阅读说明：本技术 一种高精度高稳定度恒流源电路 (High-precision high-stability constant current source circuit ) 是由 张国平 吴明辉 娄素兵 曹晓辉 于 2021-02-15 设计创作，主要内容包括：本发明涉及一种高精度高稳定度恒流源电路,解决的是精度低、不稳定的的技术问题,通过采用包括电源模块,与电源模块连接的温控电路、恒温装置以及处理器；恒温装置内置有与电源模块连接的电压基准源电路模块、运算放大电路模块,电压基准源电路模块与运算放大电路模块连接,运算放大电路模块连接功率管,恒温装置还有高精度采样电阻单元；处理器连接开关切换模块,开关切换模块通过高精度采样电阻单元连接到功率管；高精度采样电阻单元包含至少2路采样电阻支路；开关切换模块控制高精度采样电阻的支路选通调节电流大小；温控电路控制恒温装置的温度的技术方案,较好的解决了该问题,可用于恒流源电路中。(The invention relates to a high-precision high-stability constant current source circuit, which solves the technical problems of low precision and instability by adopting a constant current source circuit, which comprises a power module, a temperature control circuit, a constant temperature device and a processor, wherein the temperature control circuit, the constant temperature device and the processor are connected with the power module; the constant temperature device is internally provided with a voltage reference source circuit module and an operational amplification circuit module which are connected with the power supply module, the voltage reference source circuit module is connected with the operational amplification circuit module, the operational amplification circuit module is connected with the power tube, and the constant temperature device is also provided with a high-precision sampling resistance unit; the processor is connected with the switch switching module, and the switch switching module is connected to the power tube through the high-precision sampling resistor unit; the high-precision sampling resistance unit comprises at least 2 sampling resistance branches; the switch switching module controls the branch gating of the high-precision sampling resistor to regulate the current; the technical scheme that the temperature control circuit controls the temperature of the constant temperature device better solves the problem and can be used in a constant current source circuit.)

1. The utility model provides a high accuracy high stability constant current source circuit which characterized in that: the temperature control device comprises a power supply module, a temperature control circuit, a constant temperature device and a processor, wherein the temperature control circuit, the constant temperature device and the processor are connected with the power supply module;

the constant temperature device is internally provided with a voltage reference source circuit module and an operational amplification circuit module which are connected with the power supply module, the voltage reference source circuit module is connected with the operational amplification circuit module, the operational amplification circuit module is connected with the power tube, and the constant temperature device is also internally provided with a high-precision sampling resistance unit;

the processor is connected with the switch switching module, and the switch switching module is connected to the power tube through the high-precision sampling resistor unit; the output of the power tube is used as the output end of the constant current source circuit; the high-precision sampling resistance unit comprises at least 2 sampling resistance branches;

the switch switching module controls the branch gating of the high-precision sampling resistor to regulate the current;

the temperature control circuit controls the temperature of the thermostatic device.

2. The high-precision high-stability constant current source circuit according to claim 1, wherein: the temperature control circuit comprises a temperature sampling unit and a temperature control unit connected with the temperature sampling unit, and the temperature control unit is connected with the constant temperature device to adjust the temperature of the constant temperature device.

3. The high-precision high-stability constant current source circuit according to claim 2, wherein: the temperature sampling unit adopts a high-precision temperature-sensitive resistor.

4. The high-precision high-stability constant current source circuit according to claim 2, wherein: the temperature of the thermostat device is controlled in zones.

5. The high-precision high-stability constant current source circuit according to claim 1, wherein: the high-precision sampling resistance branch comprises at least 2 same branch units, wherein one branch unit is defined as a main branch, and the other branch units are defined as spare branches;

the branch unit is controlled by a fault recovery switch; the fault recovery switch is controlled by a fault recovery switch control signal register;

the fault recovery switch control signal register is connected with a fault branch counter, and the fault branch counter is connected with a normal branch counter;

the function checker is connected with the high-precision sampling resistance branch state register, and the high-precision sampling resistance branch state register is connected with a branch number counter and a fault recovery switch control signal register; the fault recovery switch control signal register controls the fault recovery switch to complete the switching of the main branch, and the completion of the switching of the fault main branch is defined as the completion of the repair; the device also comprises an excitation signal generator;

