TDA7567PD View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

TDA7567PD

4 x 50 W differential quad power amplifier with built-in diagnostics features

STMicroelectronics 

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Diagnostics functional description

3

Diagnostics functional description

TDA7567PD

3.1

Turn-on diagnostic

It is activated at the turn-on (standby out) under I2C bus request. Detectable output faults

are:

● Short to GND

● Short to Vs

● Short across the speaker

● Open speaker

To verify if any of the above misconnections are in place, a subsonic (inaudible) current

pulse (Figure 5) is internally generated, sent through the speaker(s) and sunk back. The

turn-on diagnostic status is internally stored until a successive diagnostic pulse is requested

(after a I2C reading).

If the "standby out" and "diagnostic enable" commands are both given through a single

programming step, the pulse takes place first (power stage still in standby mode, low,

outputs= high impedance).

Afterwards, when the amplifier is biased, the PERMANENT diagnostic takes place. The

previous turn-on state is kept until a short appears at the outputs.

Figure 5.

Turn-on diagnostic: working principle

Vs~5V

I (mA)

Isource

Isource

CH+

CH-

Isink

Isink

~100mS

Measure time

t (ms)

Figure 6 and 7 show SVR and output waveforms at the turn-on (standby out) with and

without turn-on diagnostic.

Figure 6. SVR and output behavior (case 1: without turn-on diagnostic)

Vsvr

Out

Permanent diagnostic

acquisition time (100mS Typ)

12/30

Bias (power amp turn-on)

Diagnostic Enable

(Permanent)

FAULT

event

t

Read Data

I2CB DATA

Permanent Diagnostics data (output)

permitted time

Doc ID 16903 Rev 1

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