Adjustable DC voltage source device and method

Abstract

The invention discloses an adjustable DC voltage source device and method, and belongs to the technical field of measurement. On the basis of a high-integration power supply chip, a miniaturized adjustable direct-current voltage output circuit is designed through a high-precision and small-step voltage tracking method, the circuit is small in occupied size, direct-current voltage output in the wide range of 1-32 V can be achieved, the output current is larger than 1A, and the output voltage adjusting step is smaller than 0.1 V; the circuit has the characteristics of simple structure, small size, wide adjustment range, digitally adjustable output voltage and monitorable output, and is suitable for miniaturized microwave measuring instruments.

Description

Technical Field

[0001] This invention belongs to the field of measurement technology, specifically relating to an adjustable DC voltage source device and method. Background Technology

[0002] Miniaturized spectrum analyzers, miniaturized vector network analyzers, miniaturized microwave integrated testers, and other field microwave measurement instruments typically feature adjustable DC voltage output functionality. This functionality is primarily used to provide DC bias voltage to active components such as amplifiers under test. In recent years, miniaturized field microwave measurement instruments have become increasingly smaller and more powerful, placing higher demands on the performance of their internal adjustable DC voltage sources. Traditional adjustable DC voltage source circuits suffer from drawbacks such as large footprint, narrow voltage output range, large output steps, and unmonitorable output, making them unsuitable for use in new miniaturized microwave measurement instruments. To address the requirements of new miniaturized microwave measurement instruments for small size, wide adjustment range, digitally adjustable output voltage, and monitorable output of the adjustable DC voltage source circuit, this invention proposes a design method for a miniaturized adjustable DC voltage source.

[0003] The closest implementation to this invention is as follows: Figure 1 As shown.

[0004] The AT89C51 series microcontroller is used as the control unit of the whole machine. The output voltage value (the voltage value after A / D conversion) is changed by changing the input digital value. The output voltage is indirectly changed by the integrated operational amplifier and the emitter follower.

[0005] The basic design idea of ​​this scheme is to amplify the voltage output by the microcontroller (after D / A conversion) and output a digitally adjustable voltage. The circuit consists of six parts: a microcontroller control circuit, a keyboard circuit, a power supply circuit, a D / A circuit, an operational amplifier circuit, and an LED display circuit. The system controls the rise and fall of the preset voltage via buttons. The microcontroller sends out the corresponding digital signal, which, after D / A conversion, outputs current. This current is then amplified by an integrated operational amplifier and regulated by a voltage regulator circuit until it stabilizes. This scheme uses a microcontroller as the main controller, which has limited resources. It is suitable for logic control or simple calculations but cannot achieve true parallel processing, making real-time performance difficult to guarantee. This scheme also lacks an output sampling circuit and cannot provide overload protection for the connected load.

[0006] Currently, existing technologies have the following drawbacks:

[0007] 1. The output voltage range is limited.

[0008] 2. Traditional adjustable DC voltage output circuits using variable potentiometers are susceptible to temperature drift and mechanical wear, resulting in output voltage drift. They also occupy a large volume and have large output voltage steps.

[0009] 3. Traditional circuits that use DAC + operational amplifier to achieve adjustable DC voltage output have weak load capacity, poor reliability, and high output power supply noise.

[0010] 4. The lack of a comprehensive monitoring and protection mechanism for voltage, current, and power makes it difficult to meet high reliability requirements. Summary of the Invention

[0011] In view of the above-mentioned technical problems existing in the prior art, the present invention proposes an adjustable DC voltage source device and method, which is reasonably designed, overcomes the shortcomings of the prior art, and has good effect.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] An adjustable DC voltage source device, comprising:

[0014] The host computer is configured to set the voltage output value and overload protection threshold, and to perform real-time monitoring and diagnosis.

[0015] The FPGA main control unit is configured to receive the target voltage value set by the host computer and convert the target voltage value into the digital signal required by the DAC.

[0016] The DAC module is configured to convert digital signals output from the FPGA into analog voltage signals;

[0017] An operational amplifier is configured to amplify the analog voltage signal output by the DAC;

[0018] The Boost converter circuit is configured to boost the input DC voltage to a stable voltage level to power the buck and voltage tracking circuits.

