Heating film power supply circuit

Abstract

The utility model discloses a heating film power supply circuit. The heating film power supply circuit comprises an on-off module and a protection module. The on-off module is respectively connected with a power supply and the heating film, and the protection module is connected with the on-off module and the single chip microcomputer; the protection module is used for sending a conduction signal to the on-off module when receiving the pulse electric signal sent by the single chip microcomputer; and the on-off module is used for conducting the connection between the power supply and the heating film when receiving the conduction signal. The single-chip microcomputer circularly generates a PWM signal and transmits the PWM signal to the protection module, the protection module generates a conduction signal and controls the on-off module through the conduction signal, and the on-off module controls the heating film to start; when the single-chip microcomputer crashes, the PWM signal cannot be generated and transmitted to the protection module, the protection module sends a disconnection signal to the on-off module, and the on-off module disconnects the power supply and the heating film to protect the heating film.

Description

Technical Field

[0001] This utility model relates to the field of circuit protection technology, and in particular to a heating film power supply circuit. Background Technology

[0002] Heating films are typically composed of a composite of conductive materials (such as metal foil, conductive ink, etc.) and insulating materials. When current passes through the conductive material, electrical energy is converted into heat energy due to resistance, thus raising the temperature of the heating film. It heats up evenly and rapidly. However, if the control program malfunctions or the control circuit malfunctions, causing the heating film to remain in a continuously heating state, its temperature may rise significantly exceeding the preset target heating temperature, potentially damaging the heated object. For example, if the heated object is a bottled gas, continuous heating could lead to serious accidents such as a gas cylinder explosion. Currently, the control circuit only has on / off functions and does not consider protection measures for single-component failures in the control circuit or control program malfunctions. Utility Model Content

[0003] The main purpose of this invention is to propose a heating film power supply circuit, which aims to solve abnormal situations such as single device failure and control program crash in the control circuit.

[0004] To achieve the above objectives, the heating film power supply circuit proposed in this utility model includes: a switching module and a protection module;

[0005] The on / off module is connected to the power supply and the heating film respectively, and the protection module is connected to the on / off module and the microcontroller;

[0006] The protection module is used to send a conduction signal to the on / off module when it receives a pulse electrical signal sent by the microcontroller;

[0007] The on / off module is used to connect the power supply and the heating film when the on signal is received.

[0008] In one embodiment, the heating film power supply circuit further includes: a driving module;

[0009] The driving module is connected to the negative electrode and ground wire of the heating film and the microcontroller;

[0010] The driving module is used to control the heating film to start heating when it receives the turn-on signal from the microcontroller and the connection between the power supply and the heating film is made active.

[0011] In one embodiment, the heating film power supply circuit further includes: an isolation module;

[0012] The isolation module connects the microcontroller and the protection module;

[0013] The isolation module is used to control the protection module to send a disconnect signal to the on / off module when it detects that the microcontroller has stopped sending pulse electrical signals;

[0014] The on / off module is used to disconnect the power supply and the heating film when the disconnection signal is received.

[0015] In one embodiment, the heating film power supply circuit further includes: a first bias module and a second bias module;

[0016] The first bias module is connected to the power supply and the switching module respectively, and the second bias module is connected to the isolation module and the protection module respectively;

[0017] The first bias module is used to provide a first bias voltage to the on / off module;

[0018] The second bias module is used to provide a second bias voltage to the protection module.

[0019] In one embodiment, the on / off module includes: a first MOS transistor;

[0020] The source of the first MOS transistor is connected to the power supply, the gate of the first MOS transistor is connected to the protection module, and the drain of the first MOS transistor is connected to the heating film.

[0021] In one embodiment, the first bias module includes: a first capacitor and a first resistor;

[0022] One end of the first resistor is connected to the power supply, one end of the first capacitor, and the source of the first MOSFET. The other end of the first resistor is connected to the other end of the first capacitor, the gate of the first MOSFET, and the protection module. The drain of the first MOSFET is connected to the driving module.

