CN104345749A - Thermostat automatic adjustment control circuit - Google Patents

Abstract

An automatic thermostat regulation control circuit for controlling the temperature in an incubator to be uniform and constant, comprising: the device comprises a power supply module, a voltage stabilizing module, a thermosensitive module, a heating module, a voltage dividing module and a switch control module. The switch control module compares the reference voltage with the voltage of the detection voltage division module to determine the temperature in the thermostat. Specifically, the detected detection voltage is a voltage drop between the thermosensitive module and the voltage dividing module. When the detection voltage detected by the switch control module is greater than the reference voltage, namely the temperature in the incubator is higher than the set temperature, the switch control module controls the heating module to stop heating. When the detection voltage detected by the switch control module is lower than the reference voltage, namely the temperature in the constant temperature box is lower than the set temperature, the switch control module controls the heating module to start heating.

Description

Thermostat automatic adjustment control circuit

technical field

The invention relates to a thermostatic box control circuit, in particular to a simple thermostatic box automatic adjustment control circuit.

Background technique

Lamp lighting can be seen everywhere in modern society, and the lamps and lanterns used in all walks of life are different. The purpose is lighting, improving productivity and worker safety. However, in the production of lamps, it is necessary to estimate and test the life and safety of lamps. In the structure of the luminaire, for example, plastic or rubber parts are also used, because the luminaire will generate heat during the use of the luminaire. Plastic or rubber parts age at higher temperatures and become brittle after aging. After becoming brittle, the previous functions of plastic and rubber parts will be reduced, and the reliability and safety performance of such lamps will be reduced, causing danger or accidents.

In order to reduce the occurrence of such dangerous accidents, it is necessary to control the service temperature of rubber and plastic parts, that is to say, the plastic and rubber parts are at a certain temperature. It is safe and reliable in a certain period of time; the aging life test of rubber and plastic parts is stipulated in the explosion-proof standard. The aging of these parts needs to be aged in a certain environment for a corresponding time to check whether the plastic and rubber parts meet the requirements. Therefore, it is necessary to provide an environment with a constant temperature, and the current constant temperature control circuit is relatively complicated and requires a high manufacturing process, which leads to an increase in production cost.

Contents of the invention

Based on this, it is necessary to provide a simple thermostat automatic adjustment control circuit.

An automatic adjustment control circuit for a constant temperature box, used to control the temperature in the constant temperature box to be uniform and constant, including: a power supply module for providing power to the circuit, and a voltage regulator for converting the output voltage of the power supply module into a stable voltage drop module, a thermosensitive module for sensing the temperature in the thermostat, a heating module, a voltage dividing module, and a switch control module for controlling the heating of the heating module and stopping heating;

The power module is used to connect with the input end of the voltage stabilizing module and the input end of the heating module;

The output terminal of the voltage stabilizing module is connected to the input terminal of the thermal module and the input terminal of the switch control module, and the grounding terminal of the voltage stabilizing module is grounded;

The output terminal of the thermal module is connected to the input terminal of the voltage divider module, the output terminal of the voltage divider module is connected to the detection terminal of the switch control module, and the ground terminal of the voltage divider module is grounded;

The reference terminal of the switch control module inputs a reference voltage, and the control terminal of the switch control module is connected to the input terminal of the heating module;

The output voltage of the power supply module is stabilized by the voltage stabilizing module and then output to the switch control module. The switch control module compares the reference voltage input at the reference terminal with the detection voltage at the detection terminal. When the detection voltage is greater than the reference voltage, the The switch control module is turned off, and the heating module is controlled to stop heating; when the detection voltage is lower than the reference voltage, the switch control module is turned on, and the heating module is controlled to start heating.

In one of the embodiments, the power module includes a fuse FU1, a fuse FU2, a transformer T and a rectifier bridge BD;

The fuse FU1 and the fuse FU2 are respectively connected in series with the live line and neutral line of the AC power supply, and the fuse FU1 and the fuse FU2 are connected to the AC power supply and then connected to the primary coil of the transformer T, so The secondary coil of the transformer T is connected to the input end of the rectifier bridge BD, and the rectifier bridge BD outputs a rated DC voltage;

The heating module is connected to both ends of the primary coil of the transformer T in parallel.

