Voltage conversion circuit and control method thereof

Abstract

The invention provides a control method of a voltage conversion circuit, wherein the control method is applied to the voltage conversion circuit. The voltage conversion circuit comprises a direct-current voltage input end, a transformer primary side switch network, a resonant inductor, a transformer, a transformer secondary side switch network and a direct-current voltage output end which are electrically coupled, wherein the resonant inductor is connected with the transformer in series, and the voltage conversion circuit further comprises a resonant capacitor which resonates with the resonantinductor. The control method comprises the steps of controlling switching elements in a transformer primary side switching network and a transformer secondary side switching network, so that the numerical range of the ratio Ton / Tr of the total conduction time Ton of the voltage conversion circuit to the resonance period Tr of the voltage conversion circuit is (0, 1.8) U (2.7, 3.7) U (4.8, 5.5), and the quality factor Q of the voltage conversion circuit is less than or equal to 5. The control method provided by the embodiment of the invention can reduce the conduction loss and switching loss of the voltage conversion circuit so as to improve the efficiency and reduce the cost.

Description

technical field [0001] The present disclosure relates to the technical field of power circuits, in particular, to a voltage conversion circuit and a control method thereof. Background technique [0002] figure 1 Shown is a two-stage cascaded converter structure, which usually adopts the working mode of reducing voltage first and then regulating voltage. For example, the first-stage converter can use a high-efficiency DC transformer to reduce the input 48V bus voltage (Uin) to a lower intermediate bus voltage (Uib), such as 4V, with an efficiency of η1, and the second-stage converter uses a multi-phase interleaved The parallel-connected BUCK converter controls the BUCK output voltage Uo through closed-loop control, and the efficiency is η2, which ensures the power supply of the load (such as a processor chip). [0003] figure 2 shown as figure 1 Typical topology of the first-stage converter of a two-stage converter—LLC series resonant circuit, Figure 3A ~ Figure 3C yes...

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Problems solved by technology

[0007] The purpose of the present disclosure is to provide a voltage conversion circuit and its control method, which are used to overcome at least to some extent the problem of large circuit loss caused by the large effective value of the current of the resonant circuit itself due to the limitations and defects of the related technology

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