TLE 5216 G

Semiconductor Group

5

1998-06-22

Application Description

This IC is specially designed to drive inductive loads up to 2 A nominal current (valves,

relays, etc.). Integrated clamp-diodes limit the output voltage when inductive loads are

turned off.

For the detection of errors at the load there is a serial diagnostic interface, which

monitors the following errors for every output separately:

– open load in inactive mode

– shorted output (shorted to ground) in inactive mode

– overload or shorted load in active mode

Circuit Description

The block diagram shows the four independent power drivers with the referring logic

block and the serial diagnostic interface which stores and transfers the diagnostic

signals to the external circuit. Each power switch connects a high side load to ground

when a LOW signal applies at the inputs. To protect the IC against short circuit and over

load each output is provided with a current limitation and a delayed overload shutdown.

The slew rate of the switching process is limited internally.

The integrated clamp diodes limit the voltage at the output to

V

loads are switched off. The maximum power dissipation, which is given from the static

and dynamic thermal resistance, limits the allowable inductive energy. A diode in parallel

to every output clamps negative voltage.

All outputs, preferably the outputs 1 and 2 and the outputs 3 and 4 may be used in

parallel (no addition of max. freewheeling energy).

A curve of the output voltage is shown in figure 6.

The diagnostic block monitors the voltages across the power switch. If in active mode

(LOW level input) there is a higher voltage than

V

diagnostic block will show an overload in the error register and the affected power switch

will be shut off. The switch can only be reactivated if the corresponding input is switched

off and then on again.

In inactive mode (HIGH level at input) open load or shorted output (shorted load to

ground) is detected and signalled to the serial diagnostic interface. If the voltage across

the power switch is lower than

V

identified. If the voltage is even lower than

V

"shorted to ground" is detected. An internal voltage divider will pull the output to the

voltage

V

A new error on the same output stage will over-write the old error report. The protocol of

the serial diagnostic interface includes independent error reports for each output driver.

As soon as an error is latched into the error register the serial data output (SEROUT) of

the interface will go LOW (while CS is still HIGH). If the chip select gets a LOW signal