Switch-type power converter, clock module, control circuit and related control method

Abstract

The invention provides a switch-type power converter, a clock module, a control circuit and a related control method of clock signals. The clock module of the embodiment is used for providing signals for the power converter. When the power converter is started, the clock module sets the clock frequency of the clock signals at the moment as first set frequency, and in the starting process of the power converter, the clock module adjusts the clock frequency to jump to second set frequency in a stepped mode from the first set frequency through growth frequency jumping with preset number of times. Therefore, a sensibility energy storage element of the power converter can reach volt-second balance in the whole starting process, and the problem that an inductive current flowing through the sensibility energy storage element surges can not happen, so that the switch-type power converter safely and stably finishes the starting process.

Description

technical field [0001] Embodiments of the present disclosure relate to power converters, and in particular to a switch-type power converter and its clock module, a control circuit and a method for controlling a clock signal of the power converter. Background technique [0002] Switching power converters have been widely used in various industrial electronic equipment and consumer electronic equipment. A switch-type power converter generally includes at least one main switch, and the purpose of converting the input voltage received by the power converter into a suitable output voltage is realized by controlling the on and off switching of the main switch. [0003] One of the control modes commonly used in switching power converters includes the peak current control pulse width modulation mode. In short, in the peak current control pulse width modulation mode, the switching power converter adjusts its main switch to switch on and off at a roughly constant switching frequency ...

AI Technical Summary

Problems solved by technology

But in fact, the step-down power converter operates with a minimum system duty cycle of 1.5%, which will cause the energy storage inductor of the step-down power converter to fail to reach the volt-second balance, resulting in a continuous increase in the current of the energy storage inductor

In this case, the current of the energy storage inductor may suddenly increase beyond its maximum allowable current in a short period of time and saturate the energy storage inductor, causing the power converter to fail to work normally.

In addition, if the buck power converter uses an integrated metal-oxide-semiconductor field-effect transistor (MOSFET) as the main switch, the current handling capability of the integrated MOSFET is limited, and the continuous increase of the current of the energy storage inductor also means that the current The switching current through the MOSFET continues to increase, which is likely to saturate the MOSFET, resulting in a sudden increase in its drain-source voltage and a sudden increase in conduction loss

This not only makes the MOSFET bear a large voltage and temperature burden, but also the MOSFET is in danger of burning, which is not conducive to the stability and durability of the entire power converter system

[0006] Commonly used system soft-start schemes such as the peak threshold of the soft-start switch current or the reference voltage that characterizes the expected value of the output voltage for soft-start cannot solve the above technical problems

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