CN212160467U

CN212160467U - Hardware control protection circuit for preventing overhigh water of instant water heater

Info

Publication number: CN212160467U
Application number: CN202020644350.2U
Authority: CN
Inventors: 许亚平; 张伟; 盛飞
Original assignee: Suzhou Langgao Intelligent Technology Co ltd
Current assignee: Suzhou Langgao Intelligent Technology Co ltd
Priority date: 2020-04-26
Filing date: 2020-04-26
Publication date: 2020-12-15
Anticipated expiration: 2030-04-26

Abstract

The utility model discloses an instant heating type water heater prevents too high hardware control protection circuit of water, it includes MCU control chip IC1, temperature sensing return circuit, oscillating circuit, dual voltage comparator chip IC4, triode Q1, optical coupling return circuit and silicon controlled rectifier return circuit, temperature sensing return circuit, oscillating circuit and triode Q1 respectively with MCU control chip IC1 electricity is connected, dual voltage comparator chip IC4 electricity respectively is connected between temperature sensing return circuit and triode Q1 and between oscillating circuit and the triode Q1, optical coupling return circuit electricity is connected between triode Q1 and the silicon controlled rectifier return circuit. The utility model discloses an instant heating type water heater prevents the too high hardware control protection circuit of water, can effectively avoid the too high potential safety hazard of temperature to and the software runs and flies and the potential safety hazard that causes.

Description

Hardware control protection circuit for preventing overhigh water of instant water heater

Technical Field

The utility model relates to an instant heating type water heater technical field, in particular to instant heating type water heater prevents too high hardware control protection circuit of water.

Background

In the technical field of instant water heaters, for example, the instant water heater applied in the kitchen and bathroom industry, the temperature control of the heater is realized by acquiring the resistance value of a thermistor by an MCU control chip and converting the resistance value into a temperature value, the power output of the heater is compared with a heating target temperature value by depending on the acquired temperature value, and then the power is controlled to be increased or reduced. The MCU is used as an electronic element, so that the risk of damage exists, a control power output pin is possibly in a high level state, the power is always output, the water outlet temperature is overhigh, and in addition, the control software in the MCU also has the possibility of running away, so that the power cannot be normally output.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to the above-mentioned defect among the prior art, provide an instant heating type water heater and prevent the too high hardware control protection circuit of water, can effectively avoid the too high potential safety hazard of temperature to and the software runs to fly and the potential safety hazard that causes.

In order to realize the purpose of the utility model, the utility model adopts the following technical scheme:

the utility model provides an instant heating type water heater prevents too high hardware control protection circuit of water, its includes MCU control chip IC1, temperature sensing return circuit, oscillation circuit, two voltage comparator chip IC4, triode Q1, optical coupling return circuit and silicon controlled rectifier return circuits, temperature sensing return circuit, oscillation circuit and triode Q1 respectively with MCU control chip IC1 electricity is connected, two voltage comparator chip IC4 electricity are connected respectively between temperature sensing return circuit and triode Q1 and between oscillation circuit and triode Q1, optical coupling return circuit electricity is connected between triode Q1 and the silicon controlled rectifier return circuit.

Furthermore, the utility model discloses still include following subsidiary technical scheme:

pin 3 of the dual-voltage comparator chip IC4 is electrically connected with the thermosensitive loop, and pin 5 of the dual-voltage comparator chip IC4 is electrically connected with the oscillating loop.

The oscillation circuit comprises a resistor R8, a capacitor C3, a switch diode IC5 and a capacitor C4, and the PA8 pin of the MCU control chip IC1 is electrically connected to the No. 5 pin of the double-voltage comparator chip IC4 through the resistor R8, the capacitor C3, the switch diode IC5 and the capacitor C4 in sequence.

The thermosensitive circuit comprises a plug CN1, a resistor R3, a resistor R4 and a resistor R5, wherein a pin 4 of the plug CN1 is electrically connected to a pin PA0 of the MCU control chip IC1 through the resistor R3, the resistor R4 and the resistor R5 in sequence, and a pin 3 of the dual-voltage comparator chip IC4 is electrically connected between the resistor R4 and the resistor R5.

The pin No. 2 of the plug CN1 is electrically connected to the pin No. 3 of the dual-voltage comparator chip IC4, and the pin No. 1 and the pin No. 2 of the plug CN1 are externally connected with thermistors.

The thermosensitive circuit further comprises a resistor R2, a capacitor C1 and a capacitor C2, the pin No. 4 of the plug-in CN1 is further electrically connected to the pin PA0 of the MCU control chip IC1 through the resistor R2, the capacitor C1 and the capacitor C2 in sequence, the pin PA1 of the MCU control chip IC1 is electrically connected between the resistor R2 and the capacitor C1, and the capacitor C1 and the capacitor C2 are grounded.