after the fault branch counter, the normal branch counter and the branch number counter are connected with an OR gate together, the OR gate outputs a repair completion signal;

the fault branch counter outputs the fault number and the fault carry of the high-precision sampling resistance branch, the normal branch counter outputs the normal number and the normal carry of the high-precision sampling resistance branch, and the branch number counter outputs the high-precision sampling resistance branch number;

the high-precision sampling resistance branch state diagnosis result is stored in a high-precision sampling resistance branch state register; the branch number counter starts to count all the high-precision sampling resistance branches from the first high-precision sampling resistance branch in a traversing manner;

the function checker calculates the high-precision sampling resistance branch state diagnosis result of the high-precision sampling resistance branch by receiving the checking information of the high-precision sampling resistance branch and analyzing the response signal fed back by the high-precision sampling resistance branch and outputs the result to the high-precision sampling resistance branch state register.

6. The high-precision high-stability constant current source circuit according to claim 5, wherein: the high-precision sampling resistance branch comprises 3 same branch units.

7. The high-precision high-stability constant current source circuit according to claim 5, wherein: the counter is a synchronous counter with counting, maintaining, setting and carry output functions.

8. The high-precision high-stability constant current source circuit according to claim 5, wherein: the input end of the function checker is connected with a high-precision sampling resistance branch fault detection signal;

the function checker comprises a comparator, an AND gate, an OR gate, a first D trigger and a second D trigger;

one end of the first D trigger is connected with the AND gate, the other end of the first D trigger is connected with the comparator, the input of the other end of the AND gate is connected with the reset end and the input end of the AND gate connected with the second D trigger, one end of the output of the AND gate is connected with the OR gate, and the other end of the output of the AND gate is connected with the logic 0;

one end of the first D trigger is connected with the AND gate, the other end of the first D trigger is connected with the comparator, the input of the other end of the AND gate is connected with the reset end and the input end of the AND gate connected with the first D trigger, one end of the output of the AND gate is connected with the OR gate, and the other end of the output of the AND gate is connected with the logic 1;

the input of the comparator is check information; and when the detection result is the same as the verification information, outputting logic 1, otherwise, outputting logic 0.

Technical Field

The invention relates to the field of power supplies, in particular to a high-precision high-stability constant current source circuit.

Background

The high-precision and high-stability current signal is provided in the test of the high-precision I/F conversion circuit (current frequency conversion) of the inertial navigation system. The performance index of the I/F conversion circuit, which is an important component in the inertial navigation system, directly determines the accuracy of the navigation system, so the inertial navigation system must strictly test the performance parameters of the I/F conversion circuit in the development process. The testing of the I/F conversion circuit has become a very important component in the production process of the inertial navigation product.

The testing of high-precision I/F conversion circuits by various institutes of previous inertial navigation systems is carried out by providing high-precision and high-stability current signals by using foreign calibration sources, such as FLUKE 5700, which are expensive, large in size and weight, inconvenient to carry and not beneficial to system integration, and have the risk of being forbidden for the high-precision instruments.

The invention provides a high-precision high-stability constant current source circuit which is used for solving the problems of low precision and instability of the current constant current source circuit.

Disclosure of Invention

The invention aims to solve the technical problems of low precision and instability in the prior art. The high-precision high-stability constant current source circuit has the characteristics of high precision and high stability.

In order to solve the technical problems, the technical scheme is as follows:

a high-precision high-stability constant current source circuit comprises a power module, a temperature control circuit, a constant temperature device and a processor, wherein the temperature control circuit, the constant temperature device and the processor are connected with the power module; the constant temperature device is internally provided with a voltage reference source circuit module and an operational amplification circuit module which are connected with the power supply module, the voltage reference source circuit module is connected with the operational amplification circuit module, the operational amplification circuit module is connected with the power tube, and the constant temperature device is also internally provided with a high-precision sampling resistance unit;

the processor is connected with the switch switching module, and the switch switching module is connected to the power tube through the high-precision sampling resistor unit; the output of the power tube is used as the output end of the constant current source circuit; the high-precision sampling resistance unit comprises at least 2 sampling resistance branches;

the switch switching module controls the branch gating of the high-precision sampling resistor to regulate the current; the temperature control circuit controls the temperature of the thermostatic device.

