TDA7564BPDTR View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

TDA7564BPDTR

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

STMicroelectronics 

Diagnostics functional description

4

Diagnostics functional description

TDA7564B

4.1

Turn-on diagnostic

It is activated at the turn-on (stand-by 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 19) 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 "stand-by out" and "diag. enable" commands are both given through a single

programming step, the pulse takes place first (power stage still in stand-by 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 19. Turn - on diagnostic: working principle

Vs~5V

I (mA)

Isource

Isource

CH+

CH-

Isink

Isink

~100mS

Measure time

t (ms)

Figure 20 and 21 show SVR and OUTPUT waveforms at the turn-on (stand-by out) with and

without turn-on diagnostic.

Figure 20. SVR and output behavior (case 1: without turn-on diagnostic)

Vsvr

Out

Permanent diagnostic

acquisition time (100mS Typ)

14/34

Bias (power amp turn-on)

Diagnostic Enable

(Permanent)

FAULT

event

t

Read Data

I2CB DATA

Permanent Diagnostics data (output)

permitted time

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