A low-power MOS tube switch circuit and a new water meter

Abstract

The utility model discloses a low-power MOS switch circuit and a new water meter, including: a MOS Q1, the source of which is coupled to a DC power supply, and the drain of which is used to couple an electrical appliance; a pull-up resistor R2, the resistance of which is not higher than 200 kilo-ohms, one end of which is coupled to the gate of the MOS Q1, and the other end of which is coupled to the source of the MOS Q1; a main control chip, which has a GPIO control pin, the GPIO control pin is coupled to a resistor R1, and the other end of the resistor R1 is coupled to the electrical connection point between the resistor R2 and the gate of the MOS Q1; a switching element is configured, coupled to the main control chip, and is used to switch the pin mode of the GPIO control pin between a floating mode and a push-pull mode. When the MOS is turned off, the pin mode of the main control chip is configured to be a floating mode. According to the design of the pin mode of the main control chip, when the GPIO end is floating, the level of the pin is completely determined by the external circuit, and the voltage difference between the GPIO end and the VCC end is small, thereby reducing the power consumption generated when the MOS is turned off.

Description

Technical Field

[0001] The utility model belongs to the technical field of water meter measurement, and in particular relates to a low-power consumption MOS tube switch circuit. Background Art

[0002] In the water meter circuit, the switch circuit exists as an important function. In the application of smart water meters, MOS tubes are usually used as power switches. This design allows the conduction state of the MOS tube to be controlled by changing the gate voltage, thereby achieving precise control of the circuit.

[0003] MOS tubes are often used as switching circuits in hardware design, such as Figure 1 As shown in the figure, VCC_M is the power supply terminal, and GPIO is the pin of the control chip, and its maximum voltage is 3.3V. When the voltage required by the appliance is higher, the voltage of VCCC_M needs to meet the minimum rated voltage of the appliance. The general practice is to configure the GPIO control pin of the control chip to push-pull mode, and select a 1MΩ resistor as the pull-up resistor. However, when the MOS tube is turned off, there is a certain voltage difference between VCC_M and GPIO, which will generate certain power consumption. Utility Model Content

[0004] In view of the above problems existing in the prior art, the utility model provides a low-power MOS tube switch circuit.

[0005] In a first aspect, the utility model provides a low power consumption MOS tube switch circuit.

[0006] A low power consumption MOS tube switch circuit, comprising:

[0007] MOS tube Q1, the source is coupled to the DC power supply, and the drain is used to couple the electrical appliance;

[0008] A pull-up resistor R2 has a resistance range of 100 kilo-ohms to 200 kilo-ohms, one end of which is coupled to the gate of the MOSFET Q1 and the other end of which is coupled to the source of the MOSFET Q1;

[0009] The main control chip has a GPIO control pin, the GPIO control pin is coupled to a resistor R1, and the other end of the resistor R1 is coupled to an electrical connection point between the resistor R2 and the gate of the MOS tube Q1;

[0010] A switching element is configured and coupled to the main control chip to switch the pin mode of the GPIO control pin between a floating mode and a push-pull mode.

[0011] Through the above settings, the resistance value of the pull-up resistor is optimized. When the MOS tube is turned off, the pin mode of the main control chip is configured to the floating mode (the pin mode needs to be push-pull output when the MOS is turned on). According to the design of the pin mode of the main control chip, when the GPIO end is floating, the level of the pin is completely determined by the external circuit. Under the action of the pull-up resistor with a lower resistance value, the voltage difference between the GPIO end and the VCC end is small, thereby reducing the power consumption generated when the MOS tube is turned off.

[0012] As a preferred embodiment, it also includes:

[0013] The filter module is coupled to the drain of the MOS tube Q1 and is used to filter out the current noise of the drain current of the MOS tube Q1.

[0014] As a preferred implementation, the filtering module includes capacitors C1, C2 and C3, one end of each of the capacitors C1, C2 and C3 is coupled to the drain of the MOS tube Q1, and the other end is grounded.

[0015] As a preferred implementation, the capacitor C1 is a polar capacitor, the positive electrode of the capacitor C1 is coupled to the drain of the MOS tube Q1, and the negative electrode is grounded.

