Precise voltage stabilizing circuit for 110V direct current work

Abstract

The utility model discloses a precise voltage stabilizing circuit used for 110V direct current work, relates to the technical field of voltage stabilizing circuits, and aims to solve the problems that an existing DC-DC conversion mode circuit is mainly applied to the situation that load current is large and has the defects of being high in cost and large in noise. The key points of the technical scheme are that the circuit comprises a power conversion circuit and a measurement and control circuit, the power conversion circuit internally comprises a polarity protection diode D1, one end of the polarity protection diode D1 is connected with a power supply, and the other end of the polarity protection diode D1 is electrically connected with a power resistor R1 and a power resistor R2. The other end of the power resistor R1 is electrically connected with a switching diode D2 and a switching diode D4, and the switching diode D4 and the other end of the power resistor R2 are electrically connected with a triode Q1. The defects of high cost of DC-DC conversion and unstable voltage of a measurement and control circuit of series resistor voltage reduction under the conventional condition are overcome.

Description

Technical Field

[0001] The utility model relates to the technical field of voltage stabilizing circuits, and in particular to a precision voltage stabilizing circuit for 110V DC operation. Background Art

[0002] In some specific application fields, the power supply provided on site is 110V DC, while the measurement and control circuits used for on-site detection and control generally operate at a low voltage state. Typical operating circuit power supply voltages are DC 24V, 12V, 5V, etc. To ensure the stability and reliability of the detection and control of the circuit, the operating voltage of the measurement and control circuit must be stable and reliable. Therefore, it is necessary to convert the 110V DC power supply through a conversion circuit to provide a stable and reliable low voltage signal;

[0003] Currently, the main processing methods are: DC-DC conversion and series resistance voltage reduction;

[0004] The DC-DC conversion method generally refers to converting a fixed DC voltage into a variable DC voltage, also known as a DC chopper. By adjusting its PWM (duty cycle), the magnitude of the output effective voltage is controlled. This circuit is mainly used in the case of relatively large load current. The disadvantages are relatively high cost and large noise;

[0005] The series resistance voltage reduction method means using one or more high-power resistors connected in series in the power supply circuit. Through the voltage division function of the resistor, the voltage is converted from a high voltage to a low voltage for use by the measurement and control circuit.

[0006] The above existing technical solutions have the following defects: The DC-DC conversion method circuit is mainly used in the case of relatively large load current. The disadvantages are relatively high cost and large noise. And the series resistance voltage reduction method circuit has a simple working method and low cost. The disadvantage is that when the current increases, the voltage value drops, resulting in errors in detection and control and poor reliability. Especially when the current value changes relatively greatly during the use of the measurement and control circuit, this problem is more prominent. Summary of the Utility Model

[0007] The purpose of the utility model is to provide a precision voltage stabilizing circuit for 110V DC operation.

[0008] To achieve the above purpose, the utility model provides the following technical solutions:

[0009] A precision voltage stabilizing circuit for 110V DC operation, including a power conversion circuit and a measurement and control circuit. Inside the power conversion circuit, there is a polarity protection diode D1. One end of the polarity protection diode D1 is connected to the power supply, and the other end of the polarity protection diode D1 is electrically connected to a power resistor R1 and a power resistor R2. The other end of the power resistor R1 is electrically connected to a switching diode D2 and a switching diode D4. The switching diode D4 and the other end of the power resistor R2 are electrically connected to a triode Q1;

[0010] The 3rd pin of the triode Q1 is electrically connected to the other end of the switching diode D4, and the 2nd pin of the triode Q1 is electrically connected to the other end of the power resistor R2;

[0011] The 1st pin of the triode Q1 is electrically connected to a capacitor C1, a capacitor C2, and a TVS diode D5. The voltage is output from the 1st pin of the triode Q1, one end of the capacitor C1, one end of the capacitor C2, and one end of the TVS diode D5.

[0012] By adopting the above technical solution, D1 is a polarity protection diode to prevent the power supply from being connected reversely and burning out the circuit. R1 is a power resistor, mainly providing the zener diode voltage stabilizing current and the triode base current. A 20KΩ / 2W resistor can be selected. R2 is a power resistor, mainly providing the current when the current of the measurement and control circuit is relatively large. A 2KΩ / 10W resistor can be selected.

