CN203326555U

CN203326555U - Power supply overvoltage protection circuit of electronic product port

Info

Publication number: CN203326555U
Application number: CN2013204379287U
Authority: CN
Inventors: 张其锋
Original assignee: Huizhou Desay SV Automotive Co Ltd
Current assignee: Huizhou Desay SV Automotive Co Ltd
Priority date: 2013-07-23
Filing date: 2013-07-23
Publication date: 2013-12-04
Anticipated expiration: 2023-07-23

Abstract

The utility model discloses a power supply overvoltage protection circuit of an electronic product port. The protection circuit is connected between a power supply module circuit and a port power supply pin VCC, and includes a voltage stabilizing diode ZD1, a resistor R1, a resistor R2, a resistor R3, an N-channel enhanced field effect transistor Q1, and an N-channel enhanced field effect transistor Q2. A drain electrode d1 of the field effect transistor Q1 is connected with the port power supply pin VCC and a source electrode s1 of the field effect transistor Q1 is connected with the power supply module circuit; a grid g1 is connected to a drain electrode d2 of the field effect transistor Q2; the resistor R1 is connected between the source electrode s1 of the field effect transistor Q1 and the grid g1; a cathode of the voltage stabilizing diode ZD1 is connected with the port power supply pin VCC, and an anode of the voltage stabilizing diode ZD1 is sequentially in series connection with the resistor R2 and one end of the resistor R3; the other end of the resistor R3 is grounded; a node between the resistor R2 and the resistor R3 is connected to a grid g2 of the field effect transistor Q2; and a source electrode s2 of the field effect transistor Q2 is grounded. The power supply overvoltage protection circuit of the electronic product port, through the reverse breakdown of the voltage stabilizing diode, controls the on-off of the field effect transistor and cuts off the external power flow, so that the circuit components in the module are ensured to be secure and not to be damaged; and the application of the circuit structure is simple and practical.

Description

A kind of electronic product port power overvoltage crowbar

Technical field

The utility model relates to a kind of electronic product port power overvoltage crowbar.

Background technology

The output ports such as the external USB port of a lot of electronic products, DC power output are arranged at present on the market; these port power great majority are all the anti-external high pressure safeguard measures of not design; the consumer in use, often can, with wrong, apply this port by other power supply and cause electronic product to damage.

For example when port because unknown cause or misoperation have applied one than the high abnormal voltage of the inner output of electronic product from outside, now this abnormally high-voltage can directly enter into power module circuitry and other modular circuit of electronic product inside, from outside abnormal voltage value, be indefinite, likely can exceed the normal working voltage of module, there is certain injury ability, can cause in this case the electronic product internal component to be damaged and can't to work.

The utility model content

For addressing the above problem, the utility model provides a kind of electronic product port power overvoltage crowbar.

Technical solution adopted in the utility model is:

A kind of electronic product port power overvoltage crowbar, described protective circuit is connected between power module circuitry and port power pin VCC, comprises voltage stabilizing didoe ZD1, resistance R 1, R2, R3 and N channel enhancement field effect transistor Q1, Q2; The drain electrode d1 of described field effect transistor Q1 and source electrode s1 be connectivity port supply pin VCC and power module circuitry respectively, and grid g1 connects the drain electrode d2 of field effect transistor Q2, between the source electrode s1 of field effect transistor Q1 and grid g1, is connected to resistance R 1; Described voltage stabilizing didoe ZD1 negative pole connectivity port supply pin VCC, positive pole is series resistance R2, R3 successively, resistance R 3 other end ground connection, resistance R 2 is connected the grid g2 of field effect transistor Q2, the source electrode s2 ground connection of field effect transistor Q2 with the node between R3.

The utility model is by the voltage stabilizing didoe reverse breakdown, and the power remove of control field effect transistor conducting cut-off, outer flow being come in, guaranteed that the safety of circuit elements device in module is not damaged, and the circuit structure application is simple and practical.

The accompanying drawing explanation

Fig. 1 is the embodiment circuit theory diagrams of overvoltage crowbar described in the utility model.

Embodiment

Understand technology contents of the present utility model for convenience of those skilled in the art, below in conjunction with drawings and Examples, the utility model is described in further detail.

As shown in Figure 1, the overvoltage crowbar that the utility model discloses, comprise voltage stabilizing didoe ZD1, resistance R 1, R2, R3 and N channel enhancement metal-oxide-semiconductor field effect transistor Q1, Q2; The drain electrode d1 of described field effect transistor Q1 and source electrode s1 are connected respectively P4 pin and the power module circuitry of supply socket J1, described P4 pin level is VCC, grid g1 connects the drain electrode d2 of field effect transistor Q2, between the source electrode s1 of effect pipe Q1 and grid g1, by resistance R 1, is connected; Described voltage stabilizing didoe ZD1 negative pole connectivity port supply pin VCC, positive pole is series resistance R2, R3 successively, resistance R 3 other end ground connection, resistance R 2 is connected the grid g2 of field effect transistor Q2, the source electrode s2 ground connection of field effect transistor Q2 with the node between R3.

When J1 socket P4 port because unknown cause or misoperation have applied one than the high abnormal voltage of the inner output of electronic product from outside, now abnormally high-voltage is added in voltage-stabiliser tube ZD1 negative pole, the abnormally high-voltage applied when voltage-stabiliser tube ZD1 outside is during higher than voltage stabilizing didoe voltage stabilizing value, this reverse breakdown of voltage stabilizing didoe, under the dividing potential drop effect of R2, R3, the grid g2 to field effect transistor Q2 provides bias voltage, field effect transistor Q2 conducting simultaneously; Under the effect of the grid g1 voltage being on the scene effect pipe Q2 conducting of field effect transistor Q1, it will be low level; now field effect transistor Q1 is in cut-off state; the abnormally high-voltage that comes from the P4 of J1 port can't flow into electronic product internal electric source module or other modular circuit; the safety that has guaranteed the modular circuit components and parts is not damaged, and has realized the purpose of protection.

After outside applies abnormally high-voltage and removes, J1 socket port P4 voltage is replied normal operating conditions, voltage-stabiliser tube ZD1 negative terminal voltage does not reach its reverse breakdown voltage, in not on-state, corresponding field effect transistor Q2 is in cut-off state, now resistance R 1 provides normal bias voltage to the grid g1 of field effect transistor Q1, and field effect transistor Q1 is in opening state, for the electronic product outside port provides original normal supply power voltage.

Above-described embodiment is only wherein specific implementation of the present utility model, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the utility model the scope of the claims.It should be pointed out that for the person of ordinary skill of the art, without departing from the concept of the premise utility, can also make some distortion and improvement, these apparent replacement forms all belong to protection range of the present utility model.

Claims

1. an electronic product port power overvoltage crowbar, described protective circuit is connected between power module circuitry and port power pin VCC, it is characterized in that: comprise voltage stabilizing didoe ZD1, resistance R 1, R2, R3 and N channel enhancement field effect transistor Q1, Q2; The drain electrode d1 of described field effect transistor Q1 and source electrode s1 be connectivity port supply pin VCC and power module circuitry respectively, and grid g1 connects the drain electrode d2 of field effect transistor Q2, between the source electrode s1 of field effect transistor Q1 and grid g1, is connected to resistance R 1; Described voltage stabilizing didoe ZD1 negative pole connectivity port supply pin VCC, positive pole is series resistance R2, R3 successively, resistance R 3 other end ground connection, resistance R 2 is connected the grid g2 of field effect transistor Q2, the source electrode s2 ground connection of field effect transistor Q2 with the node between R3.