STA530

The STA530 is a BASH^® power amplifier where BASH^® means "High Efficiency".

In fact it's permits to build a BASH® architecture amplifier adding only few external components and a variable Buck regulator tracking the audio signal. Notice that normally only one Buck regulator is used to supply a multichannel
amplifiers system , therefore most of the functions implemented in the STA530 have a summing output  pin.

The signal circuits STA530 are biased by fixed negative and positive voltages referred to Ground. Instead the final stages of the output amplifiers are supplied by two external voltages that are following the audio signal . In this way the headroom for the output transistors is kept at minimum level to obtain a high efficiency power amplifier. 

The STA530 contains all the blocks to build a configurable four channel amplifier.

The tracking signal for the external Buck regulator is generated from the Absolute Value Block (AVB) that rectifies the audio signal. The outputs of these blocks are decoupled by a diode to permit an easy sum of this signal for the multichannel application. The gain of the stage AVB is equal to 70 (+36.9 dB). A sophisticated STA530 performs the output transistor power detector that , with the buck regulator, reduces the power supply voltage . Moreover, a maximum current output limiting and the over temperature sensor have been added to protect the circuit itself. The external voltage applied to the STBY/MUTE pin forces the two amplifiers in the proper condition to guarantee a silent turn-on and turn-off.