Direct-current power supply slow startup control circuit

Abstract

The invention relates to a slow startup control circuit of DC electrical source, comprising a switching transistor VT1 which is connected with a negative RTN input voltage terminal in series, a bleeder circuit which is arranged between a positive VIN input voltage terminal and the negative RTN input voltage terminal, and a capacitor C1 arranged between the negative RTN input voltage terminal and the bleeder node of the bleeder circuit; wherein the control terminal of the switching transistor VT1 is connected with the bleeder node. The circuit employs a MOSFET which serves as the switching transistor to migrate from a pinch-off region to a constant-current region and at last to an ohm area, which is equivalent to that series impedances from big to small are applied to restrain impulse current so as to reach slow startup; meanwhile, a quick charge circuit is added to the control terminal to quicken the shutoff of the MOSFET after charge release; therefore the slow startup control circuit is suitable for occasions with quick and frequent swaps.

Description

technical field [0001] The invention relates to electronic circuits, in particular to a DC power supply slow start control circuit. Background technique [0002] (1) The cause of the problem [0003] The high reliability of the communication system requires the power board and the user board to support hot swapping. During the hot swapping process, the impact of long-term large starting current often causes electronic equipment failure. Tests have shown that the fault basically lies in the following aspects: [0004] 1), under the impact of a large current at the input end, the connector is ignited and oxidized and discolored; [0005] 2), there will be ringing interference on the power supply 48V, 24V bus. [0006] 3), some power supply equipment with undervoltage protection will malfunction due to this, resulting in problems such as output voltage reduction and circuit reset. [0007] 4), the long-term high current impact makes the fast fuse blown, and the capacity of ...

AI Technical Summary

Problems solved by technology

[0005] 2), there will be ringing interference on the power supply 48V, 24V bus

[0006] 3), some power supply equipment with undervoltage protection will malfunction due to this, resulting in problems such as output voltage reduction and circuit reset

[0007] 4), the long-term high current impact makes the fast fuse blown, and the capacity of the fuse is often increased

And according to formula 1, the larger the capacity of the input capacitor C2, the longer it takes for the voltage of Vc1 to rise, and the longer the charging current lasts

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