Power switch circuit device and control method

Abstract

The present invention provides a power switch circuit device and a control method, including: a power switch circuit, a voltage detection circuit module and a main power supply; the voltage detection circuit module includes: a first voltage detection circuit and a second voltage detection circuit; the first voltage detection circuit is connected to the power switch circuit; the power switch circuit is connected to the second voltage detection circuit; the power switch circuit includes: a resistor R1, a resistor R2, a capacitor C3, a triode Q1, a triode Q2 and a triode Q3; one end of the resistor R1 is connected to the triode Q1 and the triode Q2; the other end of the resistor R1 is connected to the triode Q3; the present invention uses a battery capacitor as a backup power supply, achieving advantages in cost and volume. After the main power is off, the present invention can turn off the power supply circuit of the battery capacitor after the system completes the power-off operation to prevent over-discharge of the battery capacitor.

Description

Technical Field

[0001] The present invention relates to the technical field of switch circuits, and in particular to a power switch circuit device and a control method. Background Art

[0002] The power supply scheme of today's NB smart water meters and gas meters usually consists of a main power supply and a backup power supply. The main power supply (hereinafter referred to as the main power) is generally a 3.6V disposable lithium-ion battery or a multi-cell dry cell. There are also multiple options for the backup power supply (hereinafter referred to as the backup power): one option is a small disposable lithium battery, which is mainly used for valve closing operation after the main power is lost and the clock of the MCU system afterwards; the other is a farad capacitor (super capacitor), which stores electrical energy for valve closing and power-off protection of some MCU systems after the main power is lost; the discharge capacity or power of the above two options cannot support NB upload after the main power is lost; now water companies or gas companies need to upload data after the main power is lost in order to understand the actual situation of users. The more common backup power solution is to use a small disposable lithium battery plus a battery capacitor in parallel. The battery capacitor has a strong discharge capacity and can support the current required for NB upload. This parallel combination can not only perform valve operation and data upload after the main power is lost, but also keep the MCU powered on, which has many advantages. However, in most current application requirements, after the main power is off, the system only needs valve operation, data recording, and the newly added data upload function, and then the system can be completely shut down. These functions can be completed by only one battery capacitor. Compared with the parallel combination of small batteries and battery capacitors, a single battery capacitor has advantages in volume and cost. However, this battery capacitor has a disadvantage that it cannot be over-discharged. If the problem of over-discharge of battery capacitors can be solved, it can gain advantages in volume and cost.

[0003] Patent document CN106157864A discloses a power switch circuit and a method for controlling the power switch circuit. The power switch circuit includes a frequency control circuit, a pulse modulation circuit and a switching converter. The frequency control circuit receives a first reference signal for driving a load from a timing controller, and generates a second reference signal based on the first reference signal. The pulse modulation circuit generates a pulse control signal by performing pulse width modulation (PWM) or pulse frequency modulation (PFM) on the second reference signal. In response to the pulse control signal, the switching converter generates a voltage of an output power supply by switching a switching element connected to the output power supply. The pulse control signal is synchronized with the first reference signal for driving the load. The structure and performance of this patent still have room for improvement. Summary of the invention

[0004] In view of the defects in the prior art, an object of the present invention is to provide a power switch circuit device and a control method.

[0005] A power switch circuit device provided according to the present invention includes: a power switch circuit 1, a voltage detection circuit module and a main power supply; the voltage detection circuit module includes: a first voltage detection circuit 2 and a second voltage detection circuit 3; the first voltage detection circuit is connected to the power switch circuit; the power switch circuit is connected to the second voltage detection circuit; the power switch circuit includes: a resistor R1, a resistor R2, a capacitor C3, a triode Q1, a triode Q2 and a triode Q3; one end of the resistor R1 is connected to the triode Q1 and the triode Q2; the other end of the resistor R1 is connected to the triode Q3; the triode Q3 is connected to the capacitor C3 and the resistor R2; the capacitor C3 is connected to the resistor R2; the main power supply is connected to the power switch circuit and the first voltage detection circuit.

