High-precision peak current control method for switching power supply and circuits

Abstract

The invention discloses a high-precision peak current control method for a switching power supply. The method includes: S1, detecting the current Ics of the switching power supply flowing through the inductance coil in this cycle, and recording the current peak value Icsmax; S2, recording the current peak value Icsmax of the current cycle Compare with the preset value Ith, and adjust the value of the inductor threshold current Iset in the next cycle according to the first comparison result; S3, output the control signal according to the second comparison result between the current Ics of the current cycle and the inductor threshold current Iset of the current cycle. The invention also discloses a switching power supply high-precision peak current circuit, a control circuit and an adjustment circuit. The invention realizes the high-precision control of the peak current of the switching power supply and improves the precision of the power supply.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a switching power supply high-precision peak current control method, circuit, control circuit and adjustment circuit. Background technique [0002] At present, the application of switching power supply is becoming more and more extensive, no matter it is AC-DC / DC-DC power supply, the requirements for the precision of the main control chip of the power supply are also getting higher and higher. A switching power supply usually includes a switching device and a switching control circuit, with inductors, capacitors, switching tubes, sampling resistors, etc., according to different applications, select different components to build peripheral topologies according to different connection relationships, the basic control principle is the same or Similarly, the output or input is fed back to the switch control circuit, and the duty cycle of the switching device is adjus...

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Problems solved by technology

[0017] It can be seen from the formula that the actual inductor peak current changes with the changes of Lp, Vin, and Td. The existing technology generally adopts two methods to compensate the above changes: one is to superimpose a threshold voltage Vset with The slope voltage with a fixed slope that changes with Ton time has a large range of changes in Lp and Vin in practical applications. This compensation method with a fixed slope cannot be changed correspondingly under different Lp and Vin conditions, and it is difficult to achieve optimality. Compensation and precise control; one is to use a chip pin to connect a resistor to Vin, an

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