[0019] The buck and voltage tracking circuit is configured to precisely adjust the output voltage according to the voltage signal output by the operational amplifier to achieve voltage tracking.

[0020] The multi-parameter acquisition circuit is configured to monitor the voltage, current and power at the output terminal in real time and feed the monitoring results back to the FPGA main control unit.

[0021] The reverse voltage protection circuit is configured to implement hardware-level reverse voltage input protection, and directly shuts down when the circuit detects a reverse voltage input.

[0022] A power adapter or lithium battery is configured to provide power to the device;

[0023] The first filter circuit is configured to filter out noise and other interference signals from the power adapter or lithium battery, providing a stable DC voltage input to the downstream Boost converter circuit.

[0024] The second filter circuit is configured to filter out high-frequency noise, switching noise, and other harmonic components generated during the operation of the buck and voltage tracking circuits; wherein...

[0025] The power adapter or lithium battery, the first filter circuit, the boost converter circuit, the buck and voltage tracking circuit, the second filter circuit, the reverse protection circuit, and the load are connected in sequence through the lines.

[0026] The closed-loop control circuit consists of an FPGA main control unit, a DAC module, an operational amplifier, a buck and voltage tracking circuit, a second filter circuit, and a multi-parameter acquisition circuit.

[0027] Preferably, the Boost converter circuit adopts a four-switch Buck-Boost topology and integrates four MOSFET switches and an inductor, combined with synchronous rectification and PWM control technology to achieve energy conversion.

[0028] Preferably, the buck and voltage tracking circuit includes:

[0029] An error amplifier is configured to compare the feedback voltage with a reference voltage generated by the DAC in real time.

[0030] The PWM controller is configured to dynamically adjust the duty cycle based on the comparison result;

[0031] By comparing the feedback voltage with the reference voltage, the PWM duty cycle is dynamically adjusted. When the external reference voltage changes, the feedback voltage follows the reference voltage, ultimately achieving an output voltage equal to the reference voltage.

[0032] Preferably, the multi-parameter acquisition circuit can continuously read the shunt voltage value and the bus voltage value, calculate the current value and the power value, and update the register after averaging the N measurement results.

[0033] Preferably, the FPGA main control unit presets overvoltage threshold, overcurrent threshold, and overpower threshold; when any parameter exceeds the limit, the FPGA main control unit forces the DAC module output to be set to 0.

[0034] Preferably, the adjustable DC voltage source has an output voltage range of 1–32V; an output current capability of ≥1A; a voltage regulation step of ≤0.1V; and a voltage tracking response time of ≤10ms.

[0035] Furthermore, this invention also mentions an adjustable DC voltage source control method, which employs the adjustable DC voltage source device described above, and specifically includes the following steps:

[0036] Step 1: Set the target voltage and protection threshold parameters via the host computer;

[0037] Step 2: Receive the target voltage value set by the host computer through the FPGA main control unit, convert the target voltage value into the digital signal required by the DAC, and update the register through the SPI interface;

[0038] Step 3: Convert the digital signal output from the FPGA into an analog voltage signal using the DAC module;

[0039] Step 4: Amplify the analog voltage signal output from the DAC using an operational amplifier and then feed it to the buck converter and voltage tracking circuit;

[0040] Step 5: By using a step-down and voltage tracking circuit, the output voltage is adjusted according to the voltage signal output by the operational amplifier to achieve voltage tracking;

[0041] Step 6: Monitor the voltage, current and power at the output terminal in real time through a multi-parameter acquisition circuit, and feed the monitoring results back to the FPGA main control unit;

[0042] Step 7: Collect load-side parameters in real time and calculate the current value I and power value P;

[0043] Step 8: When the parameter exceeds the limit, the FPGA main control unit forces the DAC module output to be set to 0.

