SHORT CIRCUIT PROTECTION

The TDA2030 has an original circuit which limits the

current of the output transistors. Fig. 18 shows that

the maximum output current is a function of the

collector emitter voltage; hence the output transis-

tors work within their safe operating area (Fig. 2).

This function can therefore be considered as being

peak power limiting rather than simple current lim-

iting.

It reduces the possibility that the device gets dam-

aged during an accidental short circuit from AC

output to ground.

Fi g ure 1 8. M aximum

ou t pu t

c urr en t

vs.

each output transistor

Figure 19. Safe operating area and

collector characteristics of the

protected power transistor

THERMAL SHUT-DOWN

The presence of a thermal limiting circuit offers the

following advantages:

1. An overload on the output (even if it is perma-

nent), or an above limit ambient temperature can

higher than 150

°C.

2. The heatsink can have a smaller factor of safety

compared with that of a conventional circuit.

There is no possibility of device damage due to

high junction temperature. If for any reason, the

junction temperature increases up to 150

°C, the

thermal shut-down simply reduces the power

dissipation at the current consumption.

The maximum allowable power dissipation de-

pends upon the size of the external heatsink (i.e. its

thermal resistance); fig. 22 shows this dissipable

power as a function of ambient temperature for

different thermal resistance.

TDA2030

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