Power supply switching circuit

Abstract

The invention relates to the technical field of power supply switching, and discloses a power supply switching circuit which comprises a power supply port, a switching control circuit, an anti-reverse connection circuit, a field effect transistor, a power supply battery and a load port. The power supply port is used for being connected with an external power supply, and the power supply port is connected with the input end of the switching control circuit and the input end of the anti-reverse-connection circuit; the drain electrode of the field effect transistor is connected with the power supply battery, and the source electrode of the field effect transistor is connected with the load port; the input end of the anti-reverse-connection circuit is connected with the grid electrode of the field effect transistor, and the output end of the anti-reverse-connection circuit is connected with the source electrode of the field effect transistor and the load port. The output end of the switching control circuit is connected with the grid electrode of the field effect transistor, and the switching control circuit is used for detecting the port power supply parameter of the power supply port and controlling the on-off of the field effect transistor according to the port power supply parameter. The reverse voltage is prevented from damaging the field effect transistor and the power supply battery, and the stability and reliability of the circuit are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power switching, and in particular to a power supply switching circuit. Background Art

[0002] In the prior art, most electronic devices usually have built-in lithium batteries. When an electronic device is connected to an external power source through a power supply port, it is necessary to realize that the external power source supplies power through the power supply port while charging the lithium battery. During the power switching process, the power supply may be reversely connected, generating a reverse voltage, causing damage to the semiconductor devices and lithium batteries in the circuit. Summary of the invention

[0003] The main purpose of the embodiments of the present application is to provide a power supply switching circuit to prevent reverse voltage from damaging the field effect transistor and the power supply battery, thereby improving the stability and reliability of the circuit.

[0004] To achieve the above-mentioned purpose, some embodiments of the present application provide a power supply switching circuit, including: a power supply port, a switching control circuit, an anti-reverse connection circuit, a field effect transistor, a power supply battery and a load port;

[0005] The power supply port is used to connect an external power supply, and the power supply port is respectively connected to the input end of the switching control circuit and the input end of the anti-reverse connection circuit;

[0006] The drain of the field effect tube is connected to the power supply battery, and the source of the field effect tube is connected to the load port;

[0007] The input end of the anti-reverse connection circuit is connected to the gate of the field effect tube, and the output end of the anti-reverse connection circuit is connected to the source of the field effect tube and the load port respectively;

[0008] The output end of the switching control circuit is connected to the gate of the field effect tube. The switching control circuit is used to detect the port power supply parameters of the power supply port and control the on and off of the field effect tube according to the port power supply parameters.

[0009] Further, the anti-reverse connection circuit comprises: an anti-reverse connection diode and a pull-down resistor;

[0010] The anode of the anti-reverse diode is connected to the power supply port and the gate of the field effect tube respectively, and the cathode of the anti-reverse diode is connected to the load port and the source of the field effect tube respectively;

[0011] One end of the pull-down resistor is connected to the gate of the field effect transistor, and the other end of the pull-down resistor is grounded.

[0012] Further, the switching control circuit includes: a port detection circuit and a regulation circuit;

[0013] The input end of the port detection circuit is connected to the power supply port, the output end of the port detection circuit is connected to the input end of the control circuit, and the output end of the control circuit is connected to the gate of the field effect transistor;

[0014] The port detection circuit is used to detect the port power supply parameters, and the regulation circuit is used to control the on and off of the field effect tube according to the port power supply parameters.

[0015] Further, the port detection circuit is a port voltage detection circuit;

[0016] The input end of the port voltage detection circuit is connected to the power supply port, the output end of the port voltage detection circuit is connected to the input end of the control circuit, and the port voltage detection circuit is used to detect the power supply voltage of the power supply port to detect the port power supply parameters.

[0017] Further, the port detection circuit is a port current detection circuit;

[0018] The input end of the port current detection circuit is connected to the power supply port, the output end of the port current detection circuit is connected to the input end of the control circuit, and the port current detection circuit is used to detect the power supply current of the power supply port to detect the port power supply parameters.

[0019] Furthermore, a power supply switching circuit further includes: a battery detection circuit;

[0020] The input end of the battery detection circuit is connected to the power supply battery, and the output end of the battery detection circuit is connected to the input end of the control circuit. The battery detection circuit is used to detect the battery power supply parameters of the power supply battery and output the battery power supply parameters to the control circuit.

[0021] Further, the battery detection circuit is a battery voltage detection circuit;

[0022] The input end of the battery voltage detection circuit is connected to the power supply battery, the output end of the battery voltage detection circuit is connected to the input end of the control circuit, and the battery voltage detection circuit is used to detect the power supply voltage of the power supply battery to detect the battery power supply parameters.

