Application method of PFC (power factor correction) controller in Buck circuit

Abstract

The invention discloses an application method of a PFC (power factor correction) controller in a Buck circuit. A switch tube and a free-wheel inductor TR2 are serially connected into a main power loop in the Buck circuit, a reference voltage source is connected into a MULT end of the PFC controller, current of the free-wheel inductor TR2 is detected by a ZCD (zero current detection) end of the PFC controller, and the switch tube is driven to be switched on and off by a GD (general dynamic) end of the PFC controller. The high-voltage Buck circuit is controlled by a PFC controller chip, and problems that a Buck type resonant soft switching circuit is high in implementation cost and poor in resonant soft switching effect, voltage stress of a switch tube is high and the like are solved. In addition, circuits of the application method are simple in structure and fine in resonant effect, and switching-on and switching-off of zero voltage are realized simultaneously.

Description

technical field [0001] The invention discloses an application method of a PFC controller, in particular an application method of the PFC controller in a Buck circuit. Background technique [0002] The Buck circuit is a step-down conversion circuit, which is a switching circuit commonly used in switching power supplies. Realizing the resonant soft switching function in the Buck circuit requires a lot of auxiliary components, please refer to the attached figure 2 , attached image 3 And attached Figure 4 , with figure 2 , attached image 3 And attached Figure 4 There are three common Buck-type resonant soft switching circuits at present. The design of these three circuits is complicated, and many auxiliary components need to be added, so the cost of implementation is high. Moreover, the effect of the above-mentioned resonant soft switching circuit is not good, and it can only realize zero-voltage turn-on or zero-voltage turn-off, and its resonance process will make the...

AI Technical Summary

Problems solved by technology

Realizing the resonant soft switching function in the Buck circuit requires a lot of auxiliary components, please refer to the attached figure 2 , attached image 3 And attached Figure 4 , with figure 2 , attached image 3 And attached Figure 4 There are currently three common Buck-type resonant soft switching circuits. The design of these three circuits is complicated, and many auxiliary components need to be added, which makes the implementation cost high.

Moreover, the effect of the above-mentioned resonant soft switching circuit is not good, and it can only achieve zero-voltage turn-on or zero-voltage turn-off, and its resonance process will make the voltage stress or current stress of the switch tube too high

At present, there is no chip specially used for Buck circuits to realize resonant soft switching without adding auxiliary components. The chips that can realize this function are generally current-mode phase-shifting full-bridge chips or DSP processors, but the price of this chip is relatively low. tall and complicated to use

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