Feedback circuit and method for compensating line loss voltage

Abstract

The invention discloses a feedback circuit for compensating line loss voltage. The feedback circuit is used for compensating the line loss voltage caused by line loss resistance in a power output circuit. The circuit comprises a current detection module, a voltage outer loop feedback module and an output current inner loop feedback module; the current detection module is used for detecting outputcurrent Io of the feedback circuit in real time through a sampling resistor Rc; the voltage outer loop feedback module is used for introducing the line loss voltage Us calculated according to preset line loss resistance Rs and the output current Io, combining the line loss voltage Us, reference voltage VREF and a voltage feedback value Uop on a load and outputting an outer loop feedback voltage deviation Uob; the output current inner loop feedback module is used for combining the received outer loop feedback voltage deviation Uob with output voltage UIo corresponding to the output current andoutputting an inner loop feedback circuit voltage EAP signal to a power chip. The line loss voltage is compensated by increasing an expected value of the output voltage, the voltage which is output bya switch power supply and connected to a load terminal is more accurate, and meanwhile the maximum value of the output current can be limited for short circuit protection.

Description

technical field [0001] The invention relates to the field of switching power supplies, in particular to a feedback circuit and a feedback method for compensating line loss voltage. Background technique [0002] Switching power supply is an important power conversion device, which is indispensable in all walks of life. [0003] When the switching power supply is in use, it is necessary to connect the output positive and negative poles of the switching power supply to the electrical load equipment through external wires and connectors. Since the external wires have internal resistance and the connectors have contact resistance, when the current flows through them The loss voltage is the line loss voltage. The line loss voltage causes the voltage at both ends of the electrical load equipment to be lower than the output voltage of the switching power supply. The voltage at the terminal will be much lower than the output voltage of the switching power supply, so that the actual ...

AI Technical Summary

Problems solved by technology

[0003] When the switching power supply is in use, it is necessary to connect the output positive and negative poles of the switching power supply to the electrical load equipment through external wires and connectors. Since the external wires have internal resistance and the connectors have contact resistance, when the current flows through them The loss voltage is the line loss voltage. The line loss voltage causes the voltage at both ends of the electrical load equipment to be lower than the output voltage of the switching power supply. The voltage at the terminal will be much lower than the output voltage of the switching power supply, so that the actual power supply voltage supplied to the electrical load equipment is insufficient, and it is easy to cause the electrical load equipment to not work normally.

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