[0013] Further, the other end of the switching diode D2 is electrically connected to a zener diode D3, the other end of the zener diode D3 is grounded, and the other ends of the capacitor C1, the capacitor C2, and the TVS diode D5 are grounded.

[0014] By adopting the above technical solution, C1 and C2 are capacitors. C1 is an electrolytic capacitor for low-frequency filtering. C2 is a 0.1μF capacitor for high-frequency filtering. The TVS diode is mainly used to prevent the circuit from being damaged due to voltage mutation in the circuit. For the 12V voltage of the measurement and control circuit, the protection voltage of the TVS diode can be selected from 14V to 15V. D2 and D4 are switching diodes to prevent ground wire power interference and measurement and control circuit noise interference. D3 is a zener diode. A 13V / 1W zener diode is selected to ensure the voltage stability in the circuit.

[0015] Further, inside the measurement and control circuit, there is a voltage dividing resistor R3. One end of the voltage dividing resistor R3 is connected to the regulated power supply, the other end of the voltage dividing resistor R3 is electrically connected to a sensor R4, the other end of the sensor R4 is electrically connected to a voltage dividing resistor R5 and an input resistor R7, the other end of the voltage dividing resistor R5 is electrically connected to a voltage dividing resistor R6, and the other end of the voltage dividing resistor R6 is grounded.

[0016] By adopting the above technical solution, R3, R5, and R6 are voltage-dividing resistors that set the voltage across the sensor to a reasonable value and transmit it to the processing circuit. R4 is a sensor that collects changes in physical quantities and converts them into processable electrical signals.

[0017] Further, the other end of the input resistor R7 is electrically connected to a comparator U1, a feedback capacitor C3, and a feedback resistor R10. The 2nd pin of the comparator U1 is electrically connected to the other end of the input resistor R7, one end of the feedback capacitor C3, and one end of the feedback resistor R10. The 6th pin of the comparator U1 is electrically connected to a transistor base resistor R11. The other end of the feedback resistor R10, the other end of the feedback capacitor C3, one end of the transistor base resistor R11, and the 6th pin of the comparator U1 are electrically connected.

[0018] By adopting the above technical solution, R10 is a feedback resistor and C3 is a feedback capacitor. The value of the feedback resistor is relatively large, generally in the order of MΩ, and the value of the capacitor is relatively small, generally in the order of pF. After comparing the signal from the sensor with the comparison voltage, high and low levels can be output. U1 is a comparator that compares the signal of the sensor with the comparison voltage and outputs high and low levels.

[0019] Further, the 3rd pin of the comparator U1 is electrically connected to a potentiometer RV1. The 2nd pin of the potentiometer RV1 is electrically connected to the 3rd pin of the comparator U1. The 1st pin of the potentiometer RV1 is electrically connected to a voltage-dividing resistor R8. The other end of the voltage-dividing resistor R8 is connected to a regulated power supply. The 3rd pin of the potentiometer RV1 is electrically connected to a voltage-dividing resistor R9. The other end of the voltage-dividing resistor R9 is grounded. The 4th pin of the comparator U1 is grounded. The 7th pin of the comparator U1 is connected to a regulated power supply.

[0020] By adopting the above technical solution, R8, R9, and RV1 are circuits that provide a comparison voltage. Resistors R8 and R9 divide the voltage in the circuit, and the potentiometer RV1 can accurately adjust the comparison voltage value to a set value.

[0021] Further, the other end of the transistor base resistor R11 is electrically connected to a transistor Q2. The 1st pin of the transistor Q2 is grounded. The 2nd pin of the transistor Q2 is electrically connected to a relay U2 and a discharge diode D6. The other ends of the relay U2 and the discharge diode D6 are connected to a regulated power supply.

[0022] By adopting the above technical solution, Q2 is a transistor that mainly controls the on and off of the relay through the conduction and cutoff of the transistor. D6 is a discharge diode that prevents the control coil of the relay from being damaged when the voltage suddenly changes. U2 is a relay that uses a low-power relay, reducing power consumption, which can reduce the heating power of the power resistor in the power supply part. By controlling the on and off of the relay, the control of the external circuit is realized.

