Switching converter and zero-cross detection circuit and zero-cross detection method thereof

Abstract

The invention discloses a switching converter and a zero-cross detection circuit and a zero-cross detection method thereof. The zero-crossing detection circuit comprises a voltage sampling module, a bias module and a zero-crossing comparator, the voltage sampling module generates a sampling signal equal to the direct-current output voltage, the bias module generates a corresponding bias signal according to the sampling signal, the zero-crossing comparator compares a superposed signal of the signal to be detected and the bias signal with a zero-crossing reference value, and the zero-crossing comparator outputs the signal to be detected. Therefore, a zero-crossing indication signal is obtained. According to the zero-cross detection circuit, the sampling signal equal to the direct-current output voltage is simulated and generated in the chip, and the compensation quantity of the bias module is adaptively adjusted according to the sampling signal, so that the compensation quantity is basically equal to the variable quantity of the switch node voltage during the delay period; under different application occasions, the influence of the zero-crossing comparator and subsequent logic control delay on the zero-crossing detection precision can be reduced, the zero-crossing detection precision is improved, the circuit loss of the switching converter is reduced, and the efficiency of the switching converter is improved.

Description

technical field [0001] The present invention relates to the technical field of semiconductor integrated circuits, and more particularly to a switching converter, a zero-crossing detection circuit and a zero-crossing detection method thereof. Background technique [0002] At present, wearable devices and IoT devices are mostly powered by lithium batteries, so the efficiency of switching power supply products is becoming more and more important. The power supplies used in modern electronic equipment are roughly divided into linear regulated power supplies and switching regulated power supplies. The regulator tube of the linear regulated power supply works in the amplification area, which has the advantages of not introducing additional interference, good reliability and low cost, but it also has the disadvantages of large volume and low conversion efficiency. Compared with linear regulated power supply, switching regulated power supply has the characteristics of boosting and ...

AI Technical Summary

Problems solved by technology

like figure 1 As shown, the current source 130 and the resistor Rc are used to superimpose a bias signal on the switch node voltage Vsw, but such a bias signal is not suitable for all applications, once the temperature, the value of the inductor or the output voltage change Change, the bias signal will not be able to well eliminate the impact of the delay of the zero-crossing comparator

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