Circuit for controlling primary side temperature control by secondary side MCU (Microprogrammed Control Unit) based on operational amplifier circuit

Abstract

The utility model relates to an operational amplifier circuit-based circuit for controlling primary side temperature control by a secondary side MCU, which is electrically connected to a control chip MCU, and comprises a reference voltage circuit, a primary side temperature control circuit and a secondary side MCU control circuit, the reference voltage end VREF of the reference voltage circuit outputs reference voltage, the resistance value of a temperature control resistor RT1 changes along with the change of temperature, and the primary side temperature control circuit is electrically connected with the secondary side MCU control circuit. When the circuit temperature reaches a preset value, the resistance value of the temperature control resistor RT1 is reduced, the output level of the first operational amplifier chip IC1-A is converted from a low level to a high level, the triode Q2 is switched on, a high-temperature signal is transmitted to the secondary side MCU control circuit through the optocoupler OT1, and after the control chip MCU detects a signal of an RT-P pin, the RT-P pin is switched on through the optocoupler OT1. Temperature protection control is performed on the circuit, potential safety hazards are avoided, and the reliability of the circuit is improved. According to the circuit, the problem that a temperature control protection circuit is inconvenient to arrange in a primary side chip circuit is solved, primary side temperature control is controlled by the secondary side MCU, and temperature control protection is carried out on the primary side chip circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, and in particular to a circuit based on an operational amplifier circuit in which a secondary-side MCU controls the temperature control of a primary side. Background Art

[0002] Temperature control resistors are widely used electronic components in electronic development and design. When used, they are usually fixed on high-loss power devices to sense the temperature changes of each power device, and then feed back the sensed temperature changes to the control chip, thereby affecting the operating state of the control chip to protect the entire circuit. Prevent high-power devices from overheating and exceeding the rated operating temperature, causing device failure or damage, and power failure.

[0003] The importance of the temperature control circuit is obvious, but the control chip of some circuits does not have an operating pin that can be set for temperature protection, resulting in the temperature control circuit not being set, which makes the power supply have the risk of failure due to overtemperature. Utility Model Content

[0004] In view of this, it is necessary to provide a circuit based on an operational amplifier circuit for a control chip without a temperature protection pin, in which the secondary side MCU controls the primary side temperature control.

[0005] A circuit based on an operational amplifier circuit, in which a secondary-side MCU controls primary-side temperature control, is electrically connected to a control chip MCU. The circuit includes a reference voltage circuit, a primary-side temperature control circuit and a secondary-side MCU control circuit. The reference voltage circuit provides a reference voltage to the primary-side temperature control circuit and the secondary-side MCU control circuit. The primary-side temperature control circuit includes a temperature control resistor RT1, a first operational amplifier chip IC1-A, a transistor Q2 and an optical coupler OT1. The first operational amplifier chip IC1-A compares the sampled voltage of the temperature control resistor RT1 with the reference voltage, the optical coupler OT1 transmits the comparison result to the secondary-side MCU control circuit, and the secondary-side MCU control circuit transmits a control signal to the control chip MCU to achieve temperature protection control.

[0006] Preferably, the primary temperature control circuit further includes a first resistor R1, a sixth resistor R6, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a thirteenth resistor R13, a third capacitor C3 and a fourth capacitor C4; the first resistor R1 and the eighth resistor R8 are connected in series to form a first voltage divider circuit, and the sixth resistor R6 and the temperature control resistor RT1 are connected in series to form a second voltage divider circuit; the first voltage divider circuit and the second voltage divider circuit are respectively connected between the reference voltage terminal VREF and the primary ground line GND; the third capacitor C3 is connected in parallel to both ends of the temperature control resistor RT1; the reverse input end of the first operational amplifier chip IC1-A is connected to the connection point between the first resistor R1 and the eighth resistor R8, and the first operational amplifier chip IC The same-direction input end of IC1-A is connected to the connection point between the sixth resistor R6 and the temperature-controlled resistor RT1, and the two ends of the ninth resistor R9 are respectively connected to the output end and the same-direction input end of the first operational amplifier chip IC1-A; the output end of the first operational amplifier chip IC1-A is connected to the base of the transistor Q2 through the tenth resistor R10, the emitter of the transistor Q2 is connected to the primary ground GND, the fourth capacitor C4 and the eleventh resistor R11 are connected in parallel between the base of the transistor Q2 and the primary ground GND, the collector of the transistor Q2 is connected to the cathode of the light-emitting diode OT1-B of the optical coupler OT1, and the anode of the light-emitting diode OT1-B of the optical coupler OT1 is connected to the power supply VCCB through the thirteenth resistor R13.