[0023] Furthermore, the field effect transistor is a P-type field effect transistor.

[0024] Furthermore, the power supply port is a USB power supply interface.

[0025] Furthermore, the anti-reverse diode is a 1N4148WS diode.

[0026] The beneficial effects of the present invention are as follows: the port power supply parameters of the power supply port are detected by a switching control circuit to detect the connection status of the power supply port, the on-off of the field effect tube is controlled by the port power supply parameters, and the field effect tube outputs a control signal according to the switching control circuit, thereby realizing the power supply switching between the power supply port and the power supply battery, and by the anti-reverse connection circuit connected in series at both ends of the field effect tube, when the power supply is reversely connected, the field effect tube is prevented from being damaged by the reverse voltage during the power supply switching process, and the reverse voltage damage to the power supply battery can be prevented, thereby improving the stability and reliability of the circuit system and ensuring the safe use of the electronic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a partial circuit diagram of a power supply switching circuit provided by an embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of a framework of a power supply switching circuit provided by an embodiment of the present invention;

[0029] Figure 3 It is a schematic diagram of a framework of a power supply switching circuit provided by another embodiment of the present invention.

[0030] Figure numerals: 100, load port, 200, power supply battery, Q1, field effect transistor, 300, anti-reverse connection circuit, D1, anti-reverse diode, R1, pull-down resistor, 400, switching control circuit, 410, port detection circuit, 420, regulation circuit, 500, power supply port. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and cannot be understood as limiting the present invention.

[0032] It should be noted that although the functional module division is performed in the schematic diagram, in some cases, the module division can be different from that in the system.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0035] As described in the background technology, in the prior art, most electronic devices usually have built-in lithium batteries. When the electronic device is connected to an external power source through a power supply port, it is necessary to realize that the external power source supplies power through the power supply port while charging the lithium battery. During the power switching process, the power supply may be reversely connected, generating a reverse voltage, causing damage to the semiconductor devices and lithium batteries in the circuit.

[0036] In view of this, the present application proposes a power supply switching circuit, which uses reverse voltage to damage the field effect transistor and the power supply battery, thereby improving the stability and reliability of the circuit.

[0037] Reference Figure 1 and Figure 2 In some embodiments of the present invention, a power supply switching circuit includes: a load port 100, a power supply battery 200, a field effect transistor Q1, an anti-reverse connection circuit 300, a switching control circuit 400 and a power supply port 500.

[0038] The power supply battery 200 is electrically connected to the drain of the field effect transistor Q1. The power supply battery 200 serves as a built-in power supply of the electronic device and can provide power to the electronic device when the external power supply is disconnected.

[0039] The source of the field effect transistor Q1 is electrically connected to the load port 100, and the drain of the field effect transistor Q1 is electrically connected to the power supply battery 200 to realize power supply by the power supply battery 200. The gate of the field effect transistor Q1 is electrically connected to the input end of the anti-reverse connection circuit 300, and the gate of the field effect transistor Q1 is also electrically connected to the output end of the switching control circuit 400 to realize power supply switching between the power supply port 500 and the power supply port 500.

[0040] In one embodiment, the field effect transistor Q1 is a P-type field effect transistor Q1.

[0041] The input end of the anti-reverse connection circuit 300 is electrically connected to the gate of the field effect transistor Q1, and the output end of the anti-reverse connection circuit 300 is electrically connected to the source of the field effect transistor Q1. The anti-reverse connection circuit 300 is connected in series at both ends of the field effect transistor Q1 to prevent the field effect transistor Q1 from being damaged by reverse voltage during the power switching process.

[0042] The power supply port 500 is electrically connected to an external power source, and the power supply port 500 can provide power to the electronic device.

[0043] In one embodiment, the power supply port 500 is a USB power supply interface.

[0044] The input end of the anti-reverse connection circuit 300 is electrically connected to the power supply port 500 , and the output end of the anti-reverse connection circuit 300 is electrically connected to the load port 100 , so that an external power source can provide power to the electronic device through the power supply port 500 .

[0045] The input end of the switching control circuit 400 is electrically connected to the power supply port 500. The output end of the switching control circuit 400 is electrically connected to the gate of the field effect transistor Q1. The switching control circuit 400 can detect the port power supply parameters of the power supply port 500 to detect the connection state of the power supply port 500, thereby controlling the on and off of the field effect transistor Q1 according to the port power supply parameters.

