Buck-boost converter and its controller and control method

Abstract

A controller used in a buck-boost converter includes a logic control circuit, a pulse width increasing circuit, a pulse width decreasing circuit, a first driving circuit and a second driving circuit. The pulse width increasing circuit generates a sum control signal based on a logic control signal generated by the logic control circuit. The pulse width increasing circuit increases the pulse width of the logic control signal by a first value to generate the pulse width of the sum control signal. The pulse width decreasing circuit generates a difference control signal based on the logic control signal. The pulse width decreasing circuit decreases the pulse width of the logic control signal by a second value to generate the pulse width of the difference control signal. The first and second driving circuit respectively generates driving signals based on the sum control signal and the difference control signal.

Description

technical field [0001] The invention relates to an electronic circuit, in particular to a buck-boost converter, a controller and a control method thereof. Background technique [0002] With the rapid development of the consumer electronics market, portable electronic products are constantly changing to miniaturization and light weight, and the smaller the size of the product, the smaller the volume and capacity of the battery. This requires improving the conversion efficiency of the power supply module of such products as much as possible, reducing power consumption, and enabling it to provide a stable output voltage within a wide range of battery voltage variations, so as to prolong the battery life. Buck-boost converters capable of operating over a wide input range are widely used in such applications. [0003] figure 1 It is the circuit schematic diagram of a traditional four-switch buck-boost converter. The buck-boost converter converts an input voltage VIN into an ou...

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Problems solved by technology

[0005] However, judging the working mode based on the relationship between the input and output voltages makes the relationship between the control loop and the voltage feedback loop complicated, increasing the difficulty of system design and testing

In addition, the transition between different operating modes will also cause sudden changes in various circuit parameters (such as voltage, current, and duty cycle), and jump peaks may appear on the output voltage VOUT

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