Novel power-off valve-closing unloading circuit
The novel valve discharge circuit with a MOSFET-based control mechanism addresses the challenge of reliable valve closure during power outages in smart water meters, ensuring protection and preventing water theft and component damage.
Patent Information
- Application Number
- CN202422196738.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-09
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-09-09
AI Technical Summary
Existing smart water meters are difficult to close the valve in time after power is powered off, resulting in an increased risk of water theft and may damage the motor and micro switches.
A new power-off valve discharge circuit is designed, and the power supply is used to store electrical energy after power-off. The power supply is to close the valve and control the discharge channel through the field effect transistor to prevent damage to the motor and micro switches.
It realizes the timely closing of the valve after power is cut off, protecting the water circuit and water meter, preventing water stolen, and avoiding damage to the motor and micro switches.
Smart Images
Figure CN223105417U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a novel power-off valve-closing and load-discharging circuit, belonging to the technical field of water meter circuits. Background Art
[0002] In the current water supply system, intelligent water meters have been widely used. The use of intelligent water meters depends on the power supply. If the power supply is abnormal, the intelligent water meter will lose power. At present, to close the valve after power-off for preventing water theft and prompting the water plant and users of the water meter abnormality, most power-off valve-closing circuits adopt the method of using an MCU detection circuit to control the continuous discharge of a charging capacitor to supply power to the system. When the selection of the MCU is restricted or for improving the program utilization rate, this power-off valve-closing and load-discharging circuit is specially designed. Content of the Utility Model
[0003] The purpose of the utility model is to provide a novel power-off valve-closing and load-discharging circuit.
[0004] To achieve the above purpose, the technical scheme adopted by the utility model is as follows:
[0005] A novel power-off valve-closing and load-discharging circuit structure, where one end of a power supply is connected to one end of a resistor R1, the other end of R1 is connected to a diode D2, the positive pole of a capacitor C1 is connected to D2, the negative pole of the capacitor C1 is connected to GND, and at the same time, the power supply is connected to a detection and control circuit through a diode D1. In the detection and control circuit, the positive pole of the capacitor C1 is connected to the gate of a Q1 through an R5 and to the source of a Q2 through an R6; the output of the diode D1 is connected to the source of the Q1, and through a resistor R7, it is connected to the gate of the Q2 and through a pull-down resistor R2 to GND; the drain of the Q1 is connected to the gate of a Q4 through a resistor R8, the drain of the Q4 is connected to the valve closed-in-place signal terminal, and the source of the Q4 is connected to the valve motor OFF terminal through a resistor R3; the drain of the Q2 is connected to the valve motor OFF terminal and through a resistor R4 to the gate of a Q3; the source of the Q3 is connected to GND, and the drain of the Q3 is connected to the valve motor ON terminal.
[0006] Due to the adoption of the above technical scheme, the technical effects obtained by the utility model are as follows:
[0007] The utility model can timely close the valve after power-off, playing a protective role for the water circuit and the water meter. Description of the Drawings
[0008] Figure 1 It is the circuit connection structure diagram of the utility model. Specific Embodiments
[0009] To make the technical means, creative features, achieved purposes and functions of the utility model easy to understand, the following further elaborates the utility model in combination with specific embodiments.
[0010] The utility model is a novel power-off valve-closing and load-discharging circuit structure used in the control of intelligent water meters.
[0011] The design principle of this circuit is that after the system is powered on, the power supply charges the capacitor. When the capacitor is fully charged, it no longer consumes electrical energy and the system works normally. After power-off, the circuit detects the loss of power in the main circuit, that is, it consumes the electrical energy stored in the capacitor to supply energy for the valve closing action. After the valve is closed, the unloading circuit is opened to release the excess electrical energy to prevent damage to the motor and micro-switch.
[0012] As Figure 1 shown, Figure 1 it is a schematic diagram of the circuit connection. In this circuit, there is a power supply VCC. One end of the power supply VCC is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to the diode D2. The diode D2 is also connected to the positive electrode of the capacitor C1, and the negative electrode of the capacitor C1 is connected to GND. At the same time, the power supply VCC is connected to the detection control circuit through the diode D1. In the detection control circuit, the positive electrode of the capacitor C1 is connected to the gate of Q1 through the resistor R5 and to the source of Q2 through the resistor R6. The output of the diode D1 is connected to the source of Q1, and through the resistor R7 to the gate of Q2, and through the pull-down resistor R2 to GND. The drain of Q1 is connected to the gate of Q4 through the resistor R8. The drain of Q4 is connected to the valve closed-in-place signal terminal. The source of Q4 is connected to the OFF terminal of the valve motor through the resistor R3. The drain of Q2 is connected to the OFF terminal of the valve motor and is connected to the gate of Q3 through the resistor R4. The source of Q3 is connected to GND, and the drain of Q3 is connected to the ON terminal of the valve motor. The above Q1, Q2, Q3, and Q4 are field effect transistors.
