A control circuit

Abstract

The application discloses a control circuit. The control circuit comprises a voltage dividing circuit, a gear selection circuit, a comparison circuit and a driving circuit. The voltage dividing circuit comprises a first resistor and a thermistor connected in series, and the first resistor and the thermistor are connected between a first power supply end and a ground end. The gear selection circuit comprises a plurality of gear units, and an input end of the gear unit is connected to the first power supply end. The first input end of the comparison circuit is connected to the voltage dividing circuit, and the second input end of the comparison circuit is connected to the output end of the gear unit. The input end of the driving circuit is connected to the output end of the comparison circuit, and the output end of the driving circuit is connected to a heating module. The driving circuit is used for controlling the heating module to be turned on or turned off according to the output signal of the comparison circuit. In the embodiment of the application, the heating module is controlled to work through a simple structure, the temperature gear of the heating module is adjustable, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of temperature control technology, and in particular to a control circuit. Background Technology

[0002] As people's living standards improve, their demand for home comfort is increasing. This is especially true for bedding, as its comfort affects sleep, and poor sleep can seriously impact work, study, and daily life.

[0003] To improve comfort, especially in southern cities, users often install heating devices such as electric blankets on their beds. However, the temperature control structures used in current electric blankets are relatively expensive. Summary of the Invention

[0004] This invention provides a control circuit to solve the problem of high cost of existing temperature control structures.

[0005] According to one aspect of the present invention, a control circuit is provided, comprising:

[0006] The voltage divider circuit includes a first resistor and a thermistor connected in series, and the first resistor and the thermistor are connected between a first power supply terminal and a ground terminal.

[0007] The gear selection circuit includes multiple gear units, the input terminal of which is connected to the first power supply terminal;

[0008] A comparator circuit, wherein the first input terminal of the comparator circuit is connected to the voltage divider circuit, and the second input terminal of the comparator circuit is connected to the output terminal of the gear unit;

[0009] A driving circuit is provided, wherein the input terminal of the driving circuit is connected to the output terminal of the comparator circuit, and the output terminal of the driving circuit is connected to the heating module. The driving circuit is used to control the heating module to turn on or off according to the output signal of the comparator circuit.

[0010] Furthermore, the thermistor is a negative temperature coefficient thermistor.

[0011] Furthermore, the control circuit is connected to an external device;

[0012] The gear unit includes a first capacitor, a first switching element, and a second resistor. The first capacitor and the first switching element are connected in parallel. The input terminal of the first switching element is also connected to the first power supply terminal. The output terminal of the first switching element is also connected to the second input terminal of the comparator circuit through the second resistor. The control terminal of the first switching element is connected to the external device.

[0013] The external device is used to control the first switching element to be turned on or off.

[0014] Furthermore, the comparison circuit includes a comparator, a third resistor, a fourth resistor, and a first diode; the gear selection circuit also includes a fifth resistor;

[0015] The inverting input of the comparator is connected to the voltage divider circuit through the third resistor, the non-inverting input of the comparator is connected to the output of the gear position unit through the fourth resistor, the positive power supply of the comparator is connected to the first power supply, the negative power supply of the comparator is connected to the ground, the output of the comparator is connected to the negative power supply of the comparator through the first diode, the fifth resistor is connected between the output of the gear position unit and the ground, and the output of the comparator is also connected to the input of the drive circuit.

[0016] Furthermore, the first diode is a Zener diode, with its anode connected to the negative power supply terminal of the comparator and its cathode connected to the output terminal of the comparator.

[0017] Furthermore, the driving circuit includes a sixth resistor, a seventh resistor, a second capacitor, and a first switching device;

[0018] The sixth resistor is connected between the output terminal of the comparator circuit and the control terminal of the first switching device.

[0019] The seventh resistor is connected between the ground terminal and the control terminal of the first switching device;

[0020] The second capacitor is connected between the ground terminal and the control terminal of the first switching device;

[0021] The first switching device is connected between the ground terminal and the heating module.