And the No. 1 pin and the No. 2 pin of the plug-in CN1 are electrically connected with a thermistor.

No. 2 pin bit and No. 6 pin bit of two voltage comparator chip IC4 are connected with the voltage circuit respectively, the voltage circuit includes resistance R6 and resistance R7, No. 2 pin bit and No. 6 pin bit of two voltage comparator chip IC4 pass through respectively resistance R6 is connected with 3.3V power electricity, No. 2 pin bit and No. 6 pin bit of two voltage comparator chip IC4 pass through respectively resistance R7 ground connection.

A diode D1 is electrically connected between the dual-voltage comparator chip IC4 and the transistor Q1, and the pin 1 and the pin 7 of the dual-voltage comparator chip IC4 are electrically connected to the base of the transistor Q1 through the diode D1 respectively.

The MCU control chip IC1 and the triode Q1 are electrically connected with a resistor R9, the base electrode of the triode Q1 is electrically connected with the PA12 pin of the MCU control chip IC1 through the resistor R9, and the collector electrode of the triode Q1 is electrically connected with the optical coupling loop.

Compared with the prior art, the utility model has the advantages of:

a double-circuit voltage comparator chip is adopted, wherein one circuit of voltage comparison is used for a thermosensitive loop, so that the potential safety hazard of overhigh water temperature is effectively avoided; the other path is used for an oscillation circuit, so that potential safety hazards caused by software running and damage of a control pin of the MCU control chip IC1 are effectively avoided, the two paths must be met simultaneously, the heater can normally work, the protection circuit plays a role in double guarantee, and the use is safer.

Drawings

FIG. 1 is a circuit diagram of a hardware control protection circuit for preventing water from being overhigh for an instant water heater

Detailed Description

The following non-limiting detailed description of the present invention is provided in connection with the preferred embodiments and accompanying drawings.

As shown in fig. 1, correspond to the utility model relates to an instant heating type water heater of preferred embodiment prevents the too high hardware control protection circuit of water, it includes MCU control chip IC1, the temperature sensing return circuit, the oscillation circuit, two voltage comparator chip IC4, triode Q1, optical coupling return circuit and silicon controlled rectifier return circuit, the temperature sensing return circuit, oscillation circuit and triode Q1 are connected with MCU control chip IC1 electricity respectively, two voltage comparator chip IC4 are electric connection respectively between temperature sensing return circuit and triode Q1 and between oscillation circuit and triode Q1, optical coupling return circuit electric connection is between triode Q1 and silicon controlled rectifier return circuit.

The dual voltage comparator IC4 is a link of the whole control circuit,

pins

1, 2 and 3 of the dual voltage comparator IC4 form a path of comparison circuit, and

pins

5, 6 and 7 form a path of comparison circuit. Specifically, pin 1 and pin 7 of the dual-voltage comparator chip IC4 are output pins, pin 2 and pin 6 are inverting input ports, pin 3 and pin 5 are inverting input ports, pin 4 is a ground pin, and pin 8 +5V is an input pin.

The No. 3 pin of the double-voltage comparator chip IC4 is electrically connected with a thermosensitive circuit, the thermosensitive circuit comprises a plug CN1, and the No. 4 pin of the plug CN1 is electrically connected with the PA0 pin of the MCU control chip IC1 through a resistor R3, a resistor R4 and a resistor R5 in sequence; pin 3 of the dual voltage comparator chip IC4 is electrically connected between the resistor R4 and the resistor R5; pin No. 2 of the card CN1 is electrically connected to pin No. 3 of the dual voltage comparator chip IC4, and intersects with an electric wire electrically connected between the resistor R4 and the resistor R5 at point H with pin No. 3 of the dual voltage comparator chip IC 4; pin 4 of the card CN1 is further electrically connected to pin PA0 of the MCU control chip IC1 through the resistor R2, the capacitor C1 and the capacitor C2 in turn; a PA1 pin of the MCU control chip IC1 is electrically connected between the resistor R2 and the capacitor C1, and the capacitor C1 and the capacitor C2 are grounded; the No. 1 pin and the No. 2 pin of the plug-in CN1 are externally connected with thermistors (not shown), the thermistors change along with the change of temperature, and the thermistors are arranged at the water outlet of the heater to collect the temperature of outlet water.

Pin 5 of the dual voltage comparator chip IC4 is electrically connected to the tank circuit. The oscillation circuit comprises a resistor R8, a capacitor C3, a switch diode IC5 and a capacitor C4, and a PA8 pin of the MCU control chip IC1 is electrically connected to a No. 5 pin of the dual-voltage comparator chip IC4 through the resistor R8, the capacitor C3, the switch diode IC5 and the capacitor C4 in sequence.

