Power supply circuit

Abstract

The invention discloses a power supply circuit. The power supply circuit comprises a DC-DC module, an LDO module, a first voltage division circuit, a voltage-controlled constant current source and anamplification circuit. An output end of the DC-DC module is connected with an input end of the LDO module, the input end of the first voltage division circuit is connected with the output end of the DC-DC module, the output end of the first voltage division circuit is connected with a feedback input end of the DC-DC module, and the first voltage division circuit divides a voltage of the input endand outputs the divided voltage from the output end; a first set voltage is input into the input end of the amplification circuit, and the output end of the amplification circuit is connected with anoutput voltage control end of the LDO module; and a first end of the voltage-controlled constant current source inputs a second set voltage, a second end of the voltage-controlled constant current source is connected with the output end of the first voltage division circuit, and the voltage-controlled constant current source controls the current of the second end according to the voltage of the first end. By adjusting input signals of the voltage-controlled constant current source and the amplification circuit, input and output of the LDO module are controlled to have a stable voltage difference, and voltage signals with low power consumption and a low ripple noise are output.

Description

technical field [0001] The embodiment of the present invention relates to a display module testing technology, in particular to a power supply circuit. Background technique [0002] At present, the power supply for the display module (such as the liquid crystal module) is required to have output characteristics such as low ripple noise, and the output voltage can be adjusted from 0V to meet the detection requirements of the liquid crystal module. [0003] In the existing power supply design, the DC / DC BUCK power supply scheme is usually adopted, but because of its own high-frequency switching characteristics, the output ripple noise of the DC / DC BUCK power supply is relatively large, and it is difficult to meet the requirements of low ripple noise . If the LDO power supply is used, although the output ripple noise can be controlled ideally, the input voltage of the LDO power supply must have a certain voltage difference from its output voltage to ensure that it has a normal...

AI Technical Summary

Problems solved by technology

[0003] In the existing power supply design, the DC / DC BUCK power supply solution is usually adopted, but because of its own high-frequency switching characteristics, the output ripple noise of the DC / DC BUCK power supply is relatively large, and it is difficult to meet the requirements of low ripple noise.

If the LDO power supply is used, although the output ripple noise can be controlled ideally, the input voltage of the LDO power supply must have a certain voltage difference from its output voltage to ensure that it has a normal voltage output. If the voltage difference increases, Then the power consumption of the LDO power supply will increase, resulting in an increase in heat generation. When the heat generation exceeds the maximum junction temperature of the LDO power supply, it will cause damage to the LDO power supply.

[0004] It can be seen that whether the DC / DC BUCK power supply scheme is adopted or the LDO power supply is sampled, there are defects, which cannot meet the output requirements of the liquid crystal module for the power supply during the detection process.

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