In one of the embodiments, the voltage stabilizing module includes a field effect transistor Q1 and a voltage stabilizing diode Z1;

The drain of the field effect transistor Q1 is connected to the output end of the power module, the source of the field effect transistor Q1 is connected to the input end of the switch control module and the input end of the thermal module, and the field effect transistor Q1 is connected to the input end of the thermal module. The gate of the effect transistor Q1 is connected to the cathode of the Zener diode Z1, and the anode of the Zener diode Z1 is grounded.

In one of the embodiments, it further includes a filter module, the input terminal of the filter module is connected to the common connection point of the power supply module and the voltage stabilizing module, and the output terminal of the filter module is grounded.

In one embodiment, the filter module includes a filter capacitor C1, and the two ends of the filter capacitor C1 correspond to the input end and the output end of the filter module.

In one embodiment, the thermistor module includes a thermistor Rt, and the two ends of the thermistor Rt correspond to the input end and the output end of the thermistor module.

In one of the embodiments, the voltage dividing module includes a sliding resistor RP1 and a sliding resistor RP2, and the two ends of the sliding resistor RP1 and the sliding resistor RP2 connected in series correspond to the input terminal and the grounding terminal of the voltage dividing module , the sliding terminals of the sliding resistor RP1 and the sliding resistor RP2 are connected to the detection terminal of the switch control module.

In one of the embodiments, the switch control module includes a 555 time base circuit, a sliding resistor RP3, a voltage dividing resistor R2 and a triac Q2,

The power supply terminal of the 555 time base circuit is connected to the output terminal of the voltage stabilizing module, the reference terminal of the 555 time base circuit is connected to the sliding end of the sliding resistor RP3, and the sliding resistor RP3 is connected in parallel to the voltage stabilizing module Between the output terminal of the 555 time base circuit and the ground terminal, the control terminal of the 555 time base circuit is connected to the voltage dividing resistor R2, and the other terminal of the voltage dividing resistor R2 is connected to the control pole of the bidirectional thyristor Q2, and the bidirectional thyristor Q2 The first anode of the thyristor Q2 is connected to the input terminal of the heating module, and the second anode of the triac Q2 is connected to the negative pole of the power supply.

In one embodiment, a filter capacitor C3 and a voltage regulator diode Z2 are further included, and the filter capacitor C3 and the voltage regulator diode Z2 are connected in parallel to both ends of the sliding resistor RP3.

In one of the embodiments, a voltage dividing resistor R1 and a light emitting diode LED1 are further included, and the voltage dividing resistor R1 and the light emitting diode LED1 are connected in series between the output terminal of the voltage stabilizing module and the 555 time base circuit.

The above-mentioned constant temperature box automatic adjustment control circuit determines the temperature in the constant temperature box by comparing the reference voltage with the voltage of the detection voltage divider module by the switch control module. Specifically, the detected detection voltage is the voltage drop between the thermal module and the voltage dividing module. When the detection voltage detected by the switch control module is greater than the reference voltage, that is, the temperature in the incubator is higher than the set temperature, the switch control module controls the heating module to stop heating. When the detection voltage detected by the switch control module is lower than the reference voltage, that is, the temperature in the incubator is lower than the set temperature, the switch control module controls the heating module to start heating.

Description of drawings

Fig. 1 is a block diagram of the thermostat automatic adjustment control circuit;

Figure 2 is a schematic diagram of the thermostat automatic adjustment control circuit.

Detailed ways

As shown in Figure 1, it is a block diagram of the thermostat automatic adjustment control circuit.

An automatic regulation control circuit for a constant temperature box, used to control the temperature in the constant temperature box to be uniform and constant, comprising: a power supply module 101 for supplying power to the circuit, and a power supply module 101 for converting the output voltage of the power supply module 101 into a stable voltage drop The voltage stabilizing module 103, the thermosensitive module 105 for sensing the temperature in the thermostat, the heating module 111, the voltage dividing module 107, and the switch control module 109 for controlling the heating module 111 to generate heat and stop heating.

