600~2000W AC-DC Power Supply Design

1Key Input/Output Specifications

Input voltage: AC100V~AC240V

Output power

601-2000W,

Output voltage

DC 10V~100V (specific voltage to be specified), regulation accuracy ±1%

Output current

5A-50A, current accuracy ±5%

Standby power

below 1W (AC100V)

Power efficiency

92% @AC100V, 95% @AC220V

2Overall Circuit Scheme

For AC-DC supplies or chargers in the 600~2000W range, the circuit mainly consists of five parts: an input EMI filter unit, a single-inductor CCM PFC power-factor-correction unit based on the NCP1654 control IC, a half-bridge LLC power conversion unit with the L6599 as core control IC, a CV/CC control unit based on an MCU and operational amplifiers, and an auxiliary power unit.

Within the 600W~2200W range the topology and circuit diagram are identical; only the selection of power semiconductors, power inductors, transformers and energy-storage capacitors differs. For the PFC and LLC power switches, prefer superjunction-process MOSFETs rated 600V or higher; for the output synchronous rectifier, ordinary low-voltage low-Rds(on) MOSFETs rated at more than 2× the output voltage suffice. The PFC inductor should use high-permeability Sendust or HIGH FLUX material; the transformer and resonant inductor should use N95 or similar ferrite.

See the key components BOM list below for details; the block diagram of each circuit unit is as follows:

Figure 1: 600W~2000W main circuit block diagram

The auxiliary power supply is simple; for details refer to the "AI - Auxiliary Power Supply" document

3Main circuit schematic

Figure 2: 600W~2000W main circuit schematic

4Key components BOM calculation of the main circuit (this example is designed for 58V 13A; for other output power/voltage/current refer to "LLC Circuit Calculation" for a detailed evaluation)

5Key Power-Device Loss & Thermal Evaluation

The main heat-generating components are the input rectifier bridge, the magnetic components of the PFC and LLC stages, power switches and power rectifiers. Heat dissipation differs with output power, voltage and current, but for well-designed products the thermal performance is roughly similar. The table below gives several concrete examples.