CN101369742A - Apparatus for preventing overcurrent of high-capacity capacitor - Google Patents

Abstract

The invention provides a apparatus for preventing electrification over current of large-capacity capacitance, wherein the apparatus is provided with a electrification current limiting circuit composed of two diodes D1, D2, a resistances R1, a capacitance C1, a switching circuit and a discharging circuit on a large-capacity capacitance of a system equipment power supply, therefore it is able to avoid moment charging current augmentation of the large-capacity capacitance when using the large-capacity capacitance, the impact to the system equipment power supply, and it is able to prolong the service lifetime of the power supply and the large-capacity capacitance as well as improve system reliability.

Description

A kind of device that prevents overcurrent of high-capacity capacitor

Technical field

This patent relates to a kind of Computer Applied Technology, specifically a kind of device that prevents overcurrent of high-capacity capacitor.

Technical background

Because the complexity of system is more and more higher; in the power down process; system needs continuous firing long more at preservation significant data or processing important service; thereby need power supply continual and steady; compare with battery; large bulk capacitance has advantages such as cost is low, reliability; be used widely; but because large bulk capacitance momentary charge electric current is very big; can impact to power supply; cause power supply overcurrent protection or damage, thereby also there are some an open questions in the big extensive use of electric capacity on computer power supply.

Summary of the invention

The purpose of this invention is to provide a kind of problem that can prevent overcurrent of high-capacity capacitor, have that current-limiting charging circuit is succinct, reliability is high, cost is low, can not cause the excessive power loss simultaneously.

The device that can prevent overcurrent of high-capacity capacitor of the present invention, comprise charging current limiter circuit, commutation circuit, discharge circuit, circuit structure is made up of diode D1, D2, resistance R 1, capacitor C 1, the negative pole of diode D1, D2 also meets power output end 5V, the positive pole of diode D1 meets power input 5V_IN, resistance R 1 also meets diode D2, the positive pole of diode D2 serial connection capacitor C 1 ground connection, and it is as follows to discharge and recharge step:

1) the charging current limiter circuit is made up of resistance R 1: power supply charges to large bulk capacitance by current-limiting resistance in the power up, with charge-current limit within the power supply tolerance range, along with charging process is carried out, charging current reduces gradually, large bulk capacitance C1 both end voltage progressively is raised to 5V, until being full of;

2) commutation circuit is made up of D1, D2: after power up neutralizing capacitance C1 was full of, because 5V_IN voltage is higher than large bulk capacitance C1 voltage, the saturated D2 of D1 disconnected, and system equipment is powered by 5V_IN;

3) discharge circuit is made up of capacitor C 1 and Schottky diode D2: after input power supply 5V_IN power down; input power supply 5V_IN voltage is lower than capacitor C 1 voltage; large bulk capacitance C1 powers to system equipment by Schottky diode D2; utilize the little characteristics of Schottky diode D2 pressure drop and impedance; most energy among the large bulk capacitance C1 are discharged in the system equipment, effectively prolong the system equipment power down protection time.

The invention has the beneficial effects as follows; simple in structure; reasonable in design; the momentary charge electric current of large bulk capacitance increases in the time of can avoiding using large bulk capacitance fully; the system equipment power supply is impacted; cause power supply overcurrent protection or damage, can prolong the useful life of power supply and large bulk capacitance, improve the reliability of system.

Description of drawings:

Fig. 1 is the circuit working schematic diagram that prevents the method for overcurrent of high-capacity capacitor.

Embodiment:

Below in conjunction with accompanying drawing the method for overcurrent of high-capacity capacitor that prevents of the present invention is further described.

As shown in drawings, circuit structure of the present invention is made up of diode D1, D2, resistance R 1, capacitor C 1, and the negative pole of diode D1, D2 also connects the 5V output, and the positive pole of diode D1 connects the input of 5V, resistance R 1 also meets diode D2, positive pole serial connection capacitor C 1 ground connection of diode D2.In power up, to large bulk capacitance C1 charging, its charging current can limit 5V/ (R1+R to power supply 5V by current-limiting resistance R1 _{Electric capacity}) within the scope, charging current reduces gradually, large bulk capacitance C1 both end voltage progressively is raised to 5V, until being full of.As do not have current-limiting resistance R1, because the internal resistance R of large bulk capacitance _{Electric capacity}Very little, momentary charge electric current 5V/R _{Electric capacity}Can be very big, bring great impact to power supply, often cause power supply overcurrent protection or damage.

After power up neutralizing capacitance C1 was full of, because 5V_IN is higher than large bulk capacitance C1 voltage, system was powered by 5V_IN, D1 is saturated, and D2 disconnects, in power supply 5V_IN power down process, the 5V_IN supply voltage begins to be lower than capacitor C 1 voltage, and system is powered by large bulk capacitance C1.

In 5V_IN power down process, large bulk capacitance C1 powers to system by Schottky diode D2, and Schottky diode D2 pressure drop and impedance are very little, thereby large bulk capacitance C1 can be discharged into most energy in the system, thereby prolongs system's power down protection time.

5V_IN connects the anode of D1, and the negative electrode 5V of D1 connects the anode of D2 simultaneously, and the negative electrode of D2 connects the positive pole of C1, and R1 resistance connects the positive pole of 5V and C1, the minus earth of C1.

Claims (1)

1. device that prevents overcurrent of high-capacity capacitor, comprise charging current limiter circuit, commutation circuit, discharge circuit, it is characterized in that circuit structure is made up of diode D1, D2, resistance R 1, capacitor C 1, the negative pole of diode D1, D2 also meets power output end 5V, the positive pole of diode D1 meets power input 5V_IN, resistance R 1 also meets diode D2, the positive pole of diode D2 serial connection capacitor C 1 ground connection, and it is as follows to discharge and recharge step:

1) the charging current limiter circuit is made up of resistance R 1: power supply charges to large bulk capacitance by current-limiting resistance in the power up, with charge-current limit within the power supply tolerance range, along with charging process is carried out, charging current reduces gradually, large bulk capacitance C1 both end voltage progressively is raised to 5V, until being full of;

2) commutation circuit is made up of D1, D2: after power up neutralizing capacitance C1 was full of, because 5V_IN voltage is higher than large bulk capacitance C1 voltage, the saturated D2 of D1 disconnected, and system equipment is powered by 5V_IN;

3) discharge circuit is made up of capacitor C 1 and Schottky diode D2: after input power supply 5V_IN power down; input power supply 5V_IN voltage is lower than capacitor C 1 voltage; large bulk capacitance C1 powers to system equipment by Schottky diode D2; utilize the little characteristics of Schottky diode D2 pressure drop and impedance; most energy among the large bulk capacitance C1 are discharged in the system equipment, effectively prolong the system equipment power down protection time.