Boost-buck type power supply converter and control method thereof

Abstract

The invention relates to a control method of a boost-buck type power supply converter, and the power supply converter comprises an inductor, a first switch connected between the input end of the power supply converter and the first end of the inductor, a second switch connected between the first end of the inductor and the grounding end, a third switch connected between the second end of the inductor and the grounding end, and a fourth switch connected between the second end of the inductor and the output end of the power supply converter; and the control method is characterized in that the control method comprises the following steps: detecting voltage at the input end and the output end and load current at the output end for deciding whether the power supply converter performs the operation in the buck mode, the first boost-buck mode, the second boost-buck mode or the boost mode; and controlling the first, the second, the third and the fourth switches during the first and the second boost-buck modes.

Description

technical field [0001] The present invention relates to a power converter, in particular, to a buck-boost power converter and a control method thereof which can improve switching loss and correct switching mode. Background technique [0002] figure 1 A known buck-boost power converter 10 is shown, including a power stage 12 and a control circuit 14 . In the power stage 12, the switch SW1 is connected between the input voltage Vin and the inductor L, the switch SW2 is connected between the inductor L and the ground terminal GND, the switch SW3 is connected between the inductor L and the ground terminal GND, and the switch SW4 is connected between the inductor L and the ground terminal GND. between L and the output voltage Vout. The output voltage Vout is divided by the resistors R1 and R2 to generate the feedback signal VFB. In the control circuit 14, the error amplifier 24 generates the error signal VEA according to the feedback signal VFB and the reference voltage Vref, a...

AI Technical Summary

Problems solved by technology

However, whether figure 1 Or the power converter proposed by Chen et al., in the buck-boost mode, the switching cycle of the switch is (1) turn on (turn on) switches SW2 and SW4 and turn off (turn off) switches SW1 and SW3, (2) turn on switch SW1 and SW4 and close switches SW2 and SW3, (3) open switches SW1 and SW3 and close switches SW2 and SW4, (4) open switches SW1 and SW4 and close switches SW2 and SW3, due to the The number of times is more, so the switching loss (switching loss) is also larger

[0004] Therefore, there are above-mentioned inconveniences and problems in the known buck-boost power converter.

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