Differential high-precision voltage acquisition circuit and switch thereof
By using a differential high-precision voltage acquisition circuit, operational amplifiers and adjustable resistors and filter capacitors are employed to filter out high-frequency interference, thus solving the problem of low voltage acquisition accuracy in the switch power management system. This achieves high-precision voltage monitoring and stability, meeting the real-time response requirements of the switch power management system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- UNIPOE IOT TECH CO LTD
- Filing Date
- 2025-04-30
- Publication Date
- 2026-05-05
AI Technical Summary
The voltage acquisition circuit in the existing power management system of the switch has low accuracy and low stability, which cannot meet the accuracy requirements of ±0.5% and the real-time response requirements of 200μs level of the next generation of data center switches. In particular, it is prone to misjudgment when the dynamic power adjustment of PoE equipment is performed.
A differential high-precision voltage acquisition circuit is adopted, which uses operational amplifier U4.2 and adjustable resistors R1 and R13 to amplify the signal, combined with filter capacitors C4 and C5 to filter out high-frequency interference, and diodes Q1 and Q2 to provide amplitude limiting protection, so as to achieve accurate signal acquisition and stable output.
It achieves high-precision voltage acquisition, meeting the power management system requirements of the switch for real-time and accurate power status monitoring, and ensuring the safe and efficient operation of the switch.
Smart Images
Figure CN224203288U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of power management system for switches, and in particular to a differential high-precision voltage acquisition circuit and its switch. Background Technology
[0002] In current switch power management systems, the performance bottleneck of voltage acquisition circuits has become increasingly apparent. Traditional voltage acquisition schemes often employ single-ended input operational amplifier structures, with common-mode rejection ratios (CMRR) generally below 60dB, making them susceptible to common-mode noise interference in complex electromagnetic environments. For example, in a typical application, the OP07 amplifier circuit used in a certain type of switch power monitoring module exhibits a power noise suppression capability attenuation of -30dB / decade above 20kHz, resulting in acquisition errors exceeding ±3% under dynamic operating conditions. Furthermore, existing designs often employ feedback networks with fixed resistance values, requiring resistor replacement to adjust the amplification factor, failing to meet the flexible configuration requirements of different current ranges. These inherent defects make existing solutions unable to meet the ±0.5% accuracy requirements and 200μs real-time response requirements of next-generation data center switches for power management systems, especially when handling dynamic power adjustments of PoE (Power over Ethernet) devices, where voltage monitoring lag or misjudgment is highly likely. In existing technologies, voltage acquisition circuits suffer from low accuracy and low stability, failing to meet the real-time and accurate power status monitoring requirements of switch power management systems. Summary of the Invention
[0003] This invention addresses the problems of existing technologies by providing a differential high-precision voltage acquisition circuit and its switch. The circuit features an ingenious design: operational amplifier U4.2 amplifies the input voltage signal; current flows through sampling resistor R1, generating a voltage signal proportional to the current across R1. This voltage signal is fed into the input of operational amplifier U4.2, amplified, and then output. The amplification factor is determined by the ratio of sampling resistor R1 to feedback resistor R13. The amplified signal is then processed by filter capacitor C5 to remove high-frequency interference components, resulting in a smoother and more stable signal.
[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0005] This invention provides a differential high-precision voltage acquisition circuit, which includes an operational amplifier U4.2, a sampling resistor R1, a feedback resistor R13, a filter capacitor C3, a filter capacitor C4, and a filter capacitor C5. The operational amplifier U4.2 amplifies the input voltage signal. One end of the sampling resistor R1 is connected to an external power supply, and the other end of the sampling resistor R1 is connected to the non-inverting input terminal of the operational amplifier U4.2. The filter capacitor C4 is connected in parallel with the sampling resistor R1. One end of the feedback resistor R13 is connected to the inverting input terminal of the operational amplifier U4.2, and the other end of the feedback resistor R13 is connected to the output terminal of the operational amplifier U4.2. The filter capacitor C5 is connected in parallel with the feedback resistor R13. The output terminal of the operational amplifier U4.2 is connected to one end of the filter capacitor C3, and the other end of the filter capacitor C3 is grounded. Both the sampling resistor R1 and the feedback resistor R13 are adjustable resistors.
