No need for MCU control of the water switch trigger holding circuit

Abstract

The present invention provides a triggering and holding circuit of a water switch that does not require MCU control. The circuit includes: a contact circuit, a first level inverting circuit, a second level inverting circuit, a reset circuit and a power supply circuit, wherein the contact circuit adopts a double contact structure, and triggers the subsequent circuit according to whether the two contacts are conductive; the first level inverting circuit and the second level inverting circuit are cascaded with each other, and are both used to achieve level inversion, and the output end of the second level inverting circuit is connected to the input end of the first level inverting circuit; the output end of the first level inverting circuit is connected to the input end of the power supply circuit. The triggering and holding circuit of a water switch that does not require MCU control provided by the present invention can use a discrete link to realize the self-locking closure of the water switch after falling into the water.

Description

Technical Field

[0001] The invention relates to the technical field of water fall detection, and in particular to a water fall switch trigger holding circuit that does not require MCU control. Background Art

[0002] The common practice of the current water switch circuit is to use double contacts (probes) for water detection. Since river water, sea water, etc. are not pure water and therefore not insulators, the contacts are turned on (equivalent to connecting a large resistor between the two contacts). By using this, when the contacts are under water, the control circuit of the water switch can be closed, thereby generating a control signal.

[0003] Directly using this control signal to control the on and off of the water switch can achieve the closure of the water switch when the contact (probe) is underwater. However, the disadvantage of this approach is that the water contact (probe) needs to remain below the water surface. Once the contact (probe) leaves the water surface, the water switch will be disconnected again, and the switch cannot be triggered once to close. Regardless of whether the subsequent contact leaves the water surface, the switch always remains closed until the reset switch function is pressed.

[0004] Another approach is to use the aforementioned control signal as a water fall detection signal, sample it with the back-end MCU, and use this water fall signal to control the MCU to achieve self-locking of the water fall switch, that is, the switch remains in a closed state after leaving the water. The disadvantage of this approach is that the back-end MCU must always be working. Since the device is usually powered by a battery, the device will continue to consume battery power when it is not falling into the water, reducing the device's standby time. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a trigger holding circuit for a water falling switch which does not require MCU control and can use a discrete link to realize self-locking closure of the water falling switch after falling into the water.

[0006] In order to solve the above technical problems, the present invention provides a water switch trigger holding circuit that does not require MCU control, and the circuit includes: a contact circuit, a first level inverting circuit, a second level inverting circuit, a reset circuit and a power supply circuit, wherein the contact circuit adopts a double-contact structure, and triggers the subsequent circuit according to whether the two contacts are conductive; the first level inverting circuit and the second level inverting circuit are cascaded with each other, both of which are used to realize level inversion, and the output end of the second level inverting circuit is connected to the input end of the first level inverting circuit; the output end of the first level inverting circuit is connected to the input end of the power supply circuit.

[0007] In some embodiments, the contact circuit includes: contact A, contact B, a fifth resistor R5, a sixth resistor R6, and a third CMOS Q3, and the third CMOS Q3 is an NMOS, wherein one end of the fifth resistor R5 is connected to the contact A, and the other end is connected to the power supply VCC_SCTL_IN; one end of the sixth resistor R6 is connected to the contact B, and the other end is grounded; the source of the third CMOS Q3 is grounded, the gate is connected to the contact B, and the drain is connected to the input end of the first level inversion circuit.

[0008] In some embodiments, the first level inverter circuit includes: a first resistor R1, a third resistor R3, and a first integrated dual field effect transistor Q1, wherein the first integrated dual field effect transistor Q1 integrates an NMOS and a PMOS, wherein one end of the first resistor R1 is connected to the power supply VCC_SCTL_IN, and the other end is connected to the source of the PMOS; one end of the third resistor R3 is connected to the power supply VCC_SCTL_IN, and the other end is connected to the gates of the NMOS and the PMOS; the drains of the NMOS and the PMOS are connected to the output end (DC_ON) of the first level inverter circuit; the gates of the NMOS and the PMOS are both connected to the input end of the first level inverter circuit; and the source of the NMOS is grounded.

[0009] In some embodiments, the second level inverter circuit includes: a second resistor R2 and a second integrated dual field effect transistor Q2, the second integrated dual field effect transistor Q2 integrates NMOS and PMOS, wherein one end of the second resistor R2 is connected to the power supply VCC_SCTL_IN, and the other end is connected to the source of PMOS; the gates of NMOS and PMOS are both connected to the input end (DC_ON) of the second level inverter circuit; the drains of NMOS and PMOS are both connected to the input end of the first level inverter circuit; the source of NMOS is grounded.