[0022] Furthermore, the first switching device is an N-type transistor.

[0023] Furthermore, it also includes: a temperature protection switch;

[0024] The heating module is connected between the output terminal of the drive circuit and the temperature protection switch.

[0025] Furthermore, it also includes: a power switch;

[0026] The power switch is connected between the first power supply terminal and the temperature protection switch.

[0027] Furthermore, the control circuit is connected to an external device;

[0028] The power switch includes a third capacitor and a second switching element. The third capacitor and the second switching element are connected in parallel. The input terminal of the second switching element is also connected to the first power terminal. The output terminal of the second switching element is also connected to the heating module through the temperature protection switch. The control terminal of the second switching element is connected to the external device.

[0029] The external device is used to control the second switching element to be turned on or off.

[0030] In this embodiment of the invention, the voltage divider circuit includes a first resistor and a thermistor connected in series, and the gear selection circuit includes multiple gear units connected between a first power supply terminal and a second input terminal of a comparator circuit. The first input terminal of the comparator circuit is connected to the voltage divider circuit, and the output terminal of the comparator circuit is connected to the input terminal of a drive circuit. In this embodiment, the first input terminal of the comparator circuit receives the voltage divider value provided by the voltage divider circuit, and the second input terminal of the comparator circuit receives the gear selection signal provided by the gear selection circuit. The comparator circuit compares the voltage divider value and the gear selection signal and outputs the comparison result, enabling the drive circuit to control the heating module to turn on or off based on the comparison result. This simple structure controls the operation of the heating module and achieves adjustable temperature levels for the heating module at a low cost.

[0031] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

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

[0033] Figure 1 This is a schematic diagram of a control circuit provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of another control circuit provided in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of another control circuit provided in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of another control circuit provided in an embodiment of the present invention;

[0037] Figure 5This is a schematic diagram of another control circuit provided in an embodiment of the present invention. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] Figure 1 This is a schematic diagram of a control circuit provided in an embodiment of the present invention. This embodiment is applicable to controlling the heating of a heating module. Figure 1 As shown, the control circuit includes: a voltage divider circuit 10, including a first resistor R11 and a thermistor R12 connected in series, and the first resistor R11 and the thermistor R12 are connected between the first power supply terminal VCC and the ground terminal GND; a gear selection circuit 11, including multiple gear units 12, the input terminal of the gear unit 12 being connected to the first power supply terminal VCC; a comparator circuit 13, the first input terminal of the comparator circuit 13 being connected to the voltage divider circuit 10, and the second input terminal of the comparator circuit 13 being connected to the output terminal of the gear unit 12; and a drive circuit 14, the input terminal of the drive circuit 14 being connected to the output terminal of the comparator circuit 13, and the output terminal of the drive circuit 14 being connected to the heating module 15, the drive circuit 14 being used to control the heating module 15 to turn on or off according to the output signal of the comparator circuit 13.

[0041] In this embodiment, the control circuit includes a voltage divider circuit 10. The voltage divider circuit 10 includes a first resistor R11 and a thermistor R12 connected in series. The first end of the thermistor R12 is connected to the first power supply terminal VCC, the first end of the first resistor R11 is connected to the ground terminal GND, and the second end of the first resistor R11 is connected to the second end of the thermistor R12. The second end of the thermistor R12 also serves as the output terminal of the voltage divider circuit 10 to output the divided voltage value. The resistance of the thermistor R12 varies at different temperatures; therefore, the change in the resistance of the thermistor R12 at different temperatures will affect the voltage at the output terminal of the voltage divider circuit 10.

