Application of LM4780 in Parallel Output Power Amplifier Circuit

The following is the circuit diagram of [LM4780 in parallel output power amplifier circuit]

The LM4780 is used for parallel output audio power amplifiers. The circuit is shown below. Parallel output audio power amplifiers are primarily used for large output currents to drive low impedance loads. The gain of the two parallel amplifiers must be the same. Therefore, the resistors Rf1, Ri1 and Rf2, Ri2 which determine the gain of the amplifier must be selected to have a resistance of 0.1% tolerance. In order to prevent the output currents of the two amplifiers from being inconsistent, a small resistor ROUT1, ROUT2 is connected in series at the output end for equalization and current sharing. Parallel output audio power amplifier load impedance is RL (parallel) = RL (total) × number of amplifiers connected in parallel (2 in the figure), so the power consumption of each amplifier PD (MAX) = VCC2 / 2π2RL (parallel).

(Editor: Circuit Diagram)