Under-voltage protection circuit and electronic equipment

Abstract

According to the under-voltage protection circuit and the electronic equipment provided by the utility model, the power supply circuit is connected with the output end of the power supply and the load, the voltage detection circuit is used for detecting the magnitude of the output voltage, and when the detected voltage is smaller than a preset value, the output voltage is detected to be smaller than the preset value. And closing the channel of the voltage detection circuit to limit the power supply circuit to output the input voltage, thereby preventing the load from running in an undervoltage state to cause faults.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of power electronics, especially to a circuit and electronic equipment of under voltage protection. BACKGROUND

[0002] With the popularization and use scene complication of electronic equipment, the output voltage of power adapter often fluctuates, and when the input voltage is low, it will enter a dangerous working area, and if it runs in the under voltage condition for a long time, it may cause equipment failure.

[0003] Therefore, the present application is proposed. UTILITY MODEL CONTENT

[0004] The utility model discloses a kind of circuits and electronic equipment of under voltage protection, to limit electronic equipment in the case of under voltage operation.

[0005] The utility model first embodiment provides a kind of circuits of under voltage protection, comprising: power supply circuit and voltage detection circuit;

[0006] Wherein, the input end of the power supply circuit is used to connect input voltage, the output end of the power supply circuit is used to connect the power supply end of electronic equipment, the control end of the voltage detection circuit is electrically connected with the input voltage, the passage of the voltage detection circuit is used to connect the control end of the power supply circuit and ground;

[0007] The power supply circuit is configured to close the passage when the input voltage is lower than preset value, to limit the power supply circuit to the input voltage output.

[0008] Preferably, the power supply circuit includes: MOSFET, first capacitor, first resistance, second resistance;

[0009] The S pole of the MOSFET is used to connect the input voltage, the D pole of the MOSFET is used to connect the power supply end of the electronic equipment, the first capacitor is connected between the S pole and G pole of the MOSFET, and the G pole of the MOSFET is electrically connected with the passage through the second resistance.

[0010] Preferably, the voltage detection circuit includes: MOS tube, third resistance, fourth resistance, fifth resistance, second capacitor;

[0011] The D pole of the MOS tube is electrically connected with the G pole of the MOSFET through the second resistor, the S pole of the MOS tube is grounded, the first end of the third resistor is used for connecting the input voltage, the second end of the third resistor is electrically connected with the first end of the fourth resistor, the second end of the fourth resistor is electrically connected with the G pole of the MOS tube, the second end of the fourth resistor is grounded through the fifth resistor, and the second end of the fourth resistor is grounded through the second capacitor.

[0012] Preferably, the first resistor and the second resistor are configured to divide the voltage at the G pole of the MOSFET when the MOS tube is open.

[0013] Preferably, the first resistor, the second resistor, the third resistor and the fourth resistor are configured to divide the input voltage and provide the divided voltage to the G pole of the MOS tube.

[0014] Preferably, the resistance of the fourth resistor is adjustable.

[0015] The second embodiment of the utility model provides an electronic device, including power supply, load and one kind of under voltage protection circuit as any one described above, wherein, the output end of the power supply and the input end of the power supply circuit, the control end of the voltage detection circuit are electrically connected, the output end of the power supply circuit and the power supply end of the load are electrically connected.

[0016] Based on the circuit and the electronic device for under voltage protection provided by the utility model, the output end of the power supply and the load are connected through the power supply circuit, the voltage detection circuit is used for detecting the voltage size of the output, when detecting that the voltage is less than the preset value, the channel of the voltage detection circuit is closed to limit the power supply circuit to output the input voltage, so that the load is prevented from running in the state of under voltage and causing the occurrence of failure. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a kind of under voltage protection circuit schematic diagram provided by the utility model. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only to represent selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0019] The specific embodiments of the present application will be described in detail below in combination with the drawings.

[0020] The present application discloses a kind of under-voltage protection circuit and electronic equipment, to limit electronic equipment in the case of under-voltage operation.