[0042] The control circuit includes a gear selection circuit 11, which includes multiple gear selection units 12, such as... Figure 1 As shown, the gear selection circuit 11 includes three gear units 12 connected in parallel, labeled S1, S2, and S3, but the number of gear units 12 in the gear selection circuit 11 is not limited to this. For any gear unit 12, the input terminal of the gear unit 12 is connected to the first power supply terminal VCC, and the output terminal of the gear unit 12 is connected to the second input terminal of the comparator circuit 13. Different gear units 12 have different resistance values ​​when they are in the open state. Therefore, when different gear units 12 are in the open state, the electrical signals transmitted to the second input terminal of the comparator circuit 13 are different. The second input terminal of the comparator circuit 13 can determine the gear position of the gear selection circuit 11 based on the different electrical signals received. Therefore, the electrical signal received by the second input terminal of the comparator circuit 13 can also be defined as the gear position signal. The change in the resistance of the thermistor R12 at different temperatures will affect the voltage at the output of the voltage divider circuit 10. The change in the voltage at the output of the voltage divider circuit 10 will control the switching state of different gear switches 12. For example, the change in temperature from low to high will cause the resistance of the thermistor R12 to change, thereby ensuring that the gear unit 12 switches from low gear to high gear.

[0043] The control circuit is connected to an external device (not shown), which is connected to the control terminal of each gear unit 12. The external device is used to control the gear unit 12 to open or close. Specifically, when a user operates an external device, the external device adjusts the gear position of the control circuit according to the user's command. For example, if the user operates the external device to switch to gear S1, the external device controls gear unit S1 to open and controls other gear units 12 to close according to the user's command. Then, the electrical signal provided by the first power supply terminal VCC is transmitted to the second input terminal of the comparator circuit 13 through the opened gear unit S1. The second input terminal of the comparator circuit 13 can determine the open gear position of the gear selection circuit 11 as gear unit S1 based on the received electrical signal. Alternatively, if the user operates the external device to switch to gear S3, the external device controls gear unit S3 to open and controls other gear units 12 to close according to the user's command. Then, the electrical signal provided by the first power supply terminal VCC is transmitted to the second input terminal of the comparator circuit 13 through the opened gear unit S3. The second input terminal of the comparator circuit 13 can determine the open gear position of the gear selection circuit 11 as gear unit S3 based on the received electrical signal.

[0044] The control circuit includes a comparator circuit 13. The first input terminal of the comparator circuit 13 is connected to the output terminal of the voltage divider circuit 10. Specifically, the first input terminal of the comparator circuit 13 is connected to the second terminal of the thermistor R12. The second input terminal of the comparator circuit 13 is connected to the output terminal of each gear unit 12, and the output terminal of the comparator circuit 13 is connected to the input terminal of the drive circuit 14.

[0045] Specifically, the change in resistance of the thermistor R12 at different temperatures affects the voltage output of the voltage divider circuit 10. The voltage divided by the voltage divider circuit 10 is input to the first input of the comparator circuit 13. Therefore, the electrical signal received at the first input of the comparator circuit 13 is related to the current temperature of the thermistor R12. Different gear units 12 have different resistance values ​​when in the active state. An external device controls one gear unit 12 to be active and controls other gear units 12 to be deactivated according to user commands. For example, if the user switches the external device to gear S3, the electrical signal provided by the first power supply terminal VCC is transmitted to the second input of the comparator circuit 13 through the active gear unit S3. The comparator circuit 13 compares the electrical signal received at the first input and the electrical signal received at the second input, and then outputs the comparison result to the drive circuit 14. This comparison result may be a high voltage or a low voltage.