[0016] As a preferred embodiment, it also includes:

[0017] A high-resistance pull-up resistor R3, whose resistance is higher than that of the pull-up resistor R2, has one end coupled to the gate of the MOS tube Q1 and the other end coupled to the DC power supply;

[0018] A control unit for controlling the on / off of the circuit where the pull-up resistor R2 is located is also connected in series between the pull-up resistor R2 and the drain of the MOS tube Q1.

[0019] As a preferred embodiment, it also includes: the control unit includes a transistor Q2, the collector of the transistor Q2 is coupled to the source of the MOS tube Q1, the emitter of the transistor Q2 is coupled to the end of the pull-up resistor R2, and the base of the transistor Q2 is coupled to another control pin of the main control chip.

[0020] A second aspect of the present application provides a new type of water meter, including a low-power MOS tube switch circuit and a communication serial port, wherein the communication serial port is communicatively connected to a main control chip of the switch circuit.

[0021] Compared with the prior art, the beneficial effects of the utility model are:

[0022] In this application, when the MOS tube is turned off, the pin mode of the main control chip is configured to be in floating mode. According to the design of the pin mode of the main control chip, when the GPIO terminal is floating, the level of the pin is completely determined by the external circuit, and the voltage difference between the GPIO terminal and the VCC terminal is small, thereby reducing the power consumption generated when the MOS tube is turned off. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a circuit diagram of the prior art.

[0025] Figure 2 This is a circuit diagram of a low-power MOS tube switch circuit provided in Embodiment 1 of the utility model.

[0026] Figure 3 This is a circuit diagram of a low-power MOS tube switch circuit provided in Embodiment 2 of the present utility model.

[0027] Figure numerals: 1. main control chip; 2. filter module; 3. control unit. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments.

[0029] In the description of the embodiments of the present application, words such as "illustrative", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "illustrative", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "illustrative", "for example" or "for example" is intended to present related concepts in a concrete way.

[0030] In the description of the embodiments of the present application, the term "and / or" is only a kind of association relationship describing the associated objects, indicating that there may be three kinds of relationships, for example, A and / or B, which can represent: A exists alone, B exists alone, and A and B exist at the same time. In addition, unless otherwise specified, the meaning of the term "multiple" refers to two or more. For example, multiple systems refer to two or more systems, and multiple screen terminals refer to two or more screen terminals. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the indicated technical features. Thus, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. The terms "include", "comprise", "have" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0031] Reference Figure 1 In the circuit of the prior art, VCC_M is the power supply terminal, and GPIO is the pin of the control chip, and its maximum voltage is 3.3V. When the voltage required by the appliance is relatively large, the voltage of VCC_M needs to meet the minimum rated voltage of the appliance. The general practice is to configure the GPIO control pin of the control chip to push-pull mode, and select a 1MΩ resistor as the pull-up resistor R8 to pull up the level and reduce clutter interference;

[0032] According to the above circuit, when the MOS tube is turned off, since the GPIO control pin of the control chip is in push-pull mode, resistors R8 and R9 are turned on, so that there is a voltage less than VCC_M at the electrical connection point between R8 and R9, which makes the MOS tube turned on and generates certain power consumption.

[0033] According to the above-mentioned shortcomings of the prior art, the present invention optimizes the pull-up resistor R8 and the GPIO pin mode to eliminate the voltage difference between VCC_M and the GPIO terminal, thereby reducing power consumption.

[0034] Embodiment 1:

[0035] Reference Figure 2 , this embodiment provides a low-power MOS tube switch circuit, including a MOS tube Q1, a pull-up resistor R2, a main control chip 1, a configuration switching element and a filter module 2;

[0036] Among them, MOS tube, the full name of which is metal oxide semiconductor field effect transistor, is a semiconductor device widely used in electronic devices. It controls the switching state of the semiconductor conductive channel by applying voltage between the gate of the metal layer and the source separated by the insulating layer to generate an electric field effect. A common use of MOS tube in circuits is as an electronic switch, which makes it very useful in applications such as switching power supplies. Its conduction and cutoff can be controlled by changing the gate voltage, thereby achieving precise control of the current;

[0037] The source of the mos tube Q1 is coupled to the DC power supply VCC, and the drain is used to couple the electrical appliance. The electrical appliance in this embodiment can be an electric water meter to control the operation of the water meter. The gate of the mos tube Q1 is coupled to a pull-up resistor R2. The resistance range of the pull-up resistor R2 is 100 kilo-ohms-200 kilo-ohms. In this embodiment, the pull-up resistor R2 adopts 200 kilo-ohms. The other end of the pull-up resistor R2 is coupled to the source of the mos tube Q1.