[0013] The working principle of this circuit is as follows: After the power supply is powered on, the capacitor C1 is charged through the current-limiting resistor R1 and the unidirectional diode D2. D2 prevents the capacitor C1 from discharging into the system circuit. After C1 is fully charged, the gate of Q1 is at a high level, the source and drain of Q1 are conducting, the power supply diode D1 is at a high level after power supply, the gate of Q4 is at a high level, Q4 is not conducting, the unloading channel is closed, and it does not affect the normal judgment of the system for the valve to reach the position. After D1 is at a high level, the gate of Q2 is at a high level, Q2 is not conducting, and it does not affect the OFF state of the valve motor. When the system opens the valve and OFF is low, Q3 is not conducting and it does not affect the system to open the valve. When the system closes the valve and OFF is high, Q3 is conducting and ON is low, and it does not affect the system to close the valve.
[0014] When the system is powered off, the capacitor C1 discharges. The pull-down resistor R2 after D1 pulls it down to a low level. So it is at a low level, Q2 is conducting, the current passes through R6, Q2 to the OFF terminal, OFF is at a high level, so the gate of Q3 is at a high level, Q3 is conducting, ON is grounded, and the valve motor gets power to close the valve; The pull-down resistor R2 after D1 pulls it down to a low level, the source of Q1 is at a low level. Since the gate of Q1 is at a high level, Q1 is conducting, so the gate of Q4 is at a low level, Q4 is conducting, and the unloading channel is opened, waiting for the detection of the closed position.
[0015] After the switch is closed, OFF is connected to the source of Q4 through R3, and the switch-closed detection is connected to the common terminal GND. If there is more than the required power, the current flows through the resistor R3 into GND to avoid damaging the motor and the micro switch.
[0016] This circuit operates under normal conditions. The pull-down resistor R2 will consume current and increase power consumption. If you want to optimize low power consumption, then increase the value of R2 accordingly. When testing, R2 is selected as 1MΩ, and the increased current is 3.3uA. Select a suitable resistor according to the power consumption requirements. The threshold voltage of the MOS transistor is about 1.3V. Therefore, when the voltage of the capacitor is lower than 1.3V, the circuit is cut off and the valve no longer operates. The resistor R1 affects the charging speed of the capacitor C1. The full charge time is about 5RC. If the capacitor is 1F and the resistor is 100Ω, it takes about 500 seconds to be fully charged. The required charge Q for closing the valve = I * t, which is about 0.4 coulombs. Considering circuit losses and the MOS transistor threshold voltage to ensure that the valve can be closed in place, the capacitor C1 is selected as 1F, and the maximum stored charge Q = CU, which is about 3.3 coulombs.
[0017] The utility model can timely close the valve after power failure, playing a protective role for the water circuit and the water meter.
[0018] The above shows and describes the basic principles, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model will have various changes and improvements, and these changes and improvements all fall within the scope of the utility model claimed. The scope of protection claimed by the utility model is defined by the appended claims and their equivalents.
Claims
1. A novel power-off valve-closing unloading circuit structure, characterized in that: One end of the power connection resistor R1 is connected to one end of the power supply, and the other end of R1 is connected to the diode D2. The D2 is connected to the positive electrode of the capacitor C1, and the negative electrode of the capacitor C1 is connected to GND. At the same time, the power supply is connected to the detection and control circuit through the diode D1. In the detection and control circuit, the positive electrode of the capacitor C1 is connected to the gate of Q1 through R5 and to the source of Q2 through R6. The output of the diode D1 is connected to the source of Q1, connected to the gate of Q2 through the resistor R7, and connected to GND through the pull-down resistor R2. The drain of Q1 is connected to the gate of Q4 through the resistor R8. The drain of Q4 is connected to the valve closed signal terminal, and the source of Q4 is connected to the OFF terminal of the valve motor through the resistor R3. The drain of Q2 is connected to the OFF terminal of the valve motor and connected to the gate of Q3 through the resistor R4. The source of Q3 is connected to GND, and the drain of Q3 is connected to the ON terminal of the valve motor.