Boost converter and control circuit and control method thereof

By introducing components such as a threshold voltage generation circuit and a sawtooth wave generation circuit into the boost converter, and adjusting the sawtooth wave signal and the threshold voltage signal, zero duty cycle constant frequency stable operation is achieved when the input voltage and output voltage are close, thus solving the problem of unstable operation of traditional converters.

CN116566203BActive Publication Date: 2026-05-29SG MICRO CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
SG MICRO CORP
Filing Date
2023-03-06
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

Traditional boost architecture switching converters cannot achieve stable operation at a constant frequency with zero duty cycle when the input and output voltages are close, and the system cannot function properly due to the limitation of minimum conduction time.

Method used

The system employs a threshold voltage generation circuit, a sawtooth wave generation circuit, a comparator, a logic circuit, and a driver circuit. By generating a threshold voltage signal and a sawtooth wave signal related to the input and output voltages, and adjusting the slope of the sawtooth wave signal and the threshold voltage signal using a loop, the system achieves the early generation of the reset signal, thereby controlling the turn-on and turn-off times of the low-side switching transistor.

Benefits of technology

It achieves near-zero duty cycle stable operation at a fixed frequency when the input voltage and output voltage are close, solving the problem of unstable operation of traditional converters under this condition.

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Abstract

The application discloses a boost converter and a control circuit thereof. The control circuit comprises a threshold voltage generating circuit, a sawtooth wave generating circuit, a comparator, a logic circuit and a driving circuit. The threshold voltage generating circuit is used for generating a threshold voltage signal related to an input voltage and an output voltage, the sawtooth wave generating circuit is used for generating a sawtooth wave signal related to the output voltage, the comparator is used for comparing the sawtooth wave signal and the threshold voltage signal to obtain a reset signal, and the logic circuit is used for controlling a conduction time of a low-side switch according to a second clock signal and controlling an off time of the low-side switch according to the reset signal. When the input voltage and the output voltage are very close, the slope of the sawtooth wave signal is increased and the threshold voltage signal is reduced through loop adjustment, so that the reset signal can arrive before the second clock signal, the pulse width modulation signal is maintained in an invalid state through the logic circuit, and then the frequency-stable operation with a near-zero duty cycle is realized.
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