12V power supply circuit based on MOS tube control

Abstract

The utility model relates to a 12V power supply circuit based on MOS tube control. The 12V power supply circuit comprises a resistor RD3, a resistor RD4, a resistor RD2, a resistor RD1, a resistor RN1, an electrolytic capacitor E1, a triode QD1, a diode D1 and an MOS tube Q1. One end of the resistor RN3 is connected with a control pin IOPowerCt of the MCU, the other end of the resistor RN3 is connected with a base electrode of the triode QD1, one end of the resistor RD4 is connected with the base electrode of the triode QD1, the other end of the resistor RD4 is connected with the GND, and an emitting electrode of the triode QD1 is connected with the GND. The device is reasonable in design, compact in structure and convenient to use.

Description

Technical Field

[0001] The utility model relates to a 12V power supply circuit based on MOS tube control. Background Art

[0002] The technical background of using MOS tubes as switches stems from their unique voltage control characteristics and superior electrical performance. MOS tubes are voltage-controlled devices, unlike bipolar transistors, which require current to control current. Only a certain voltage is applied to the gate to control the conduction and cutoff between the drain and the source. This feature makes MOS tubes particularly suitable for use as switches, and only a small control signal is needed to control the on and off of a large current. MOS tubes have fast switching speeds and low on-resistance, especially devices such as power MOSFETs and insulated gate bipolar transistors (IGBTs), which have extremely low on-resistance and extremely short switching time, which is crucial for high-frequency switching operations and reducing switching losses.

[0003] The applicant found that the voltage domain of mainstream single-chip microcomputer systems is usually 3.3V and 5V. When the GPIO port is needed to control the module power supply 12V, if the transistor is used directly to drive, it is impossible to control the opening and closing of the 12V power supply, so it is necessary to add a MOS tube voltage driver device to solve this problem. Utility Model Content

[0004] The technical problem to be solved by the utility model is generally to provide a 12V power supply circuit based on MOS tube control.

[0005] In order to control the opening and closing of the 12V power supply, the technical solution adopted by the utility model is a 12V power supply circuit based on MOS tube control, including resistors RD3, RD4, RD2, RD1, RN1, electrolytic capacitor E1, triode QD1, diode D1, MOS tube Q1;

[0006] One end of the resistor RN3 is connected to the control pin IO_Power_Ct of the MCU, and the other end is connected to the base of the transistor QD1. One end of the resistor RD4 is connected to the base of the transistor QD1 and the other end is connected to GND. The emitter of the transistor QD1 is connected to GND.

[0007] The collector of transistor QD1 is connected to one end of resistor RD2, the other end of resistor RD2 is connected to one end of resistor RD1, the other end of resistor RD1 is connected to the cathode of diode D1, and the anode of diode D1 is connected to 12V. The gate of MOS tube is connected to RD1 and RD2, the source of MOS tube is connected to 12V, and the drain of MOS tube Q1 is connected to 12V_OUT;

[0008] The positive electrode of the electrolytic capacitor E1 is connected to 12V_OUT, the negative electrode of the electrolytic capacitor E1 is connected to GND, one end of the resistor RN1 is connected to 12V_OUT and the other end is connected to GND.

[0009] As a further improvement of the above technical solution:

[0010] When the IO_Power_Ct of the MCU IO port outputs a high level state, the transistor QD1 is in a conducting state, the gate of the MOS tube is pulled low, and the gate of the MOS tube Q1 is in a state lower than the source of the MOS tube Q1.

[0011] When the transistor QD1 is in the on state, the gate of the MOS tube is in the pulled-down state, the gate of the MOS tube Q1 is close to 0V, and the MOS tube Q1 is in the on state;

[0012] Electrolytic capacitor E1 is an energy storage electrolytic capacitor, which supplies power to the module for 12V_OUT;

[0013] Resistor RN1 is a dummy load.

[0014] When the IO_Power_Ct of the MCU IO port outputs a low level state, the transistor QD1 is in the cut-off state and the MOS tube Q1 is in the cut-off state.

[0015] The utility model realizes the on-off and off-off of MOS and the power supply of the module by the on-off of the three-pole tube. The drain current of the MOS tube needs to be above 2A. Otherwise, the MOS tube will be burned out due to excessive current during communication.

[0016] The utility model uses a triode and MOS core parts, has fast response, simple structure, low cost, safety and reliability, convenient use, simple circuit, low cost, high sensitivity, and strong adaptability and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the circuit structure of the utility model.

[0018] Figure 2 It is a schematic diagram of the pin interface structure of the utility model.

[0019] Figure 3 This is a filter circuit schematic diagram A of the utility model.

[0020] Figure 4 This is a filter circuit schematic diagram B of the utility model.

[0021] Figure 5 This is a filter circuit schematic diagram C of the utility model.

[0022] Figure 6It is a circuit flow control schematic diagram of the utility model. DETAILED DESCRIPTION

[0023] like Figure 1-6 As shown, the 12V power supply circuit based on MOS tube control of this embodiment includes resistors RD3, RD4, RD2, RD1, RN1, an electrolytic capacitor E1, a transistor QD1, a diode D1, and a MOS tube Q1.

