Practical circuit of full-bridge switching regulated power supply

The picture shows a practical circuit of a full-bridge switching regulated power supply. It is a 1500W bipolar power tube switching regulated power supply circuit controlled by CW494. In the circuit, four bipolar high reverse voltage transistors F661 are used as switching tubes. Under the control of the integrated circuit CW494, the two pairs of tubes are alternately turned on and off to convert the direct current into high-frequency alternating current, which is then stepped down by the high-frequency transformer. , through rectification and filtering, a stable DC voltage of 12V is obtained. The BVceo of the F661 power switch tube is ≥400V, and the tooff time is 1μs, so under high-power working conditions, its power loss is small. High-frequency transformer T1 is the core component of the circuit. Its magnetic properties have high requirements: the frequency characteristics must reach MHz; the saturation magnetic flux density must reach 5 000Gs; the hysteresis loss must be small; when using EC70 core, the output power can reach 1000W; when using EC90 core. The output power can reach 2000W.