Temperature control circuit for monitoring equipment

Abstract

The utility model relates to the field of monitoring equipment, in particular to a temperature control circuit for monitoring equipment, which comprises a thermistor, a heating control circuit connected to a high-voltage end of the thermistor and a heat dissipation control circuit connected to a low-voltage end of the thermistor, and the heating / heat dissipation control circuit comprises a comparator, a triode and a metal oxide semiconductor (MOS) tube. The non-inverting input end of the comparator is connected with the high-voltage / low-voltage end of the thermistor, the inverting input end of the comparator is connected with reference voltage, the output end of the comparator is connected to the base electrode of the triode, the collector electrode of the triode is connected with the grid electrode of the MOS tube and + 5V voltage, the emitter electrode of the triode is grounded, the source electrode of the MOS tube is connected with a voltage source VCC, and the drain electrode of the MOS tube is connected with the heating / radiating device. According to the utility model, the temperature of the monitoring equipment is controlled through a hardware circuit, the control interface resource of the main control module is saved, and the temperature of the monitoring equipment is controlled within a set range.

Description

Technical Field

[0001] The utility model relates to the technical field of monitoring equipment, in particular to a temperature control circuit used for monitoring equipment. Background Art

[0002] Most of the existing temperature control systems for monitoring equipment are controlled by the single-chip microcomputer of the main control unit. Although the design is simple, it occupies the resources of the main control module. When the IO port is insufficient, its disadvantages will be reflected; and the existing circuits that control temperature through hardware often only realize a single heating or cooling function. As the requirements of equipment for the environment become increasingly stringent, the existing temperature control circuit cannot accurately achieve the requirement of controlling the temperature within the set range. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a temperature control circuit for monitoring equipment, which controls the temperature of the monitoring equipment through a hardware circuit, saves control interface resources of a main control module, and controls the temperature of the monitoring equipment within a set range.

[0004] In order to solve the technical problem, the technical solution adopted by the utility model is: a temperature control circuit for monitoring equipment, including a thermistor, a heating control circuit connected to the high-voltage end of the thermistor, and a heat dissipation control circuit connected to the low-voltage end of the thermistor, the heating control circuit includes a comparator U1, a transistor Q1 and a MOS tube Q3, the same-phase input end of the comparator U1 is connected to the high-voltage end of the thermistor, the inverting input end of the comparator U1 is connected to the reference voltage, the output end of the comparator U1 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the gate of the MOS tube Q3 and the +5V voltage, and the transistor The emitter of Q1 is grounded, the source of MOS tube Q3 is connected to the voltage source VCC, and the drain of MOS tube Q3 is connected to the heating device; the heat dissipation control circuit includes a comparator U2, a transistor Q2 and a MOS tube Q4, the non-inverting input end of the comparator U2 is connected to the low voltage end of the thermistor, the inverting input end of the comparator U2 is connected to the reference voltage, the output end of the comparator U2 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the gate of the MOS tube Q4 and the +5V voltage, the emitter of the transistor Q2 is grounded, the source of the MOS tube Q4 is connected to the voltage source VCC, and the drain of the MOS tube Q4 is connected to the heat dissipation device.

[0005] Furthermore, resistors R4 and R2 are connected in series at both ends of the thermistor, the +5V voltage is connected to the high voltage end of the thermistor through the resistor R4, and the low voltage end of the thermistor is grounded through the resistor R2.

[0006] Furthermore, the inverting input terminal of the comparator U1 is connected to the potentiometer RP1 via the resistor R3, and the reference voltage of the inverting input terminal of the comparator U1 is regulated by adjusting the potentiometer RP1.

[0007] Furthermore, the inverting input terminal of the comparator U2 is connected to the potentiometer RP2, and the reference voltage of the inverting input terminal of the comparator U2 is regulated by adjusting the potentiometer RP2.

[0008] Furthermore, the output ends of the comparators U1 and U2 are both connected to diodes for displaying the working status of the heating control circuit and the heat dissipation control circuit.

[0009] Furthermore, a resistor R11 is connected between the non-inverting input terminal of the comparator U1 and the high voltage terminal of the thermistor, a capacitor C1 is connected between the inverting input terminal of the comparator U1 and its output terminal, and the resistor R11 and the capacitor C1 form an integration circuit.