[0021] Please refer to Figure 1 The first embodiment of the present application provides an under-voltage protection circuit, comprising: power supply circuit 1, and voltage detection circuit 2;

[0022] The input end of the power supply circuit 1 is used to connect the input voltage, the output end of the power supply circuit 1 is used to connect the power supply end of the electronic device, the control end of the voltage detection circuit 2 is electrically connected with the input voltage, and the channel of the voltage detection circuit 2 is used to connect the control end of the power supply circuit 1 and ground;

[0023] The power supply circuit 1 is configured to close the channel when the input voltage is lower than the preset value, to limit the power supply circuit to output the input voltage.

[0024] It should be noted that the input end of the power supply circuit 1 is used to receive the input voltage provided by the external power supply, and the output end is connected with the power supply end of the electronic device, to provide stable voltage output for the electronic device. At the same time, the voltage detection circuit 2 is electrically connected with the input voltage, responsible for real-time detection of the level of input voltage. When the input voltage is lower than the preset threshold, the voltage detection circuit 2 controls the working state of the power supply circuit 1 through its channel, to ensure that the power supply circuit 1 closes the output to the electronic device, and solves the problem of device damage caused by too low input voltage.

[0025] In one possible implementation of the present application, the power supply circuit 1 comprises: MOSFET Q1, first capacitor C1, first resistor R1, second resistor R2;

[0026] The S pole of the MOSFET Q1 is used for connecting the input voltage, the D pole of the MOSFET Q1 is used for connecting the power supply end of the electronic device, the first capacitor C1 is connected in parallel between the S pole and the G pole of the MOSFET Q1, and the G pole of the MOSFET Q1 is electrically connected with the channel through the second resistor R2.

[0027] It should be noted that when the input voltage is normal and higher than the preset under-voltage protection threshold, the channel of the voltage detection circuit 2 is in the on state, the first resistor R1 and the second resistor R2 divide the input voltage, the voltage at the G pole of the MOSFET Q1 is lower than the input voltage at the S pole of the MOSFET Q1 after voltage division, at this time, the MOSFET Q1 can be turned on, and the input voltage supplies power to the load through the MOSFET Q1.

[0028] However, when the input voltage is lower than the preset under-voltage protection threshold, the channel of the voltage detection circuit 2 is closed, the input voltage cannot be transmitted to the power supply end of the electronic device through the MOSFET Q1, and the circuit enters the protection state, thereby effectively preventing the electronic device from running in the under-voltage state and avoiding damage or abnormal function of the device caused by unstable power supply.

[0029] In a possible implementation manner of the present application, the voltage detection circuit 2 comprises a MOS tube Q2, a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a second capacitor C2.

[0030] The D pole of the MOS tube Q2 is electrically connected with the G pole of the MOSFET Q1 through the second resistor R2, the S pole of the MOS tube Q2 is grounded, the first end of the third resistor R3 is used for connecting the input voltage, the second end of the third resistor R3 is electrically connected with the first end of the fourth resistor R4, the second end of the fourth resistor R4 is electrically connected with the G pole of the MOS tube Q2, the second end of the fourth resistor R4 is grounded through the fifth resistor R5, and the second end of the fourth resistor R4 is grounded through the second capacitor C2.

[0031] It should be noted that the input voltage controls the MOS tube Q2, the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are configured to divide the input voltage and provide the voltage to the G pole of the MOS tube Q2. R3 / (R1+R2+R4), only when the voltage at the G electrode of the MOS tube Q2 is higher than the Vgs of the MOS tube Q2, the MOS tube Q2 is opened, only after the MOS tube Q2 is opened (i.e. the channel is opened), the second resistor R2 is grounded, further, the input voltage is divided by the first resistor R1 and the second resistor R2, the MOSFET Q1 is opened, and the Vout voltage is outputted.

[0032] Wherein, the minimum value of the Vgs of the MOS tube Q2 is 1V, the resistance voltage division is 0.3, when the Vin is lower than 1 / 0.3≈3.33V, the MOS tube Q2 will not be opened, the MOSFET Q1 is closed, and the Vout is 0. The under-voltage protection state is entered.