The invention realizes the control of the output current of the constant current source by a scheme of multi-path fixed current value parallel gating switching, and the stability of the constant current source is superior to 1 ppm. Meanwhile, a temperature control scheme is adopted to provide a constant ambient temperature for a temperature sensitive device in the circuit, and the influence of ambient temperature change on a current signal is reduced.

In the above scheme, for optimization, further, the temperature control circuit includes a temperature sampling unit, and a temperature control unit connected with the temperature sampling unit, and the temperature control unit is connected with the thermostatic device to adjust the temperature of the thermostatic device.

Further, the temperature sampling unit adopts a high-precision temperature-sensitive resistor.

Further, the temperature of the thermostat device is subjected to zone control. The partition control can more accurately control the stability of the temperature-sensitive period.

In order to ensure the stability, the high-precision sampling resistance branch circuit adopts a main branch circuit unit and a standby branch circuit unit to ensure the stability. Meanwhile, the fault of the high-precision sampling resistor branch is recovered by adopting state monitoring detection and a switching mode, so that automatic detection, automatic recovery and automatic switching are realized.

Specifically, the high-precision sampling resistor branch comprises at least 2 same branch units, wherein one branch unit is defined as a main branch, and the rest branch units are defined as spare branches;

the branch unit is controlled by a fault recovery switch; the fault recovery switch is controlled by a fault recovery switch control signal register;

the fault recovery switch control signal register is connected with a fault branch counter, and the fault branch counter is connected with a normal branch counter;

the function checker is connected with the high-precision sampling resistance branch state register, and the high-precision sampling resistance branch state register is connected with a branch number counter and a fault recovery switch control signal register; the fault recovery switch control signal register controls the fault recovery switch to complete the switching of the main branch, and the completion of the switching of the fault main branch is defined as the completion of the repair; the device also comprises an excitation signal generator;

after the fault branch counter, the normal branch counter and the branch number counter are connected with an OR gate together, the OR gate outputs a repair completion signal;

the fault branch counter outputs the fault number and the fault carry of the high-precision sampling resistance branch, the normal branch counter outputs the normal number and the normal carry of the high-precision sampling resistance branch, and the branch number counter outputs the high-precision sampling resistance branch number;

the high-precision sampling resistance branch state diagnosis result is stored in a high-precision sampling resistance branch state register; the branch number counter starts to count all the high-precision sampling resistance branches from the first high-precision sampling resistance branch in a traversing manner;

the function checker calculates the high-precision sampling resistance branch state diagnosis result of the high-precision sampling resistance branch by receiving the checking information of the high-precision sampling resistance branch and analyzing the response signal fed back by the high-precision sampling resistance branch and outputs the result to the high-precision sampling resistance branch state register.

Further, the high-precision sampling resistor branch comprises 3 same branch units.

Further, the counter is a synchronous counter with counting, holding, setting and carry output functions.

Furthermore, the input end of the function checker is connected with a high-precision sampling resistance branch fault detection signal;

the function checker comprises a comparator, an AND gate, an OR gate, a first D trigger and a second D trigger;

one end of the first D trigger is connected with the AND gate, the other end of the first D trigger is connected with the comparator, the input of the other end of the AND gate is connected with the reset end and the input end of the AND gate connected with the second D trigger, one end of the output of the AND gate is connected with the OR gate, and the other end of the output of the AND gate is connected with the logic 0;

one end of the first D trigger is connected with the AND gate, the other end of the first D trigger is connected with the comparator, the input of the other end of the AND gate is connected with the reset end and the input end of the AND gate connected with the first D trigger, one end of the output of the AND gate is connected with the OR gate, and the other end of the output of the AND gate is connected with the logic 1;

the input of the comparator is check information; and when the detection result is the same as the verification information, outputting logic 1, otherwise, outputting logic 0.

