Power-up Overshoot Suppression Circuit Applied to Linear Stabilized Voltage Source

Abstract

The invention relates to a power-on overshoot suppression circuit applied to a linear regulator. The power-on overshoot suppression circuit comprises a power-on delay control module, an inverse ratio pull-down module and a positive feedback module, wherein the power-on delay control module comprises a switching tube, a second field-effect tube, a first resistor, a second resistor and an external regulation capacitor, the source electrode of the switching tube is connected with a power supply system, the drain electrode of the switching tube is connected with the source electrode of the second field-effect tube, the grid electrode of the second field-effect tube is grounded after passing through the second resistor and the external regulation capacitor which are connected in series, the first resistor is connected between the source electrode and the grid electrode of the second field-effect tube in parallel, the inverse ratio pull-down module is connected between the drain electrode of the second field-effect tube and the ground, the positive feedback module is connected between the drain electrode of the second field-effect tube and the grid electrode of the switching tube, and the drain electrode of the switching tube is connected with the input end of the linear regulator. The power-on overshoot suppression circuit has the advantages of enabling the linear regulator to work after a power supply becomes stable and effectively suppressing power-on overshoot, being convenient for being interfaced with a linear regulator circuit and being convenient to apply.

Description

technical field [0001] The invention relates to a circuit for eliminating overshoot when a linear voltage stabilizer is powered on. Background technique [0002] See attached figure 1 And attached figure 2 As shown, the dotted line is the equivalent circuit diagram of a typical power supply system. for figure 1 , the switch K1 is closed, and the power supply system supplies power to the linear regulated source. Since the capacitor Cs is usually large, the voltage at point S will not change abruptly, and the linear regulated source has a good power-on output. when using figure 2 When supplying power to the outside world, the typical application diagram of its linear voltage regulator is as follows: image 3 As shown, the external power supply current at point S and the voltage at the IN terminal will change suddenly, and the gate (base) voltage of the drive tube of some linear voltage regulators will change abnormally, resulting in power-on overshoot of the linear volt...

AI Technical Summary

Problems solved by technology

[0003] The current method of suppressing overshoot is to increase the load capacitance or input capacitance of the linear voltage regulator, but its suppression ability is limited

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