CN208078644U

CN208078644U - A kind of Inrush current restraining soft-start circuit

Info

Publication number: CN208078644U
Application number: CN201820703629.6U
Authority: CN
Inventors: 魏晨光
Original assignee: Shenzhen Jie Neng Technology Co Ltd
Current assignee: Shenzhen Jie Neng Technology Co Ltd
Priority date: 2018-05-12
Filing date: 2018-05-12
Publication date: 2018-11-09
Anticipated expiration: 2028-05-12

Abstract

The utility model is related to a kind of Inrush current restraining soft-start circuits, power input VIN is respectively through capacitance CL and resistance RL ground connection, power input VIN connects the base stage of transistor Q1 through resistance R2 simultaneously, resistance R2 is respectively through capacitance C1, diode ZD1 and resistance R3 ground connection, the collector connecting resistance R4 of transistor Q1, the collector of transistor Q1 is grounded through resistance R1 simultaneously, resistance R4 distinguishes connecting resistance R5 and diode ZD2, diode ZD2 ground connection, resistance R5 connects the base stage of transistor Q2, resistance R5 is grounded through resistance R6 simultaneously, the emitter of transistor Q2 is grounded, the emitter of transistor Q1 is grounded, a kind of Inrush current restraining soft-start circuit control of the utility model design is accurate, it is low in energy consumption, securely and reliably.

Description

A kind of Inrush current restraining soft-start circuit

Technical field

The utility model is related to circuit arrangement field more particularly to a kind of Inrush current restraining soft-start circuits.

Background technology

Since current power supply application field is very extensive, LED drive power, TV power supplys, adapter, automobile charger, hand Machine fast charge etc..And its property difference of the power supply of different field is very big, common adaptor power supplies, TV power supplys use constant voltage Output, it is of less demanding to the capacitive reactances of load, therefore prodigious surge current can be born without being protected in using and testing Shield, but for part LED drive power, automobile charger, its load is non-capacitive to the products such as mobile phone fast charge in actual use, Booting moment does not have surge current, therefore current protection sensitivity is relatively high in Power Management Design.When output load impedance is to hold Property when, can be in booting moment, there is prodigious surge current to load input capacitance charging in electric power output voltage, this is directly resulted in Power supply product is protected.Therefore it to having to inhibit surge current when the power supply test of the type, otherwise can not be surveyed Examination.Surge current can effectively be inhibited and can guarantee that test is smoothed out by needing to design a circuit.

Utility model content

The purpose of this utility model is to provide a kind of Inrush current restraining soft-start circuits, are asked with solving above-mentioned technology Topic, the utility model is using following technical scheme to achieve the above object：

A kind of Inrush current restraining soft-start circuit, power input VIN is respectively through capacitance CL and resistance RL ground connection, simultaneously Power input VIN connects the base stage of transistor Q1 through resistance R2, and resistance R2 connects through capacitance C1, diode ZD1 and resistance R3 respectively Ground, the collector connecting resistance R4 of transistor Q1, while the collector of transistor Q1 are grounded through resistance R1, and resistance R4 distinguishes connecting resistance R5 and diode ZD2, diode ZD2 ground connection, resistance R5 connects the base stage of transistor Q2, while resistance R5 is grounded through resistance R6, brilliant The emitter of body pipe Q2 is grounded, the emitter ground connection of transistor Q1.

A kind of Inrush current restraining soft-start circuit of the utility model design uses NMOS tube Q1 and Q2, NMOS tube Q1 At low cost, low in energy consumption with Q2, control conducting is accurate, whole lifting means circuit performance, ensures user's control operational stability, greatly The big working efficiency for improving user.

Description of the drawings

Fig. 1 is the structural schematic diagram of the utility model.

Specific implementation mode

The utility model is further elaborated in the following with reference to the drawings and specific embodiments.

When a kind of Inrush current restraining soft-start circuit operation of the utility model design, voltage is input to CL through VIN, RL, booting moment CL can be considered short-circuit condition, and voltage is given after RL by power supply after start-up resistor R1 current limlitings through VIN through CL at this time CL charges, and VOGND voltages are very high at this time, and the voltage is through R4, and triode Q2 is in the conduction state after R5, R6 detection.Due to three poles Pipe Q2 conducting, VIN voltage is directly by triode Q2 to ground after R2, therefore NMOS tube Q1 G pole tensions are low level, NMOS Pipe Q1 cut-offs.When power supply continues as CL chargings through VIN, CL, R1, CL both end voltages start to be gradually increasing, under VOGND voltages start Drop, works as R4, R5, R6, and when the detection circuit constituted detects that VOGND voltages drop to certain value, triode Q2 is from conducting state Becoming cut-off state, VIN charges through R2 and C1 at this time, and VG voltages start to increase, when VG voltages rise to Q1 conducting voltages, NMOS tube Q1 conducting, by R1 short circuits, CL at this time, RL can normal carry load work, surge restraint circuit startup terminates, only NMOS tube Q1 ON operations, and Q1 internal resistances are very small, in CL, the lower loss of RL effects can be ignored, therefore the circuit can effectively inhibit Current surge problem.

Circuit ZD1 is that NMOS tube protects circuit, and at the end of start-up course, triode Q2 cut-offs, power supply is through VIN, R2 It charges with C1, since metal-oxide-semiconductor G pole impedances are high, C1 both end voltages continue to increase, when the voltage rises to ZD1 clamp voltages, C1 both end voltages are stablized, and no longer increasing leads to the extremely breakdown damages of NMOS tube G.

R4, R5, R6 constitute VOGND voltage detecting adjustment circuits, and VOGND voltages control triode through R4, R5, R6 after dividing The voltage of VOGND when cut-off adjusts the ratio of R4, R5 and R6, VOGND voltages when can adjust triode cut-off, in this way can be with Adjust the R1 current-limiting charge times.ZD2 is protection diode, and it is excessive and damage triode can to limit triode Q2 B electrode currents Q2。

The above is the utility model preferred embodiment, for the ordinary skill in the art, according to this reality With novel introduction, in the case where not departing from the principles of the present invention with spirit, the change that is carried out to embodiment is repaiied Change, replace and modification is still fallen within the scope of protection of the utility model.

Claims

1. a kind of Inrush current restraining soft-start circuit, which is characterized in that power input VIN is respectively through capacitance CL and resistance RL Ground connection, while power input VIN connects the base stage of transistor Q1 through resistance R2, resistance R2 respectively through capacitance C1, diode ZD1 and Resistance R3 ground connection, the collector connecting resistance R4 of transistor Q1, while the collector of transistor Q1 is grounded through resistance R1, R4 points of resistance Other connecting resistance R5 and diode ZD2, diode ZD2 ground connection, resistance R5 connects the base stage of transistor Q2, while resistance R5 is through resistance R6 Ground connection, the emitter ground connection of transistor Q2, the emitter ground connection of transistor Q1.