High-temperature-resistant precise direct-current constant-current source circuit
By using dual integrated operational amplifiers and resistor capacitors in the DC constant current source circuit, combined with voltage-regulating diodes and capacitor filtering, a high-temperature precision DC constant current source circuit is built, which solves the problem of poor temperature stability in existing circuits in high temperature environments and achieves high stability of output current.
Patent Information
- Application Number
- CN202422249279.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-13
- Publication Date
- 2025-06-20
- Estimated Expiration
- 2034-09-13
AI Technical Summary
The existing DC constant current source circuit has problems of discretency and poor temperature stability in high temperature environments, which is difficult to meet the needs of special environments such as petroleum exploration.
Using a dual integrated operational amplifier and resistive capacitor, a voltage reference is formed through a voltage-regulating diode, combined with capacitor filtering and resistor network, a high-temperature precision DC constant current source circuit is built.
Within the temperature range of -55℃ to +200℃, the circuit output current drift is no more than 1%, and the output current is stable, which can meet the high-temperature and high-pressure environmental requirements of the petroleum logging industry.
Smart Images
Figure CN223006411U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of constant current source circuits, and particularly relates to a high-temperature resistant precision DC constant current source circuit. Background Art
[0002] Common DC constant current source circuits have many structural forms, but most of them are composed of discrete components such as resistors, capacitors, diodes, triodes or field effect transistors. In some special environments, such as oil exploration, the discreteness and temperature stability of the circuit are relatively poor. This application uses an integrated operational amplifier and resistors and capacitors to constitute a high-temperature resistant precision DC constant current source circuit. Content of the Utility Model
[0003] The purpose of the utility model is to provide a high-temperature resistant precision DC constant current source circuit to solve the problems existing in the background art.
[0004] To solve this technical problem, the technical solution of the utility model is as follows:
[0005] A high-temperature resistant precision DC constant current source circuit includes a dual-channel integrated operational amplifier. The dual-channel integrated operational amplifier includes a first operational amplifier U1-A and a second operational amplifier U1-B. It also includes a resistor R1. The first end of the resistor R1 is connected to the power supply. The second end of the resistor R2 is connected to the negative end of the voltage stabilizing diode DW. A voltage reference VREF is formed between the negative end of the voltage stabilizing diode DW and the second end of the resistor R2. The positive end of the voltage stabilizing diode DW is grounded;
[0006] The inverting input terminal 6 of the first operational amplifier U1-A is connected to the first end of the resistor R2. The second end of the resistor R2 is grounded. The non-inverting input terminal 5 of the first operational amplifier U1-A is connected to the first end of the resistor R3. The second end of the resistor R3 is connected to the voltage reference VREF. The output terminal 7 of the first operational amplifier U1-A is connected to the first end of the resistor R6. The second end of the resistor R6 is connected to the circuit output terminal. The 4th terminal of the first operational amplifier U1-A is grounded; It also includes a resistor R4. The first end of the resistor R4 is respectively connected to the inverting input terminal 6 of the first operational amplifier U1-A and the first end of the resistor R2; The second end of the resistor R4 is respectively connected to the output terminal 7 of the first operational amplifier U1-A and the first end of the resistor R6;
[0007] The output terminal 1 of the second operational amplifier U1-B is connected to the first end of the resistor R5. The second end of the resistor R5 is respectively connected to the non-inverting input terminal 5 of the first operational amplifier U1-A and the first end of the resistor R3. The inverting input terminal and the output terminal of the second operational amplifier U1-B are connected. The non-inverting input terminal 3 of the second operational amplifier U1-B is connected to the short-circuit output terminal. A load resistor RL is connected to the circuit output terminal.
[0008] Preferably, it further includes a capacitor C3. The first end of the capacitor C3 is connected to the positive terminal of the voltage stabilizing diode DW, and the second end is connected to the voltage reference VREF and the second end of the resistor R3.
