Philips TDA2613

July 1994 9

Philips Semiconductors Product speciﬁcation

6 W hi-ﬁ audio power ampliﬁer TDA2613

Input mute circuit

The input mute circuit operates only during switching on and off of the supply voltage. The circuit compares the1⁄2supply

voltage (at pin 3) with an internally fixed reference voltage (Vref), derived directly from the supply voltage. When the

voltage at pin 3 is lower than Vref the non-inverting input (pin 9) is disconnected from the amplifier. The voltage at pin 3

is determined by an internal voltage divider and the external 100 µF capacitor.

During switching on, a time delay is created between the reference voltage and the voltage at pin 3, during which the

input terminal is disconnected, (as illustrated in Fig.5).

Fig.5 Input mute circuit; time delay.