Self-calibration zero-crossing comparator and direct-current conversion circuit

Abstract

The invention discloses a self-calibration zero-crossing comparator and a direct-current conversion circuit. The self-calibration zero-crossing comparator comprises a first comparison module, a logicmodule, a compensation module and a second comparison module, wherein the first comparison module is used for comparing the reference voltage with the sampling voltage and outputting a state signal; the logic module is used for generating a logic control signal according to the state signal; the compensation module is used for biasing the first power supply signal to generate a bias signal and compensating the sampling voltage according to the logic control signal to generate a compensation signal; the second comparison module is used for comparing the bias signal with the compensation signaland outputting a zero-crossing comparison signal. The precision of the zero-crossing comparator can be improved on the basis of not increasing the cost.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of zero-crossing detection, in particular to a self-calibrating zero-crossing comparator and a DC conversion circuit. Background technique [0002] In the DC-DC circuit, the power efficiency requirement of the system is very high. In order to take into account both heavy load and light load, DC-DC power supply generally adopts Pulse Width Modulation (Pulse Width Modulation, PWM) control mode when the load is heavy, and the output is adjusted by adjusting the duty cycle at a fixed frequency; When the power supply is loaded, the pulse frequency modulation (Pulse Frequency Modulation, PFM) control method can be used to improve efficiency by reducing the switching frequency. When the load current is large, the system works in continuous current mode (Continuous Conduction Mode, CCM), and the average value of the inductor current is equal to the triangular wave of the load current; when...

AI Technical Summary

Problems solved by technology

Due to the accuracy and delay of the comparator itself, the zero-crossing detection will be inaccurate, and the chip design needs to pay a great price to improve the accuracy, and if the delay of the comparator and the entire circuit is to be reduced, it is often necessary Pays the price of power consumption and circuit reliability

Therefore, there is a conflicting relationship between accuracy and cost of existing zero-crossing comparators

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