Dual power supply audio power amplifier circuit composed of LM4730/LM4731

As shown in the figure, this is the dual-power supply audio power amplifier circuit of LM4730/4731. Two audio input signals A and B are input from the socket, and added to the 3rd pin (INA) and 13th pin (INB) of LM4730 through RB1 and RB2 respectively. After power amplification, they are output from the 3rd pin (VoA) and the 1st pin (VoB) to their respective speakers. RB1 and RB2 are isolation resistors at the in-phase input end, which are used for current limiting; RIN1 and RIN2 can set the DC bias operating point of the amplifier, and at the same time form an input high-pass filter with CIN1, CIN2; RSN1, CSN1 and RSn2, CSN2 are used to eliminate high-frequency noise at the output of the amplifier. LM4730/4731 has a thermal protection function. When the temperature rises to 150℃, the circuit is shut down, and when the temperature drops to 145℃, it starts to work again. The temperature then rises again, and it will shut down again when it rises to 150℃ again. The maximum power consumption of LM4730/4731 is PD(MAX)=VCC2/(2π2RL), VCC is the total power supply voltage applied to LM4730, and RL is the load resistance. LM4730/4731 has two modes: mute mode and standby mode. When pin 6 (Mute A) and pin 11 (Mute B) are at a logic high level, it is in mute mode and the audio signal is disabled; when pins 6 and 11 are at a logic low level, the mute mode is released and the audio signal is amplified normally. When pin 9 (Standby A) and pin 14 (Standby B) are at a logic high level, it is in standby mode (when the amplifier is idle), and the power consumption of the amplifier is reduced to the minimum (VCC current is less than 10μA, and the typical value of VEE current is 3.5mA). LM340S-5.0 is a three-terminal integrated voltage regulator circuit with an output voltage of 5V.