CN204967232U

CN204967232U - Computer USB mouth power supply protection circuit

Info

Publication number: CN204967232U
Application number: CN201520636007.2U
Authority: CN
Inventors: 徐来
Original assignee: Tianjin Wangying Technology Co Ltd
Current assignee: Tianjin Wangying Technology Co Ltd
Priority date: 2015-08-20
Filing date: 2015-08-20
Publication date: 2016-01-13
Anticipated expiration: 2025-08-20

Abstract

The utility model discloses a computer USB mouth power supply protection circuit, including resistance R1, diode D1, electric capacity C1, take damped field effect transistor Q1, comparator U1 and resistance R2, take damped field effect transistor Q1's S extremely to connect output vo, the D utmost point of taking damped field effect transistor Q1 connect respectively diode D1 anodal with the D utmost point of taking damped field effect transistor Q2. The utility model discloses full play diode D1's forward switches on and the reverse effect that ends to fast recovery diode utilizes among the damped field effect transistor to taking, utilize a comparator U1 alright in order constituting a window comparator, if the voltage of VBUS end drops on (example outside the window like 12V power supply voltage or earth level), comparator U1 output low level so closes the MOS pipe on the outage source channel, so both made the unable logging in of power VCC voltage inside, prevented also that the power supply of system output end vo from taking place to overflow because of the shorted to earth, played the effect that protection system did not receive the short circuit invasion.

Description

A kind of computer USB port power supply protection circuit

Technical field

The utility model relates to a kind of protective circuit, specifically a kind of computer USB port power supply protection circuit.

Background technology

Generally; the external interface of computer all will have various fault secure circuit; wherein most important no more than to the power supply input of USB or protective circuit when being short-circuited over the ground, because USB interface directly can export 5 volts of power supplys, so short-circuit protection seems particularly important.

Utility model content

The purpose of this utility model is to provide a kind of computer USB port power supply protection circuit, to solve the problem proposed in above-mentioned background technology.

For achieving the above object, the utility model provides following technical scheme:

A kind of computer USB port power supply protection circuit, comprise resistance R1, diode D1, electric capacity C1, with the field effect transistor Q1 of damping, comparator U1 and resistance R2, the S pole of the field effect transistor Q1 of described band damping connects output end vo, the D pole of the field effect transistor Q1 with damping connects the D pole of the field effect transistor Q2 of diode D1 positive pole and band damping respectively, the S pole of the field effect transistor Q2 with damping connects VBUS end and the diode D2 negative pole of USB respectively, diode D2 positive pole connects the in-phase input end of comparator U1 respectively, ground capacity C2 and resistance R4, the resistance R4 other end connects power supply VCC1, the inverting input of comparator U1 connects earth resistance R3 and resistance R2 respectively, the resistance R2 other end connects ground capacity C1 and diode D1 negative pole respectively, the power end of comparator U1 connects power supply VCC and resistance R1 respectively, the resistance R1 other end connects the output of comparator U1 respectively, the D pole of the D pole of the field effect transistor Q3 with damping and the field effect transistor Q1 of band damping, the S pole ground connection of the field effect transistor Q3 with damping, the G pole connection universal I/O interface of the field effect transistor Q3 with damping.

As further program of the utility model: described power supply VCC voltage is 12V.

As the utility model further scheme: described power supply VCC1 voltage is 3.3V.

Compared with prior art, the beneficial effects of the utility model are: the utility model gives full play to the forward conduction of diode D1 and the effect of oppositely cut-off, and fast recovery diode in the field effect transistor of band damping is used, utilize a comparator U1 just can form a window comparator, if the voltage of VBUS end drops on (such as 12V supply power voltage or ground level) outside window, so comparator U1 output low level, metal-oxide-semiconductor on power cutoff passage, power supply VCC voltage is so both made to enter internal system, also prevent system output Vo to power, because of shorted to earth, overcurrent occurs, serve protection system not by the effect that short circuit is invaded and harassed.

Accompanying drawing explanation

Fig. 1 is the circuit diagram of computer USB port power supply protection circuit.

Embodiment

Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.

