DC step-down voltage regulator and pulse frequency modulation control circuit and method thereof

Abstract

The invention relates to a DC step-down voltage regulator and a pulse frequency modulation control circuit and method thereof, and belongs to the field of electronic circuits. The power consumption can be reduced. The circuit comprises a triangular wave generator, a sampling unit, a PFM control unit and a synchronization unit, wherein the triangular wave generator generates a triangular wave when an enable signal of the triangular wave generator is enabled; the sampling unit is used for sampling peak current of an inductive component and output voltage of the DC step-down voltage regulator; the PFM control unit controls the inductive component to be in a charged state when a first condition is met, and controls the inductive component to be in a follow current state when the peak current is greater than a default peak current threshold; the first condition is that two of the following three conditions are met and the remaining one is changed into a satisfied state from an unsatisfied state: the peak current is smaller than the default peak current threshold, the output voltage is lower than default reference voltage and a triangular wave charge-discharge cycle is completed; and the synchronization unit is used for synchronizing the moment when the enable signal of the triangular wave generator begins to be enabled and the moment when the inductive component begins to be charged.

Description

technical field [0001] Embodiments of the present disclosure relate to the field of electronic circuits, and in particular, to a DC step-down voltage stabilizer and a pulse frequency modulation control circuit and method thereof. Background technique [0002] With the demand for high current output of the system on chip and various modules of the mobile phone, the DC step-down regulator needs to have high efficiency under both light load and heavy load conditions. [0003] In order to improve efficiency at a light load, a more commonly used light load control mode is a Pulse Skip Modulation (PSM) control mode. The control principle of PSM current mode control mode is as follows: figure 1 As shown, the schematic diagram is for the buck of the DC step-down regulator, the upper transistor is PMOS, and the lower transistor is NMOS. It works as follows: [0004] The working loop of Pulse Width Modulation (PWM) mode is: the output voltage Vout of the buck passes through the fee...

AI Technical Summary

Problems solved by technology

[0006] The disadvantage of the above scheme is that the PSM control mode is actually an intermittent working mode of the PWM mode

In PSM mode, each module required for PWM work is enabled, so the efficiency cannot be maximized

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