In the invention: the power module is responsible for providing different working power for each circuit module, and voltage reference source circuit produces the reference voltage signal of high accuracy, high stability and gives the operational amplifier circuit and follow the processing, then control power tube output corresponding electric current, and the treater is responsible for realizing the communication with external equipment, and control switch switching module accomplishes the gate switching to high accuracy sampling resistor and realizes the regulation of electric current size simultaneously. The temperature control circuit is responsible for realizing the temperature control of the constant temperature device, and the constant temperature device is responsible for providing a constant ambient temperature for the temperature sensitive device in the circuit, and reducing the influence of the ambient temperature change on the current signal.

The invention has the beneficial effects that: the invention has the advantages of adjustable program control of output current, high precision and high stability, and the stability of the invention is better than 1ppm in 2 hours; and the output minimum current and the adjustable step length can be flexibly modified by replacing the high-precision sampling resistor.

Drawings

The invention is further illustrated with reference to the following figures and examples.

Fig. 1 is a schematic circuit diagram of a constant current source in embodiment 1.

FIG. 2 is a schematic diagram of a temperature control circuit.

Fig. 3 is a schematic diagram of a high-precision sampling resistor branch fault recovery control unit.

Fig. 4, a schematic diagram of a counter.

FIG. 5 is a schematic diagram of a function checker.

FIG. 6 is a schematic diagram of a high-precision sampling resistor branch state register.

Fig. 7, a schematic diagram of a fail-back switch control signal register.

FIG. 8 is another schematic diagram of a temperature control circuit.

Fig. 9 is a specific schematic circuit diagram of each module.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

The present embodiment provides a high-precision high-stability constant current source circuit, as shown in fig. 1, including a power module, a temperature control circuit connected to the power module, a thermostat, and a processor; the constant temperature device is internally provided with a voltage reference source circuit module and an operational amplification circuit module which are connected with the power supply module, the voltage reference source circuit module is connected with the operational amplification circuit module, the operational amplification circuit module is connected with the power tube, and the constant temperature device is also internally provided with a high-precision sampling resistance unit; the processor is connected with the switch switching module, and the switch switching module is connected to the power tube through the high-precision sampling resistor unit; the output of the power tube is used as the output end of the constant current source circuit; the high-precision sampling resistance unit comprises at least 2 sampling resistance branches; the switch switching module controls the branch gating of the high-precision sampling resistor to regulate the current; the temperature control circuit controls the temperature of the thermostatic device.

In the embodiment, the control of the output current of the constant current source is realized by a scheme of parallel gating and switching of multiple paths of fixed current values, and the stability of the constant current source is superior to 1 ppm. Meanwhile, a temperature control scheme is adopted to provide a constant ambient temperature for a temperature sensitive device in the circuit, and the influence of ambient temperature change on a current signal is reduced.

Fig. 9 is a specific schematic circuit diagram of each module. Specifically, as shown in fig. 2, the temperature control circuit includes a temperature sampling unit, and a temperature control unit connected to the temperature sampling unit, and the temperature control unit is connected to the thermostat device to adjust the temperature of the thermostat device. The temperature control circuit may also employ the scheme of fig. 8.

Specifically, the temperature sampling unit adopts a high-precision temperature-sensitive resistor.

The temperature control unit and the thermostat can both adopt the existing circuits and devices, and the details are not repeated in this embodiment.

Preferably, the temperature of the thermostatic device is subject to zone control. The partition control can more accurately control the stability of the temperature-sensitive period. The scheme of temperature zone control may also adopt the prior art, and this embodiment is not described again.

In order to ensure the stability, the high-precision sampling resistance branch circuit adopts a main branch circuit unit and a standby branch circuit unit to ensure the stability. Meanwhile, the fault of the high-precision sampling resistor branch is recovered by adopting state monitoring detection and a switching mode, so that automatic detection, automatic recovery and automatic switching are realized.

Preferably, the high-precision sampling resistor branch comprises 2 same branch units, wherein one branch unit is defined as a main branch, and the rest branch units are defined as spare branches; the same number of branch units is balanced under the balance of failure rate and volume size, and can be 2, 3, 4 and the like.