[0023] In one embodiment, the isolation module includes: a second capacitor and a second resistor;

[0024] One end of the second capacitor is connected to the microcontroller, the other end of the second capacitor is connected to the second resistor, and the other end of the second resistor is connected to the second bias module.

[0025] In one embodiment, the second bias module includes: a third capacitor and a third resistor;

[0026] One end of the third capacitor is connected to the isolation module, one end of the third resistor, and the protection module, while the other end of the third capacitor and the other end of the third resistor are grounded.

[0027] In one embodiment, the protection module includes: a first transistor;

[0028] The base of the first transistor is connected to one end of the third capacitor, the other end of the second resistor, and one end of the third resistor. The collector of the first transistor is connected to the switching module, and the emitter of the first transistor is grounded.

[0029] In one embodiment, the driving module includes: a second MOSFET and a first diode;

[0030] The cathode of the first diode is connected to the positive electrode of the heating film, the anode of the first diode is connected to the negative electrode of the heating film and the drain of the second MOS transistor, the gate of the second MOS transistor is connected to the microcontroller, and the source of the second MOS transistor is connected to the source of the microcontroller.

[0031] This utility model discloses a power supply circuit for a heating film. The power supply circuit includes an on / off module and a protection module. The on / off module is connected to a power supply and a heating film, respectively, and the protection module is connected to the on / off module and a microcontroller. The protection module sends a conduction signal to the on / off module when it receives a pulse electrical signal from the microcontroller. The on / off module, upon receiving the conduction signal, connects the power supply and the heating film. The microcontroller cyclically generates PWM signals and transmits them to the protection module. The protection module generates a conduction signal, which controls the on / off module to start the heating film. When the microcontroller crashes, it cannot generate and transmit PWM signals to the protection module. The protection module then sends a disconnect signal to the on / off module, which disconnects the power supply and the heating film to protect the heating film. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0033] Figure 1 A schematic diagram of the first embodiment of the heating film power supply circuit provided by this utility model;

[0034] Figure 2 A circuit diagram of the second embodiment of the heating film power supply circuit provided by this utility model.

[0035] Explanation of icon numbers:

[0036]

[0037] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0038] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0039] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0040] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0041] Heating films are typically composed of a composite of conductive materials (such as metal foil, conductive ink, etc.) and insulating materials. When current passes through the conductive material, electrical energy is converted into heat energy due to resistance, thus raising the temperature of the heating film. It heats up evenly and rapidly. However, if the control program malfunctions or the control circuit malfunctions, causing the heating film to remain in a continuously heating state, its temperature may rise significantly exceeding the preset target heating temperature, potentially damaging the heated object. For example, if the heated object is a bottled gas, continuous heating could lead to serious accidents such as a gas cylinder explosion. Currently, the control circuit only has on / off functions and does not consider protection measures for single-component failures in the control circuit or control program malfunctions.

[0042] Please see Figure 1 , Figure 1This is a module diagram of the first embodiment of the heating film power supply circuit proposed in this utility model.

[0043] This utility model discloses a power supply circuit for a heating film. The power supply circuit for the heating film includes a switching module 200 and a protection module 300; the switching module is connected to a power supply 100 and a heating film 400 respectively, and the protection module is connected to the switching module 200 and a microcontroller 500; the protection module 300 is used to send a conduction signal to the switching module when it receives a pulse electrical signal sent by the microcontroller; the switching module 200 is used to connect the power supply 100 and the heating film 400 when it receives the conduction signal.

[0044] Understandably, a microcontroller is a controller that uses very large-scale integrated circuit technology to integrate functions such as a central processing unit (CPU) with data processing capabilities, random access memory (RAM), read-only memory (ROM), multiple I / O ports and interrupt system, timer / counter, etc. It can be a CPU, MCU, MPU, SOC, DSP, ECU, GPU, FPGA, etc.