[0010] In some embodiments, the power supply circuit includes: a fourth resistor R4, a fourth CMOS Q4 and a fifth CMOS Q5, and the fourth CMOS Q4 is an NMOS, and the fifth CMOS Q5 is a PMOS, wherein one end of the fourth resistor R4 is connected to the power supply VCC_SCTL_IN, and the other end is connected to the gate of the fifth CMOS Q5; the gate of the fourth CMOS Q4 is connected to the input end (DC_ON) of the second level reverse circuit, the source is grounded, and the drain is connected to the gate of the fifth CMOS Q5; the source of the fifth CMOS Q5 is connected to the power supply VCC_SCTL_IN, and the drain is the system power supply output.

[0011] In some embodiments, the power circuit includes: a first key switch S1 , wherein one end of the first key switch S1 is connected to the input end (DC_ON) of the second level inversion circuit, and the other end of the first key switch S1 is grounded.

[0012] After adopting such a design, the present invention has at least the following advantages:

[0013] The dual-level inverting circuit is effectively used to form a self-locking steady-state circuit, which can complete the water fall detection without an MCU and control the subsequent power switch to turn on, thereby realizing the water fall detection and water fall switch closure self-locking function with ultra-low power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0015] Figure 1 This is the block diagram of the self-locking switch for detecting falling into water;

[0016] Figure 2 This is the schematic diagram of the water fall detection self-locking switch. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0018] A water drop switch trigger holding circuit that does not require MCU control: includes a level inversion circuit, an initial state signal, a contact circuit, a water drop switch control signal, a reset circuit and a controllable power supply circuit. The level inversion circuit is responsible for forming a steady-state circuit. The initial state signal is responsible for initializing the steady-state circuit and stabilizing it in a "high-low-high" state. The contact circuit is responsible for generating a trigger signal after the double-contact water drop is turned on, and adjusting the steady-state circuit to a "low-high-low" state. The water drop switch control signal is a control signal of the subsequent controllable power supply circuit, which is effective at a high level (conducting), and takes the intermediate level signal of the two-stage inversion circuit, that is, high in the "low-high-low" state and low in the "high-low-high" state. The controllable power supply circuit is responsible for powering the system, and is controlled by the water drop switch control signal, with a high level turning on and a low level turning off. The reset circuit is responsible for pressing the switch after the device leaves the water surface, pulling down the "high" level in the "low-high-low" stable state of the circuit, and restoring the circuit to the initial state of "high-low-high".

[0019] The two-stage level inversion circuit cascade can achieve two stable states of "high-low-high" or "low-high-low";

[0020] After the initial state signal is applied to the above-mentioned level inversion circuit, the stable state of this circuit can be kept initialized to a stable state of "high-low-high";

[0021] Responsible for converting the state of the equipment falling into water into a trigger signal (low-level signal), changing the state of the steady-state circuit from "high-low-high" to "low-high-low";

[0022] The water drop switch control signal is the intermediate stage signal of the steady-state circuit. The initial state is "low", at which time the power supply of the subsequent stage is turned off; after the equipment falls into the water, this signal becomes "high", turning on the power supply of the subsequent stage;

[0023] Controlled by the control signal of the water falling switch, the control end is shut down at a low level and turned on at a high level, and the system is powered after being turned on.

[0024] The reset circuit is responsible for pressing the switch after the device leaves the water surface, pulling down the "high" level in the "low-high-low" stable state of the circuit, and restoring the circuit to the initial state of "high-low-high";

[0025] The present invention adopts the following technical solution:

[0026] A water switch trigger holding circuit that does not require MCU control includes a level inversion circuit, an initial state signal, a contact circuit, a water switch control signal, a reset circuit and a controllable power supply circuit. Among them:

[0027] The level inversion circuit is composed of a P-type field effect transistor and an N-type field effect transistor to achieve the inversion of the input level (high-low level conversion);

[0028] The inverting circuit, with the input and output ends connected end to end, forms a closed-loop feedback circuit, which can realize a "high-low-high" or "low-high-low" stable state circuit;

[0029] The initial state signal is responsible for giving the above-mentioned closed-loop feedback circuit an initial state when powered on. In this solution, the initial state is selected as a high level to achieve a stable state of "high-low-high" for the closed-loop feedback circuit;

[0030] The contact circuit is responsible for generating a "ground" signal (low-level signal) after the device contact falls into water, changing the state of the closed-loop feedback circuit from "high-low-high" to a stable state of "low-high-low". Before falling into water, this circuit is not conducting, which is equivalent to an open circuit, and does not affect the initial state of the closed-loop feedback circuit;

[0031] The water drop switch control signal is a control signal of the subsequent controllable power supply circuit, and the high level is effective (conduction);

