TDA7562

10/17

with the 4 ohm speaker unconnected is considered as double fault.

S. GND (so) / S. GND (sk) in the above table make a distinction according to which of the 2 outputs is shorted

to ground (test-current source side= so, test-current sink side = sk). More precisely, so = CH+, sk = CH-.

FAULTS AVAILABILITY

All the results coming from I2Cbus, by read operations, are the consequence of measurements inside a defined

period of time. If the fault is stable throughout the whole period, it will be sent out.

To guarantee always resident functions, every kind of diagnostic cycles will be reactivate after any I2C reading

operation. So, when the micro reads the I2C, a new cycle will be able to start, but the read data will come from

the previous diag. cycle (i.e. The device is in turned On, with a short to Gnd, then the short is removed and micro

reads I2C. The short to Gnd is still present in bytes, because it is the result of the previous cycle. If another I2C

reading operation occurs, the bytes do not show the short). In general to observe a change in Diagnostic bytes,

two I2C reading operations are necessary.

I2C PROGRAMMING/READING SEQUENCES

A correct turn on/off sequence respectful of the diagnostic timings and producing no audible noises could be as

follows (after battery connection):

TURN-ON: PIN2 > 7V --- 10ms --- (STAND-BY OUT + DIAG ENABLE) --- 500 ms (min) --- MUTING OUT

TURN-OFF: MUTING IN --- 20 ms --- (DIAG DISABLE + STAND-BY IN) --- 10ms --- PIN2 = 0

Car Radio Installation: PIN2 > 7V --- 10ms DIAG ENABLE (write) --- 200 ms --- I2C read (repeat until All faults

disappear).

OFFSET TEST: Device in Play (no signal) -- OFFSET ENABLE - 30ms - I2C reading (repeat I2C reading until

high-offset message disappears).

FAST MUTING

The muting time can be shortened to less than 1ms by setting (IB2) D5 = 1. This option can be useful in transient

battery situations (i.e. during car engine cranking) to quickly turnoff the amplifier for avoiding any audible effects

caused by noise/transients being injected by preamp stages.

Double fault table for Turn On Diagnostic

S. GND (so)

S. GND (sk)

S. Vs

S. Across L.

S. GND (so)

S. GND

S. GND

S. Vs + S. GND

S. GND

S. GND (sk)

/

S. GND

S. Vs

S. GND

S. Vs

/

/

S. Vs

S. Vs

S. Across L.

/

/

/

S. Across L.