Bidirectional protection circuit and electronic device having the same
By designing a bidirectional protection circuit, the voltage status is managed by using the control unit and NMOS tube to prevent the Type C power from flowing back, ensuring that the laptop can charge normally when plugging in or unplugging the Type C power, solving the problem of insufficient power.
Patent Information
- Application Number
- CN202011305882.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-11-20
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2040-11-20
AI Technical Summary
When using a laptop, if you insert the DC power supply first and then plug in the Type C power supply, due to the different input voltages of the two, the Type C power supply will flow backwards into the DC power supply, causing the DC power supply to stop output, and the computer will shut down due to low power.
Design a bidirectional protection circuit, including the input terminal, the output terminal and the voltage control module, use the control unit and the NMOS tube to compare the voltages of the input terminal and the output terminal, control the working status of the MOS tube, and ensure that it is turned off when the Type C power is connected and connected. When conducting, prevent backflow, and filtering through voltage-regulating diodes and capacitors to ensure normal power supply.
It realizes that when the Type C power is plugged in or unplugged, the electronic device can be charged normally, avoiding the shutdown problem caused by insufficient power.
Smart Images
Figure CN114518796B_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a protection circuit, in particular to a bidirectional protection circuit and an electronic device having the bidirectional protection circuit. [Background technology]
[0002] Currently, most laptops are equipped with Type C power supplies. Therefore, when using a laptop, it can be charged directly through a DC power supply or through a Type C power supply. The DC power supply input voltage for the laptop is 19V, while the Type C power supply input voltage for the laptop is 20V.
[0003] When using a laptop, if the user plugs in a DC power supply first and then a Type C power supply, because the input voltages of the two power supplies are different, there will be a problem of the Type C power supply backflowing into the DC power supply, causing the DC power supply to stop outputting. When the Type C power supply is unplugged, the computer will shut down due to low battery because the DC power supply stops outputting.
[0004] In view of this, it is necessary to develop a bidirectional protection circuit and an electronic device having the bidirectional protection circuit to solve the above problems. [Summary of the invention]
[0005] Therefore, an object of the present invention is to provide a bidirectional protection circuit and an electronic device having the bidirectional protection circuit, which can enable the electronic device to charge normally when a Type C power source is inserted into or unplugged.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions:
[0007] A bidirectional protection circuit includes an input end, an output end, and a voltage control module connected between the input end and the output end. The input end is connected to a DC power supply, and the output end is connected to or disconnected from a Type C power supply. The voltage control module includes a control unit and a MOS tube. The control unit compares the voltages at the input end and the output end to control the working state of the MOS tube.
[0008] Furthermore, the MOS tube is an NMOS tube, a source of the NMOS tube is connected to an input end, a drain is connected to an output end, and a gate is connected to a control unit.
[0009] Furthermore, when the input terminal voltage is lower than the output terminal voltage, the control unit controls the MOS tube to shut off the source and drain paths, and the internal diode is reverse blocked.
[0010] Furthermore, when the input terminal voltage is greater than the output terminal voltage, the control unit controls the MOS tube to be turned on, and the current flows through a path from the input terminal to the source to the drain to the output terminal.
[0011] Furthermore, the bidirectional protection circuit also includes a voltage stabilizing diode, one end of the voltage stabilizing diode is connected to the input end, and the other end is grounded.
[0012] Furthermore, the bidirectional protection circuit also includes a first capacitor and a second capacitor, wherein one end of the first capacitor is connected to the input end and the other end is grounded, and one end of the second capacitor is connected to the output end and the other end is grounded.
[0013] Furthermore, the control unit is a LM74700 chip, the EN pin and the ANODE pin of the LM74700 chip are connected to the input end, the third capacitor is connected between the VCAP pin and the ANODE pin, the GND pin is grounded, the GATE pin is connected to the gate of the MOS tube, and the CATHODE pin is connected to the output end.
[0014] The present invention also provides an electronic device, wherein the electronic device has the bidirectional protection circuit, and the bidirectional protection circuit controls a DC power supply or a Type C power supply to supply power to the electronic device.
[0015] Compared with the prior art, the bidirectional protection circuit and the electronic device having the bidirectional protection circuit of the present invention control the working state of the MOS tube by comparing the voltages at the input end and the output end through the control unit. After the Type C power supply is connected, the MOS tube is turned off, and the Type C power supply powers the electronic device. After the Type C power supply is removed, the MOS tube is turned on, and the DC power supply powers the electronic device. Therefore, the electronic device can be charged normally when the Type C power supply is inserted or unplugged.
Brief Description of the Drawings
[0016] Figure 1 A block diagram of a bidirectional protection circuit of the present invention is shown.
[0017] Figure 2 A schematic diagram of a control unit in a preferred embodiment of a bidirectional protection circuit of the present invention is shown.
[0018] Figure 3 A circuit schematic diagram of a voltage control module in a preferred embodiment of a bidirectional protection circuit of the present invention is shown.
[0019] Figure 4 A circuit diagram of a preferred embodiment of a bidirectional protection circuit of the present invention is shown. [Specific implementation method]
[0020] In order to have a further understanding of the purpose, technical effects and technical means of the present invention, it is described in detail as follows in conjunction with the accompanying drawings.
[0021] See also Figure 1As shown, it depicts a block diagram of the bidirectional protection circuit of the present invention. The bidirectional protection circuit provided by the present invention is applied to an electronic device that can be charged by both a DC power supply and a Type C power supply. The bidirectional protection circuit includes an input terminal 100, an output terminal 200, and a voltage control module 300 connected between the input terminal 100 and the output terminal 200. The input terminal 100 is connected to a DC power supply, and the DC power supply is 19V. The output terminal 200 is connected to or disconnected from a Type C power supply, and the Type C power supply is 20V. The voltage control module 300 includes a control unit 301 and a MOS tube 302. The control unit 301 compares the voltages at the input terminal 100 and the output terminal 200 to control the working state of the MOS tube 302.