[0023] In summary, the beneficial technical effects of the present utility model are as follows:

[0024] 1. When the current of the measurement and control circuit is small, for example, the current is 8 ± 1 mA during operation. At this time, the principle of the voltage stabilizing diode circuit can be utilized, and a 13V voltage stabilizing diode and a power resistor are used to form a stable voltage, and then the voltage is stepped down through the base of the triode to form a stable working voltage of 12.3V for the measurement and control circuit;

[0025] 2. Ensure voltage stability. Use a 13V voltage stabilizing diode and a power resistor to form a stable voltage, and then step down the voltage through the base of the triode to form a stable working voltage for the measurement and control circuit, and prevent the voltage value from dropping after the current increases: when the current in the measurement and control circuit increases, the base current of the triode increases, and the collector current will also be amplified, ensuring that the power supply voltage of the measurement and control circuit will not drop when the current in the measurement and control circuit increases;

[0026] 3. In the initial state, the current of the measurement and control circuit is relatively small, and the voltage stability of the measurement and control circuit is achieved through the voltage stabilizing diode, and the power resistor generates slight heat. When the sensor detection reaches the set value, the current of the measurement and control circuit is relatively large, and the voltage stability of the measurement and control circuit is achieved through the voltage stabilizing diode, and the circuit current is increased through the triode, realizing that the voltage of the measurement and control circuit remains stable in the state where the circuit current changes significantly;

[0027] 4. Through the voltage division of the power resistor and the voltage stabilizing diode, the voltage stability of the measurement and control circuit under a 110V DC working power supply is achieved, and by selecting the triode and the power resistor, the voltage stability of the measurement and control circuit is achieved when the current of the measurement and control circuit changes significantly, and the disadvantages of high cost of DC-DC conversion and unstable voltage of the measurement and control circuit with series resistor voltage reduction in the conventional situation are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the power conversion circuit of the present utility model;

[0029] Figure 2 It is a schematic diagram of the measurement and control circuit of the present utility model;

[0030] Figure 3 It is a schematic diagram of the front structure of the circuit board in the actual application of the present utility model;

[0031] Figure 4 It is a schematic diagram of the back structure of the circuit board in the actual application of the present utility model;

[0032] Figure 5 It is a flow chart of small current voltage stabilization of the present utility model;

[0033] Figure 6 It is a flow chart of large current voltage stabilization of the present utility model. DETAILED DESCRIPTION OF THE INVENTION

[0034] The present utility model will be further described in detail below with reference to the accompanying drawings.

[0035] Referring to Figure 1 and Figure 3 , a precision voltage stabilizing circuit for 110V DC operation includes a power conversion circuit and a measurement and control circuit. Inside the power conversion circuit, there is a polarity protection diode D1. One end of the polarity protection diode D1 is connected to the power supply, and the other end of the polarity protection diode D1 is electrically connected to a power resistor R1 and a power resistor R2. The other end of the power resistor R1 is electrically connected to a switching diode D2 and a switching diode D4. The switching diode D4 and the other end of the power resistor R2 are electrically connected to a triode Q1. The 3rd pin of the triode Q1 is electrically connected to the other end of the switching diode D4, the 2nd pin of the triode Q1 is electrically connected to the other end of the power resistor R2, and the 1st pin of the triode Q1 is electrically connected to a capacitor C1, a capacitor C2, and a TVS diode D5. The 1st pin of the triode Q1 and one end of the capacitor C1, one end of the capacitor C2, and one end of the TVS diode D5 output voltage. The other end of the switching diode D2 is electrically connected to a zener diode D3, and the other end of the zener diode D3 is grounded. The other ends of the capacitor C1, the capacitor C2, and the TVS diode D5 are grounded. D1 is a polarity protection diode to prevent the power supply from being connected reversely and burning out the circuit. R1 is a power resistor, mainly providing the zener diode's voltage stabilizing current and the triode's base current. A 20KΩ / 2W resistor can be selected. D2 and D4 are switching diodes to prevent ground wire power interference and measurement and control circuit noise interference. D3 is a zener diode, and a 13V / 1W zener diode is selected to ensure the voltage stability in the circuit. R2 is a power resistor, mainly providing current when the current in the measurement and control circuit is relatively large. A 2KΩ / 10W resistor can be selected. Q1 is a triode. Considering factors such as circuit voltage and power consumption, the triode model 2SC2688 is selected, with parameters IC = 200mA and VCEO = 300V, which can ensure the safety and performance requirements of the circuit. C1 and C2 are capacitors. C1 is an electrolytic capacitor for low-frequency filtering, and C2 is a 0.1μF capacitor for high-frequency filtering. D5 is a TVS diode, mainly to prevent damage to the circuit caused by voltage mutations in the circuit. For the 12V voltage of the measurement and control circuit, the protection voltage of the TVS diode can be selected from 14V to 15V.