As shown in fig. 3, the branching unit is controlled by a fault recovery switch; the fault recovery switch is controlled by a fault recovery switch control signal register; the fault recovery switch control signal register is connected with a fault branch counter, and the fault branch counter is connected with a normal branch counter; the function checker is connected with a high-precision sampling resistance branch state register, and the high-precision sampling resistance branch state register is connected with a branch number counter and a fault recovery switch control signal register; the fault recovery switch control signal register controls the fault recovery switch to complete the switching of the main branch, and the completion of the switching of the fault main branch is defined as the completion of the repair; the device also comprises an excitation signal generator; after the fault branch counter, the normal branch counter and the branch number counter are connected with an OR gate together, the OR gate outputs a repair completion signal;

the fault branch counter outputs the fault number and the fault carry of the high-precision sampling resistance branch, the normal branch counter outputs the normal number and the normal carry of the high-precision sampling resistance branch, and the branch number counter outputs the high-precision sampling resistance branch number;

the high-precision sampling resistance branch state diagnosis result is stored in a high-precision sampling resistance branch state register; the branch number counter starts to count all the high-precision sampling resistance branches from the first high-precision sampling resistance branch in a traversing manner;

the function checker calculates the high-precision sampling resistance branch state diagnosis result of the high-precision sampling resistance branch by receiving the checking information of the high-precision sampling resistance branch and analyzing the response signal fed back by the high-precision sampling resistance branch and outputs the result to the high-precision sampling resistance branch state register.

The unit has 3 working states, and one working state is a normal state, namely a reset state, of the high-precision sampling resistor branch circuit. And the other is a fault detection state when the high-precision sampling resistor branch fails. One is a repair state that initiates the backup path after fault detection. According to the response signal, the control unit of the high-precision sampling resistance branch enters a fault detection state, and the excitation signal generator generates an excitation signal to be loaded to the fault recovery switch.

After resetting is completed, the control unit enters a fault detection state and performs parallel detection on all high-precision sampling resistor branches in the cluster. The counter generates 4-bit excitation signals to be sent to all high-precision sampling resistance branches, the function checker receives response signals from all high-precision sampling resistance branches and checking information generated by the current main channel of the high-precision sampling resistance branches, analyzes and judges the response signals and sends a judgment result to the high-precision sampling resistance branch state register. After the high-precision sampling resistor branch state register is updated, the fault detection state is finished, the branch number counter is activated, and the control unit enters a fault recovery state.

The high-precision sampling resistance branch state register outputs state information of each high-precision sampling resistance branch, and the branch number counter controls the multi-path selector to traverse all the high-precision sampling resistance branches and sequentially output states of the high-precision sampling resistance branches.

And the fault recovery switch control signal register outputs a fault recovery switch gating signal according to the output high-precision sampling resistor branch state, and controls the gating of all fault recovery switches.

And the fault branch counter and the normal branch counter count according to the output high-precision sampling resistance branch state value, and carry out fault counting when the high-precision sampling resistance branch state fails, or carry out normal counting. And activating a fault recovery switch control signal register to store the fault number signal in the current fault branch counter when the normal branch counter counts, and otherwise, updating the normal branch counter. At this time, the fault number signal is a control signal of the fault recovery switch. The maximum count value of the faulty branch counter is the predefined minimum value of the number of faults that need to be repaired. And if the count value exceeds the threshold value, outputting a fault repair demand signal, starting repair, and outputting a repair completion signal after the repair is completed. In addition, under the condition that the control unit normally works, the count value of the branch number counter is equal to the sum of the count values of the fault branch counter and the normal branch counter, otherwise, the counter fails, and the characteristic can be utilized to carry out simple fault self-detection on the control unit.

Specifically, the high-precision sampling resistor branch comprises 3 identical branch units.

As shown in fig. 4, a 4-bit counter is adopted, and the 4-bit counter is a synchronous counter with counting, holding, setting and carry output functions. The bit counter has 5D triggers, 4 for completing counting function, and 1 for storing carry result. The 4-bit counter can be adopted by the fault branch counter and the normal branch counter.