[0007] Preferably, the secondary side MCU control circuit includes a fifteenth resistor R15, a sixteenth resistor R16 and a sixth capacitor C6, the fifteenth resistor R15 and the sixteenth resistor R16 are connected in series to form a third voltage divider circuit, the free end of the sixteenth resistor R16 is connected to the RT-P pin of the control chip MCU, the free end of the fifteenth resistor R15 is connected to the secondary side ground line AGND, and the sixth capacitor C6 is connected in parallel to both ends of the fifteenth resistor R15; the emitter of the phototransistor OT1-A of the optocoupler OT1 is connected to the connection point between the fifteenth resistor R15 and the sixteenth resistor R16, and the collector of the phototransistor OT1-A of the optocoupler OT1 is connected to the power supply pin SMCU of the control chip MCU.

[0008] Preferably, the reference voltage circuit includes a precision voltage regulator U1, a voltage regulator Q1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first capacitor C1; the third resistor R3 and the fourth resistor R4 are connected in series to form a fourth voltage divider circuit, the fourth voltage divider circuit is arranged between the reference voltage terminal VREF and the primary ground line GND, and the first capacitor C1 is connected in parallel to both ends of the fourth voltage divider circuit; the reference end of the precision voltage regulator U1 is connected to the connection point between the third resistor R3 and the fourth resistor R4, the anode of the precision voltage regulator U1 is connected to the primary ground line GND, and the cathode of the precision voltage regulator U1 is connected to the power supply VCCB through the second resistor R2; the base of the voltage regulator Q1 is connected to the connection point between the cathode of the precision voltage regulator U1 and the second resistor R2, the collector of the voltage regulator Q1 is connected to the power supply VCCB, and the emitter of the voltage regulator Q1 is connected to the reference voltage terminal VREF.

[0009] In the above-mentioned circuit based on the operational amplifier circuit in which the secondary side MCU controls the primary side temperature control, the reference voltage terminal VREF of the reference voltage circuit outputs a reference voltage, and the resistance of the temperature control resistor RT1 changes with the temperature. When the circuit temperature reaches a predetermined value, the resistance of the temperature control resistor RT1 decreases, so that the output level of the first operational amplifier chip IC1-A changes from a low level to a high level, the transistor Q2 is turned on, and the high temperature signal is transmitted to the secondary side MCU control circuit through the optical coupler OT1. After the control chip MCU detects the signal of the RT-P pin, the circuit is temperature protected to avoid safety hazards and improve the reliability of the circuit. This circuit solves the problem that it is inconvenient to set a temperature control protection circuit in the primary side chip circuit. The secondary side MCU controls the primary side temperature control and performs temperature control protection on the primary side chip circuit. The circuit structure of the utility model is simple, easy to implement, low cost, and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a circuit structure schematic diagram of a primary side temperature control circuit and a secondary side MCU control circuit of a circuit in which a secondary side MCU controls a primary side temperature control based on an operational amplifier circuit according to an embodiment of the utility model.

[0011] Figure 2 The utility model is a circuit structure diagram of a reference voltage circuit of a circuit in which a secondary-side MCU controls a primary-side temperature control based on an operational amplifier circuit according to an embodiment of the utility model. DETAILED DESCRIPTION

[0012] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0013] See also Figure 1 and Figure 2, showing a circuit based on an operational amplifier circuit provided by an embodiment of the utility model, in which a secondary-side MCU controls primary-side temperature control, which is electrically connected to a control chip MCU. The circuit includes a reference voltage circuit, a primary-side temperature control circuit and a secondary-side MCU control circuit. The reference voltage circuit provides a reference voltage to the primary-side temperature control circuit and the secondary-side MCU control circuit; the primary-side temperature control circuit includes a temperature control resistor RT1, a first operational amplifier chip IC1-A, a transistor Q2 and an optical coupler OT1. The first operational amplifier chip IC1-A compares the sampled voltage of the temperature control resistor RT1 with the reference voltage, and the optical coupler OT1 transmits the comparison result to the secondary-side MCU control circuit. The secondary-side MCU control circuit transmits a control signal to the control chip MCU to achieve temperature protection control.