[0046] Exemplarily, when the external power supply is connected to the power supply port 500, the switching control circuit 400 detects the power supply port 500 and obtains the port power supply parameters. When it is confirmed through the port power supply parameters that the power supply port 500 is in a connected state, the switching control circuit 400 outputs a cut-off signal to the field effect transistor Q1 to control the field effect transistor Q1 to be cut off, so that the power supply battery 200 does not supply power to the load port 100 through the field effect transistor Q1, and the external power supply supplies power to the load port 100 through the power supply port 500 and the anti-reverse connection circuit 300.

[0047] Exemplarily, when the external power supply is not connected to the power supply port 500, the switching control circuit 400 detects the power supply port 500 and obtains the port power supply parameters. When it is confirmed through the port power supply parameters that the power supply port 500 is in a disconnected state, the switching control circuit 400 outputs a conduction signal to the field effect transistor Q1 to control the field effect transistor Q1 to be turned on, and the power supply battery 200 supplies power to the load port 100 through the field effect transistor Q1, and the anti-reverse connection circuit 300 does not supply power to the load port 100.

[0048] In the scheme of the present application, the port power supply parameters of the power supply port 500 are detected by the switching control circuit 400 to detect the connection status of the power supply port 500. The on and off of the field effect transistor Q1 are controlled by the port power supply parameters. The field effect transistor Q1 outputs a control signal according to the switching control circuit 400, thereby realizing the power supply switching between the power supply port 500 and the power supply battery 200. In addition, by connecting the anti-reverse connection circuit 300 in series at both ends of the field effect transistor Q1, when the power supply is reversed, the field effect transistor Q1 is prevented from being damaged by the reverse voltage during the power switching process. In addition, the reverse voltage damage of the power supply battery 200 can be prevented, thereby improving the stability and reliability of the circuit system and ensuring the safe use of electronic equipment.

[0049] Reference Figure 1 and Figure 2 In some embodiments of the present invention, the reverse connection protection circuit 300 includes: a reverse connection protection diode D1 and a pull-down resistor R1.

[0050] The anode of the anti-reverse diode D1 is electrically connected to the power supply port 500 , and the cathode of the anti-reverse diode D1 is electrically connected to the load port 100 , so that when an external power source is connected to the power supply port 500 , power is supplied to the load port 100 .

[0051] The anode of the anti-reverse diode D1 is electrically connected to the gate of the field effect transistor Q1, and the cathode of the anti-reverse diode D1 is electrically connected to the source of the field effect transistor Q1. The anti-reverse diode D1 is connected in series at both ends of the field effect transistor Q1 to prevent the field effect transistor Q1 from being damaged by reverse voltage during the power switching process.

[0052] The anti-reverse diode D1 may be a single diode or a diode group. The present application does not limit the number of the anti-reverse diodes D1.

[0053] In one embodiment, the anti-reverse diode D1 is a 1N4148WS diode.

[0054] One end of the pull-down resistor R1 is electrically connected to the gate of the field effect transistor Q1, and the other end of the pull-down resistor R1 is connected to the ground. When the power supply battery 200 supplies power, the field effect transistor Q1 is turned on, and the pull-down resistor R1 steadily pulls down the gate potential to ensure that the field effect transistor Q1 is turned on normally and prevent hidden dangers caused by high gate impedance.

[0055] In the solution of the present application, the anti-reverse connection circuit 300 can not only prevent the field effect transistor Q1 from being damaged by reverse voltage during power switching, but also supply power to the load port 100 when an external power source is connected to the power supply port 500 to achieve power supply.

[0056] Reference Figures 1 to 3 In some embodiments of the present invention, the switching control circuit 400 includes: a port detection circuit 410 and a regulation circuit 420 .

[0057] The input end of the port detection circuit 410 is electrically connected to the power supply port 500 , the output end of the port detection circuit 410 is electrically connected to the input end of the control circuit 420 , and the output end of the control circuit 420 is electrically connected to the gate of the field effect transistor Q1 .

[0058] The port detection circuit 410 can detect the port power supply parameters and output them to the control circuit 420. The control circuit 420 can receive the port power supply parameters and control the on and off of the field effect transistor Q1 according to the port power supply parameters.

[0059] Exemplarily, when the external power supply is connected to the power supply port 500, the port detection circuit 410 detects the power supply port 500 and obtains the port power supply parameters. When the control circuit 420 confirms that the power supply port 500 is in a connected state through the port power supply parameters, the control circuit 420 outputs a cut-off signal to the field effect transistor Q1 to control the field effect transistor Q1 to be cut off. Then, the power supply battery 200 does not supply power to the load port 100 through the field effect transistor Q1, and the external power supply supplies power to the load port 100 through the power supply port 500 and the anti-reverse connection circuit 300.