[0006] Preferably, the first voltage detection circuit comprises: a resistor R3, a resistor R4 and a transistor Q4;

[0007] The resistor R3 is connected to the transistor Q4;

[0008] The resistor R4 is connected to the transistor Q4;

[0009] The transistor Q4 is connected to the ground line.

[0010] Preferably, the first voltage detection circuit comprises: a resistor R5, a resistor R6 and a transistor Q5;

[0011] The resistor R4 is connected to the transistor Q5;

[0012] The transistor Q5 is connected to the resistor R5;

[0013] The resistor R6 is connected to the resistor R5.

[0014] Preferably, the second voltage detection circuit comprises: a resistor R7, a resistor R8 and a transistor Q6;

[0015] The resistor R7 is connected to the transistor Q6;

[0016] The resistor R8 is connected to the transistor Q6;

[0017] The transistor Q6 is connected to the ground line.

[0018] Preferably, the second voltage detection circuit comprises: a resistor R9, a transistor Q7;

[0019] The resistor R9 is connected to the transistor Q7;

[0020] The resistor R8 is connected to the transistor Q7.

[0021] Preferably, the second voltage detection circuit comprises: a resistor R10;

[0022] The resistor R9 is connected to the resistor R10;

[0023] The resistor R10 is connected to the ground line.

[0024] Preferably, it also includes: a capacitor C1;

[0025] The transistor Q2 is connected to one end of the capacitor C1;

[0026] The other end of the capacitor C1 is connected to the ground line.

[0027] Preferably, it also includes: a diode D1 and a capacitor C2;

[0028] The anode of the diode D1 is connected to the anode of the main power supply;

[0029] The cathode of the diode D1 is connected to the capacitor C2.

[0030] Preferably, it also includes: a diode D2 and a diode D3;

[0031] The anode of the diode D2 is connected to the anode of the main power supply;

[0032] The anode of the diode D3 is connected to the anode of the main power supply.

[0033] Preferably, it also includes: a capacitor C4;

[0034] The cathode of the diode D2 is connected to the capacitor C4;

[0035] The cathode of the diode D3 is connected to the capacitor C4.

[0036] A power switch circuit device control method adopts the power switch circuit device to obtain over-discharge control result information.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The present invention uses a battery capacitor as a backup power source, achieving advantages in cost and volume.

[0039] 2. After the main power is cut off, the present invention can shut down the power supply circuit of the battery capacitor after the system completes the power-off operation to prevent the battery capacitor from over-discharging.

[0040] 3. The present invention can select battery capacitors of different capacities according to actual conditions to adapt to different current and energy requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0042] Figure 1 This is a block diagram of the system principle of the present invention.

[0043] In the figure:

[0044] 1 power switch circuit, 2 first voltage detection circuit, 3 second voltage detection circuit. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0046] A power switch circuit device, a resistor R1, a resistor R2, a capacitor C3, a transistor Q1, a transistor Q2, and a transistor Q3 form a power switch circuit for connecting a battery capacitor C1 as a backup power source to V_BAK. Taking a 3.6V disposable lithium battery as the main power source as an example, during normal operation, the main power supplies power to the system through the diode D2. After the MCU is working, the main power voltage detection circuit composed of resistors R3, R4, R5, R6 and transistors Q4 and Q5 detects that the main power is working normally; after the backup power voltage detection circuit composed of resistors R7, R8, R9, R10, transistors Q6 and Q7 detects that the backup power state is normal, the IO port PW_SW_H of the MCU is pulled high and PW_SW_L is pulled low. At this time, the transistor Q3 is turned on, the gates of the transistors Q1 and Q2 are low, the source and drain of the transistors Q1 and Q2 are turned on, the power switch circuit is turned on, and the battery capacitor C1 is charged through D1. After the switch is turned on, C1 is charged and exists as a backup power source at the same time. When the main power is off, the battery capacitor C1 continues to supply power to the system through the power switch circuit and the diode D3. When the MCU detects the main power failure, the system starts the main power failure operation, such as valve closing, data recording and information uploading. When all the main power failure operations are completed, the MCU pulls down the IO port PW_SW_H and pulls up the PW_SW_L to turn off the transistor Q3. After the transistor Q3 is turned off, the transistor Q1 and the transistor Q2 are not turned on, and the switch circuit is turned off. Capacitor C2 is used to ensure that the MCU is powered for a short time during the IO port operation to ensure that the switch can be completely turned off. After the switch circuit is turned off, the system has no power supply, and the system is completely powered off after a short time. The battery capacitor C1 no longer supplies power to any circuit, which can prevent it from over-discharging. Resistors R2 and C3 can ensure that there is no voltage difference between the gate and source of the transistor Q3 after the MCU is powered off, preventing the transistor Q3 from being turned on under abnormal circumstances. After the main power supply is powered on, the MCU detects that the main power and backup power are normal, and then opens the switch circuit again to charge the battery capacitor C1. At the same time, C1 becomes the backup power of the system.