[0046] The control circuit includes a drive circuit 14, whose input is connected to the output of a comparator circuit 13, and whose output is connected to a heating module 15. The drive circuit 14 receives the comparison result output by the comparator circuit 13 and controls the heating module 15 to turn on or off according to the output signal of the comparator circuit 13. For example, if the comparison result output by the comparator circuit 13 is a high-voltage signal, the drive circuit 14 controls the transmission path with the heating module 15 to be connected according to the high-voltage signal, then the heating module 15 turns on and begins heating; if the comparison result output by the comparator circuit 13 is a low-voltage signal, the drive circuit 14 controls the transmission path with the heating module 15 to be disconnected according to the low-voltage signal, then the heating module 15 turns off and does not heat. In other embodiments, the comparison result output by the comparator circuit may also be a high-voltage signal, and the drive circuit may control the transmission path with the heating module to be disconnected according to the high-voltage signal; or the comparison result output by the comparator circuit may be a low-voltage signal, and the drive circuit may control the transmission path with the heating module to be connected according to the low-voltage signal.

[0047] A negative temperature coefficient (NTC) thermistor can be selected. The resistance of an NTC thermistor decreases as temperature increases. This characteristic can be used to manufacture temperature measurement, temperature compensation, and temperature control components, offering high sensitivity and low cost. In this embodiment, the NTC thermistor is placed near the heating module as a temperature sensor, or it can be attached to the surface of the heating module. The NTC thermistor detects the temperature of the heating module, and the control circuit controls the temperature of the heating module based on the temperature parameters fed back by the NTC thermistor, achieving precise control and adjustment of the heating module's temperature. However, this is not a limitation; in other embodiments, a positive temperature coefficient (PTC) thermistor can also be selected.

[0048] In this embodiment of the invention, the voltage divider circuit includes a first resistor and a thermistor connected in series, and the gear selection circuit includes multiple gear units connected between a first power supply terminal and a second input terminal of a comparator circuit. The first input terminal of the comparator circuit is connected to the voltage divider circuit, and the output terminal of the comparator circuit is connected to the input terminal of a drive circuit. In this embodiment, the first input terminal of the comparator circuit receives the voltage divider value provided by the voltage divider circuit, and the second input terminal of the comparator circuit receives the gear selection signal provided by the gear selection circuit. The comparator circuit compares the voltage divider value and the gear selection signal and outputs the comparison result, enabling the drive circuit to control the heating module to turn on or off based on the comparison result. This simple structure controls the operation of the heating module and achieves adjustable temperature levels for the heating module at a low cost.

[0049] The optional control circuit can be connected to an external device; the gear unit includes a first capacitor, a first switching element, and a second resistor. The first capacitor and the first switching element are connected in parallel. The input terminal of the first switching element is also connected to a first power supply terminal. The output terminal of the first switching element is also connected to the second input terminal of the comparator circuit through the second resistor. The control terminal of the first switching element is connected to an external device; the external device is used to control the first switching element to be turned on or off.

[0050] Figure 2 This is a schematic diagram of another control circuit provided in an embodiment of the present invention. Figure 2 As shown, the optional control circuit is connected to an external device (not shown); the gear unit S1 includes a first capacitor C11, a first switching element S11, and a second resistor R21. The first end of the first capacitor C11 is connected to the input end of the first switching element S11, and the second end of the first capacitor C11 is connected to the output end of the first switching element S11. The input end of the first switching element S11 is also connected to the first power supply terminal VCC. The output end of the first switching element S11 is also connected to the second input end of the comparator circuit 13 through the second resistor R21. The control end of the first switching element S11 is connected to the external device; the external device is used to control the first switching element S11 to be turned on or off.

[0051] The gear unit S2 includes a first capacitor C12, a first switching element S12, and a second resistor R22. The first end of the first capacitor C12 is connected to the input end of the first switching element S12, and the second end of the first capacitor C12 is connected to the output end of the first switching element S12. The input end of the first switching element S12 is also connected to the first power supply terminal VCC. The output end of the first switching element S12 is also connected to the second input end of the comparator circuit 13 through the second resistor R22. The control end of the first switching element S12 is connected to an external device; the external device is used to control the first switching element S12 to be turned on or off.