[0014] Preferably, the primary temperature control circuit further includes a first resistor R1, a sixth resistor R6, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a thirteenth resistor R13, a third capacitor C3 and a fourth capacitor C4; the first resistor R1 and the eighth resistor R8 are connected in series to form a first voltage divider circuit, and the sixth resistor R6 and the temperature control resistor RT1 are connected in series to form a second voltage divider circuit; the first voltage divider circuit and the second voltage divider circuit are respectively connected between the reference voltage terminal VREF and the primary ground line GND; the third capacitor C3 is connected in parallel to both ends of the temperature control resistor RT1; the reverse input end of the first operational amplifier chip IC1-A is connected to the connection point between the first resistor R1 and the eighth resistor R8, and the first operational amplifier chip IC The same-direction input end of IC1-A is connected to the connection point between the sixth resistor R6 and the temperature-controlled resistor RT1, and the two ends of the ninth resistor R9 are respectively connected to the output end and the same-direction input end of the first operational amplifier chip IC1-A; the output end of the first operational amplifier chip IC1-A is connected to the base of the transistor Q2 through the tenth resistor R10, the emitter of the transistor Q2 is connected to the primary ground GND, the fourth capacitor C4 and the eleventh resistor R11 are connected in parallel between the base of the transistor Q2 and the primary ground GND, the collector of the transistor Q2 is connected to the cathode of the light-emitting diode OT1-B of the optical coupler OT1, and the anode of the light-emitting diode OT1-B of the optical coupler OT1 is connected to the power supply VCCB through the thirteenth resistor R13.

[0015] Specifically, the third capacitor C3 is a filter capacitor, which makes the voltage signal at the same-direction input terminal of the first operational amplifier chip IC1-A more accurate and stable.

[0016] Specifically, the fourth capacitor C4 is a filter capacitor, which makes the voltage signal of the base of the transistor Q2 more accurate and stable.

[0017] Preferably, the secondary side MCU control circuit includes a fifteenth resistor R15, a sixteenth resistor R16 and a sixth capacitor C6, the fifteenth resistor R15 and the sixteenth resistor R16 are connected in series to form a third voltage divider circuit, the free end of the sixteenth resistor R16 is connected to the RT-P pin of the control chip MCU, the free end of the fifteenth resistor R15 is connected to the secondary side ground line AGND, and the sixth capacitor C6 is connected in parallel to both ends of the fifteenth resistor R15; the emitter of the phototransistor OT1-A of the optocoupler OT1 is connected to the connection point between the fifteenth resistor R15 and the sixteenth resistor R16, and the collector of the phototransistor OT1-A of the optocoupler OT1 is connected to the power supply pin SMCU of the control chip MCU.

[0018] Preferably, the reference voltage circuit includes a precision voltage regulator U1, a voltage regulator Q1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first capacitor C1; the third resistor R3 and the fourth resistor R4 are connected in series to form a fourth voltage divider circuit, the fourth voltage divider circuit is arranged between the reference voltage terminal VREF and the primary ground line GND, and the first capacitor C1 is connected in parallel to both ends of the fourth voltage divider circuit; the reference end of the precision voltage regulator U1 is connected to the connection point between the third resistor R3 and the fourth resistor R4, the anode of the precision voltage regulator U1 is connected to the primary ground line GND, and the cathode of the precision voltage regulator U1 is connected to the power supply VCCB through the second resistor R2; the base of the voltage regulator Q1 is connected to the connection point between the cathode of the precision voltage regulator U1 and the second resistor R2, the collector of the voltage regulator Q1 is connected to the power supply VCCB, and the emitter of the voltage regulator Q1 is connected to the reference voltage terminal VREF.

[0019] Specifically, the first capacitor C1 is a filter capacitor, which makes the voltage signal of the reference voltage terminal VREF more accurate and stable.

[0020] Specifically, see Figure 1, showing the primary side temperature control circuit and the secondary side MCU control circuit. When the circuit is running, in the primary side temperature control circuit, the resistance of the temperature control resistor RT1 changes as the temperature of the detection point increases (for example, 25 degrees, the resistance is 10K ohms). The voltage of the reference voltage terminal VREF is 5V. When the sixth resistor R6 divides the voltage with the temperature control resistor RT1, the voltage at the same direction input terminal of the first operational amplifier chip IC1-A is also getting smaller and smaller. When the voltage value of the same direction input terminal of the first operational amplifier chip IC1-A is compared with the voltage value of the reverse input terminal of the first operational amplifier chip IC1-A, the voltage of the same direction input terminal is greater than the voltage value of the reverse input terminal. After passing through the first operational amplifier chip IC1-A, the output terminal of the first operational amplifier chip IC1-A outputs a low voltage signal, and the tenth resistor R10 plays a filtering role. The base of the transistor Q2 is at a low level, and the transistor Q2 is not conducting; the eleventh resistor R11 plays a voltage dividing role, and C4 is a filter capacitor, so that the voltage signal of the base of the transistor Q2 is more accurate and stable.