[0038] The electrical connection between the pull-up resistor R2 and the gate of the MOS tube Q1 is coupled with a resistor R1, and the other end of the resistor R1 is coupled to the GPIO control pin of the main control chip 1. It should be noted that the main control chip 1 can be a single-chip microcomputer. In this embodiment, the resistance value of the resistor R1 is 10 kilo-ohms;

[0039] The configuration switching element is coupled to the main control chip 1, and is used to switch the pin mode of the GPIO control pin between the floating mode and the push-pull mode. The configuration switching element can specifically be a timer in the main control chip 1. The personnel sets the working cycle according to the actual working needs of the electric water meter. During the working cycle, the configuration switching element will send a working signal to drive the main control chip 1 to adjust the pin mode of the GPIO control pin to the push-pull mode. After the working cycle ends, the mos tube Q1 is turned off to drive the main control chip 1 to adjust the pin mode of the GPIO control pin to the floating mode. In other embodiments, the configuration switching element can also be a button for manual operation by personnel to output a high level; after the personnel presses the configuration switching element, it will input a high level signal to the main control chip 1. After the main control chip 1 receives the high level signal, it switches the pin mode of the GPIO control pin between the floating mode and the push-pull mode.

[0040] The filter module 2 is coupled to the drain of the MOS tube Q1, and is used to filter out the current noise of the drain current of the MOS tube Q1. Specifically: the filter module 2 includes capacitors C1, C2, and C3, and one end of the capacitors C1, C2, and C3 are all coupled to the drain of the MOS tube Q1, and the other ends are all grounded. Among them, the capacitor C1 is a polar capacitor, and the positive pole of the capacitor C1 is coupled to the drain of the MOS tube Q1, and the negative pole is grounded. The setting of the filter module 2 can filter out the clutter of the current input into the electrical appliance, and the electrical appliance works more stably, thereby extending the life of the electrical appliance.

[0041] The working principle of a low-power MOS switch circuit provided in this embodiment is as follows: on the basis of the original conventional design, the resistance value of the pull-up resistor R8 is optimized and replaced with a 200 kilo-ohm pull-up resistor R2, and the pin mode of the main control chip 1 is configured to be a floating mode when the MOS is turned off (the pin mode needs to be a push-pull output when the MOS is turned on); then according to the design of the pin mode of the main control chip 1, when the GPIO terminal is floating, the GPIO terminal is in a high-impedance state, and the level of the pin is completely determined by the external circuit. Under the action of R2, the voltage difference between the GPIO terminal and the VCC terminal is small, thereby reducing the power consumption generated when the MOS is turned off.

[0042] Embodiment 2:

[0043] Since most water meters are powered by batteries, the lower the power consumption of the metering circuit, the longer the life cycle of the water meter. Therefore, it is very important to reduce the power consumption of the metering circuit, and thus the second embodiment is further designed.

[0044] Reference Figure 3 The difference between this embodiment and the first embodiment is that: the gate of the MOS tube Q1 is coupled with a high-resistance pull-up resistor R3, and the resistance of the high-resistance pull-up resistor R3 is higher than that of the pull-up resistor R2; in this embodiment, the specific resistance of the pull-up resistor R3 is 1 megohm;

[0045] The other end of the high-resistance pull-up resistor R3 is coupled to a control unit 3, and the control unit 3 is used to control whether the pull-up resistor R2 is connected to the drain of the MOS tube Q1. Specifically:

[0046] The control unit 3 includes a transistor Q2, the collector of the transistor Q2 is coupled to the source of the MOS tube Q1, the emitter of the transistor Q2 is coupled to the pull-up resistor R2, and the base of the transistor Q2 is coupled to another control pin of the main control chip 1 except the GPIO control pin. It should be noted that the control voltage of the control pin of the main control chip 1 to which the transistor Q2 is coupled is less than the DC voltage VCC.

