75W audio power amplifier made with TMOS150

This 75W+75W audio power amplifier made of high-power integrated block TMOS150 features high output power and low distortion, and is suitable for large entertainment venues, units and individuals.

1. Principle circuit

As shown in the figure below. The left channel signal is input by C1, filtered by R1 and C3 to add to the ④th pin of IC1, and after amplification, it outputs a maximum of 75W undistorted power from the ①th pin. Among them, R5, C5, and R7 form a negative feedback circuit to minimize the distortion. The right channel signal is added to the ⑤th pin of IC1 by C2 and R2, and the maximum 75W undistorted power is output from the ⑧th pin to drive RL to work.

Power supply: AC220V is input from the primary of power transformer T1, and the secondary gets 28V+2BV AC voltage, which is rectified by D1~D4 and filtered by C7-C12 to output ±40V voltage. The positive pole is connected to the ②th pin of IC1, and the negative pole is connected to the ⑦th pin to supply power to IC1.

2. Component production

1. Production of choke coils L1 and L2: Use φ1.0mm enameled wire to flat-wind 20 turns on a cylindrical frame with a diameter of 8mm and then cast it.

2. The power transformer is made by winding 880 turns of φ1.0mm enameled wire on a silicon steel sheet with a cross-sectional area of ​​4.8cmx5.6cm for the primary. 112+112 turns of 1.6mm enameled wire are used for the secondary. The output power is 300W.

3. Heat sink: 400mmx400mmx3mm aluminum plate. Apply a layer of thermal grease evenly between the manifold and the heat sink, and fix them with screws with spring washers.