[0006] The differential high-precision voltage acquisition circuit further includes resistors R3, R5, and R7. One end of resistor R5 is connected to the non-inverting input of operational amplifier U4.2, one end of resistor R7 is connected to the inverting input of operational amplifier U4.2, one end of resistor R3 is connected to the output of operational amplifier U4.2, and the other end of resistor R3 is connected to one end of filter capacitor C3.
[0007] The differential high-precision voltage acquisition circuit further includes diodes Q1 and Q2, which are connected to the output of the operational amplifier U4.2.
[0008] Preferably, the operational amplifier U4.2 is model TP2412-SR.
[0009] This utility model also provides a switch, which includes the aforementioned differential high-precision voltage acquisition circuit.
[0010] The beneficial effects of this utility model are:
[0011] This invention features an ingenious design. Operational amplifier U4.2 serves as the core component, amplifying the input voltage signal. A feedback resistor R13 and a sampling resistor R1 are connected to operational amplifier U4B to ensure the signal is amplified and processed within a suitable range. Filtering capacitors C4, C5, and C3 are connected to the output of operational amplifier U4.2 or its surrounding area to filter out high-frequency interference. During operation, as the battery discharges, current flows through the sampling resistor R1, generating a voltage signal proportional to the current. This voltage signal is fed into the input of operational amplifier U4.2, amplified, and then output. The amplification factor is determined by the ratio of the sampling resistor R1 to the feedback resistor R13. Preferably, both the sampling resistor R1 and the feedback resistor R13 are adjustable resistors. The amplified signal is processed by the filtering capacitor C5 to remove high-frequency interference, making the signal smoother and more stable. The processed signal is then limited and protected by diodes Q1 and Q2 before being output to the V_DISC_AD terminal for further processing and monitoring by subsequent circuits. Attached Figure Description
[0012] Figure 1 This is a circuit diagram of a differential high-precision voltage acquisition circuit according to the present invention. Detailed Implementation
[0013] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention. The present invention will be described in detail below with reference to the accompanying drawings.
[0014] Example 1
[0015] Embodiment 1 of this application provides a differential high-precision voltage acquisition circuit, which includes an operational amplifier U4.2, a sampling resistor R1, a feedback resistor R13, a filter capacitor C3, a filter capacitor C4, and a filter capacitor C5. The operational amplifier U4.2 is used to amplify the input voltage signal. One end of the sampling resistor R1 is connected to an external power supply, and the other end of the sampling resistor R1 is connected to the non-inverting input terminal of the operational amplifier U4.2. The filter capacitor C4 is connected in parallel with the sampling resistor R1. One end of the feedback resistor R13 is connected to the inverting input terminal of the operational amplifier U4.2, and the other end of the feedback resistor R13 is connected to the output terminal of the operational amplifier U4.2. The filter capacitor C5 is connected in parallel with the feedback resistor R13. The output terminal of the operational amplifier U4.2 is connected to one end of the filter capacitor C3, and the other end of the filter capacitor C3 is grounded. Both the sampling resistor R1 and the feedback resistor R13 are adjustable resistors. Preferably, the operational amplifier U4.2 is a TP2412-SR. In this embodiment, the differential high-precision voltage acquisition circuit further includes diodes Q1 and Q2, which are connected to the output of the operational amplifier U4.2. Specifically, this configuration is used to limit and protect the output signal, preventing excessive voltage from damaging subsequent circuits.