[0047] The working principle of the second embodiment is as follows: by setting the high-resistance pull-up resistor R3 and the transistor Q2, the resistance of the pull-up resistor of the MOS tube Q3 can be controlled. When the MOS tube Q3 is working, the pull-up resistor R2 is disconnected, and the high-resistance pull-up resistor R3 provides a pull-up voltage for the circuit. The resistance of the high-resistance pull-up resistor R3 is higher than that of the pull-up resistor R2, the circuit current is smaller, and the consumption is lower; after the MOS tube Q3 is turned off, the pull-up resistor R2 is connected to the circuit by the transistor Q2, so that the pull-up resistor R2 is connected in parallel with the high-resistance pull-up resistor R3, and the total resistance of the pull-up resistor is smaller, so that the voltage between the pull-up resistor R2 and the resistor R1 and the voltage difference at the VCC end are smaller, thereby reducing the power consumption generated when the MOS tube is turned off.

[0048] The present application also provides a novel water meter, comprising a low-power MOS tube switch circuit and a communication serial port, wherein the communication serial port is communicatively connected to a main control chip 1 of the switch circuit.

[0049] The above are only exemplary embodiments of the present disclosure and cannot be used to limit the scope of the present disclosure. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of other embodiments of the present disclosure. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field that are not recorded in the present disclosure. The description and examples are only regarded as exemplary, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A low power consumption MOS tube switch circuit, characterized in that: include: MOS tube Q1, the source is coupled to the DC power supply, and the drain is used to couple the electrical appliance; A pull-up resistor R2 has a resistance range of 100 kilo-ohms to 200 kilo-ohms, one end of which is coupled to the gate of the MOSFET Q1 and the other end of which is coupled to the source of the MOSFET Q1; A main control chip (1) has a GPIO control pin, the GPIO control pin is coupled to a resistor R1, and the other end of the resistor R1 is coupled to an electrical connection point between a resistor R2 and a gate of a MOS tube Q1; A switching element is configured and coupled to the main control chip (1) for switching the pin mode of the GPIO control pin between a floating mode and a push-pull mode.

2. A low power consumption MOS switch circuit according to claim 1, characterized in that: Also includes: The filter module (2) is coupled to the drain of the MOSFET Q1 and is used to filter out the current noise of the drain current of the MOSFET Q1.

3. A low power consumption MOS switch circuit according to claim 2, characterized in that: The filter module (2) comprises a capacitor C1, a capacitor C2 and a capacitor C3, one end of each of the capacitors C1, C2 and C3 is coupled to the drain of the MOSFET Q1, and the other end is grounded.

4. A low power consumption MOS switch circuit according to claim 3, characterized in that: The capacitor C1 is a polar capacitor, the positive electrode of the capacitor C1 is coupled to the drain of the MOS tube Q1, and the negative electrode of the capacitor C1 is grounded.

5. A low power consumption MOS switch circuit according to claim 1, characterized in that: Also includes: A high-resistance pull-up resistor R3, whose resistance is higher than that of the pull-up resistor R2, has one end coupled to the gate of the MOS tube Q1 and the other end coupled to the DC power supply; A control unit (3) for controlling the on / off of the circuit where the pull-up resistor R2 is located is also connected in series between the pull-up resistor R2 and the drain of the MOS tube Q1.

6. A low power consumption MOS switch circuit according to claim 5, characterized in that: The control unit (3) comprises a transistor Q2, the collector of the transistor Q2 is coupled to the source of the MOS tube Q1, the emitter of the transistor Q2 is coupled to the end of the pull-up resistor R2, and the base of the transistor Q2 is coupled to another control pin of the main control chip (1).

7. A new type of water meter, characterized by: It comprises a low-power MOS switch circuit as claimed in any one of claims 1 to 6, and a communication serial port, wherein the communication serial port is communicatively connected to a main control chip (1) of the switch circuit.

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