Resonant charge pump of zero-voltage switch and control method thereof

Abstract

The invention discloses a resonant charge pump of a zero-voltage switch and a control method thereof, one end of a first switch tube is connected with a first voltage conversion end, and the other end of the first switch tube is connected with a second voltage conversion end after sequentially passing through a second switch tube, a third switch tube and a fourth switch tube; a fifth switch tube and a sixth switch tube are connected in series and are connected between the second voltage conversion end and the ground, and the series connecting point is connected with the series connecting point of the third switch tube and the fourth switch tube after passing through a third flying capacitor on one hand, and is connected with the series connecting point of the first switch tube and the second switch tube after passing through a first flying capacitor and a resonant inductor on the other hand; and a seventh switch tube and an eighth switch tube are connected in series and are connected between the second voltage conversion end and the ground, and the series connecting point is connected with the series connecting point of the second switch tube and the third switch tube after passing through a second flying capacitor. According to the invention, the resonant inductor and the first flying capacitor are connected in series to form a resonant cavity, ZVS turn-on of the six switching tubes is realized by matching with sequential control and utilizing a common resonant element, and the voltage conversion efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of high-power fast charging of lithium batteries in portable devices, and relates to a ZVS (zero voltage switch) resonant charge pump and a control method thereof. Background technique [0002] As mobile devices represented by mobile phones have higher and higher requirements for charging power, charging chips with a charge pump structure have been widely used in various mobile devices due to their high efficiency. In the range of charging power below 50W, a single 2:1 structure charge pump or two parallel schemes can basically meet the demand. However, when the charging power rises above 50W, in order to further reduce the loss on the charging cable, a converter with a higher conversion ratio has to be sought, and the charge pump with a 4:1 structure can well solve the large Power charging puzzle. In addition, in portable devices, currently commercially available charge pump charging chips are purely capa...

AI Technical Summary

Problems solved by technology

[0006] For the two resonant cavities in the above-mentioned STC converter, the resonant frequency needs to be strictly the same, which leads to the problem of high precision and high cost of the resonant element, and the STC can only realize ZCS (Zero Current Switching) shutdown and cannot realize ZVS (Zero Current Switching). The switching loss caused by the opening of the voltage switch) is relatively large, and there is a problem of limitation when increasing the switching frequency. The present invention proposes a resonant charge pump with zero voltage switching. On the basis of the 4:1 Dickson charge pump, only one resonant inductor is added and the withstand voltage is the highest The resonant cavity is composed of flying capacitors in series, which solves the parameter matching problem of multiple resonant cavities, and reduces the capacitance requirements for the flying capacitors connected in series with the resonant inductor; setting the resonant inductor current detection module can ensure that the switching frequency of the resonant charge pump tracks the external The resonant frequency of the resonant element enables the resonant element to adopt common elements; combined with the control method proposed by the present invention, the ZVS opening of six switching tubes can be realized, and the efficiency of the converter can be further improved

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