[0009] The capacitance of the capacitor C3 is 0.1 uF / 50V, and it is a filter capacitor for the reference voltage VREF.
[0010] Preferably, it further includes a capacitor C1. The positive end of the capacitor C1 is connected to the +15V power supply, and the negative end is grounded. The capacitor C1 is a tantalum capacitor, and its capacitance is generally about 10 uF / 25V, used to eliminate the low-frequency fluctuations of the power supply.
[0011] Preferably, it further includes a capacitor C2. The capacitor C2 is connected in parallel to the capacitor C1. The capacitance of the capacitor C2 is a ceramic capacitor of 0.1 uF / 50V, and it is a coupling capacitor on the power supply to eliminate the high-frequency fluctuations on the power supply.
[0012] Preferably, the resistors R2, R3, R4, and R5 are four equal-value resistors, and their resistance values are 10K - 100K.
[0013] Preferably, the resistance value of the resistor R6 is 6.2K.
[0014] With such a value in this application, the output current is exactly 1 mA. Of course, by adjusting the resistance value of R6, the magnitude of the output current can also be adjusted.
[0015] Preferably, the voltage stabilizing diode DW is a 6.2V voltage. The 6.2V voltage stabilizing diode is between avalanche breakdown and Zener breakdown, so the temperature drift of this voltage is the smallest.
[0016] For the above technical solution, the beneficial effect of the present utility model is:
[0017] In this application, the operating temperature range of the circuit is wide. The output current drift within the entire temperature range (-55°C - +200°C) is not greater than 1%, and the output current of the circuit is very stable, which can meet the requirements of the downhole high-temperature and high-pressure environment in the oil well logging industry. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the principle structure of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0019] As Figure 1 shown, in order to further explain the technical solution of the present utility model, the present utility model will be elaborated in detail below through specific embodiments.
[0020] Embodiment 1
[0021] A high-temperature-resistant precision DC constant current source circuit includes a dual-channel integrated operational amplifier. The dual-channel integrated operational amplifier includes a first operational amplifier U1-A and a second operational amplifier U1-B. It also includes a resistor R1. The first end of the resistor R1 is connected to the +15V power supply. The second end of the resistor R2 is connected to the negative terminal of the voltage regulator diode DW. A voltage reference VREF is formed between the negative terminal of the voltage regulator diode DW and the second end of the resistor R2. The positive terminal of the voltage regulator diode DW is grounded. The inverting input terminal 6 of the first operational amplifier U1-A is connected to the first end of the resistor R2. The second end of the resistor R2 is grounded. The non-inverting input terminal 5 of the first operational amplifier U1-A is connected to the first end of the resistor R3. The second end of the resistor R3 is connected to the voltage reference VREF. The output terminal 7 of the first operational amplifier U1-A is connected to the first end of the resistor R6. The second end of the resistor R6 is connected to the circuit output terminal. The 4th pin of the first operational amplifier U1-A is grounded. It also includes a resistor R4. The first end of the resistor R4 is respectively connected to the inverting input terminal 6 of the first operational amplifier U1-A and the first end of the resistor R2. The second end of the resistor R4 is respectively connected to the output terminal 7 of the first operational amplifier U1-A and the first end of the resistor R6. The output terminal 1 of the second operational amplifier U1-B is connected to the first end of the resistor R5. The second end of the resistor R5 is respectively connected to the non-inverting input terminal 5 of the first operational amplifier U1-A and the first end of the resistor R3. The inverting input terminal and the output terminal of the second operational amplifier U1-B are connected. The non-inverting input terminal 3 of the second operational amplifier U1-B is connected to the short-circuit output terminal. A load resistor RL is connected to the circuit output terminal. It also includes a capacitor C3. The first end of the capacitor C3 is connected to the positive terminal of the voltage regulator diode DW. The second end is connected to the voltage reference VREF and the second end of the resistor R3. The capacitance of the capacitor C3 is 0.1uF / 50V, which is the filter capacitor of the reference voltage VREF. It also includes a capacitor C1. The positive terminal of the capacitor C1 is connected to the +15V power supply, and the negative terminal is grounded. The capacitor C1 is a tantalum capacitor with a capacitance generally about 10uF / 25V, used to eliminate the low-frequency fluctuations of the power supply. It also includes a capacitor C2. The capacitor C2 is connected in parallel with the capacitor C1. The capacitor C2 is a ceramic capacitor with a capacitance of 0.1uF / 50V, which is the coupling capacitor on the power supply to eliminate the high-frequency fluctuations on the power supply. The resistors R2, R3, R4, and R5 are four equal-value resistors with a resistance value of 10K - 100K. The resistance value of the resistor R6 is 6.2K. With such values in this application, the output current is exactly 1mA. Of course, by adjusting the resistance value of R6, the magnitude of the output current can also be adjusted. The voltage regulator diode DW is a 6.2V voltage. The 6.2V zener diode is between avalanche breakdown and Zener breakdown, so this voltage has the smallest temperature drift.
