TS4871 datasheet(24/42 Pages) STMICROELECTRONICS

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Figure 84. Demoboard top solder layer

Figure 85. Demoboard bottom solder layer

5.1

BTL configuration principle

The TS4871 is a monolithic power amplifier with a BTL output type. BTL (bridge tied load) means that each end of

the load is connected to two single ended output amplifiers. Thus, we have:

Single ended output 1 = Vout1 = Vout (V)

Single ended output 2 = Vout2 = -Vout (V)

And Vout1 - Vout2 = 2Vout (V)

The output power is:

Pout= 2VoutRMS2

RL W

(1)

For the same power supply voltage, the output power in BTL configuration is four times higher than the output

power in single ended configuration.

5.2

Gain In typical application schematic

In flat region (no effect of Cin), the output voltage of the first stage is:

Vout1= −VinRfeedRin V

For the second stage : Vout2 = -Vout1 (V)

The differential output voltage is:

Vout2−Vout1=2VinRfeedRinV

The differential gain named gain (Gv) for more convenient usage is:

Gv= Vout2−Vout1

Vin =2RfeedRin

Remark : Vout2 is in phase with Vin and Vout1 is 180 phased with Vin. It means that the positive terminal of the

loud speaker should be connected to Vout2 and the negative to Vout1.

TS4871

Application information

DS2547 - Rev 10

page 24/42

TS4871 Arkusz danych(PDF) 24 Page - STMicroelectronics