[0036] Referring to Figure 2 and Figure 3, the measurement and control circuit internally includes a voltage-dividing resistor R3. The other end of the voltage-dividing resistor R3 is electrically connected to a sensor R4. The other end of the sensor R4 is electrically connected to a voltage-dividing resistor R5 and an input resistor R7. The other end of the voltage-dividing resistor R5 is electrically connected to a voltage-dividing resistor R6. The other end of the voltage-dividing resistor R6 is grounded. The other end of the input resistor R7 is electrically connected to a comparator U1, a feedback capacitor C3, and a feedback resistor R10. The 2nd pin of the comparator U1 is electrically connected to the other end of the input resistor R7, one end of the feedback capacitor C3, and one end of the feedback resistor R10. The 6th pin of the comparator U1 is electrically connected to a triode base resistor R11. The other end of the feedback resistor R10, the other end of the feedback capacitor C3, one end of the triode base resistor R11, and the 6th pin of the comparator U1 are electrically connected. The 3rd pin of the comparator U1 is electrically connected to a potentiometer RV1. The 2nd pin of the potentiometer RV1 is electrically connected to the 3rd pin of the comparator U1. The 1st pin of the potentiometer RV1 is electrically connected to a voltage-dividing resistor R8. The other end of the voltage-dividing resistor R8 is connected to a comparison power supply. The 3rd pin of the potentiometer RV1 is electrically connected to a voltage-dividing resistor R9. The other end of the voltage-dividing resistor R9 is grounded. The 4th pin of the comparator U1 is grounded. The other end of the triode base resistor R11 is electrically connected to a triode Q2. The 1st pin of the triode Q2 is grounded. The 2nd pin of the triode Q2 is electrically connected to a relay U2 and a current-discharging diode D6. R3, R5, and R6 are voltage-dividing resistors that set the voltage across the sensor to a reasonable value and transmit it to the processing circuit. R4 is a sensor used to collect changes in physical quantities and convert them into processable electrical signals. R8, R9, and RV1 are circuits that provide a comparison voltage. Resistors R8 and R9 divide the voltage in the circuit, and the potentiometer RV1 can accurately adjust the comparison voltage value to the set value. R10 is a feedback resistor, and C3 is a feedback capacitor. The feedback resistor value is relatively large, generally in the MΩ level, and the capacitor value is relatively small, generally in the pF level. After comparing the signal from the sensor with the comparison voltage, high and low levels can be output. U1 is a comparator that compares the sensor signal with the comparison voltage and outputs high and low levels. Q2 is a triode that mainly controls the on and off of the relay through the conduction and cut-off of the triode. D6 is a current-discharging diode that prevents the control coil of the relay from being damaged when the voltage suddenly changes. U2 is a relay that uses a low-power relay. Reducing the power consumption can reduce the heating power of the power resistor in the power supply part. By controlling the on and off of the relay, the control of the external circuit is achieved.