[0022] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A high temperature resistant precision DC constant current source circuit, characterized in that: The dual-channel integrated operational amplifier includes a first operational amplifier U1-A and a second operational amplifier U1-B, and also includes a resistor R1, a first end of the resistor R1 is connected to a power supply, a second end of the resistor R2 is connected to a negative terminal of a voltage-stabilizing diode DW, a voltage reference VREF is formed between the negative terminal of the voltage-stabilizing diode DW and the second end of the resistor R2, and a positive terminal of the voltage-stabilizing diode DW is grounded; The inverting input terminal 6 pin of the first operational amplifier U1-A is connected to the first end of the resistor R2, and the second end of the resistor R2 is grounded; the non-inverting input terminal 5 pin of the first operational amplifier U1-A is connected to the first end of the resistor R3, and the second end of the resistor R3 is connected to the voltage reference VREF; the output terminal 7 pin of the first operational amplifier U1-A is connected to the first end of the resistor R6, and the second end of the resistor R6 is connected to the circuit output terminal; the first operational amplifier U1-A also includes a resistor R4, the first end of the resistor R4 is respectively connected to the inverting input terminal 6 pin of the first operational amplifier U1-A and the first end of the resistor R2; the second end of the resistor R4 is respectively connected to the output terminal 7 pin of the first operational amplifier U1-A and the first end of the resistor R6; Pin 1 of the output terminal of the second operational amplifier U1-B is connected to the first end of the resistor R5, and the second end of the resistor R5 is respectively connected to pin 5 of the in-phase input terminal of the first operational amplifier U1-A and the first end of the resistor R3, the inverting input terminal and the output terminal of the second operational amplifier U1-B are connected, and pin 3 of the in-phase input terminal of the second operational amplifier U1-B is connected to the short-circuit output terminal, and a load resistor RL is connected to the output terminal of the circuit.
2. A high temperature resistant precision DC constant current source circuit according to claim 1, characterized in that: The device further comprises a capacitor C3, a first end of which is connected to the positive terminal of the voltage stabilizing diode DW, and a second end of which is connected to the voltage reference VREF and the second end of the resistor R3.
3. The high temperature resistant precision DC constant current source circuit according to claim 1, characterized in that: It also includes a capacitor C1, the positive end of the capacitor C1 is connected to a +15V power supply, and the negative end is grounded.
4. The high temperature resistant precision DC constant current source circuit according to claim 1, characterized in that: The device further comprises a capacitor C2, which is connected in parallel to the capacitor C1.
5. The high temperature resistant precision DC constant current source circuit according to claim 1, characterized in that: Resistors R2, R3, R4, and R5 are four resistors of equal value, and the resistance value is 10K-100K.
6. A high temperature resistant precision DC constant current source circuit according to claim 1, characterized in that: The resistance of resistor R6 is 6.2K.
7. The high temperature resistant precision DC constant current source circuit according to claim 1, characterized in that: The voltage of the Zener diode DW is 6.2V.