Battery charging system and its control circuit based on digital control

Abstract

The invention provides a battery charging system and its control circuit. The battery charging system includes a switching circuit with a first switching tube, and the control circuit includes a plurality of analog control loops and a digital control unit, wherein each analog control loop generates a high-low voltage signal according to the corresponding feedback signal, reference signal and slope compensation signal. Level loop control signal, the digital control unit generates switch control signals according to multiple loop control signals and a fixed duration control signal to control the first switch tube, wherein the digital control unit automatically selects the active analog control loop to control The turn-on moment or turn-off moment of the first switch tube. Compared with the prior art, the digital control circuit parameter design is simple, the reliability is good, and it has stronger portability.

Description

technical field [0001] The present invention relates generally to electronic circuits, and more particularly to battery charging systems. Background technique [0002] With the development of portable electronic devices, battery charging systems are also widely used in portable electronic devices. figure 1 A schematic diagram of the circuit structure of a conventional battery charging system 100 adopting buck circuit topology is shown. The battery charging system 100 includes multiple control loops such as battery voltage, battery charging current, input voltage and input current, and each control loop includes an error amplifier and a compensation network. Taking the battery voltage control loop as an example, in each switching cycle, the clock signal CLK sets the RS flip-flop FF0 to make it output the switching control signal PWM to turn on the upper power transistor PM1 and turn off the lower power transistor PM2 at the same time . The current is supplied to the load R...

AI Technical Summary

Problems solved by technology

And because different circuit parameters require different compensation networks, figure 1 The illustrated battery charging system 100 is not very portable

At the same time, because the signal values ​​of the error amplification signals Vcom1~Vcomn output by each control loop are relatively close, there may be problems in switching between control loops, for example, there may be multiple control loops working at the same time, or the control Loop switching errors, etc.

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