The power supply module 101 is used to connect with the input end of the voltage stabilizing module 103 and the input end of the heating module 111 .

The output terminal of the voltage stabilizing module 103 is connected to the input terminal of the thermal module 105 and the input terminal of the switch control module 109 , and the ground terminal of the voltage stabilizing module 103 is grounded.

The output terminal of the thermal module 105 is connected to the input terminal of the voltage dividing module 107, the output terminal of the voltage dividing module 107 is connected to the detection terminal of the switch control module 109, and the grounding terminal of the voltage dividing module 107 is grounded.

The reference terminal of the switch control module 109 inputs a reference voltage, and the control terminal of the switch control module 109 is connected to the input terminal of the heating module 111 .

The output voltage of the power supply module 101 is stabilized by the voltage stabilizing module 103 and then output to the switch control module 109. The switch control module 109 compares the input reference voltage of the reference terminal with the detection voltage of the detection terminal, and when the detection voltage is greater than the reference voltage voltage, the switch control module 109 is turned off, and the heating module 111 is controlled to stop heating; when the detected voltage is lower than the reference voltage, the switch control module 109 is turned on, and the heating module 111 is controlled to start heating.

The thermosensitive module 105 is used for sensing the temperature in the thermostat and converting the sensed temperature into a voltage. The thermal module 105 and the voltage dividing module 107 are connected between the output terminal of the voltage stabilizing module 103 and the ground terminal. Therefore, the voltage at the output terminal of the voltage dividing module 107 is determined by the voltage converted by the temperature sensing module 105 . Meanwhile, whether the switch control module 109 is turned on or not is determined by the output voltage of the voltage divider module 107 and the reference voltage input from the reference terminal of the switch control module 109 . Therefore, setting the reference terminal of the switch control module 109 to input a reference voltage can preset the temperature in the incubator.

Please combine with Figure 2.

The power module 101 includes a fuse FU1 , a fuse FU2 , a transformer T and a rectifier bridge BD.

The fuse FU1 and the fuse FU2 are respectively connected in series with the live line and the neutral line of the AC power supply. The fuse FU1 and the fuse FU2 are connected to the AC power supply and then connected to the primary coil of the transformer T. The secondary coil of the electrical appliance T is connected to the input terminal of the rectifier bridge BD, and the rectifier bridge BD outputs a rated DC voltage. The heating module 111 is connected in parallel with both ends of the primary coil of the transformer T.

The voltage stabilizing module 103 includes a field effect transistor Q1 and a voltage stabilizing diode Z1.

The drain of the field effect transistor Q1 is connected to the output terminal of the power module 101, the source of the field effect transistor Q1 is connected to the input terminal of the switch control module 109 and the input terminal of the thermal module 105, The gate of the field effect transistor Q1 is connected to the cathode of the Zener diode Z1, and the anode of the Zener diode Z1 is grounded.

The thermistor module 105 includes a thermistor Rt, and the two ends of the thermistor Rt correspond to the input end and the output end of the thermistor module 105 .

The voltage dividing module 107 includes a sliding resistor RP1 and a sliding resistor RP2. The two ends of the sliding resistor RP1 and the sliding resistor RP2 connected in series correspond to the input terminal and the grounding terminal of the voltage dividing module 107. The sliding resistor RP1 and the sliding resistor RP2 are connected in series. The sliding terminal of the sliding resistor RP2 is connected to the detection terminal of the switch control module 106 .

The switch control module 109 includes a 555 time base circuit, a sliding resistor RP3, a voltage dividing resistor R2 and a triac Q2.

The power supply terminal of the 555 time base circuit is connected to the output terminal of the voltage stabilizing module 103, the reference terminal of the 555 time base circuit is connected to the sliding end of the sliding resistance RP3, and the sliding resistance RP3 is connected in parallel to the voltage stabilizing Between the output terminal of the module 103 and the ground terminal, the control terminal of the 555 time base circuit is connected to the voltage dividing resistor R2, and the other terminal of the voltage dividing resistor R2 is connected to the control pole of the bidirectional thyristor Q2, so The first anode of the bidirectional thyristor Q2 is connected to the input terminal of the heating module 111, and the second anode of the bidirectional thyristor Q2 is connected to the negative pole of the power supply.