[0033] In a possible implementation manner of the utility model, the fourth resistor R4 is adjustable.

[0034] It should be noted that when a higher under-voltage protection threshold is required, the resistance value of the fourth resistor R4 can be increased to increase the voltage output after voltage division, so that when the input voltage decreases slightly, the G electrode voltage of the MOS tube Q2 cannot maintain its conduction state, thereby triggering the protection mechanism rapidly, closing the power supply circuit 1 and cutting off the current transmission to the electronic device. For some devices that allow lower input voltage to work, the resistance value of the fourth resistor R4 can be reduced to lower the trigger threshold of the under-voltage protection and expand the available range of the input voltage, thereby improving the utilization efficiency of the power supply under the premise of ensuring the safety of the device.

[0035] The utility model discloses a second embodiment provides a kind of electronic equipment, including power supply, load and as any one described in above a kind of under-voltage protection circuit, wherein, the output terminal of the power supply is electrically connected with the input terminal of the power supply circuit, the control terminal of the voltage detection circuit, the output terminal of the power supply circuit is electrically connected with the power supply end of the load.

[0036] Based on the circuit and electronic equipment for under-voltage protection provided by the utility model, the output terminal of the power supply and the load are connected by the power supply circuit, the voltage detection circuit is used to detect the voltage size of output, when detecting that the voltage is less than preset value, the channel of the voltage detection circuit is closed to limit the power supply circuit to output the input voltage, to avoid the load running in the state of under-voltage, leading to the emergence of fault.

[0037] The above is only the preferred embodiment of the utility model, the protection scope of the utility model is not only limited to the above-mentioned embodiment, and all technical solutions belonging to the idea of the utility model belong to the protection scope of the utility model.

Claims

1. A circuit for under-voltage protection, characterized in that include: Power supply circuit and voltage detection circuit; The power supply circuit has an input terminal for connecting to an input voltage, an output terminal for connecting to a power supply terminal of an electronic device, a control terminal for electrically connecting to the input voltage, and a channel for connecting the control terminal of the power supply circuit to ground. The power supply circuit is configured to shut down the channel when the input voltage is lower than a preset value, thereby limiting the power supply circuit from outputting the input voltage. The power supply circuit includes: a MOSFET, a first capacitor, a first resistor, and a second resistor; The source (S) terminal of the MOSFET is used to connect to the input voltage, the drain (D) terminal of the MOSFET is used to connect to the power supply terminal of the electronic device, the first capacitor is connected in parallel between the source (S) and gate (G) terminals of the MOSFET, and the gate (G) terminal of the MOSFET is electrically connected to the channel through the second resistor. The voltage detection circuit includes: a MOSFET, a third resistor, a fourth resistor, a fifth resistor, and a second capacitor; The drain (D) of the MOSFET is electrically connected to the gate (G) of the MOSFET through the second resistor. The source (S) of the MOSFET is grounded. The first end of the third resistor is used to connect to the input voltage. The second end of the third resistor is electrically connected to the first end of the fourth resistor. The second end of the fourth resistor is electrically connected to the gate (G) of the MOSFET. The second end of the fourth resistor is grounded through the fifth resistor. The second end of the fourth resistor is grounded through the second capacitor.

2. An under-voltage protection circuit according to claim 1, characterised in that, The first resistor and the second resistor are configured to divide the voltage at the gate of the MOSFET when the MOSFET is turned on.

3. An under-voltage protection circuit according to claim 1, wherein The first resistor, the second resistor, the third resistor, and the fourth resistor are configured to divide the input voltage and provide it to the gate (G) of the MOSFET.

4. The under-voltage protection circuit of claim 1, wherein The resistance value of the fourth resistor is adjustable.

5. An electronic device, comprising: The device includes a power supply, a load, and an undervoltage protection circuit as described in any one of claims 1 to 4, wherein the output terminal of the power supply is electrically connected to the input terminal of the power supply circuit and the control terminal of the voltage detection circuit, and the output terminal of the power supply circuit is electrically connected to the power supply terminal of the load.

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