[0052] The gear unit S3 includes a first capacitor C13, a first switching element S13, and a second resistor R23. The first end of the first capacitor C13 is connected to the input end of the first switching element S13, and the second end of the first capacitor C13 is connected to the output end of the first switching element S13. The input end of the first switching element S13 is also connected to the first power supply terminal VCC. The output end of the first switching element S13 is also connected to the second input end of the comparator circuit 13 through the second resistor R23. The control end of the first switching element S13 is connected to an external device; the external device is used to control the first switching element S13 to be turned on or off.

[0053] In this embodiment, the first capacitor in the gear shift unit serves as a filter, further improving the control accuracy of the control circuit. In other embodiments, the first capacitor can be omitted from the gear shift unit to reduce costs.

[0054] Figure 3 This is a schematic diagram of another control circuit provided in an embodiment of the present invention. (See diagram below.) Figure 3 As shown, the optional comparator circuit 13 includes a comparator U1, a third resistor R3, a fourth resistor R4, and a first diode D1; the gear selection circuit 11 also includes a fifth resistor R5; the inverting input terminal (-) of comparator U1 is connected to the voltage divider circuit 10 through the third resistor R3, the non-inverting input terminal (+) of comparator U1 is connected to the output terminal of the gear selection unit 12 through the fourth resistor R4, the positive power supply terminal P1 of comparator U1 is connected to the first power supply terminal VCC, the negative power supply terminal P2 of comparator U1 is connected to the ground terminal GND, the output terminal of comparator U1 is connected to the negative power supply terminal P2 of comparator U1 through the first diode D1, the fifth resistor R5 is connected between the output terminal of the gear selection unit 12 and the ground terminal GND, and the output terminal of comparator U1 is also connected to the input terminal of the drive circuit 14. Optionally, the first diode D1 can be a Zener diode, with the anode of Zener diode D1 connected to the negative power supply terminal P2 of comparator U1 and the cathode of Zener diode D1 connected to the output terminal of comparator U1.

[0055] In this embodiment, the first end of the third resistor R3 is connected to the second end of the thermistor R12, and the second end of the third resistor R3 is connected to the inverting input (-) of the comparator U1.

[0056] The first end of the fourth resistor R4 is connected to the output terminal of each gear unit 12, and the second end of the fourth resistor R4 is connected to the non-inverting input terminal (+) of comparator U1. Specifically, the first end of the fourth resistor R4 is connected to the second resistor R21 of gear unit S1, the first end of the fourth resistor R4 is also connected to the second resistor R22 of gear unit S2, and the first end of the fourth resistor R4 is also connected to the second resistor R23 of gear unit S3.

[0057] The first end of the fifth resistor R5 is connected to the output terminal of each gear selection unit 12, and the second end of the fifth resistor R5 is connected to ground GND. Specifically, the first end of the fifth resistor R5 is connected to the second resistor R21 of gear selection unit S1, the second resistor R22 of gear selection unit S2, and the second resistor R23 of gear selection unit S3. The fifth resistor R5 acts as a voltage divider in the gear selection circuit 11.

[0058] The first diode, D1, is a Zener diode. The anode of Zener diode D1 is connected to the negative power supply terminal P2 of comparator U1, and the cathode of Zener diode D1 is connected to the output terminal of comparator U1. In comparator circuit 13, the first diode D1 ensures a stable output signal level for comparator U1.

[0059] The positive power supply terminal P1 of comparator U1 is connected to the first power supply terminal VCC, the negative power supply terminal P2 of comparator U1 is connected to the ground terminal GND, and the output terminal of comparator U1 is also connected to the input terminal of drive circuit 14.

[0060] Figure 4 This is a schematic diagram of another control circuit provided in an embodiment of the present invention. (See diagram below.) Figure 4 As shown, the optional drive circuit 14 includes a sixth resistor R6, a seventh resistor R7, a second capacitor C2, and a first switching device Q1; the sixth resistor R6 is connected between the output terminal of the comparator circuit 13 and the control terminal of the first switching device Q1; the seventh resistor R7 is connected between ground GND and the control terminal of the first switching device Q1; the second capacitor C2 is connected between ground GND and the control terminal of the first switching device Q1; and the first switching device Q1 is connected between ground GND and the heating module 15. The first switching device Q1 can optionally be an N-type transistor.

