TLE 5203

Semiconductor Group

4

1998-02-01

Monitoring Functions

An internal circuit ensures that all output transistors are turned-OFF if the supply voltage

is below the operating range.

A monitoring circuit for each output transistor detects whether the particular transistor is

active and in this case prevents the corresponding source transistor (sink transistor) from

conducting in sink operation (source operation). Therefore no crossover currents can

occur. Pulse-width operation is possible up to a maximum switching frequency of 1 kHz

for any load.

Depending on the load current higher frequencies are possible.

Protective Function

Various errors like short-circuit to +

V

result in turn-OFF of the output stages after a delay of 40

µs and setting of the error flag

EF to ground. Changing the inputs resets the error flag.

Output Shorted to Ground Detection

If a high side transistor is switched on and its output is shorted to ground, the output

current is limited to typ 8 A. After a delay of 40

µs all outputs will be switched off and the

error flag EF is set to ground.

Functional Truth Table

E1

E2

Q1

Q2

Comments

L

L

H

L

Motor turns counterclockwise

L

H

L

H

Motor turns clockwise

H

LLLBrake; both low side transistors turned-ON

H

H

Z

Z

Open circuit detection

Notes for Output Stage

Symbol

Value

L

Low side transistor is turned-ON

High side transistor is turned-OFF

H

High side transistor is turned-ON

Low side transistor is turned-OFF

Z

High side transistor is turned-OFF

Low side transistor is turned-OFF