com-

pletely controlled by the input and output ICs respective-

ly, making the internal isolation boundary transparent to

the microcontroller.

Under normal operation, the input gate control signal

directly controls the IGBT gate through the isolated output

detector IC. LED2 remains off and a fault latch in the input

buffer IC is disabled. When an IGBT fault is detected, the

output detector IC immediately begins a “soft” shutdown

sequence, reducing the IGBT current to zero in a controlled

manner to avoid potential IGBT damage from inductive

over-voltages. Simultaneously, this fault status is transmit-

ted back to the input buffer IC via LED2, where the fault

latch disables the gate control input and the active low

fault output alerts the microcontroller.

During power-up, the Under Voltage Lockout (UVLO)

feature prevents the application of insufficient gate

voltage to the IGBT, by forcing the ACPL-38JT’s output

low. Once the output is in the high state, the DESAT (VCE)

detection feature of the ACPL-38JT provides IGBT pro-

tection. Thus, UVLO and DESAT work in conjunction to

provide constant IGBT protection.

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