A switching power supply output voltage linear start control circuit

Abstract

The invention relates to a starting control circuit for the output linear voltage of a switching power supply. The circuit comprises an error amplifier unit, an output sampling unit, a reference voltage unit, a current control unit, a discharging circuit unit and a first capacitor C1. One end of the first capacitor C1 is connected with the input end of the error amplifier unit, and the other end of the first capacitor C1 is grounded. The input end of the output sampling unit is connected with the output voltage of a power supply, and the output end of the output sampling unit is connected with the input end of the error amplifier unit. The output end of the reference voltage unit is connected with the input end of the error amplifier unit. The output end of the current control unit is connected with the input end of the error amplifier unit. The input end of the discharging circuit unit is connected with the output end of the reference voltage unit. According to the technical scheme of the invention, during the starting process of the switching power supply, the waveform of the output voltage of the switching power supply can be controlled to have the linear rising characteristic. Therefore, the circuit security and the circuit adaptivity are improved. Meanwhile, the safety of a load system can be ensured.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a linear start-up control circuit for the output voltage of a switching power supply. Background technique [0002] Switching power supply and DC / DC converter as the secondary power supply of the system are widely used in military and civilian electronic systems such as aerospace, aviation, ships, weapons, electronics, railways, communications, medical electronics, and industrial automation equipment. When the switching power supply is turned on, that is, when the input power is powered on, the output voltage waveform of the switching power supply has a great influence on the load system. Different rise times and slopes of the output voltage will cause different impacts on the load, for example, a large inrush current will be generated when a large capacitive load is used. If the output voltage has a large start-up overshoot, it will cause overvoltage damage to ...

AI Technical Summary

Problems solved by technology

Different rise time and slope of the output voltage will cause different impacts on the load, such as a large inrush current when a large capacitive load is used

If the output voltage has a large start-up overshoot, it will cause load overvoltage damage in severe cases

In some applications, the power supply will be turned on and off frequently. In this state, if the voltage on the first capacitor is not fully discharged within the shutdown time, the output voltage will not rise linearly when the power is turned on again, and may cause Load failure or damage due to overshoot

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