[0047] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0048] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A power switch circuit device, characterized in that: include: Power switch circuit, voltage detection circuit module and main power supply; The voltage detection circuit module includes: a first voltage detection circuit and a second voltage detection circuit; The first voltage detection circuit is connected to the power switch circuit; The power switch circuit is connected to the second voltage detection circuit; The power switch circuit includes: a resistor R1, a resistor R2, a capacitor C3, a transistor Q1, a transistor Q2 and a transistor Q3; One end of the resistor R1 is connected to the transistor Q1 and the transistor Q2; The other end of the resistor R1 is connected to the transistor Q3; The transistor Q3 is connected to the capacitor C3 and the resistor R2; The capacitor C3 is connected to the resistor R2; The main power supply is connected to the power switch circuit and the first voltage detection circuit; The first voltage detection circuit includes: a resistor R3, a resistor R4 and a transistor Q4; The resistor R3 is connected to the transistor Q4; The resistor R4 is connected to the transistor Q4; The transistor Q4 is connected to the ground wire; The second voltage detection circuit includes: a resistor R7, a resistor R8 and a transistor Q6; The resistor R7 is connected to the transistor Q6; The resistor R8 is connected to the transistor Q6; The transistor Q6 is connected to the ground line.

2. The power switch circuit device according to claim 1, characterized in that: The first voltage detection circuit includes: a resistor R5, a resistor R6 and a transistor Q5; The resistor R4 is connected to the transistor Q5; The transistor Q5 is connected to the resistor R5; The resistor R6 is connected to the resistor R5.

3. The power switch circuit device according to claim 1, characterized in that: The second voltage detection circuit includes: a resistor R9 and a transistor Q7; The resistor R9 is connected to the transistor Q7; The resistor R8 is connected to the transistor Q7; The second voltage detection circuit also includes: a resistor R10; The resistor R9 is connected to the resistor R10; The resistor R10 is connected to the ground line.

4. The power switch circuit device according to claim 1, characterized in that: Also includes: Capacitor C1; The transistor Q2 is connected to one end of the capacitor C1; The other end of the capacitor C1 is connected to the ground line.

5. The power switch circuit device according to claim 1, characterized in that: Also includes: Diode D1, capacitor C2; The anode of the diode D1 is connected to the anode of the main power supply; The cathode of the diode D1 is connected to the capacitor C2.

6. The power switch circuit device according to claim 1, characterized in that: Also includes: Diode D2, diode D3; The anode of the diode D2 is connected to the anode of the main power supply; The anode of the diode D3 is connected to the anode of the main power supply.

7. The power switch circuit device according to claim 6, characterized in that: Also includes: Capacitor C4; The cathode of the diode D2 is connected to the capacitor C4; The cathode of the diode D3 is connected to the capacitor C4.

8. A power switch circuit control method, characterized in that: The power switch circuit device according to any one of claims 1 to 7 is used to obtain over-discharge control result information.

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