[0032] When the closed-loop feedback circuit is in a stable state, the control signal of the water switch is taken from the middle of the two inverting circuits. When the closed-loop feedback circuit is in a stable state of "high-low-high", the level of the water switch control signal is "low", and the controllable power supply circuit is disconnected; conversely, when the closed-loop feedback circuit is in a stable state of "low-high-low", the level of the water switch control signal is "high", and the controllable power supply circuit is turned on;

[0033] The controllable power supply circuit is the power supply path of the system, which is controlled on and off by the water fall switch control signal to realize the system power supply after the equipment falls into the water;

[0034] The reset circuit is a key switch. After the device leaves the water surface, the switch is pressed to pull down the "high" level in the "low-high-low" stable state of the circuit, so that the circuit is restored to the initial state of "high-low-high";

[0035] The technical solution of the present invention effectively utilizes a dual-level inverting circuit to form a self-locking steady-state circuit, thereby completing water fall detection without an MCU and controlling the subsequent power switch to turn on, thereby realizing water fall detection and water fall switch closure self-locking function with ultra-low power consumption.

[0036] The advantage of the present invention is that without using MCU control, a discrete link is used to realize the self-locking closure of the water switch after falling into the water. Even if the contact (probe) leaves the water surface again, the closed state of the water switch can be maintained until the reset button is pressed. Therefore, water detection and self-locking closure of the water switch can be realized with ultra-low power consumption.

[0037] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Those skilled in the art may make some simple modifications, equivalent changes or modifications using the technical contents disclosed above, which all fall within the protection scope of the present invention.

Claims

1. A water switch trigger holding circuit without MCU control, characterized in that: include: A contact circuit, a first level inverting circuit, a second level inverting circuit, a reset circuit and a power supply circuit, wherein: The contact circuit adopts a double contact structure, and triggers the subsequent circuit according to whether the two contacts are conductive. The contact circuit includes: contact A, contact B, a fifth resistor R5, a sixth resistor R6, and a third CMOS Q3, and the third CMOS Q3 is NMOS, wherein, One end of the fifth resistor R5 is connected to the contact A, and the other end is connected to the power supply VCC_SCTL_IN; One end of the sixth resistor R6 is connected to the contact B, and the other end is grounded; The source of the third CMOS Q3 is grounded, the gate is connected to the contact B, and the drain is connected to the input terminal of the first level inversion circuit; The first level inverting circuit and the second level inverting circuit are cascaded to each other, and are both used to achieve level inversion, and the output end of the second level inverting circuit is connected to the input end of the first level inverting circuit; The output terminal of the first level inverting circuit is connected to the input terminal of the power supply circuit; The first level inversion circuit includes: a first resistor R1, a third resistor R3, and a first integrated dual-path field effect transistor Q1. The first integrated dual-path field effect transistor Q1 integrates an NMOS and a PMOS, wherein: One end of the first resistor R1 is connected to the power supply VCC_SCTL_IN, and the other end is connected to the source of the PMOS; One end of the third resistor R3 is connected to the power supply VCC_SCTL_IN, and the other end is connected to the gates of the NMOS and the PMOS; The drains of the NMOS and the PMOS are connected to the output end (DC_ON) of the first level inverter circuit; The gates of the NMOS and the PMOS are both connected to the input end of the first level inverting circuit; The source of the NMOS is grounded; The second level inversion circuit includes: a second resistor R2 and a second integrated dual-path field effect transistor Q2, wherein the second integrated dual-path field effect transistor Q2 integrates NMOS and PMOS, wherein: One end of the second resistor R2 is connected to the power supply VCC_SCTL_IN, and the other end is connected to the source of the PMOS; The gates of the NMOS and the PMOS are both connected to the input terminal (DC_ON) of the second level inversion circuit; The drains of the NMOS and the PMOS are both connected to the input end of the first level inverting circuit; The source of the NMOS is grounded.

2. The water switch trigger holding circuit without MCU control according to claim 1 is characterized in that: The power circuit includes: a fourth resistor R4, a fourth CMOS Q4 and a fifth CMOS Q5, wherein the fourth CMOS Q4 is an NMOS and the fifth CMOS Q5 is a PMOS, wherein: One end of the fourth resistor R4 is connected to the power supply VCC_SCTL_IN, and the other end is connected to the gate of the fifth CMOS Q5; The gate of the fourth CMOS Q4 is connected to the input terminal (DC_ON) of the second level inversion circuit, the source is grounded, and the drain is connected to the gate of the fifth CMOS Q5; The source of the fifth CMOS Q5 is connected to the power supply VCC_SCTL_IN, and the drain is the system power supply output.

3. The water switch trigger holding circuit without MCU control according to claim 1, characterized in that: The reset circuit includes: a first key switch S1, wherein: One end of the first key switch S1 is connected to the input end (DC_ON) of the second level inverting circuit, and the other end is grounded.

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