Pulse width modulating switch power source and power supply control method thereof

Abstract

The invention provides a pulse width modulating PWM switch power source which solves the problem that the efficiency of a PWM power source in the prior art is locally optimized. The switch power source comprises a pulse width modulating PWM controller and MOSFET group, wherein the MOSFET group also comprises at least one controlled MOSFET, and the at least one controlled MOSFET is connected with a first MOSFET or a second MOSFET in parallel; and the pulse width modulating PWM switch power source also comprises a state control module which controls the working condition of the at least one controlled MOSFET according to the control parameter to convert the first working condition of the MOSFET group to the second working condition, thus lowering the total power loss of the MOSFET group. The invention improves the switch power source efficiency and realizes overall optimal efficiency.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a pulse width modulation switching power supply and a power supply control method thereof. Background technique [0002] With the development of the chip manufacturing process, more and more switching power supplies are implemented using PWM (Pulse Wide Modulation, pulse width modulation). [0003] A switching power supply implemented using PWM such as figure 1 shown, including: [0004] a PWM controller that generates a first PWM signal and a second PWM signal that is inverted from the first PWM signal; [0005] A first MOSFET (Metallic Oxide Semiconductor Field Effect Transistor, Metal Oxide Semiconductor Field Effect Transistor) and a second MOSFET, the gates of the first MOSFET and the second MOSFET respectively receive the first PWM signal and the second PWM signal, And the first terminal of the first MOSFET is connected to the power input terminal, the s...

AI Technical Summary

Problems solved by technology

[0014] In the case of high load of PWM switching power supply, the PWM switching power supply of MOSEFT parallel connection will lead to the increase of parasitic capacitance and increase the switching energy loss, but because the conduction energy loss dominates, the PWM switching power supply of MOSEFT parallel connection can effectively Reduce the conduction energy loss, so it can improve the power supply efficiency. However, compared with the low load, the switching energy loss dominates the energy loss of the PWM switching power supply. At this time, the PWM switching power supply of the MOSFET parallel mode reduces the conduction energy loss. , but the switching energy loss is increased, and because the switching energy loss is in a dominant position, the PWM switching power supply of the MOSFET parallel connection mode has low power supply efficiency under low load conditions

[0015] However, the PWM switching power supply using a single MOSFET has low power efficiency under high load conditions.

[0016] However, in general, once the switching power supply is designed, the circuit structure is fixed, but the power load is constantly changing, so the power efficiency of the existing PWM switching power supply is only a local optimization, and no global optimization has been achieved.

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