No. 2 pin and No. 6 pin of two voltage comparator chip IC4 are connected with the voltage circuit respectively, and the voltage circuit includes resistance R6 and resistance R7, and No. 2 pin and No. 6 pin of two voltage comparator chip IC4 are connected with the 3.3V power supply electricity through resistance R6 respectively, and No. 2 pin and No. 6 pin of two voltage comparator chip IC4 are through resistance R7 ground connection respectively. The pin 2 and the pin 6 of the dual voltage comparator IC4 are inserted into a 3.3V voltage loop formed by resistors R6 and R7, and the IN point IN the voltage loop obtains a stable and unchangeable voltage value which can be used as the reference voltage of the pin 3 and the pin 5 of the dual voltage comparator IC 4. The voltage value of the IN power is 3.3/(R6+ R7) × R7 is 0.992V, which is used as a voltage reference value.

A diode D1 is electrically connected between the dual-voltage comparator chip IC4 and the transistor Q1, and the pin 1 and the pin 7 of the dual-voltage comparator chip IC4 are electrically connected to the base of the transistor Q1 through the diode D1 respectively. The base of the triode Q1 is electrically connected to the PA12 pin of the MCU control chip IC1 through a resistor R9, the collector of the triode Q1 is electrically connected with the optical coupling loop, and the emitter of the triode Q1 is grounded through a resistor R10.

The optical coupling loop and the thyristor loop are both in the prior art, and the optical coupling loop and the thyristor loop which are commonly used are adopted, so that further description is omitted.

The utility model discloses an instant heating type water heater prevents that water from too high hardware control protection circuit's theory of operation does:

the thermistor is arranged at the water outlet of the heater to collect the water outlet temperature, when the water outlet temperature is too high, the thermistor changes to cause the voltage of the H point to be less than the reference voltage, the No. 1 pin of the double-voltage comparator chip IC4 outputs low level, the optical coupling loop is immediately turned off to stop the power output of the silicon controlled loop, and the water outlet temperature is controlled to be continuously too high; when the water outlet temperature is normal, the voltage of the point H is higher than the pin No. 2 of the double-voltage comparator chip IC4, the pin No. 1 of the double-voltage comparator chip IC4 is in high-level output, and the optical coupling loop and the silicon controlled loop can work normally. The power output circuit is switched off after the temperature is overhigh through the hardware circuit, and MCU software is not needed for control.

Secondly, when the MCU control chip IC1 is in a normal state, the PA8 pin of the MCU control chip IC1 outputs a pulse with a certain frequency, the inherent characteristic of the capacitor C3 is that the capacitor C3 is in a conducting state when a pulse voltage with a certain frequency passes through, a constant high level cannot pass through, and by using the characteristic, a resistor R8 and a capacitor C3 form a rc oscillation loop, through the switch diode IC5 and the capacitor C4, the No. 5 pin of the dual-voltage comparator chip IC4 obtains a voltage of more than 2V, so the No. 5 pin voltage of the dual-voltage comparator chip IC4 is compared with the No. 6 voltage of the dual-voltage comparator chip IC4, and the No. 5 pin is greater than the No. 6 pin, the No. 7 pin of the dual-voltage comparator chip IC4 outputs a high level, the diode D1 cannot be turned on, and the PA12 pin of the MCU control chip IC1 can normally control the on/off of the triode Q1. When the pin of PA8 of MCU control chip IC1 is constantly in low level or high level state, because capacitor C3 cannot pass through, so pin 5 voltage of dual-voltage comparator chip IC4 is 0V, which is smaller than pin 6 voltage, then output pin 7 of dual-voltage comparator chip IC4 is in low level, diode D1 can be conducted, when pin PA12 output level of MCU control chip IC1 triggers triode Q1, the current flows to resistor R9, diode D1 is connected to ground, triode Q1 cannot be opened, thereby realizing optical coupling loop, thyristor loop cannot work, when the control pin of MCU control chip IC1 is damaged, the circuit must be safe.

The hardware control protection circuit for preventing the water from being overhigh for the instant water heater adopts a double-circuit voltage comparator chip, wherein one circuit of voltage comparison is used for a thermosensitive loop, thereby effectively avoiding the potential safety hazard of overhigh water temperature; the other path is used for an oscillation circuit, so that potential safety hazards caused by software running and damage of a control pin of the MCU control chip IC1 are effectively avoided, the two paths must be met simultaneously, the heater can normally work, the protection circuit plays a role in double guarantee, and the use is safer.