[0010] Furthermore, a resistor R12 is connected between the non-inverting input terminal of the comparator U2 and the low voltage terminal of the thermistor, a capacitor C2 is connected between the inverting input terminal of the comparator U1 and its output terminal, and the resistor R12 and the capacitor C2 form an integration circuit.

[0011] Beneficial effects of the utility model: the utility model realizes intelligent control of the temperature of the equipment by only one thermal sensing component without the help of the main control module. When the temperature is lower than the set range, the heating device starts to work; when the temperature is higher than the set range, the heat dissipation device starts to work. Through the temperature control circuit, the control of the monitoring equipment can be realized in hardware. Through the subsequent heating and heat dissipation devices, the temperature of the monitoring equipment is controlled within the set range, saving the control interface resources of the main control module. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a circuit schematic diagram of the utility model. DETAILED DESCRIPTION

[0013] The utility model is further described below in conjunction with the accompanying drawings and specific implementations.

[0014] Example 1

[0015] This embodiment discloses a temperature control circuit for monitoring equipment, such as Figure 1As shown, it includes an NTC thermistor R5, a heating control circuit connected to the high-voltage end of the thermistor R5, and a heat dissipation control circuit connected to the low-voltage end of the thermistor R5. The heating control circuit includes a comparator U1, a transistor Q1 and a MOS transistor Q3, wherein the non-inverting input end of the comparator U1 is connected to the high voltage end of the thermistor R5, the inverting input end of the comparator U1 is connected to the reference voltage, the output end of the comparator U1 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the gate of the MOS transistor Q3 and a +5V voltage, the emitter of the transistor Q1 is grounded, the source of the MOS transistor Q3 is connected to a voltage source VCC, and the drain of the MOS transistor Q3 is connected to a heating device; the heat dissipation control circuit includes a comparator U2, a transistor Q2 and a MOS transistor Q4, wherein the non-inverting input end of the comparator U2 is connected to the low voltage end of the thermistor R5, the inverting input end of the comparator U2 is connected to the reference voltage, the output end of the comparator U2 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the gate of the MOS transistor Q4 and a +5V voltage, the emitter of the transistor Q2 is grounded, the source of the MOS transistor Q4 is connected to the voltage source VCC, and the drain of the MOS transistor Q4 is connected to a heat dissipation device.

[0016] In this embodiment, resistors R4 and R2 are connected in series at both ends of the thermistor R5, and the +5V voltage is connected to the high voltage end of the thermistor through the resistor R4, and the low voltage end of the thermistor is grounded through the resistor R2. The resistor R4, thermistor R5, and resistor R2 connected in series form a voltage divider resistor, and the thermistor R5 has different voltage drops, forming a high voltage end and a low voltage end.

[0017] In this embodiment, the inverting input terminal of the comparator U1 is connected to the potentiometer RP1 through the resistor R3, and the reference voltage of the inverting input terminal of the comparator U1 is adjusted by adjusting the potentiometer RP1. Similarly, the inverting input terminal of the comparator U2 is connected to the potentiometer RP2, and the reference voltage of the inverting input terminal of the comparator U2 is adjusted by adjusting the potentiometer RP2. By adjusting the potentiometers RP1 and RP2, the temperature range in which the resistor needs to operate is set.

[0018] In this embodiment, a resistor R11 is connected between the non-inverting input terminal of the comparator U1 and the high voltage terminal of the thermistor, a capacitor C1 is connected between the inverting input terminal of the comparator U1 and its output terminal, and the resistor R11 and the capacitor C1 form an integration circuit, which prevents the circuit from oscillating back and forth between the heating and cooling states.

[0019] Similarly, a resistor R12 is connected between the non-inverting input terminal of the comparator U2 and the low voltage terminal of the thermistor, and a capacitor C2 is connected between the inverting input terminal of the comparator U1 and its output terminal. The resistor R12 and the capacitor C2 form an integration circuit, which prevents the circuit from oscillating back and forth between the heating and cooling states.

[0020] In this embodiment, the output ends of the comparators U1 and U2 are connected to diodes for displaying the working status of the heating control circuit and the heat dissipation control circuit. Specifically, the output end of the comparator U1 is connected to the positive electrode of the diode D1, and the negative electrode of the diode D1 is grounded through the resistor R9. When the heating control circuit is turned on, a current passes through the diode D1, which emits light, indicating that the heating control circuit is working. Similarly, the output end of the comparator U2 is connected to the positive electrode of the diode D2, and the negative electrode of the diode D2 is grounded through the resistor R10. When the heat dissipation control circuit is turned on, a current passes through the diode D2, which emits light, indicating that the heat dissipation control circuit is working.