Refer to Fig. 1, in the utility model embodiment, a kind of computer USB port power supply protection circuit, comprise resistance R1, diode D1, electric capacity C1, with the field effect transistor Q1 of damping, comparator U1 and resistance R2, the S pole of the field effect transistor Q1 with damping connects output end vo, the D pole of the field effect transistor Q1 with damping connects the D pole of the field effect transistor Q2 of diode D1 positive pole and band damping respectively, the S pole of the field effect transistor Q2 with damping connects VBUS end and the diode D2 negative pole of USB respectively, diode D2 positive pole connects the in-phase input end of comparator U1 respectively, ground capacity C2 and resistance R4, the resistance R4 other end connects power supply VCC1, the inverting input of comparator U1 connects earth resistance R3 and resistance R2 respectively, the resistance R2 other end connects ground capacity C1 and diode D1 negative pole respectively, the power end of comparator U1 connects power supply VCC and resistance R1 respectively, the resistance R1 other end connects the output of comparator U1 respectively, the D pole of the D pole of the field effect transistor Q3 with damping and the field effect transistor Q1 of band damping, the S pole ground connection of the field effect transistor Q3 with damping, the G pole connection universal I/O interface of the field effect transistor Q3 with damping.

Power supply VCC voltage is 12V.

Power supply VCC1 voltage is 3.3V.

Operation principle of the present utility model is: refer to Fig. 1, Q1 and Q2 is two MOSFET on USB power source passage, for the output of control output end Vo, their G end is all connected on the output of comparator U1, the in-phase input end terminal potential value of comparator U1 is by VCC1 and VBUS joint effect, negative terminal potential value is decided by resistance R2 dividing potential drop, and the magnitude of voltage at diode D1 positive pole place is always identical with the large person in VBUS with output end vo.

The utility model gives full play to the forward conduction of diode D1 and the effect of oppositely cut-off, and fast recovery diode in the field effect transistor of band damping is used, utilize a comparator U1 just can form a window comparator, if the voltage of VBUS end drops on (such as 12V supply power voltage or ground level) outside window, so comparator U1 output low level, metal-oxide-semiconductor on power cutoff passage, power supply VCC voltage is so both made to enter internal system, also prevent system output Vo to power, because of shorted to earth, overcurrent occurs, serve protection system not by the effect that short circuit is invaded and harassed.

To those skilled in the art, obvious the utility model is not limited to the details of above-mentioned one exemplary embodiment, and when not deviating from spirit of the present utility model or essential characteristic, can realize the utility model in other specific forms.Therefore, no matter from which point, all should embodiment be regarded as exemplary, and be nonrestrictive, scope of the present utility model is limited by claims instead of above-mentioned explanation, and all changes be therefore intended in the implication of the equivalency by dropping on claim and scope are included in the utility model.Any Reference numeral in claim should be considered as the claim involved by limiting.

In addition, be to be understood that, although this specification is described according to execution mode, but not each execution mode only comprises an independently technical scheme, this narrating mode of specification is only for clarity sake, those skilled in the art should by specification integrally, and the technical scheme in each embodiment also through appropriately combined, can form other execution modes that it will be appreciated by those skilled in the art that.

Claims

1. a computer USB port power supply protection circuit, comprise resistance R1, diode D1, electric capacity C1, with the field effect transistor Q1 of damping, comparator U1 and resistance R2, it is characterized in that, the S pole of the field effect transistor Q1 of described band damping connects output end vo, the D pole of the field effect transistor Q1 with damping connects the D pole of the field effect transistor Q2 of diode D1 positive pole and band damping respectively, the S pole of the field effect transistor Q2 with damping connects VBUS end and the diode D2 negative pole of USB respectively, diode D2 positive pole connects the in-phase input end of comparator U1 respectively, ground capacity C2 and resistance R4, the resistance R4 other end connects power supply VCC1, the inverting input of comparator U1 connects earth resistance R3 and resistance R2 respectively, the resistance R2 other end connects ground capacity C1 and diode D1 negative pole respectively, the power end of comparator U1 connects power supply VCC and resistance R1 respectively, the resistance R1 other end connects the output of comparator U1 respectively, the D pole of the D pole of the field effect transistor Q3 with damping and the field effect transistor Q1 of band damping, the S pole ground connection of the field effect transistor Q3 with damping, the G pole connection universal I/O interface of the field effect transistor Q3 with damping.

2. computer USB port power supply protection circuit according to claim 1, is characterized in that, described power supply VCC voltage is 12V.

3. computer USB port power supply protection circuit according to claim 1, is characterized in that, described power supply VCC1 voltage is 3.3V.