[0022] The MOS transistor 302 is a voltage control device, which changes the thickness of the conductive channel of the internal induced electric field and acoustic field by adjusting the gate voltage to achieve the purpose of controlling the current between the source and the drain. In a preferred embodiment, the MOS transistor 302 is an NMOS transistor, the source of the NMOS transistor is connected to the input end, the drain is connected to the output end, and the gate is connected to the control unit.
[0023] See also Figure 2 and Figure 3 As shown, Figure 2 A schematic diagram of a control unit in a preferred embodiment of a bidirectional protection circuit of the present invention is shown. Figure 3 The circuit schematic diagram of the voltage control module in a preferred embodiment of the bidirectional protection circuit of the present invention is shown. The control unit 301 can be a LM74700 chip. Specifically, the EN pin and the ANODE pin of the LM74700 chip are connected to the input terminal 100, the third capacitor 700 is connected between the VCAP pin and the ANODE pin, the GND pin is grounded, the GATE pin is connected to the gate of the MOS tube, and the CATHODE pin is connected to the output terminal 200. Of course, other chips can also be selected, such as LM74610.
[0024] See also Figure 4 As shown, it depicts a circuit schematic diagram of a preferred embodiment of a bidirectional protection circuit of the present invention. The bidirectional protection circuit also includes a voltage stabilizing diode 400, one end of which is connected to the input terminal 100 and the other end is grounded, and the voltage stabilizing diode 400 plays a role in voltage stabilization. The bidirectional protection circuit also includes a first capacitor 500 and a second capacitor 600, one end of the first capacitor 500 is connected to the input terminal 100 and the other end is grounded, one end of the second capacitor 600 is connected to the output terminal 200 and the other end is grounded, the first capacitor 500 and the second capacitor 600 play a filtering role, wherein the second capacitor 600 can be a polarized capacitor.
[0025] like Figure 4As shown in , the input end 100 is connected to a DC power supply of 19V, and the output end 200 is connected to a Type C power supply of 20V. The voltage of the input end 100 is less than the voltage of the output end 200. After the control unit 301 detects that the voltage of the input end 100 is less than the voltage of the output end 200, it controls the MOS tube 302 to turn off the source and drain paths, and the internal diode is reversely blocked, thereby achieving the purpose of turning off the current path of the MOS tube 302 and preventing the Type C power supply from backflowing into the DC power supply. At this time, the Type C power supply supplies power to the electronic device.
[0026] After the output terminal 200 Type C power supply 20V is removed, the voltage of the input terminal 100 is greater than the voltage of the output terminal 200. The control unit 301 detects that the voltage of the input terminal 100 is greater than the voltage of the output terminal 200, and controls the MOS tube 302 to be turned on. The current flows from the input terminal 100 to the source to the drain to the output terminal 200. At this time, the DC power supply powers the electronic device.
[0027] The present invention also provides an electronic device, which has the bidirectional protection circuit, and the bidirectional protection circuit controls a DC power supply or a Type C power supply to power the electronic device, and the electronic device is a laptop computer, etc.
[0028] In summary, the bidirectional protection circuit and the electronic device having the bidirectional protection circuit of the present invention control the working state of the MOS tube 302 by comparing the voltages at the input end 100 and the output end 200 through the control unit 301. After the Type C power supply is connected, the MOS tube 302 is turned off, and the Type C power supply powers the electronic device. After the Type C power supply is removed, the MOS tube 302 is turned on, and the DC power supply powers the electronic device. Therefore, the electronic device can be charged normally when the Type C power supply is inserted or unplugged.
Claims
1. A bidirectional protection circuit, characterized in that: It includes an input end, an output end, and a voltage control module connected between the input end and the output end. The input end is connected to a DC power supply, and the output end is connected to or disconnected from a Type C power supply. The voltage control module includes a control unit and a MOS tube. The control unit compares the voltages at the input end and the output end to control the working state of the MOS tube; The MOS tube is an NMOS tube, the source of the NMOS tube is connected to the input end, the drain is connected to the output end, and the gate is connected to the control unit; When the input voltage is lower than the output voltage, the control unit controls the MOS tube to shut off the source and drain paths, and the internal diode is reverse blocked; when the input voltage is higher than the output voltage, the control unit controls the MOS tube to conduct, and the current flows from the input to the source to the drain to the output; The control unit is a LM74700 chip, the EN pin and the ANODE pin of the LM74700 chip are connected to the input end, the third capacitor is connected between the VCAP pin and the ANODE pin, the GND pin is grounded, the GATE pin is connected to the gate of the MOS tube, and the CATHODE pin is connected to the output end.
2. The bidirectional protection circuit according to claim 1, characterized in that: The bidirectional protection circuit further comprises a voltage stabilizing diode, one end of which is connected to the input end and the other end of which is grounded.
3. The bidirectional protection circuit according to claim 1, characterized in that: The bidirectional protection circuit further includes a first capacitor and a second capacitor, wherein one end of the first capacitor is connected to the input end and the other end is grounded, and one end of the second capacitor is connected to the output end and the other end is grounded.
4. An electronic device, characterized in that: The electronic device comprises the bidirectional protection circuit according to any one of claims 1 to 3, wherein the bidirectional protection circuit controls a DC power supply or a Type C power supply to supply power to the electronic device.