The thermostat automatic adjustment control circuit also includes a filter capacitor C3 and a voltage stabilizing diode Z2, and the filter capacitor C3 and the voltage stabilizing diode Z2 are connected in parallel to both ends of the sliding resistor RP3.

The thermostat automatic adjustment control circuit also includes a voltage dividing resistor R1 and a light emitting diode LED1, and the voltage dividing resistor R1 and the light emitting diode LED1 are connected in series between the output terminal of the voltage stabilizing module and the 555 time base circuit.

The heating module 111 includes a heating resistance wire RL, one end of the heating resistance wire RL is connected to the control end of the switch control module 109, and the other end is connected to the positive pole of the power supply.

The thermostat automatic adjustment control circuit also includes a filter module 113, the input terminal of the filter module 113 is connected to the common connection point between the power supply module 101 and the voltage stabilizing module 103, and the output terminal of the filter module 113 is grounded.

The filter module 113 includes a filter capacitor C1, and the two ends of the filter capacitor C1 correspond to the input end and the output end of the filter module 113 .

The thermostat automatic adjustment control circuit also includes a filter capacitor C2, which is connected in parallel between the output terminal of the voltage stabilizing module 103 and the ground terminal.

The thermostatic box automatic adjustment control circuit also includes a thermal balance module 115, and the thermal balance module 115 is connected in parallel to both ends of the AC power supply. The heat equalization module 115 is used for evenly distributing the heat emitted by the heating module 111 into the thermostat.

The thermal balance module 115 includes a fan M connected in parallel to both ends of the AC power supply. Wherein, the fan M is installed adjacent to the heating module 111 .

Based on all the above-mentioned embodiments, the working principle of the thermostatic box automatic adjustment control circuit is as follows:

FU1 and FU2 are fuses, which mainly protect the back-end circuit when the front power supply fails.

M is the fan. In the confined space, the heat emitted by the heating resistance wire is blown to every corner of the rice noodles in the confined space, so that the temperature of each corner in the confined space is uniform.

RL is a heating resistance wire, which generates a lot of heat when it is energized, so that the temperature inside the space rises to the temperature value that needs to be set.

SCR is a bidirectional thyristor Q2, which mainly plays the role of controlling the heating on and off of the resistance wire;

T is a transformer, which converts AC220V voltage to AC AC12V.

BD is a bridge stack, which mainly converts AC AC12V voltage into DC12V voltage.

C1 and C2 are capacitors, mainly for filtering and absorbing peak voltage.

Z1 is a regulator tube that provides a stable DC voltage.

Q1 is a moss tube, which forms a voltage regulator circuit with Z1 to provide a stable DC voltage.

R1 and R2 are resistors, which mainly play the role of current limiting and voltage dividing.

LED1 is an indicator light, which mainly plays a role in displaying work.

555 is a time base circuit, which mainly performs high-low level conversion to control the on-off of the bidirectional thyristor Q2 to control the heating of the heating resistance wire RL.

Rt is a thermistor, which is mainly used to collect the internal temperature of the box, and the voltage division control circuit is performed by reducing the resistance as the temperature rises.

RP1 and RP2 are sliding resistors, which are mainly used to adjust the resistance value to make pin 2 and pin 6 perform high-low level conversion.

RP3 is a sliding resistor, and adjusting the sliding resistor RP3 provides a reference voltage for the 555 time base circuit, and adjusts the temperature value that needs to be set in the thermostat.

The C3 capacitor acts as a trigger for the transition between levels.

Z2 is a voltage regulator tube, and the sliding resistor RP3 provides a reference voltage to adjust the temperature.