[0016] Specifically, this utility model features an ingenious design. Operational amplifier U4.2 (model TP2412-SR) serves as the core component, amplifying the input voltage signal. A feedback resistor R13 and a sampling resistor R1 are connected to operational amplifier U4B to ensure the signal is amplified and processed within a suitable range. Filtering capacitors C4, C5, and C3 are connected to the output of operational amplifier U4.2 or its surrounding area to filter out high-frequency interference components. During operation, when the battery discharges, current flows through the sampling resistor R1, generating a signal related to the voltage across the sampling resistor R1. A voltage signal proportional to the current is fed into the input of operational amplifier U4.2, amplified, and then output. The amplification factor is determined by the ratio of sampling resistor R1 to feedback resistor R13. Preferably, both sampling resistor R1 and feedback resistor R13 are adjustable resistors. The amplified signal is processed by filter capacitor C5 to remove high-frequency interference components, making the signal smoother and more stable. The processed signal is limited and protected by diodes Q1 and Q2, and finally output to the V_DISC_AD terminal for further processing and monitoring by subsequent circuits (such as microcontrollers).
[0017] In this embodiment of the application, the differential high-precision voltage acquisition circuit further includes resistors R3, R5 and R7. One end of resistor R5 is connected to the non-inverting input of operational amplifier U4.2, one end of resistor R7 is connected to the inverting input of operational amplifier U4.2, one end of resistor R3 is connected to the output of operational amplifier U4.2, and the other end of resistor R3 is connected to one end of filter capacitor C3.
[0018] Example 2
[0019] Embodiment 2 of this application also provides a switch, which includes the aforementioned differential high-precision voltage acquisition circuit. Specifically, with the differential high-precision voltage acquisition circuit, accurate voltage monitoring is achieved through precise signal sampling, amplification, and processing. This is crucial for the switch's power management system, as it can acquire the power status in real time, thereby enabling functions such as overcurrent protection, power calculation, and power balancing management, ensuring the safe and efficient operation of the switch. Specifically, the differential high-precision voltage acquisition circuit has the advantages of high acquisition accuracy and high stability, meeting the switch's power management system's requirements for real-time and accurate power status monitoring.
[0020] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the present utility model without departing from the scope of the present utility model shall fall within the scope of the present utility model.
Claims
1. A differential high-precision voltage acquisition circuit, characterized in that: The system includes an operational amplifier U4.2, a sampling resistor R1, a feedback resistor R13, and filter capacitors C3, C4, and C5. The operational amplifier U4.2 amplifies the input voltage signal. One end of the sampling resistor R1 is connected to an external power supply, and the other end is connected to the non-inverting input of the operational amplifier U4.
2. The filter capacitor C4 is connected in parallel with the sampling resistor R1. One end of the feedback resistor R13 is connected to the inverting input of the operational amplifier U4.2, and the other end is connected to the output of the operational amplifier U4.
2. The filter capacitor C5 is connected in parallel with the feedback resistor R13. The output of the operational amplifier U4.2 is connected to one end of the filter capacitor C3, and the other end of the filter capacitor C3 is grounded. Both the sampling resistor R1 and the feedback resistor R13 are adjustable resistors.
2. The differential high-precision voltage acquisition circuit according to claim 1, characterized in that: The differential high-precision voltage acquisition circuit also includes resistors R3, R5, and R7. One end of resistor R5 is connected to the non-inverting input of operational amplifier U4.2, one end of resistor R7 is connected to the inverting input of operational amplifier U4.2, one end of resistor R3 is connected to the output of operational amplifier U4.2, and the other end of resistor R3 is connected to one end of filter capacitor C3.
3. The differential high-precision voltage acquisition circuit according to claim 1, characterized in that: The differential high-precision voltage acquisition circuit also includes diodes Q1 and Q2, which are connected to the output of the operational amplifier U4.
2.
4. The differential high-precision voltage acquisition circuit according to claim 1, characterized in that: The operational amplifier U4.2 is model TP2412-SR.
5. A switch, characterized in that: Includes the differential high-precision voltage acquisition circuit as described in any one of claims 1-4.