Direct current switch power supply control circuit

Abstract

The invention discloses a direct current switch power supply controlling circuit, which comprises a pulse-width modulating comparator, a controlling unit and a logic driving unit which are connected in turn, wherein output square-wave signals of the pulse-width modulating comparator are input in a first input end of the controlling unit, maximum duty cycle square-wave signal is input in a second input end, the output end is connected with the input end of the logic driving unit, when the duty cycle of output square-wave of the pulse-width modulating comparator which is input is lager than the maximum duty cycle, the controlling outputs the square-wave with 100% duty cycle. The direct current switch power supply controlling circuit realizes smooth conversion from the maximum duty cycle to 100% duty cycle through improving the controlling unit circuit of a power supply controlling circuit, which increases respond speed of the circuit, reduces ripple of output voltage in the process of conversation of the circuit from the maximum duty cycle mode to 100% duty cycle mode, the design of the circuit is simple, and the cost of circuit reconstruction is saved.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a DC switching power supply control circuit. Background technique [0002] The DC control switching power supply control circuit mainly includes a pulse-width modulation (Pulse-width Modulation, hereinafter referred to as pulse-width modulation or PWM) comparator, a control switch and an output LC circuit. The PWM comparator is used to compare the input signals at its input terminals to generate different duty Compared with the square wave signal, the square wave signal generated by the PWM comparator is used to drive the closing and closing of the control switch. The control switch is used to connect the input voltage to the LC circuit when it is closed, and cut off the The connection of the input voltage to and release of the energy of the LC circuit comprising an inductor connected to a control switch and a capacitor in series with the inductor, the node voltage of...

AI Technical Summary

Problems solved by technology

[0013] (1) In the prior art, when the square wave input to the logic drive unit is switched between the maximum duty cycle mode and the 100% duty cycle mode, the ripple of the circuit output voltage increases significantly

[0014] (2) V EAO The range of change is very large. Due to the narrow bandwidth of the error amplifier, it takes a long time to respond to this large range of change, resulting in a relatively slow response speed of the circuit.

[0015] (3) When the circuit switches between the maximum duty cycle mode and the 100% duty cycle mode, the square wave input to the logic drive unit has an obvious state change, which is easily affected by noise and unstable

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