According to the rated temperature required by the lamp, adjust the sliding resistor RP3 to control the temperature in the thermostat, so that the starting voltage of the 555 time base circuit U2=2Uz2;

Power on the incubator, that is, connect to the 220V AC power supply. The voltage is transformed by a transformer to obtain AC12V voltage. Then, it is rectified by the rectifier bridge BD to obtain a DC12V direct current voltage, which is filtered by the filter capacitor C1. A stable DC12V voltage is obtained after passing through the Zener diode Z1 and the field effect transistor Q1. After the filter capacitor C2 absorbs the peak voltage, it supplies power to the 555 time base circuit, and at the same time, the current flows through R1 to the LED1 display circuit for heating.

The thermistor Rt is installed in the thermostat to detect the temperature inside the thermostat. The fan M is installed in the incubator, and the heat emitted by the heating resistance wire RL can be blown to every corner of the incubator through the fan M, so that the temperature in all corners of the incubator can be evenly balanced.

When the 555 time base circuit is working, because the temperature sensed by the thermistor Rt is low, the resistance value is relatively large. Therefore, the 2-pin voltage U2 on the 555 time base circuit is smaller than Uz2, and the 6-pin voltage U6 is smaller than the 5-pin voltage U5 of the 555 time base circuit. Therefore, pin 3 of the 555 time base circuit outputs a high level, which makes the bidirectional thyristor Q2 conduct, and at the same time, the heating resistance wire RL of the thermostat box also starts to work and generate heat, and the fan M also starts to work, and the heat generated by the heating resistance wire RL is blown by the fan M To every corner of the incubator, so as to reach the temperature range that the incubator needs to control.

When the temperature rises and the temperature value of the thermistor Rt is greater than the set temperature of the incubator, the temperature sensed by the thermistor Rt also increases accordingly, so the resistance value of the thermistor Rt decreases. The voltage shared by the thermistor Rt becomes smaller. On the contrary, the voltage shared by the sliding resistor RP1 and the sliding resistor RP2 increases accordingly. When the voltage U2 shared by the sliding resistor RP1 is greater than Uz2, the 6-pin voltage U6 is greater than 555 When the voltage of pin 5 of the base circuit is U5, pin 3 of the 555 time base circuit outputs a low level. The bidirectional thyristor Q2 is disconnected, and the heating resistance wire RL stops heating. When the temperature drops, the 555 time base circuit performs high-low level conversion, controls the bidirectional thyristor Q2 to turn on or off, and automatically controls the heating and cooling of the heating resistance wire RL to achieve temperature balance.

The automatic adjustment control circuit of the constant temperature box adopts key components such as thermistor Rt, 555 time base circuit, bidirectional thyristor Q2, heating resistance wire RL, sliding resistance, fan M and other key components to form a circuit to automatically control a small airtight environment with poor heat dissipation The temperature inside ensures that the temperature inside the airtight environment is constant; the manufacturing tooling is simple, and the simulation of customer use improves the reliability of the product and reduces the cost of the instrument.

The above-mentioned constant temperature box automatic adjustment control circuit determines the temperature in the constant temperature box by comparing the reference voltage and the voltage of the detection voltage divider module 107 through the switch control module 109 . Specifically, the detected detection voltage is the voltage drop between the thermal module 105 and the voltage dividing module 107 . When the detection voltage detected by the switch control module 109 is greater than the reference voltage, that is, the temperature in the thermostat is higher than the set temperature, the switch control module 109 controls the heating module 111 to stop heating. When the detection voltage detected by the switch control module 109 is lower than the reference voltage, that is, the temperature in the incubator is lower than the set temperature, the switch control module 109 controls the heating module 111 to start generating heat.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. a constant temperature oven auto-adjustment control circuit, homogeneous temperature for controlling in constant temperature oven is constant, it is characterized in that, comprising: for providing the power module of power supply for circuit, for the output voltage of described power module being converted to the Voltage stabilizing module of stable pressure drop, the heat-sensitive module being used for responding to constant temperature the temperature inside the box, heating module, division module and being used for controlling the switch control module that described heating module generates heat and stopping is generated heat;

Described power module is used for being connected with described Voltage stabilizing module input end and described heating module input end;

The input end of heat-sensitive module described in the output termination of described Voltage stabilizing module and the input end of described switch control module, the earth terminal ground connection of described Voltage stabilizing module;