It should be noted that the above-mentioned preferred embodiments are only for illustrating the technical concepts and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention accordingly, and the protection scope of the present invention cannot be limited thereby. All equivalent changes and modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.

Claims

1. The utility model provides an instant heating type water heater prevents too high hardware control protection circuit of water which characterized in that: it includes MCU control chip IC1, temperature sensing return circuit, oscillation circuit, two voltage comparator chip IC4, triode Q1, optical coupling return circuit and silicon controlled rectifier return circuit, temperature sensing return circuit, oscillation circuit and triode Q1 respectively with MCU control chip IC1 electricity is connected, two voltage comparator chip IC4 electricity are connected respectively between temperature sensing return circuit and triode Q1 and between oscillation circuit and the triode Q1, optical coupling return circuit electricity is connected between triode Q1 and the silicon controlled rectifier return circuit.

2. The tankless water heater of claim 1, further comprising a hardware controlled protection circuit for preventing excessive water, further comprising: pin 3 of the dual-voltage comparator chip IC4 is electrically connected with the thermosensitive loop, and pin 5 of the dual-voltage comparator chip IC4 is electrically connected with the oscillating loop.

3. The tankless water heater of claim 2, further comprising a hardware controlled protection circuit for preventing excessive water, further comprising: the oscillation circuit comprises a resistor R8, a capacitor C3, a switch diode IC5 and a capacitor C4, and the PA8 pin of the MCU control chip IC1 is electrically connected to the No. 5 pin of the double-voltage comparator chip IC4 through the resistor R8, the capacitor C3, the switch diode IC5 and the capacitor C4 in sequence.

4. The tankless water heater of claim 2, further comprising a hardware controlled protection circuit for preventing excessive water, further comprising: the thermosensitive circuit comprises a plug CN1, a resistor R3, a resistor R4 and a resistor R5, wherein a pin 4 of the plug CN1 is electrically connected to a pin PA0 of the MCU control chip IC1 through the resistor R3, the resistor R4 and the resistor R5 in sequence, and a pin 3 of the dual-voltage comparator chip IC4 is electrically connected between the resistor R4 and the resistor R5.

5. The tankless water heater of claim 4 further comprising a hardware controlled protection circuit for preventing excessive water, further comprising: the pin No. 2 of the plug CN1 is electrically connected to the pin No. 3 of the dual-voltage comparator chip IC4, and the pin No. 1 and the pin No. 2 of the plug CN1 are externally connected with thermistors.

6. The tankless water heater of claim 4 further comprising a hardware controlled protection circuit for preventing excessive water, further comprising: the thermosensitive circuit further comprises a resistor R2, a capacitor C1 and a capacitor C2, the pin No. 4 of the plug-in CN1 is further electrically connected to the pin PA0 of the MCU control chip IC1 through the resistor R2, the capacitor C1 and the capacitor C2 in sequence, the pin PA1 of the MCU control chip IC1 is electrically connected between the resistor R2 and the capacitor C1, and the capacitor C1 and the capacitor C2 are grounded.

7. The tankless water heater of claim 4 further comprising a hardware controlled protection circuit for preventing excessive water, further comprising: and the No. 1 pin and the No. 2 pin of the plug-in CN1 are electrically connected with a thermistor.

8. The hardware control protection circuit for preventing the instantaneous water heater from overhigh water according to any one of claims 1 to 7, characterized in that: no. 2 pin bit and No. 6 pin bit of two voltage comparator chip IC4 are connected with the voltage circuit respectively, the voltage circuit includes resistance R6 and resistance R7, No. 2 pin bit and No. 6 pin bit of two voltage comparator chip IC4 pass through respectively resistance R6 is connected with 3.3V power electricity, No. 2 pin bit and No. 6 pin bit of two voltage comparator chip IC4 pass through respectively resistance R7 ground connection.

9. The hardware control protection circuit for preventing the instantaneous water heater from overhigh water according to any one of claims 1 to 7, characterized in that: a diode D1 is electrically connected between the dual-voltage comparator chip IC4 and the transistor Q1, and the pin 1 and the pin 7 of the dual-voltage comparator chip IC4 are electrically connected to the base of the transistor Q1 through the diode D1 respectively.

10. The hardware control protection circuit for preventing the instantaneous water heater from overhigh water according to any one of claims 1 to 7, characterized in that: the MCU control chip IC1 and the triode Q1 are electrically connected with a resistor R9, the base electrode of the triode Q1 is electrically connected with the PA12 pin of the MCU control chip IC1 through the resistor R9, and the collector electrode of the triode Q1 is electrically connected with the optical coupling loop.