Flight capacitor voltage balancing circuit of three-level step-down DC-DC converter

Abstract

The invention relates to a flight capacitor voltage balancing circuit of a three-level step-down DC-DC converter, and belongs to the technical field of electronic circuits. The flight capacitor voltage balancing circuit comprises a sampling hold circuit, a comparison selection circuit, a logic control circuit and a VCF adjusting circuit, wherein the input end of the sampling hold circuit is connected with the VA end of a three-level DC-DC main circuit, the output signal VHOLD of the sampling hold circuit is connected with the input end of the comparison selection circuit, the input end of a logic control signal is connected with the output signals VCMP2 and VCMP3 of the comparison selection circuit and detection signals V phi 2 and V phi 4 of phases phi 2 and phi 4, the input signal of the VCF adjusting circuit is connected with the output signal VCH of the logic control circuit, and the output signal of the VCF adjusting circuit is connected with the VA end of the three-level DC-DC main circuit, so that a closed loop is formed. According to the invention, the circuit does not need to be compensated by a duty ratio signal during flight capacitance balance, so that inductive current ripples and output voltage ripples are reduced, and the energy conversion efficiency of a system is improved.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, in particular to a flying capacitor voltage balancing circuit of a three-level step-down DC-DC converter. Background technique [0002] As a key component of power transmission circuits, voltage converters directly affect the size and power efficiency of electronic products. With the increasing demand for miniaturization of voltage converters in computer and communication products, high power density point-of-load (POL) converter topologies have become an urgent need in the field of modern electronic equipment. Compared with the traditional two-level buck converter, the three-level buck converter has unique advantages in reducing device voltage stress and inductor current ripple, reducing switching loss and conduction loss, and improving conversion efficiency and power density. However, due to factors such as switching frequency changes, the presence of flying capacitors and power sw...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem of large current and voltage ripple generated by using the duty cycle signal to compensate the unbalanced flying capacitor in the traditional three-level converter, the present invention proposes a flying capacitor voltage balance circuit for the three-level step-down converter, And a three-level step-down converter circuit composed of a flying capacitor voltage balance circuit, a three-level DC-DC main circuit, a loop logic control circuit, a level shift and a drive circuit

Solve the unbalance problem of flying capacitors without affecting the duty cycle, and improve the working efficiency of the three-level buck converter

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