[0045] It should be noted that the pulse electrical signal sent by the microcontroller is a PWM signal. PWM, or Pulse Width Modulation, is a method of simulating continuously changing analog signals by changing the pulse width (i.e., duty cycle). In a PWM signal, the period of each pulse is fixed, but the pulse width (i.e., the duration of the high level) can be adjusted as needed.

[0046] In this embodiment, the microcontroller cyclically generates PWM signals and transmits them to the protection module. The protection module generates a conduction signal, which controls the on / off module to start the heating film. When the microcontroller crashes, it cannot generate and transmit PWM signals to the protection module. The protection module sends a disconnection signal to the on / off module, which disconnects the power supply and the heating film to protect the heating film.

[0047] Figure 2 This is a circuit diagram of the second embodiment of the heating film power supply circuit proposed in this utility model.

[0048] The heating film power supply circuit further includes: an isolation module 600; the isolation module 600 is connected to the microcontroller 500 and the protection module 300; the isolation module 600 is used to control the protection module to send a disconnect signal to the on / off module when it detects that the microcontroller has stopped sending pulse electrical signals; the on / off module 200 is used to disconnect the power supply and the heating film when it receives the disconnect signal.

[0049] It is understandable that when the microcontroller malfunctions, such as when an overcurrent occurs, the components of the protection module will be damaged. In order to protect the components of the protection module, this application adds an isolation module. When the microcontroller malfunctions, the protection module will only detect that the microcontroller's PWM signal has stopped sending and determine that the microcontroller has crashed, without being affected by the fault current of the microcontroller.

[0050] The isolation module 600 includes: a second capacitor C2 and a second resistor R2; one end of the second capacitor is connected to the microcontroller, the other end of the second capacitor is connected to the second resistor, and the other end of the second resistor is connected to the second bias module.

[0051] It should be noted that the isolation module uses a second capacitor C2, and there is dielectric isolation between the capacitors. There is no direct electrical connection between the microcontroller and the protection module. Capacitor isolation can effectively prevent the current and interference signals of the microcontroller from propagating to the protection module 300, thereby protecting the equipment and signal source of the protection module 300.

[0052] It is understandable that when the microcontroller outputs a high level abnormally, if there is no isolation module and the protection module is directly connected to the microcontroller, the protection module will continuously output a conduction signal, and the protection module will not be able to detect that the microcontroller is in an abnormal state. Therefore, it is necessary to use capacitor isolation, while the second resistor is used to reduce the voltage and protect the second capacitor from being broken down.

[0053] The protection module includes: a first transistor T1; the base of the first transistor is connected to one end of the third capacitor, the other end of the second resistor and one end of the third resistor, the collector of the first transistor is connected to the switching module 200, and the emitter of the first transistor is grounded.

[0054] The on / off module includes: a first MOSFET Q1; the source of the first MOSFET Q1 is connected to the power supply, the gate of the first MOSFET Q1 is connected to the protection module 300, and the drain of the first MOSFET Q1 is connected to the heating film.

[0055] It should be noted that after the system is powered on, the microcontroller generates periodic high and low level signals in a loop, which turns on the first transistor T1, thereby turning on the first MOSFET Q1, allowing the heating film to start and stop normally.

[0056] Understandably, when the microcontroller crashes while the heating film is in operation, the periodic high and low level signals cannot be output normally, and can only continuously output high or low levels. At this time, the first transistor T1 is immediately turned off, thereby turning off the first MOSFET Q1, cutting off the power supply to the heating film, stopping the heating film from heating, and thus protecting the heated object.

[0057] Optionally, the first MOSFET Q1 can be replaced by a transistor or a relay, and the first transistor T1 can be replaced by a MOSFET or a relay.

[0058] The heating film power supply circuit further includes: a first bias module 800 and a second bias module 900; the first bias module is connected to the power supply and the switching module respectively, and the second bias module is connected to the isolation module and the protection module respectively; the first bias module 800 is used to provide a first bias voltage to the switching module; the second bias module 900 is used to provide a second bias voltage to the protection module.

[0059] It is understandable that resistors are used for biasing in the switching and protection modules. In voltage divider bias circuits, the combination of resistors and capacitors can significantly improve operational stability.