[0060] Exemplarily, when the external power supply is not connected to the power supply port 500, the port detection circuit 410 detects the power supply port 500 and obtains the port power supply parameters. When the control circuit 420 confirms that the power supply port 500 is in a disconnected state through the port power supply parameters, the control circuit 420 outputs a conduction signal to the field effect transistor Q1 to control the conduction of the field effect transistor Q1. The power supply battery 200 supplies power to the load port 100 through the field effect transistor Q1, and the anti-reverse connection circuit 300 does not supply power to the load port 100.

[0061] In the scheme of the present application, the port power supply parameters of the power supply port 500 are detected by the switching control circuit 400 to detect the connection status of the power supply port 500. The on and off of the field effect transistor Q1 is controlled by the port power supply parameters, thereby realizing the power supply switching between the power supply battery 200 and the power supply port 500.

[0062] Reference Figures 1 to 3 In some embodiments of the present invention, the port detection circuit 410 may be a port voltage detection circuit.

[0063] The input end of the port voltage detection circuit is electrically connected to the power supply port 500, and the output end of the port voltage detection circuit is electrically connected to the input end of the control circuit 420. The port voltage detection circuit can detect the power supply voltage of the power supply port 500, and the power supply voltage of the power supply port 500 is the port power supply parameter.

[0064] Exemplarily, when an external power supply is connected to the power supply port 500, the port voltage detection circuit detects the power supply port 500 and obtains the power supply voltage of the power supply port 500 to obtain the port power supply parameters. When the control circuit 420 confirms that the power supply port 500 is in a connected state through the power supply voltage of the power supply port 500, the control circuit 420 outputs a cut-off signal to the field effect transistor Q1 to control the field effect transistor Q1 to be cut off, so that the power supply battery 200 does not supply power to the load port 100 through the field effect transistor Q1, and the external power supply supplies power to the load port 100 through the power supply port 500 and the anti-reverse connection circuit 300.

[0065] Exemplarily, when the external power supply is not connected to the power supply port 500, the port voltage detection circuit detects the power supply port 500 and obtains the power supply voltage of the power supply port 500 to obtain the port power supply parameters. When the power supply voltage of the power supply port 500 is zero, the control circuit 420 confirms that the power supply port 500 is in a disconnected state, and the control circuit 420 outputs a conduction signal to the field effect transistor Q1 to control the conduction of the field effect transistor Q1. The power supply battery 200 supplies power to the load port 100 through the field effect transistor Q1, and the anti-reverse connection circuit 300 does not supply power to the load port 100.

[0066] The port detection circuit 410 may also be a port current detection circuit.

[0067] The input end of the port current detection circuit is electrically connected to the power supply port 500, and the output end of the port current detection circuit is electrically connected to the input end of the control circuit 420. The port current detection circuit can detect the power supply current of the power supply port 500, and the power supply current of the power supply port 500 is the port power supply parameter.

[0068] Exemplarily, when an external power supply is connected to the power supply port 500, the port current detection circuit detects the power supply port 500 and obtains the power supply current of the power supply port 500 to obtain the port power supply parameters. When the control circuit 420 confirms that the power supply port 500 is in a connected state through the power supply current of the power supply port 500, the control circuit 420 outputs a cut-off signal to the field effect transistor Q1 to control the field effect transistor Q1 to be cut off, so that the power supply battery 200 does not supply power to the load port 100 through the field effect transistor Q1, and the external power supply supplies power to the load port 100 through the power supply port 500 and the anti-reverse connection circuit 300.

[0069] Exemplarily, when the external power supply is not connected to the power supply port 500, the port current detection circuit detects the power supply port 500 and obtains the power supply current of the power supply port 500 to obtain the port power supply parameters. When the power supply current of the power supply port 500 is zero, the control circuit 420 confirms that the power supply port 500 is in a disconnected state, and the control circuit 420 outputs a conduction signal to the field effect transistor Q1 to control the conduction of the field effect transistor Q1. The power supply battery 200 supplies power to the load port 100 through the field effect transistor Q1, and the anti-reverse connection circuit 300 does not supply power to the load port 100.

