LED screen test power supply control circuit and method for accurately quantifying power-on timing

Abstract

The invention discloses an LED screen test power supply control circuit and method based on a precise quantized power-on sequence. The control circuit includes an MCU of which the output end is connected with a DC / DC power supply module and a DAC (Digital-to-Analog Converter). The output end of the DAC is connected with the negative input end of an operational amplifier AMP1. The positive input end of the operational amplifier AMP1 is connected with a voltage divider circuit. The output end of the operational amplifier AMP1 is connected with one input end of an MOS tube. The output end of the DC / DC power supply module is connected with the other input end of the MOS tube. A third end of the MOS tube is an output end which outputs a voltage Vout. The DAC inputs a voltage control waveform to the operational amplifier AMP1 under the control of the MCU, and the voltage control waveform includes the voltage value and the power-on time Tset required by an LED screen power supply. The operational amplifier AMP1 linearly amplifies the received voltage control waveform, and outputs the amplified voltage control waveform to the MOS tube. The DC / DC power supply module outputs a voltage Vdc to the MOS tube under the control of the MCU.

Description

technical field [0001] The invention relates to the technical field of LED driving, in particular to an LED screen test power supply control circuit and method for accurately quantifying the power-on sequence. Background technique [0002] During the LED screen test process, multiple power supplies are often required. Different power supply uses and output values ​​are different. During use, different power supplies are often required to precisely control the timing when they are powered on. However, in the existing power supply equipment, whether it is a switching power supply or a linear voltage regulator, the power-on time and waveform depend on fixed hardware parameters. A common solution is to design a switch circuit on the output port of the power supply, use PWM to control the switch conduction, and combine the output capacitor filter to control the power-on time. The disadvantages of this control method are: [0003] (1) The power-on time control depends on the c...

AI Technical Summary

Problems solved by technology

[0003] (1) The power-on time control depends on the capacitance parameters, the capacitance error is large, and the power-on time is not accurate enough;

[0004] (2) For the same set of control parameters, the actual control accuracy varies with the output voltage and load current, which directly leads to different power-on time under the same control parameters and different loads.

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