A switching power supply with reduced load regulation rate and high-speed response and its control method

Abstract

The invention proposes a switching power supply with reduced load regulation rate and high-speed response and a control method thereof. The switching power supply has fast response speed and low ripple output. The switching power supply includes a switch module, an LC module, a sampling module and a feedback module; the feedback module includes an error amplifier EA, a comparator, a timing circuit and a sawtooth generator; the output end of the sawtooth generator is connected to the inverting input end of the comparator, and The output frequency of the sawtooth generator is N times the switching frequency of the switching module; the circuit does not need to use the traditional method of ripple injection, and is a switching circuit with fast response, low ripple output, and no need for large ESR capacitors.

Description

technical field [0001] The invention relates to a switching power supply, in particular to a switching power supply with reduced load regulation rate and high-speed response and a control method thereof. Background technique [0002] The control methods of the existing switching power supply mainly include voltage mode, current mode, COT and so on. When the output capacitor ESR (capacitor equivalent series resistance) is small, both voltage mode and current mode control can be achieved. Under the same operating frequency, COT has a faster transient response speed, and both voltage mode and current mode control transient response speed are slower. figure 1 Shown is the existing COT control circuit diagram, figure 2 This is the waveform diagram of the circuit when it works normally; in this circuit, when the ESR of the output capacitor is small, the COT control must have ripple injection to work stably; when the capacitor ESR is large, ripple injection is not required to en...

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Problems solved by technology

figure 1 Shown is the existing COT control circuit diagram, figure 2 It is the waveform diagram of the normal operation of the circuit; in this circuit, when the ESR of the output capacitor is small, the COT control must have ripple injection to work stably; when the capacitor ESR is large, ripple injection is not required to ensure stable operation , but a larger capacitor ESR will cause larger ripples in the output voltage and affect efficiency

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