[0021] The temperature of the detection point of the temperature-controlled resistor RT1 gradually increases, and the resistance of the temperature-controlled resistor RT1 gradually decreases. When the temperature exceeds a certain temperature, the resistance of the temperature-controlled resistor RT1 (for example, 110 degrees, the resistance is about 750 ohms) is smaller than the resistance of the eighth resistor R8. The voltage value of the reverse input terminal of the first operational amplifier chip IC1-A is compared with the voltage value of the same-direction input terminal of the first operational amplifier chip IC1-A. The voltage of the same-direction input terminal of the first operational amplifier chip IC1-A is smaller. After passing through the operational amplifier circuit, the output terminal of the first operational amplifier chip IC1-A outputs a high voltage signal, and the base of the transistor Q2 is at a high level, triggering the conduction condition of the transistor Q2 (Vbe voltage increases). The transistor Q2 is turned on, and the light-emitting diode OT1-B of the optical coupler OT1 is turned on to emit light, and a signal is fed back to the secondary. The thirteenth resistor R13 acts as a voltage divider to reduce the current to ensure that the optical coupler OT1 is not damaged.

[0022] In the secondary circuit, the phototransistor OT1-A of the optocoupler OT1 is turned on after receiving the signal, and the voltage at the voltage dividing point between the sixteenth resistor R16 and the fifteenth resistor R15 increases, thereby increasing the voltage change of the RT-P pin of the control chip MCU. According to the pin definition protocol of the control chip MCU, the control chip MCU sends a signal to turn off the power supply to achieve the over-temperature protection function.

[0023] See also Figure 2, showing the reference voltage circuit. In the reference voltage circuit, after the power supply VCCB outputs the voltage, the voltage regulator Q1 is arranged between the power supply VCCB and the reference voltage terminal VREF to stabilize the voltage. The second resistor R2 is a voltage divider resistor, which is used to reduce the current and protect the precision voltage regulator U1 from being damaged. The reference terminal output voltage of the precision voltage regulator U1 (AZ431) is 2.5Vdc. After the voltage is divided and boosted by the third resistor R3 and the fourth resistor R4, the voltage of the reference voltage terminal VREF is 5Vdc. The first capacitor C1 is a filter capacitor, which makes the voltage signal of the reference voltage terminal VREF more accurate and stable.

[0024] Specifically, in this embodiment, the voltage of the power supply VCCB is 12-15 Vdc, and the voltage of the reference voltage terminal VREF is 5 Vdc.

[0025] The transistor Q2 is an NPN transistor.

[0026] The voltage regulator Q1 is a BCX56-16 chip.

[0027] The RT-P pin of the control chip MCU is an arbitrary function pin; the voltage of the power supply pin SMCU of the control chip MCU is 3.3Vdc, which is the MCU chip power supply pin with a voltage of 3.3V; the model of the control chip MCU is TAE32F5300ALF80.

[0028] Ground wire distinction: GND is the primary circuit ground wire, and AGND is the secondary circuit ground wire.

[0029] The first operational amplifier chip IC1-A is a LM2904DGKR chip.

[0030] In the above-mentioned circuit based on the operational amplifier circuit in which the secondary side MCU controls the primary side temperature control, the reference voltage terminal VREF of the reference voltage circuit outputs a reference voltage, and the resistance of the temperature control resistor RT1 changes with the temperature. When the circuit temperature reaches a predetermined value, the resistance of the temperature control resistor RT1 decreases, so that the output level of the first operational amplifier chip IC1-A changes from a low level to a high level, the transistor Q2 is turned on, and the high temperature signal is transmitted to the secondary side MCU control circuit through the optical coupler OT1. After the control chip MCU detects the signal of the RT-P pin, the circuit is temperature protected to avoid safety hazards and improve the reliability of the circuit. This circuit solves the problem that it is inconvenient to set a temperature control protection circuit in the primary side chip circuit. The secondary side MCU controls the primary side temperature control and performs temperature control protection on the primary side chip circuit. The circuit structure of the utility model is simple, easy to implement, low cost, and easy to promote.

[0031] It should be noted that the present invention is not limited to the above-mentioned embodiments. According to the creative spirit of the present invention, those skilled in the art may also make other changes. These changes made according to the creative spirit of the present invention should be included in the scope of protection required by the present invention.

