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 high-precision peak current control method comprises the steps of S1, detecting a current I<cs> which flows through an inductive coil in the current cycle of the switching power supply, and recording a current peak value I<csmax>; S2, making a comparison between the current peak value I<csmax> in the current cycle with a preset value I, and adjusting an inductive threshold value current value I<set> of a next cycle according to a first comparison result; and S3, outputting a control signal according to a second comparison result between the current I<cs> of the current cycle and the inductive threshold value current value I<set> of the current cycle. The invention also discloses a high-precision peak current circuit, control circuit and adjusting circuit of the switching power supply. High-precision control of the peak current of the switching power supply is realized, and power supply precision is improved.

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...

AI Technical Summary

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, and compensate the Vset voltage value by sampling different Vin voltage values. This solution increases the chip pin and increases the cost, and when the Vin voltage value belongs to At high voltage, high voltage devices are required for sampling, which further increases the circuit cost

The existing technology cannot make adaptive adjustments according to the changes of Lp, Vin, and Td, and the delay time Td is determined by the switching device itself and the switching control circuit, and Vin will fluctuate within a certain range at different times, so ΔI cannot be accurately adjusted. control, it is impossible to accurately control Ipeak

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