As shown in fig. 5, the input end of the function checker is connected with the check signal and the response signal to complete the fault detection and discrimination of the high-precision sampling resistor branch. The function checker comprises a comparator, an AND gate, an OR gate, a first D trigger and a second D trigger; one end of the first D trigger is connected with the AND gate, the other end of the first D trigger is connected with the comparator, the input of the other end of the AND gate is connected with the reset end and the input end of the AND gate connected with the second D trigger, one end of the output of the AND gate is connected with the OR gate, and the other end of the output of the AND gate is connected with the logic 0; one end of the first D trigger is connected with the AND gate, the other end of the first D trigger is connected with the comparator, the input of the other end of the AND gate is connected with the reset end and the input end of the AND gate connected with the first D trigger, one end of the output of the AND gate is connected with the OR gate, and the other end of the output of the AND gate is connected with the logic 1; the input of the comparator is check information; and when the detection result is the same as the verification information, outputting logic 1, otherwise, outputting logic 0.

And the Check 1-Check S are high-precision sampling resistance branch fault detection results. And taking the comparison result of the error between the real-time resistance detection value of each high-precision sampling resistance branch and the preset value as a response signal, wherein the value greater than the preset value is defined as 0, and the value less than or equal to the preset value is defined as 1. And the response signal is sent to a pair of AND gates and OR gates which are in feedback connection with the D trigger, the detection of logic 0 and logic 1 in the response signal is respectively realized, the detection result is compared with the verification information, when the detection result is the same as the verification information, logic 1 is output, otherwise, logic 0 is output. In the fault detection result output by the functional checker, logic 1 indicates no fault, and logic 0 indicates a fault.

Fig. 6 is a schematic diagram of a high-precision sampling resistor branch state register. The input is mainly high-precision sampling resistance branch fault detection result and set signal that the function checker outputs, and the output is high-precision sampling resistance branch state signal and fault recovery switch control signal.

Setting the initial time of the current high-precision sampling resistor branch state register to be all 1, setting the initial time of the fault recovery switch state register to be all 0, and taking the output of the current high-precision sampling resistor branch state register and the fault detection result phase as the input of the current high-precision sampling resistor branch state register. And negating the high-precision sampling resistor branch state data stored in the current high-precision sampling resistor branch state register, and taking the negation and the fault detection result as the input of the fault recovery switch state register.

Therefore, when a certain high-precision sampling resistance branch is judged to be in fault, the state of the high-precision sampling resistance branch is recorded as a fault state 0 by the current high-precision sampling resistance branch state register, the state register of the fault recovery switch is recorded as 0 when the trigger edge arrives, namely the fault recovery switch is controlled to act, and otherwise, the state register of the fault recovery switch is recorded as 1, namely the fault recovery switch is kept.

Fig. 7 is a schematic diagram of the control signal register of the fail-back switch. The fault recovery switch control signal register generates a control signal. Setting the setting signal at a low level, wherein the value of a D trigger in the register after setting is 0; cell _ state is a state signal of the high-precision sampling resistance branch, when Cell _ state is 1, the high-precision sampling resistance branch is normal, and when Cell _ state is 0, the high-precision sampling resistance branch is in fault; and the Shift 1-Shift S are respectively control signals for controlling the fault recovery of the S high-precision sampling resistance branches, when the control signals are logic 0, the fault recovery switches in the corresponding high-precision sampling resistance branches are gated, otherwise, the fault recovery switches are not gated. In the counting process of the branch number counter, logic values stored in S D triggers in the fault recovery switch control signal register are changed from 0 to 1 in sequence, namely corresponding control signals are locked to be logic 1 in sequence.

In this embodiment, the power module is responsible for providing different working power supplies for the circuit modules, the voltage reference source circuit generates a high-precision and high-stability reference voltage signal and sends the reference voltage signal to the operational amplifier circuit for follow-up processing, then the power tube is controlled to output corresponding current, the processor is responsible for realizing communication with external equipment, and the switch switching module is controlled to complete gating switching of the high-precision sampling resistor to realize adjustment of the current. The temperature control circuit is responsible for realizing the temperature control of the constant temperature device, and the constant temperature device is responsible for providing a constant ambient temperature for the temperature sensitive device in the circuit, and reducing the influence of the ambient temperature change on the current signal.

Although the illustrative embodiments of the present invention have been described above to enable those skilled in the art to understand the present invention, the present invention is not limited to the scope of the embodiments, and it is apparent to those skilled in the art that all the inventive concepts using the present invention are protected as long as they can be changed within the spirit and scope of the present invention as defined and defined by the appended claims.