[0070] In the scheme of the present application, the power supply port 500 can be detected by a port current detection circuit or a port voltage detection circuit to detect the port power supply parameters, thereby detecting the connection status of the power supply port 500. The on and off of the field effect transistor Q1 is controlled by the port power supply parameters, thereby realizing the power switching between the power supply battery 200 and the power supply port 500.

[0071] Reference Figures 1 to 3 In some embodiments of the present invention, the power supply switching circuit further includes: a battery detection circuit.

[0072] The input end of the battery detection circuit is electrically connected to the power supply battery 200, and the output end of the battery detection circuit is electrically connected to the input end of the control circuit 420. The battery detection circuit can detect the battery power supply parameters of the power supply battery 200 and output the battery power supply parameters to the control circuit 420, thereby realizing the monitoring of the power supply battery 200.

[0073] In one embodiment, the battery detection circuit may be a battery voltage detection circuit.

[0074] The input end of the battery voltage detection circuit is electrically connected to the power supply battery 200, and the output end of the battery voltage detection circuit is electrically connected to the input end of the control circuit 420. The battery voltage detection circuit can detect the power supply voltage of the power supply battery 200 and output the battery power supply parameters to the control circuit 420, thereby realizing the monitoring of the power supply battery 200.

[0075] The preferred embodiments of the present invention are described in detail above, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A power supply switching circuit, characterized in that: include: Power supply port, switching control circuit, anti-reverse connection circuit, field effect transistor, power supply battery and load port; The power supply port is used to connect an external power supply, and the power supply port is respectively connected to the input end of the switching control circuit and the input end of the anti-reverse connection circuit; The drain of the field effect tube is connected to the power supply battery, and the source of the field effect tube is connected to the load port; The input end of the anti-reverse connection circuit is connected to the gate of the field effect tube, and the output end of the anti-reverse connection circuit is connected to the source of the field effect tube and the load port respectively; The output end of the switching control circuit is connected to the gate of the field effect tube. The switching control circuit is used to detect the port power supply parameters of the power supply port and control the on and off of the field effect tube according to the port power supply parameters.

2. A power supply switching circuit according to claim 1, characterized in that: The anti-reverse connection circuit comprises: an anti-reverse connection diode and a pull-down resistor; The anode of the anti-reverse diode is connected to the power supply port and the gate of the field effect tube respectively, and the cathode of the anti-reverse diode is connected to the load port and the source of the field effect tube respectively; One end of the pull-down resistor is connected to the gate of the field effect transistor, and the other end of the pull-down resistor is grounded.

3. The power supply switching circuit according to claim 1, characterized in that: The switching control circuit includes: a port detection circuit and a regulation circuit; The input end of the port detection circuit is connected to the power supply port, the output end of the port detection circuit is connected to the input end of the control circuit, and the output end of the control circuit is connected to the gate of the field effect transistor; The port detection circuit is used to detect the port power supply parameters, and the regulation circuit is used to control the on and off of the field effect tube according to the port power supply parameters.

4. A power supply switching circuit according to claim 3, characterized in that: The port detection circuit is a port voltage detection circuit; The input end of the port voltage detection circuit is connected to the power supply port, the output end of the port voltage detection circuit is connected to the input end of the control circuit, and the port voltage detection circuit is used to detect the power supply voltage of the power supply port to detect the port power supply parameters.

5. The power supply switching circuit according to claim 3, characterized in that: The port detection circuit is a port current detection circuit; The input end of the port current detection circuit is connected to the power supply port, the output end of the port current detection circuit is connected to the input end of the control circuit, and the port current detection circuit is used to detect the power supply current of the power supply port to detect the port power supply parameters.

6. The power supply switching circuit according to claim 3, characterized in that: Also includes: Battery detection circuit; The input end of the battery detection circuit is connected to the power supply battery, and the output end of the battery detection circuit is connected to the input end of the control circuit. The battery detection circuit is used to detect the battery power supply parameters of the power supply battery and output the battery power supply parameters to the control circuit.

7. The power supply switching circuit according to claim 6, characterized in that: The battery detection circuit is a battery voltage detection circuit; The input end of the battery voltage detection circuit is connected to the power supply battery, the output end of the battery voltage detection circuit is connected to the input end of the control circuit, and the battery voltage detection circuit is used to detect the power supply voltage of the power supply battery to detect the battery power supply parameters.

8. The power supply switching circuit according to claim 1, characterized in that: The field effect tube is a P-type field effect tube.

9. The power supply switching circuit according to claim 1, characterized in that: The power supply port is a USB power supply interface.

10. The power supply switching circuit according to claim 2, characterized in that: The anti-reverse diode is a 1N4148WS diode.

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