The input end of division module described in the output termination of described heat-sensitive module, switch control module test side described in the output termination of described division module, the earth terminal ground connection of described division module;

The reference edge input reference voltage of described switch control module, the input end of heating module described in the control termination of described switch control module;

Described power module output voltage exports to described switch control module via after described Voltage stabilizing module voltage stabilizing, the reference voltage of input of described switch control module benchmark end and the detection voltage of test side, when detecting voltage and being greater than reference voltage, described switch control module cut-off, controls described heating module and stops heating; When detecting voltage and being less than reference voltage, described switch control module conducting, controls described heating module and starts heating.

2. constant temperature oven auto-adjustment control circuit according to claim 1, is characterized in that, described power module comprises fuse FU1, fuse FU2, power transformation device T and rectifier bridge BD;

On the live wire that described fuse FU1 and described fuse FU2 is series at AC power respectively and zero line, described fuse FU1 connects the primary coil of described power transformation device T after being connected with AC power with described fuse FU2, the secondary coil of described power transformation device T connects the input end of described rectifier bridge BD, and described rectifier bridge BD exports rated direct voltage;

Described heating module is parallel to the primary coil two ends of described power transformation device T.

3. constant temperature oven auto-adjustment control circuit according to claim 1, is characterized in that, described Voltage stabilizing module comprises field effect transistor Q1 and voltage stabilizing diode Z1;

The drain electrode of described field effect transistor Q1 is connected with the output terminal of described power module, the source electrode of described field effect transistor Q1 connects the input end of described switch control module and the input end of described heat-sensitive module, the grid of described field effect transistor Q1 is connected with the negative pole of described voltage stabilizing diode Z1, the plus earth of described voltage stabilizing diode Z1.

4. constant temperature oven auto-adjustment control circuit according to claim 1, is characterized in that, also comprise filtration module, the points of common connection of power module and described Voltage stabilizing module described in the input termination of described filtration module, the output head grounding of described filtration module.

5. constant temperature oven auto-adjustment control circuit according to claim 4, it is characterized in that, described filtration module comprises filter capacitor C1, and the two ends of described filter capacitor C1 correspond to input end and the output terminal of described filtration module.

6. constant temperature oven auto-adjustment control circuit according to claim 1, it is characterized in that, described heat-sensitive module comprises thermistor Rt, and described thermistor Rt two ends correspond to input end and the output terminal of described heat-sensitive module.

7. constant temperature oven auto-adjustment control circuit according to claim 1, it is characterized in that, described division module comprises swept resistance RP1 and swept resistance RP2, two ends after described swept resistance RP1 and described swept resistance RP2 connects correspond to input end and the earth terminal of described division module, the test side of switch control module described in the slip termination of described swept resistance RP1 and described swept resistance RP2.

8. constant temperature oven auto-adjustment control circuit according to claim 1, is characterized in that, described switch control module comprises 555 time base circuits, swept resistance RP3, divider resistance R2 and bidirectional triode thyristor Q2,

The output terminal of Voltage stabilizing module described in the power supply termination of described 555 time base circuits, the sliding end of swept resistance RP3 described in the benchmark termination of described 555 time base circuits, described swept resistance RP3 is parallel between the output and ground of described Voltage stabilizing module, divider resistance R2 described in the control termination of described 555 time base circuits, the control pole of bidirectional triode thyristor Q2 described in another termination of described divider resistance R2, the first anode of described bidirectional triode thyristor Q2 connects the input end of described heating module, and the second anode of described bidirectional triode thyristor Q2 connects power cathode.

9. constant temperature oven auto-adjustment control circuit according to claim 8, is characterized in that, also comprises filter capacitor C3 and voltage stabilizing diode Z2, and described filter capacitor C3 and described voltage stabilizing diode Z2 is parallel to described swept resistance RP3 two ends.

10. constant temperature oven auto-adjustment control circuit according to claim 8, it is characterized in that, also comprise divider resistance R1 and LED 1, described divider resistance R1 and described LED 1 are series between the output terminal of described Voltage stabilizing module and described 555 time base circuits.