[0061] In this embodiment, the first end of the sixth resistor R6 is connected to the output terminal of comparator U1, and the second end of the sixth resistor R6 is connected to the control terminal of the first switching device Q1. The first end of the seventh resistor R7 is connected to ground GND, and the second end of the seventh resistor R7 is connected to the control terminal of the first switching device Q1. The first end of the second capacitor C2 is connected to ground GND, and the second end of the second capacitor C2 is connected to the control terminal of the first switching device Q1. The first end of the first switching device Q1 is connected to ground GND, and the second end of the first switching device Q1 is connected to the heating module 15.

[0062] The first switching device Q1 can be an N-type transistor. If the electrical signal output by comparator U1 is a high voltage, the high voltage signal is transmitted to the control terminal of the first switching device Q1 through the sixth resistor R6, causing the first switching device Q1 to turn on. This connects the power path of the heating module 15, and the heating module 15 is heated. If the electrical signal output by comparator U1 is a low voltage, the low voltage signal is transmitted to the control terminal of the first switching device Q1 through the sixth resistor R6, causing the first switching device Q1 to turn off. This cuts off the power path of the heating module 15, and the heating module 15 does not heat up.

[0063] In other embodiments, the first switching device may be a P-type transistor, or other types of switching devices, such as a triode.

[0064] In this embodiment, the second capacitor C2 in the drive circuit 14 serves as a filter, further improving the control accuracy of the control circuit. In other embodiments, the second capacitor in the drive circuit can be omitted to reduce costs.

[0065] Figure 5 This is a schematic diagram of another control circuit provided in an embodiment of the present invention. (See diagram below.) Figure 5As shown, the optional control circuit further includes: a temperature protection switch 16; the heating module 15 is connected between the output terminal of the drive circuit 14 and the temperature protection switch 16. The optional control circuit also includes: a power switch 17; the power switch 17 is connected between the first power supply terminal VCC and the temperature protection switch 16. The optional control circuit is connected to an external device; the power switch 17 includes a third capacitor C3 and a second switching element S4, which are connected in parallel. The input terminal of the second switching element S4 is also connected to the first power supply terminal VCC, and the output terminal of the second switching element S4 is connected to the heating module 15 via the temperature protection switch 16. The control terminal of the second switching element S4 is connected to an external device; the external device is used to control the second switching element S4 to be on or off.

[0066] In this embodiment, the input terminal of the second switching element S4 is connected to the first power supply terminal VCC, and the output terminal of the second switching element S4 is connected to the temperature protection switch 16. The third capacitor C3 is connected in parallel with the second switching element S4, the first terminal of the third capacitor C3 is connected to the input terminal of the second switching element S4, and the second terminal of the third capacitor C3 is connected to the output terminal of the second switching element S4.

[0067] The first terminal of the temperature protection switch 16 is connected to the output terminal of the second switching element S4, and the second terminal of the temperature protection switch 16 is connected to the heating module 15. Under normal circumstances, the temperature protection switch 16 remains on.

[0068] The control terminal of the second switching element S4 is connected to an external device. The external device is used to control the second switching element S4 to be turned on or off. Specifically, when the user operates the external device, the external device controls the second switching element S4 to be turned on or off according to the user's command.

[0069] If the external device controls the second switching element S4 to turn on according to the user command, the electrical signal provided by the first power supply terminal VCC is transmitted to the heating module 15 through the second switching element S4 and the turned-on temperature protection switch 16. At this time, if the first switching device Q1 is turned on, the transmission path from the first power supply terminal VCC to the ground terminal GND through the heating module 15 is connected, and the heating module 15 is heated. If the external device controls the second switching element S4 to turn off according to the user command, the electrical signal provided by the first power supply terminal VCC will not be transmitted to the heating module 15, and the control circuit is in the open state.