[0044] The beneficial technical effects of this invention are as follows:

[0045] 1. Wide voltage range output, digitally adjustable output voltage, and millisecond-level output response speed;

[0046] 2. High-precision output, with output voltage adjustment steps less than 0.1V;

[0047] 3. Millisecond-level hardware protection response to prevent output overload from damaging components;

[0048] Based on a highly integrated power chip, this invention designs a miniaturized adjustable DC voltage output circuit using a high-precision, small-step voltage tracking method. This circuit occupies a small size and can achieve a wide range of DC voltage output from 1 to 32V, with an output current greater than 1A and an output voltage adjustment step of less than 0.1V. Its small size, wide adjustment range, digitally adjustable output voltage, and monitorable output make it suitable for use in miniaturized microwave measuring instruments. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of an existing technical solution;

[0050] Figure 2 This is a schematic block diagram of the device of the present invention;

[0051] Figure 3 This is a flowchart of the method of the present invention. Detailed Implementation

[0052] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0053] Currently, there are many types of adjustable DC voltage sources. To address the demand for adjustable DC voltage output in new miniaturized microwave measuring instruments, this invention proposes a design method for an adjustable DC voltage source based on a hybrid architecture of FPGA main control, high-frequency switching pre-regulation, and voltage tracking. This method perfectly meets the actual needs of miniaturized microwave measuring instruments. By combining distributed filtering circuits and digital closed-loop feedback control, it achieves highly stable and low-noise adjustable DC voltage output. The details are as follows:

[0054] 1. The circuit mainly consists of a host computer, an FPGA control circuit, a boost converter circuit, a buck and voltage tracking circuit, a D / A converter circuit, an operational amplifier circuit, and a multi-parameter acquisition circuit. The host computer sets the voltage output value, the FPGA sends out the corresponding digital signal, and after D / A conversion, it outputs an analog signal. This signal is then amplified by the integrated operational amplifier and regulated by the voltage tracking circuit, ultimately achieving stability. The overall principle is as follows: Figure 2 As shown.

[0055] 2. DC power is input and filtered to obtain a smoother DC output. This DC power is then converted into a stable DC voltage by the Boost converter circuit, supplying power to the buck and voltage tracking circuits. The boost principle is based on a four-switch Buck-Boost topology, combined with synchronous rectification and PWM control technology to achieve efficient energy conversion. Internally, four MOSFET switches and an inductor are integrated. In boost mode, the inductor stores and releases energy by alternately controlling the switching on and off. The inductor charging and discharging time is controlled by adjusting the duty cycle of the switches, maintaining a stable output voltage. The output voltage is monitored in real time via a feedback pin and compared with an internal reference voltage, dynamically adjusting the duty cycle accordingly.

[0056] 3. Voltage tracking principle: When the voltage applied to the voltage tracking pin changes, the error amplifier compares it with the feedback voltage and adjusts the PWM duty cycle. By increasing or decreasing the duty cycle, the output voltage rises or falls. Therefore, by comparing the feedback voltage with the comparator, when the external reference voltage changes, the feedback voltage follows the reference voltage, ultimately achieving an output voltage equal to the reference voltage. The error amplifier in this part of the circuit has high accuracy and supports fast dynamic response.

[0057] 4. When the circuit is in normal operating mode, the multi-parameter real-time monitoring circuit continuously reads the shunt voltage and bus voltage values. After reading the shunt voltage value, the current value is calculated. This current value is then used to calculate the power result. These values ​​are subsequently stored in the accumulator, and the measurement / calculation sequence is repeated until the averaging count set in the configuration register is reached. After all averaging is complete, the final values ​​of shunt voltage, bus voltage, current, and power are updated in the corresponding registers, and these values ​​can then be read. These values ​​remain in the data output register until they are replaced by the next fully completed conversion result. Reading the data output register does not affect the ongoing conversion. The mode control in the conversion register also allows selection of a mode that converts only the shunt voltage or the bus voltage, further enabling users to configure the monitoring function according to specific application requirements. All current and power calculations are performed in the background and do not affect the conversion time.

[0058] 5. The method flow of this invention is as follows: Figure 3 As shown. System initialization: After power-on, the FPGA is first configured with clock and communication interface (SPI / I2C), the DAC is initialized, the DAC operating mode is set, and overvoltage and overcurrent detection thresholds are set. User input processing: The target voltage value is read, the input range is verified, and it is converted into a digital signal for the DAC. DAC control: The digital signal is sent to the DAC via the SPI interface, the DAC output register is updated, and the DAC output voltage is triggered. Operational amplifier adjustment and output: The operational amplifier amplifies the signal, the filter circuit processes it (suppressing high-frequency noise), and the voltage is output to the voltage tracking circuit. Output sampling feedback adjustment: The actual output voltage, current, and power are sampled, calculated with the set thresholds, and fed back to the FPGA for further processing.