[0021] In this embodiment, NTC thermistor R5 is selected as the thermal sensor component. The resistance value of NTC thermistor R5 decreases as the temperature increases, and it is used to sense the temperature of the device. The in-phase input terminals of the two comparators are respectively connected to the two sides of the NTC thermistor R5, which are used to compare the voltage value changes caused by temperature; when the temperature rises to the reference voltage of the comparator U1, the voltage value of the in-phase input terminal of the comparator U2 increases, the heat dissipation control circuit is turned on, and the heat dissipation device starts to work. When the temperature drops to the reference voltage of the comparator U1, the voltage value of the in-phase input terminal of the comparator U1 increases, the heating control circuit is turned on, and the heating device starts to work. Independent control of the two devices of heating and heat dissipation is achieved through one sensor.

[0022] This embodiment realizes intelligent control of the device temperature by only one thermal sensing component without the aid of a main control module. When the temperature is lower than a set range, the heating device starts to work; when the temperature is higher than the set range, the heat dissipation device starts to work.

[0023] The above description is only the basic principle and preferred embodiments of the present invention. Improvements and substitutions made by those skilled in the art based on the present invention belong to the protection scope of the present invention.

Claims

1. A temperature control circuit for monitoring equipment, characterized in that: The invention comprises a thermistor, a heating control circuit connected to the high voltage end of the thermistor, and a heat dissipation control circuit connected to the low voltage end of the thermistor. The heating control circuit comprises a comparator U1, a transistor Q1 and a MOS tube Q3. The in-phase input end of the comparator U1 is connected to the high voltage end of the thermistor, the inverting input end of the comparator U1 is connected to the reference voltage, the output end of the comparator U1 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the gate of the MOS tube Q3 and a +5V voltage, the emitter of the transistor Q1 is grounded, and the source of the MOS tube Q3 is connected to the reference voltage. The heat dissipation control circuit includes a comparator U2, a transistor Q2 and a MOS transistor Q4, the non-inverting input end of the comparator U2 is connected to the low voltage end of the thermistor, the inverting input end of the comparator U2 is connected to the reference voltage, the output end of the comparator U2 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the gate of the MOS transistor Q4 and the +5V voltage, the emitter of the transistor Q2 is grounded, the source of the MOS transistor Q4 is connected to the voltage source VCC, and the drain of the MOS transistor Q4 is connected to the heat dissipation device.

2. The temperature control circuit for monitoring equipment according to claim 1, characterized in that: Resistors R4 and R2 are connected in series at both ends of the thermistor. The +5V voltage is connected to the high voltage end of the thermistor through the resistor R4, and the low voltage end of the thermistor is grounded through the resistor R2.

3. The temperature control circuit for monitoring equipment according to claim 1, characterized in that: The inverting input terminal of the comparator U1 is connected to the potentiometer RP1 through the resistor R3, and the reference voltage of the inverting input terminal of the comparator U1 is adjusted by adjusting the potentiometer RP1.

4. The temperature control circuit for monitoring equipment according to claim 1, characterized in that: The inverting input terminal of the comparator U2 is connected to the potentiometer RP2, and the reference voltage of the inverting input terminal of the comparator U2 is adjusted by adjusting the potentiometer RP2.

5. The temperature control circuit for monitoring equipment according to claim 1, characterized in that: The output ends of the comparators U1 and U2 are both connected with diodes for displaying the working status of the heating control circuit and the heat dissipation control circuit.

6. The temperature control circuit for monitoring equipment according to claim 1, characterized in that: A resistor R11 is connected between the non-inverting input terminal of the comparator U1 and the high voltage terminal of the thermistor, a capacitor C1 is connected between the inverting input terminal of the comparator U1 and its output terminal, and the resistor R11 and the capacitor C1 form an integration circuit.

7. The temperature control circuit for monitoring equipment according to claim 1, characterized in that: A resistor R12 is connected between the non-inverting input terminal of the comparator U2 and the low voltage terminal of the thermistor, a capacitor C2 is connected between the inverting input terminal of the comparator U1 and its output terminal, and the resistor R12 and the capacitor C2 form an integration circuit.

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