Universal input 3.3V, 12V, 36V, 200W continuous PSU reference design for Class D amplifiers

This power module generates all the voltages required to power the Class D audio amplifier. The main output voltage is 36V, which provides 200W of continuous power and 540W of peak power. The first stage is a power factor correction boost. The flyback converter provides 12V on the primary side and 12V (300mA) and 3.3V (200mA) on the secondary side. Using a hardware switch and remote input, the converter can enter standby mode: in this state, the 36V output is disabled and 12V, 3.3V are "always on". In this way, the standby power can be reduced to 150mW (115Vac) and 270mW (230Vac). A second digital input switches the main input voltage from 36V to 18V, allowing it to enter a low-current consumption mode when the audio amplifier requires less power.

characteristic

• ● Low-cost PFC + 2-switch forward topology delivers 200W average power and 540W peak power
• ● Constant switching frequency: especially suitable for audio applications
• ● Simple thermal interface: two small heat sinks on one side of the board
• ● Good plug-to-plug efficiency: 84% at 115Vac, 86% at 230Vac
• ● Compact structure: 126mm x 145mm, height 35mm