[0059] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. An adjustable DC voltage source device, characterized in that, include: The host computer is configured to set the voltage output value and overload protection threshold, and to perform real-time monitoring and diagnosis. The FPGA main control unit is configured to receive the target voltage value set by the host computer and convert the target voltage value into the digital signal required by the DAC. The DAC module is configured to convert digital signals output from the FPGA into analog voltage signals; An operational amplifier is configured to amplify the analog voltage signal output by the DAC; The Boost converter circuit is configured to boost the input DC voltage to a stable voltage level to power the buck and voltage tracking circuits. The buck and voltage tracking circuit is configured to precisely adjust the output voltage according to the voltage signal output by the operational amplifier to achieve voltage tracking. The multi-parameter acquisition circuit is configured to monitor the voltage, current and power at the output terminal in real time and feed the monitoring results back to the FPGA main control unit. The reverse voltage protection circuit is configured to implement hardware-level reverse voltage input protection, and directly shuts down when the circuit detects a reverse voltage input. A power adapter or lithium battery is configured to provide power to the device; The first filter circuit is configured to filter out noise and other interference signals from the power adapter or lithium battery, providing a stable DC voltage input to the downstream Boost converter circuit. The second filter circuit is configured to filter out high-frequency noise, switching noise, and other harmonic components generated during the operation of the buck and voltage tracking circuits; wherein... The power adapter or lithium battery, the first filter circuit, the boost converter circuit, the buck and voltage tracking circuit, the second filter circuit, the reverse protection circuit, and the load are connected in sequence through the lines. The closed-loop control circuit consists of an FPGA main control unit, a DAC module, an operational amplifier, a buck and voltage tracking circuit, a second filter circuit, and a multi-parameter acquisition circuit.

2. The adjustable DC voltage source device according to claim 1, characterized in that, The Boost converter circuit adopts a four-switch Buck-Boost topology and integrates four MOSFET switches and inductors, combined with synchronous rectification and PWM control technology to achieve energy conversion.

3. The adjustable DC voltage source device according to claim 1, characterized in that, Buck and voltage tracking circuits, including: An error amplifier is configured to compare the feedback voltage with a reference voltage generated by the DAC in real time. The PWM controller is configured to dynamically adjust the duty cycle based on the comparison result; By comparing the feedback voltage with the reference voltage, the PWM duty cycle is dynamically adjusted. When the external reference voltage changes, the feedback voltage follows the reference voltage, ultimately achieving an output voltage equal to the reference voltage.

4. The adjustable DC voltage source device according to claim 1, characterized in that, The multi-parameter acquisition circuit can continuously read the shunt voltage value and the bus voltage value, calculate the current value and the power value, and update the register after averaging the N measurement results.

5. The adjustable DC voltage source device according to claim 1, characterized in that, The FPGA main control unit presets overvoltage threshold, overcurrent threshold, and overpower threshold; when any parameter exceeds the limit, the FPGA main control unit forces the DAC module output to be set to 0.

6. The adjustable DC voltage source device according to claim 1, characterized in that, The adjustable DC voltage source has an output voltage range of 1 to 32V; an output current capability of ≥1A; a voltage adjustment step of ≤0.1V; and a voltage tracking response time of ≤10ms.

7. A method for controlling an adjustable DC voltage source, characterized in that, The adjustable DC voltage source device as described in claim 1 specifically includes the following steps: Step 1: Set the target voltage and protection threshold parameters via the host computer; Step 2: Receive the target voltage value set by the host computer through the FPGA main control unit, convert the target voltage value into the digital signal required by the DAC, and update the register through the SPI interface; Step 3: Convert the digital signal output from the FPGA into an analog voltage signal using the DAC module; Step 4: Amplify the analog voltage signal output from the DAC using an operational amplifier and then feed it to the buck converter and voltage tracking circuit; Step 5: By using a step-down and voltage tracking circuit, the output voltage is adjusted according to the voltage signal output by the operational amplifier to achieve voltage tracking; Step 6: Monitor the voltage, current and power at the output terminal in real time through a multi-parameter acquisition circuit, and feed the monitoring results back to the FPGA main control unit; Step 7: Collect load-side parameters in real time and calculate the current value I and power value P; Step 8: When the parameter exceeds the limit, the FPGA main control unit forces the DAC module output to be set to 0.

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