[0024] One end of the resistor RN3 is connected to the control pin IO_Power_Ct of the MCU, and the other end is connected to the base of the transistor QD1. One end of the resistor RD4 is connected to the base of the transistor QD1, and the other end is connected to GND. The collector of the transistor QD1 is connected to RD2, and the emitter of the transistor QD1 is connected to GND. The other end of the resistor RD2 is connected to the resistor RD1, and the other end of the resistor RD1 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to 12V. The gate of the MOS tube is connected to RD1 and RD2, the source of the MOS tube is connected to 12V, and the drain of the MOS tube Q1 is connected to 12V_OUT. The anode of the electrolytic capacitor E1 is connected to 12V_OUT, the cathode of the electrolytic capacitor E1 is connected to GND, and one end of the resistor RN1 is connected to 12V_OUT, and the other end is connected to GND.

[0025] When the MCU IO port IO_Power_Ct outputs a high level, the transistor QD1 is turned on, and the gate of the MOS tube is pulled down by the transistor QD1. The conduction condition of the PMOS is that under the conditions of VDS=VGS, ID=-250μA, Gate Threshold Voltage=-0.62V is turned on, that is, the gate of the MOS tube Q1 is lower than the source of the MOS tube Q1 by 0.62V to be turned on. Therefore, when the transistor QD1 is turned on, the gate of the MOS tube is pulled down by the transistor QD1, the gate of the MOS tube Q1 is almost equal to 0V, and the source of the MOS tube Q1 is 12V. The conduction condition is met, so the MOS tube is turned on, and the voltage of 12_OUT is 12V. E1 is an energy storage electrolytic capacitor, which supplies power to the module for 12V_OUT, and RN1 is a dummy load, which ensures that when the module is not connected, a certain current is consumed on 12V_OUT to ensure the stability of the circuit. When the IO_Power_Ct of the MCU IO port outputs a low level, the transistor QD1 is turned off, and the voltage of the gate of the MOS tube Q1 is 12V minus the voltage drop of the diode D1. The MOS tube conduction condition is not met, the MOS tube Q1 is turned off, 12V_OUT has no voltage, and the module does not work. Therefore, the IO port of the MCU can be used to control the opening and closing of the power supply of the 12V module. When the module soft reset REST does not work, the power supply of the module can be reset. Ensure reliable reset of the module.

[0026] Workflow: At the beginning, the smart meter is powered on, and each circuit module starts working, generating a power-on signal and inputting it into the corresponding IO port of the microcontroller. The microcontroller detects the power-on signal and sets the IO_Power_Ct signal high. IO_Power_Ct outputs a high level, such as Figure 1 As shown in the circuit, when the IO_Power_Ct signal is at a high level, the transistor QD1 is in the on state. At this time, the gate of the MOS tube Q1 is about 0V, and the source of the MOS tube Q1 is connected to 12V. At this time, the on condition of the MOS tube Q1 is met, the MOS tube Q1 is turned on, 12V_OUT outputs a voltage of 12V, and the 12V voltage is supplied to the module. The module is powered on and starts working, and then exchanges data with the MCU, and the communication is successful.

[0027] The present invention is fully described for a clearer disclosure, and the prior art will not be listed one by one.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it; although the utility model is described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features therein with equivalents; it is obvious for those skilled in the art to combine multiple technical solutions of the utility model. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.

Claims

1. A 12V power supply circuit based on MOS tube control, characterized in that: Including resistors RD3, RD4, RD2, RD1, RN1, electrolytic capacitor E1, transistor QD1, diode D1, MOS tube Q1; One end of the resistor RN3 is connected to the control pin IO_Power_Ct of the MCU, and the other end is connected to the base of the transistor QD1. One end of the resistor RD4 is connected to the base of the transistor QD1 and the other end is connected to GND. The emitter of the transistor QD1 is connected to GND. The collector of transistor QD1 is connected to one end of resistor RD2, the other end of resistor RD2 is connected to one end of resistor RD1, the other end of resistor RD1 is connected to the cathode of diode D1, and the anode of diode D1 is connected to 12V. The gate of MOS tube is connected to RD1 and RD2, the source of MOS tube is connected to 12V, and the drain of MOS tube Q1 is connected to 12V_OUT; The positive electrode of the electrolytic capacitor E1 is connected to 12V_OUT, the negative electrode of the electrolytic capacitor E1 is connected to GND, one end of the resistor RN1 is connected to 12V_OUT and the other end is connected to GND.

2. The 12V power supply circuit based on MOS tube control according to claim 1 is characterized in that: When the IO_Power_Ct of the MCU IO port outputs a high level state, the transistor QD1 is in a conducting state, the gate of the MOS tube is pulled low, and the gate of the MOS tube Q1 is in a state lower than the source of the MOS tube Q1.

3. The 12V power supply circuit based on MOS tube control according to claim 1 is characterized in that: When the transistor QD1 is in the on state, the gate of the MOS tube is in the pulled-down state, the gate of the MOS tube Q1 is close to 0V, and the MOS tube Q1 is in the on state; Electrolytic capacitor E1 is an energy storage electrolytic capacitor, which supplies power to the module for 12V_OUT; Resistor RN1 is a dummy load.

4. The 12V power supply circuit based on MOS tube control according to claim 1, characterized in that: When the IO_Power_Ct of the MCU IO port outputs a low level state, the transistor QD1 is in the cut-off state and the MOS tube Q1 is in the cut-off state.

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