Power supply having ripple-based constant ON-time and control circuit and control method thereof

Abstract

The invention provides a power supply having ripple-based constant ON-time and a control circuit and control method thereof. A switch type power supply having ripple-based constant ON-time includes a power level and a control circuit. In the power level, an upper bridge switch and a lower bridge switch are connected to a phase node in series. The control circuit generates an upper bridge driving signal and a lower bridge driving signal according to a feedback signal associated with an output voltage, a phase node voltage of the phase node, and an upper bridge driving signal and / or a lower bridge driving signal. The control circuit includes a driving signal generation circuit and a ripple slope compensating circuit. The driving signal generation circuit generates the upper bridge driving signal and the lower bridge driving signal according to the feedback signal and a ripple slope compensating signal. The ripple slope compensating circuit is coupled to the driving signal generation circuit and is used for generating the ripple slope compensating signal according to the phase node voltage and the upper bridge driving signal and / or the lower bridge driving signal.

Description

technical field [0001] The present invention relates to a ripple modulation constant on-time power supply and its control circuit and control method, in particular to a ripple modulation constant on-time power supply that adaptively compensates the ripple slope according to the phase node voltage Provider and its control circuit and control method. Background technique [0002] Figure 1A A schematic circuit diagram of a typical switching power supply 100 with ripple-based constant ON-time (RBCOT) is shown. Such as Figure 1A As shown, the switching mode power supply 100 with constant on-time ripple modulation includes a control circuit 110 and a power stage 120 . The control circuit 110 includes a comparator 111 , a control signal generating circuit 112 , and an upper bridge driving circuit 113 and a lower bridge driving circuit 114 . The comparator 111 compares the feedback signal Vfb with the reference signal Vref, and generates a comparison signal Comp according to the...

AI Technical Summary

Problems solved by technology

The technical means disclosed in the two prior inventions have a complicated control structure, and complex calculations are required to achieve the self-adaptive adjustment effect, which cannot be realized with a simple circuit. Time (RBCOT) of the Switching Mode Power Supply High

[0011] Specifically speaking, the method of adjusting the external resistance needs to add an extra pin when designing the integrated circuit. From the perspective of cost, it is not worth recommending.

And the value of the external resistance needs to be obtained through a series of calculations according to the working conditions of the system, which is relatively complicated.

In addition, if the method of adjusting the resistance-capacitance time constant is adopted, it is necessary to adjust the resistance-capacitance (RC) time constant based on digital circuit calculations, and hardware implementation is not easy.

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