A method for compensating the output line voltage drop of switching power supply

Abstract

The invention discloses a method for compensating the output line voltage drop of a switching power supply. The main point of the technical solution is that the switching power supply feedback part circuit includes sampling resistor 04, reference source 03, photocoupler 02, output capacitor 05, power supply output line resistor 06, current limiting resistor 01; one end of current limiting resistor 01 and output capacitor 05 The other end is connected to the photocoupler 02, the photocoupler 02 is connected to the cathode of the reference source 03, the anode of the reference source 03 is set as the reference ground, the reference terminal of the reference source 03 is connected to the sampling resistor 04 connected in series R2, R3 The common terminal is connected; the sampling resistor 04 R2 and R3 connected in series, the R2 end of the circuit is connected to the output capacitor 05, and the R3 end is connected to the reference ground of the reference source 03; a compensation resistor is added between the reference ground of the reference source 03 and the sampling resistor 04 R3 Rd. The application of the present invention: the wire material is saved, and the load adjustment rate is improved. The occasions where this circuit can be applied include the feedback part of various switching power supplies, including but not limited to: flyback converter, forward converter, half-bridge converter, full-bridge converter, quasi-resonant converter, etc.

Description

technical field [0001] The invention relates to the fields of analog electronics, power electronics, digital electronics, automatic control, etc., and more specifically relates to a design method for compensating the output line voltage drop of a switching power supply. Background technique [0002] In the design of switching power supply, the load regulation rate is a very important design index, which is defined as the ratio of the change value of the output terminal voltage of the power supply to the rated output voltage under no-load and full-load conditions. If this value is measured at the output point on the PCB of the power supply, this parameter mainly depends on the gain of the error amplifier in the feedback loop. Generally, it is relatively small, and can reach below 0.1%. [0003] But for the voltage drop on the output line of the power supply, such as the output lead of the power adapter, it is difficult to deal with. Because the resistor on the output line o...

AI Technical Summary

Problems solved by technology

[0010] Method 2 reduces the resistance on the output line of the output power supply, which is effective in improving the load regulation rate, but the improvement effect is not clear, and the loss on the output line of the power supply is still not compensated

[0011] The adjustment rate of the third option will be significantly improved, but it needs an additional power output line, and it needs special treatment for the power output line, which is not convenient to use.

[0012] In addition, once the remote transmission line has an open circuit fault, the voltage feedback loop will be disconnected, the output voltage cannot be controlled, and the load equipment will be damaged

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