Data Sheet TLE 6220 GP

V2.1

Page

2007-05-03

11

Diagnostics

FAULT

- Fault pin. There is a general fault pin (open drain) which shows a high to low transi-

tion as soon as an error occurs for any one of the four channels. This fault indication can be

used to generate a µC interrupt. Therefore a ‘diagnosis’ interrupt routine need only be called

after this fault indication. This saves processor time compared to a cyclic reading of the SO in-

formation.

As soon as a fault occurs, the fault information is latched into the diagnosis register. A new er-

ror will over-write the old error report. Serial data out pin (SO) is in a high impedance state

when

The rising edge of

Full Diagnosis

For full diagnosis there are two diagnostic bits per channel configured as shown in Figure 1.

Normal function: The bit combination HH indicates that there is no fault condition, i.e. normal

function.

Overload, Short Circuit to Battery (SCB) or Overtemperature:HL is set when the current

limitation gets active, i.e. there is a overload, short to supply or overtemperature condition.

Open load: An open load condition is detected when the drain voltage decreases below 3 V

(typ.). LH bit combination is set.

Short Circuit to GND: If a drain to ground short circuit exists and the drain to ground current

exceeds 100 µA, short to ground is detected and the LL bit combination is set.

A definite distinction between open load and short to ground is guaranteed by design.

The standard way of obtaining diagnostic information is as follows:

Clock in serial information into SI pin and wait approximately 150 µs to allow the outputs to set-

tle. Clock in the identical serial information once again - during this process the data coming out

at SO contains the bit combinations representing the diagnosis conditions as described in Fig-

ure 1.

Diagnostic Serial OUT (SO)

HH

Normal function

HL

Overload, Shorted Load or Overtemperature

LH

Open Load

LL

Shorted to Ground

Ch.4

Ch.3

Ch.2

Ch.1

7

6

5

4

3

2

1

0

Figure 1: Two bits per channel diagnostic feedback