[0060] The first bias module includes: a first capacitor C1 and a first resistor R1; one end of the first resistor R1 is connected to the power supply, one end of the first capacitor C1 and the source of the first MOSFET Q1, the other end of the first resistor R1 is connected to the other end of the first capacitor C1, the gate of the first MOSFET Q1 and the protection module 300, and the drain of the first MOSFET Q1 is connected to the heating film 400.

[0061] The second bias module includes a third capacitor C3 and a third resistor R3; one end of the third capacitor C3 is connected to the isolation module 600, one end of the third resistor R3 and the protection module 300, and the other end of the third capacitor C3 and the other end of the third resistor R3 are grounded.

[0062] It should be noted that in the protection module, when the first transistor T1 is in the amplification region, a stable bias voltage is required at its base. The third resistor R3 between the collector and base, along with the second resistor R2 connected to the base, forms a voltage divider network. The third capacitor C3 and the third resistor R3 work together to significantly improve the stability of the operating point. In the switching module, the first resistor R1 is used to provide a bias voltage for the first MOSFET Q1 to control its operating state, ensuring that the first MOSFET Q1 operates within the correct voltage range, thereby maintaining the stability and reliability of the circuit. The parallel connection of resistors and capacitors plays several important roles in the circuit, including current limiting, controlling the gate charging and discharging speed, preventing gate oscillation, adjusting the threshold voltage, providing bias, protecting the MOSFET switching transistor, and reducing switching noise.

[0063] In this embodiment, after the system is powered on, the microcontroller generates periodic high and low level signals in a loop. The first transistor T1 is turned on, which in turn turns on the first MOSFET Q1, enabling the heating film's on / off module to start and stop heating normally. When the heating film is working, if the microcontroller crashes, the periodic high and low level signals cannot be output normally and can only continuously output a high or low level. At this time, the first transistor T1 is immediately turned off, which turns off the first MOSFET Q1, cutting off the power supply to the heating film to stop heating and thus protect the heated object.

[0064] Figure 2 This is a circuit diagram of the third embodiment of the heating film power supply circuit proposed in this utility model.

[0065] The power supply circuit for the heating film further includes a driving module; the driving module is connected to the negative terminal and ground wire of the heating film and the microcontroller; the driving module is used to control the heating film to start heating when it receives the turn-on signal from the microcontroller and the connection between the power supply and the heating film is made conductive.

[0066] It is understandable that the drive module is equivalent to the switch of the heating film. When the drive module receives the turn-on signal from the microcontroller, it controls the power supply circuit of the heating film to be turned on and starts heating.

[0067] The driving module includes a second MOSFET Q2 and a first diode D1; the cathode of the first diode D1 is connected to the positive electrode of the heating film 400, the anode of the first diode D1 is connected to the negative electrode of the heating film and the drain of the second MOSFET Q2, the gate of the second MOSFET Q2 is connected to the microcontroller, and the source of the second MOSFET Q2 is connected to the source of the second MOSFET Q2.

[0068] It should be noted that after the system is powered on, the microcontroller cyclically generates periodic high and low level signals, turning on the first transistor T1, which in turn turns on the first MOSFET Q1. This allows the heating film's driving module to normally control the heating film's start and stop. The heating operation mode after the heating film starts is as follows: the microcontroller sends a high level to the driving module, the second MOSFET Q2 turns on, the heating film's power supply circuit is turned on, and the heating film starts heating. The heating operation mode after the heating film stops is as follows: the microcontroller sends a low level to the driving module, the second MOSFET is turned off, the heating film's power supply circuit is cut off, and the heating film stops heating.

[0069] Understandably, when the microcontroller crashes while the heating film is heating, the periodic high and low level signals cannot be output normally. The microcontroller can only continuously output a high or low level to the protection module. At this time, the first transistor T1 is immediately turned off, thereby cutting off the first MOSFET, disconnecting the heating film from the power supply, stopping the heating film from heating, and thus protecting the heated object.

