Bridge output audio power amplifier circuit composed of LM1876

As shown in the figure, this is the bridge output audio power amplifier circuit of LM1876 (the * components in the figure are selected according to the application needs). The audio input signal is input from the socket, and is added to the 8th and 13th pins of LM1876 through the isolation resistors Ri and RB. The internal power amplifier A and power amplifier B form the bridge output (i.e. push-pull amplification). After power amplification, the output is added to the speaker from the 3rd and 1st pins, and the output end feedback resistor Rf returns to the amplifier input end 7th and 12th pins. The characteristics of the LM1876 bridge output structure power amplifier are: the output signal swing is large, which is twice that of the single-ended output (one end is grounded) structure. Theoretically, the output power is 4 times that of the single-ended output; due to the increase in output power, the installation of the heat sink should be very careful, and the parameters of the heat sink should be considered according to the specific application.