Claims

1. A circuit based on an operational amplifier circuit, in which a secondary-side MCU controls the primary-side temperature control, electrically connected to a control chip MCU, characterized in that: It includes a reference voltage circuit, a primary-side temperature control circuit and a secondary-side MCU control circuit. The reference voltage circuit provides a reference voltage to the primary-side temperature control circuit and the secondary-side MCU control circuit. The primary-side temperature control circuit includes a temperature control resistor RT1, a first operational amplifier chip IC1-A, a transistor Q2 and an optical coupler OT1. The first operational amplifier chip IC1-A compares the sampled voltage of the temperature control resistor RT1 with the reference voltage, and the optical coupler OT1 transmits the comparison result to the secondary-side MCU control circuit. The secondary-side MCU control circuit transmits the control signal to the control chip MCU to achieve temperature protection control.

2. The circuit based on the operational amplifier circuit and the primary side temperature control controlled by the secondary side MCU as claimed in claim 1, characterized in that: The primary temperature control circuit also includes a first resistor R1, a sixth resistor R6, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a thirteenth resistor R13, a third capacitor C3 and a fourth capacitor C4. The first resistor R1 and the eighth resistor R8 are connected in series to form a first voltage divider circuit, and the sixth resistor R6 and the temperature control resistor RT1 are connected in series to form a second voltage divider circuit; the first voltage divider circuit and the second voltage divider circuit are respectively connected between the reference voltage terminal VREF and the primary ground line GND; the third capacitor C3 is connected in parallel to both ends of the temperature control resistor RT1; the reverse input end of the first operational amplifier chip IC1-A is connected to the connection point between the first resistor R1 and the eighth resistor R8, and the first operational amplifier chip IC1- The same-direction input end of A is connected to the connection point between the sixth resistor R6 and the temperature-controlled resistor RT1, and the two ends of the ninth resistor R9 are respectively connected to the output end and the same-direction input end of the first operational amplifier chip IC1-A; the output end of the first operational amplifier chip IC1-A is connected to the base of the transistor Q2 through the tenth resistor R10, the emitter of the transistor Q2 is connected to the primary ground GND, the fourth capacitor C4 and the eleventh resistor R11 are connected in parallel between the base of the transistor Q2 and the primary ground GND, the collector of the transistor Q2 is connected to the cathode of the light-emitting diode OT1-B of the optocoupler OT1, and the anode of the light-emitting diode OT1-B of the optocoupler OT1 is connected to the power supply VCCB through the thirteenth resistor R13.

3. The circuit based on the operational amplifier circuit and the primary side temperature control controlled by the secondary side MCU as claimed in claim 1, characterized in that: The secondary side MCU control circuit includes a fifteenth resistor R15, a sixteenth resistor R16 and a sixth capacitor C6, the fifteenth resistor R15 and the sixteenth resistor R16 are connected in series to form a third voltage divider circuit, the free end of the sixteenth resistor R16 is connected to the RT-P pin of the control chip MCU, the free end of the fifteenth resistor R15 is connected to the secondary side ground line AGND, and the sixth capacitor C6 is connected in parallel to both ends of the fifteenth resistor R15; the emitter of the phototransistor OT1-A of the optocoupler OT1 is connected to the connection point between the fifteenth resistor R15 and the sixteenth resistor R16, and the collector of the phototransistor OT1-A of the optocoupler OT1 is connected to the power supply pin SMCU of the control chip MCU.

4. The circuit based on the operational amplifier circuit and the primary side temperature control controlled by the secondary side MCU as claimed in claim 2, characterized in that: The reference voltage circuit includes a precision voltage regulator U1, a voltage regulator Q1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first capacitor C1; the third resistor R3 and the fourth resistor R4 are connected in series to form a fourth voltage divider circuit, the fourth voltage divider circuit is arranged between the reference voltage terminal VREF and the primary ground line GND, and the first capacitor C1 is connected in parallel to both ends of the fourth voltage divider circuit; the reference end of the precision voltage regulator U1 is connected to the connection point between the third resistor R3 and the fourth resistor R4, the anode of the precision voltage regulator U1 is connected to the primary ground line GND, and the cathode of the precision voltage regulator U1 is connected to the power supply VCCB through the second resistor R2; the base of the voltage regulator Q1 is connected to the connection point between the cathode of the precision voltage regulator U1 and the second resistor R2, the collector of the voltage regulator Q1 is connected to the power supply VCCB, and the emitter of the voltage regulator Q1 is connected to the reference voltage terminal VREF.

Images