[0037] The implementation principle of this embodiment is as follows: Refer to Figure 5 and Figure 6, first, when the current of the measurement and control circuit is small, for example, the current is 8±1 mA during operation. At this time, the principle of the voltage stabilizing diode circuit can be utilized. A 13V voltage stabilizing diode and a power resistor are used to form a stable voltage, and then the voltage is stepped down through the base of the triode to form a stable operating voltage of 12.3V for the measurement and control circuit. When the current of the measurement and control circuit is large, for example, the current is 20±1 mA during operation, to ensure voltage stability: a 13V voltage stabilizing diode and a power resistor are used to form a stable voltage, and then the voltage is stepped down through the base of the triode to form a stable operating voltage of 12.3V for the measurement and control circuit. To prevent the voltage value from dropping when the current increases: when the current in the measurement and control circuit increases, the base current of the triode increases, and the collector current will also be amplified. By selecting an appropriate current limiting resistor, additional current can be provided for the measurement and control current, ensuring that the power supply voltage of the measurement and control circuit does not drop when the current of the measurement and control circuit increases.

[0038] The embodiments of this specific implementation manner are all preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A precision voltage stabilizing circuit for 110V DC operation, comprising a power conversion circuit and a measurement and control circuit, characterized in that: The power conversion circuit includes a polarity protection diode D1, one end of the polarity protection diode D1 is connected to the power supply, the other end of the polarity protection diode D1 is electrically connected to the power resistor R1 and the power resistor R2, the other end of the power resistor R1 is electrically connected to the switch diode D2 and the switch diode D4, and the switch diode D4 and the other end of the power resistor R2 are electrically connected to the transistor Q1; The pin 3 of the transistor Q1 is electrically connected to the other end of the switch diode D4, and the pin 2 of the transistor Q1 is electrically connected to the other end of the power resistor R2; Pin 1 of the transistor Q1 is electrically connected to capacitor C1, capacitor C2 and TVS tube D5. Pin 1 of the transistor Q1 and one end of the capacitor C1, one end of the capacitor C2 and one end of the TVS tube D5 output voltage.

2. A precision voltage stabilizing circuit for 110V DC operation according to claim 1, characterized in that: The other end of the switch diode D2 is electrically connected to a voltage regulator tube D3 , the other end of the voltage regulator tube D3 is grounded, and the other ends of the capacitor C1 , the capacitor C2 and the TVS tube D5 are grounded.

3. A precision voltage stabilizing circuit for 110V DC operation according to claim 1, characterized in that: The measurement and control circuit includes a voltage-dividing resistor R3, the other end of the voltage-dividing resistor R3 is electrically connected to a sensor R4, the other end of the sensor R4 is electrically connected to a voltage-dividing resistor R5 and an input resistor R7, the other end of the voltage-dividing resistor R5 is electrically connected to a voltage-dividing resistor R6, and the other end of the voltage-dividing resistor R6 is grounded.

4. A precision voltage stabilizing circuit for 110V DC operation according to claim 3, characterized in that: The other end of the input resistor R7 is electrically connected to the comparator U1, the feedback capacitor C3 and the feedback resistor R10, the 2nd pin of the comparator U1 is electrically connected to the other end of the input resistor R7, one end of the feedback capacitor C3 and one end of the feedback resistor R10, the 6th pin of the comparator U1 is electrically connected to the transistor base resistor R11, and the other end of the feedback resistor R10, the other end of the feedback capacitor C3, one end of the transistor base resistor R11 and the 6th pin of the comparator U1 are electrically connected.

5. A precision voltage stabilizing circuit for 110V DC operation according to claim 4, characterized in that: Pin 3 of the comparator U1 is electrically connected to the potentiometer RV1, pin 2 of the potentiometer RV1 is electrically connected to pin 3 of the comparator U1, pin 1 of the potentiometer RV1 is electrically connected to a voltage divider resistor R8, the other end of the voltage divider resistor R8 is connected to a comparison power supply, pin 3 of the potentiometer RV1 is electrically connected to a voltage divider resistor R9, the other end of the voltage divider resistor R9 is grounded, and pin 4 of the comparator U1 is grounded.

6. A precision voltage stabilizing circuit for 110V DC operation according to claim 5, characterized in that: The other end of the transistor base resistor R11 is electrically connected to the transistor Q2 , a pin 1 of the transistor Q2 is grounded, and a pin 2 of the transistor Q2 is electrically connected to the relay U2 and the leakage diode D6 .

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