[0070] It should be noted that if the temperature of the heating module 15 in the control circuit is higher than the safe temperature, the temperature protection switch 16 may be turned off. At this time, the transmission path from the first power supply terminal VCC to the ground terminal GND through the heating module 15 is turned off, and the heating module 15 stops heating, thus achieving high temperature protection.

[0071] In this embodiment, the third capacitor C3 in the power switch 17 serves as a filter, further improving the control accuracy of the control circuit. In other embodiments, the third capacitor in the power switch can be omitted to reduce costs.

[0072] The optional first power supply terminal VCC provides a 24V voltage signal. The first resistor R11 has a resistance of 100KΩ, and the thermistor R12 has a resistance of 100KΩ. The first capacitor C11 has a capacitance of 100nF. The second resistor R21 has a resistance of 75KΩ. The first capacitor C12 has a capacitance of 100nF, and the second resistor R22 has a resistance of 107KΩ. The first capacitor C13 has a capacitance of 100nF, and the second resistor R23 has a resistance of 158KΩ. The third resistor R3 has a resistance of 1KΩ, the fourth resistor R4 has a resistance of 1KΩ, the fifth resistor R5 has a resistance of 10KΩ, the sixth resistor R6 has a resistance of 5KΩ, the seventh resistor R7 has a resistance of 100KΩ, the second capacitor C2 has a capacitance of 10pF, and the third capacitor C3 has a capacitance of 100nF. Those skilled in the art will understand that the above parameters are merely an example. The electrical parameters of components such as resistors and capacitors can be reasonably designed according to the product requirements. For example, by adjusting the resistance value of the second resistor in the range unit, the output accuracy of the subsequent comparator can be adjusted.

[0073] In this embodiment, the second switching element S4 of the control circuit is the power switch of the heating module. The voltage divider circuit 10 includes an NTC temperature sensor R12. The resistance of the NTC temperature sensor is inversely proportional to the temperature; that is, the resistance of R12 decreases as the temperature increases and increases as the temperature decreases. Based on this, the voltage received at the positive input terminal (non-inverting input terminal) of the comparator U1 will change according to the ambient temperature.

[0074] The control circuit operates as follows: the second switching element S4 is turned on; the resistance of the NTC temperature sensor varies at different temperatures; the inverting input Uin- of comparator U1 receives the voltage division value transmitted by the voltage divider circuit 10; the non-inverting input Uin+ of comparator U1 (i.e., the positive input terminal) receives the gear signal transmitted by the gear unit 12; if the electrical signal of the non-inverting input Uin+ of comparator U1 is greater than the electrical signal of the inverting input Uin- of comparator U1, comparator U1 outputs a high level, and the first switching device Q1 is turned on, and the heating module 15 works; as the temperature rises, the resistance of the thermistor R12 decreases, and the electrical signal of the inverting input Uin- of comparator U1 gradually rises; when the electrical signal of the non-inverting input Uin+ of comparator U1 is less than the electrical signal of the inverting input Uin- of comparator U1, comparator U1 outputs a low level, and the first switching device Q1 is turned off, and the heating module 15 stops working, indicating that the temperature of the heating module 15 has reached the set gear. Therefore, the heating module can be operated by analog signal control and the temperature level can be adjusted. The control circuit of the heating module does not need to use high-cost components such as microcontrollers and clocks, nor does it require investment in hardware, embedded systems and other human resources, thus reducing costs.

