BTS 7741 G

Data Sheet

5

2003-03-06

1.5

Circuit Description

Input Circuit

The control inputs IH1,2 consist of TTL/CMOS compatible Schmitt-Triggers with

hysteresis. Buffer amplifiers are driven by these stages and convert the logic signal into

the necessary form for driving the power output stages. The inputs are protected by ESD

clamp-diodes.

The inputs IL1 and IL2 are connected to the internal gate-driving units of the N-channel

vertical power-MOS-FETs.

Output Stages

The output stages consist of an low

R

DS ON

Power-MOS H-bridge. In H-bridge

configuration, the D-MOS body diodes can be used for freewheeling when commutating

inductive loads. If the high-side switches are used as single switches, positive and

negative voltage spikes which occur when driving inductive loads are limited by

integrated power clamp diodes.

Short Circuit Protection

The outputs are protected against

– output short circuit to ground

– output short circuit to the supply voltage, and

– overload (load short circuit).

An internal OP-Amp controls the Drain-Source-Voltage by comparing the DS-Voltage-

Drop with an internal reference voltage. Above this trip point the OP-Amp reduces the

output current depending on the junction temperature and the drop voltage.

In the case of overloaded high-side switches the status output is set to low.

The fully protected low-side switches have no status output.

Overtemperature Protection

The high-side and the low-side switches also incorporate an over temperature protection

circuit with hysteresis which switches off the output transistors. In the case of the high-

side switches, the status output is set to low.

Undervoltage-Lockout (UVLO)

When

V

The High-Side output transistors are switched off if the supply voltage

V

the switch off value

V

UVOFF.