[0070] Alternatively, the second MOSFET can be replaced by a transistor or a relay.

[0071] In this embodiment, after the system is powered on, the microcontroller generates periodic high and low level signals, turning on the first transistor T1, which in turn turns on the first MOSFET Q1. This allows the heating film's driving module to control the heating film's start and stop normally. The heating operation mode after the heating film starts is as follows: the microcontroller sends a high level to the driving module, turning on the second MOSFET Q2, and the heating film's power supply circuit is turned on, thus starting the heating film. The heating operation mode after the heating film stops is as follows: the microcontroller sends a low level to the driving module, turning off the second MOSFET, cutting off the heating film's power supply circuit, and stopping the heating film.

[0072] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A heating film power supply circuit, characterized in that, include: On / off module and protection module; The on / off module is connected to the power supply and the heating film respectively, and the protection module is connected to the on / off module and the microcontroller; The protection module is used to send a conduction signal to the on / off module when it receives a pulse electrical signal sent by the microcontroller; The on / off module is used to connect the power supply and the heating film when the on signal is received.

2. The heating film power supply circuit as described in claim 1, characterized in that, The heating film power supply circuit also includes: a drive module; The driving module is connected to the negative electrode and ground wire of the heating film and the microcontroller; The driving module is used to control the heating film to start heating when it receives the turn-on signal from the microcontroller and the connection between the power supply and the heating film is made active.

3. The heating film power supply circuit as described in claim 1, characterized in that, The heating film power supply circuit also includes: an isolation module; The isolation module connects the microcontroller and the protection module; The isolation module is used to control the protection module to send a disconnect signal to the on / off module when it detects that the microcontroller has stopped sending pulse electrical signals; The on / off module is used to disconnect the power supply and the heating film when the disconnection signal is received.

4. The heating film power supply circuit as described in claim 3, characterized in that, The heating film power supply circuit further includes: a first bias module and a second bias module; The first bias module is connected to the power supply and the switching module respectively, and the second bias module is connected to the isolation module and the protection module respectively; The first bias module is used to provide a first bias voltage to the on / off module; The second bias module is used to provide a second bias voltage to the protection module.

5. The heating film power supply circuit as described in claim 4, characterized in that, The on / off module includes: a first MOSFET; The source of the first MOS transistor is connected to the power supply, the gate of the first MOS transistor is connected to the protection module, and the drain of the first MOS transistor is connected to the heating film.

6. The heating film power supply circuit as described in claim 5, characterized in that, The first bias module includes: a first capacitor and a first resistor; One end of the first resistor is connected to the power supply, one end of the first capacitor, and the source of the first MOSFET. The other end of the first resistor is connected to the other end of the first capacitor, the gate of the first MOSFET, and the protection module. The drain of the first MOSFET is connected to the driving module.

7. The heating film power supply circuit as described in claim 4, characterized in that, The isolation module includes: a second capacitor and a second resistor; One end of the second capacitor is connected to the microcontroller, the other end of the second capacitor is connected to the second resistor, and the other end of the second resistor is connected to the second bias module.

8. The heating film power supply circuit as described in claim 7, characterized in that, The second bias module includes: a third capacitor and a third resistor; One end of the third capacitor is connected to the other end of the second resistor, one end of the third resistor, and the protection module, while the other end of the third capacitor and the other end of the third resistor are grounded.

9. The heating film power supply circuit as described in claim 8, characterized in that, The protection module includes: a first transistor; The base of the first transistor is connected to one end of the third capacitor, the other end of the second resistor, and one end of the third resistor. The collector of the first transistor is connected to the switching module, and the emitter of the first transistor is grounded.

10. The heating film power supply circuit as described in claim 2, characterized in that, The driving module includes: a second MOSFET and a first diode; The cathode of the first diode is connected to the positive electrode of the heating film, the anode of the first diode is connected to the negative electrode of the heating film and the drain of the second MOS transistor, and the gate of the second MOS transistor is connected to the microcontroller and the source of the second MOS transistor.

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