[0075] In this embodiment, the voltage division values ​​of the NTC temperature sensor at different temperatures are collected and compared with the preset temperature setting signal. When the real-time temperature of the NTC temperature sensor has not reached the set temperature setting, the comparator U1 outputs a high level, the first switching device Q1 is turned on, and the heating module 15 continues to operate. When the real-time temperature of the NTC temperature sensor reaches the set temperature setting, the comparator U1 outputs a low level, the first switching device Q1 is turned off, and the heating module 15 stops operating. In this embodiment, there is no limit to the number of heating levels; multi-level temperature control can be achieved simply by setting the interval of the second resistor voltage division in the temperature setting unit. This control circuit can be used in various heating devices, such as electric blankets.

[0076] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A control circuit, characterized in that, include: The voltage divider circuit includes a first resistor and a thermistor connected in series, and the first resistor and the thermistor are connected between a first power supply terminal and a ground terminal. The gear selection circuit includes multiple gear units, the input terminal of which is connected to the first power supply terminal; A comparator circuit, wherein the first input terminal of the comparator circuit is connected to the voltage divider circuit, and the second input terminal of the comparator circuit is connected to the output terminal of the gear unit; A driving circuit, wherein the input terminal of the driving circuit is connected to the output terminal of the comparator circuit, and the output terminal of the driving circuit is connected to the heating module, and the driving circuit is used to control the heating module to turn on or off according to the output signal of the comparator circuit; The gear selection circuit also includes a fifth resistor; the fifth resistor is connected between the output terminal of the gear unit and the ground terminal.

2. The control circuit according to claim 1, characterized in that, The thermistor is a negative temperature coefficient thermistor.

3. The control circuit according to claim 1, characterized in that, The control circuit is connected to an external device; The gear unit includes a first capacitor, a first switching element, and a second resistor. The first capacitor and the first switching element are connected in parallel. The input terminal of the first switching element is also connected to the first power supply terminal. The output terminal of the first switching element is also connected to the second input terminal of the comparator circuit through the second resistor. The control terminal of the first switching element is connected to the external device. The external device is used to control the first switching element to be turned on or off.

4. The control circuit according to claim 1, characterized in that, The comparison circuit includes a comparator, a third resistor, a fourth resistor, and a first diode; The inverting input of the comparator is connected to the voltage divider circuit through the third resistor, the non-inverting input of the comparator is connected to the output of the gear unit through the fourth resistor, the positive power supply of the comparator is connected to the first power supply, the negative power supply of the comparator is connected to the ground, the output of the comparator is connected to the negative power supply of the comparator through the first diode, and the output of the comparator is also connected to the input of the drive circuit.

5. The control circuit according to claim 4, characterized in that, The first diode is a Zener diode, with its anode connected to the negative power supply terminal of the comparator and its cathode connected to the output terminal of the comparator.

6. The control circuit according to claim 1, characterized in that, The driving circuit includes a sixth resistor, a seventh resistor, a second capacitor, and a first switching device; The sixth resistor is connected between the output terminal of the comparator circuit and the control terminal of the first switching device. The seventh resistor is connected between the ground terminal and the control terminal of the first switching device; the second capacitor is connected between the ground terminal and the control terminal of the first switching device; the first switching device is connected between the ground terminal and the heating module.

7. The control circuit according to claim 6, characterized in that, The first switching device is an N-type transistor.

8. The control circuit according to claim 1, characterized in that, Also includes: Temperature protection switch; the heating module is connected between the output terminal of the drive circuit and the temperature protection switch.

9. The control circuit according to claim 8, characterized in that, Also includes: A power switch; the power switch is connected between the first power supply terminal and the temperature protection switch.

10. The control circuit according to claim 9, characterized in that, The control circuit is connected to an external device; The power switch includes a third capacitor and a second switching element. The third capacitor and the second switching element are connected in parallel. The input terminal of the second switching element is also connected to the first power terminal. The output terminal of the second switching element is also connected to the heating module through the temperature protection switch. The control terminal of the second switching element is connected to the external device. The external device is used to control the second switching element to be turned on or off.

Images