Large-current direct-current voltage stabilizing circuit of contact resistance tester
By combining a filter input circuit and a synchronous step-down controller, the problems of high output ripple, large size, and poor dynamic response of the high-current DC voltage regulator circuit in the contact resistance tester are solved, achieving efficient voltage regulation and portable measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- YALONG RIVER HYDROPOWER DEV CO LTD
- Filing Date
- 2025-06-27
- Publication Date
- 2026-05-19
AI Technical Summary
Existing contact resistance testers with high-current DC voltage regulation circuits suffer from problems such as high peak-to-peak output ripple, large size and weight, poor dynamic response characteristics, and insufficient adaptability to multiple operating conditions when outputting high frequency and high current, making it difficult to meet the needs of portable measurement.
The system employs a filter input circuit, a synchronous buck controller, a switching transistor circuit, a charge/discharge output circuit, a sampling circuit, and an operational amplifier circuit. The synchronous buck controller controls the orderly switching of the switching transistor, and combined with the control hardware of the inner current loop and the outer voltage loop, it achieves efficient voltage regulation.
It achieves the effects of small size, low heat generation, high efficiency, low output ripple, large output current capability and stable reliability, and adapts to the needs of multiple working conditions.
Smart Images
Figure CN224263571U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of test circuit technology, and specifically relates to a high-current DC voltage regulator circuit for a contact resistance tester. Background Technology
[0002] In power plant auxiliary power systems, excessive contact resistance in electrical connections has long threatened equipment operational safety. When contact surfaces are oxidized, screw torque is insufficient, or there are minute gaps, contact resistance may surge, leading to excessively high local temperatures and spark discharge. To achieve precise preventative maintenance, high-precision test data needs to be obtained through a contact resistance measuring instrument. However, the bottleneck of this instrument lies in the poor output capability of its high-frequency, high-current DC regulated power supply.
[0003] Existing high-current DC linear voltage regulator circuits have the following problems: high-current DC voltage regulator circuits are linearly turned on through a series regulating transistor, and the power consumption increases linearly as the input-output voltage difference increases; when faced with sudden load changes (such as current steps during contact resistance measurement), the output voltage drops significantly, affecting measurement accuracy.
[0004] The existing technology of stepping down the voltage with a power frequency transformer and then rectifying and filtering has the problem of high peak-to-peak output ripple. It requires the configuration of an electrolytic capacitor array, which increases the size of the filtering circuit and cannot meet the requirements of high-frequency pulse current. At the same time, in order to achieve high current output, a large transformer core cross-sectional area is required, resulting in a large overall weight, which is difficult to meet the needs of portable measurement.
[0005] High-frequency converters using PWM (Pulse Width Modulation) control suffer from output ripple and noise, dynamic current sharing failure, and poor input voltage adaptability. Existing high-current DC voltage regulator circuits for contact resistance testers have numerous problems in efficiency-size balance, dynamic response characteristics, and adaptability to multiple operating conditions. Especially under the harsh electromagnetic environment and space constraints of power plants, there is an urgent need for a DC voltage regulator solution that combines high efficiency, small size, and strong dynamic response to overcome the technical bottlenecks of contact resistance measuring instruments. Utility Model Content
[0006] To solve the above-mentioned technical problems, this utility model provides a high-current DC voltage regulator circuit for a contact resistance tester, including a filter input circuit, a synchronous step-down controller, a first switching transistor circuit, a second switching transistor circuit, a charge / discharge output circuit, a sampling circuit, and an operational amplifier circuit.
[0007] The input terminal of the filter input circuit is connected to the power supply input voltage; the output terminal of the filter input circuit is connected to the input terminal of the synchronous buck controller; the first output terminal of the synchronous buck controller is electrically connected to the control input terminal of the first switching transistor circuit; the input terminal of the first switching transistor circuit is electrically connected to the power supply input voltage; the output terminal of the first switching transistor circuit is electrically connected to the input terminal of the second switching transistor circuit and the first input terminal of the charge / discharge output circuit; the second output terminal of the synchronous buck controller is electrically connected to the control input terminal of the second switching transistor circuit; the output terminal of the second switching transistor circuit is electrically connected to the second input terminal of the charge / discharge output circuit.
[0008] The output terminal of the charge / discharge output circuit is electrically connected to the input terminal of the sampling circuit; the output terminal of the sampling circuit is electrically connected to the input terminal of the synchronous buck controller through an operational amplifier circuit.
[0009] Based on the above technical solution, the present invention can be further improved as follows.
[0010] Furthermore, the input terminal of the filter input circuit is connected to a voltage input interface; the voltage input interface is electrically connected to the power input terminal of the synchronous buck controller and the input terminal of the first switching transistor circuit.
[0011] Furthermore, the filter input circuit includes a first polarized capacitor, a first capacitor, a first resistor, a second resistor, a second capacitor, a third resistor, a third capacitor, a fourth capacitor, and a fourth resistor; the first input terminal of the filter input circuit is electrically connected to the anode of the first polarized capacitor, the first capacitor, the first end of the first resistor, the first end of the third resistor, the power input terminal of the synchronous buck controller, and the input terminal of the first switching transistor; the second input terminal of the filter input circuit, the cathode of the first polarized capacitor, and the second end of the first capacitor are grounded; the second end of the first resistor is electrically connected to the first end of the second capacitor and the undervoltage lockout input port of the synchronous buck controller; the second end of the second capacitor, the second end of the second resistor, the second end of the third capacitor, the second end of the fourth capacitor, and the power ground pin of the synchronous buck controller are grounded; the first end of the third capacitor is connected to the ramp pin of the synchronous buck controller; the first end of the fourth capacitor is connected to the soft-start pin of the synchronous buck controller; the first end of the second resistor is connected to the synchronization input pin of the synchronous buck controller; and the second end of the third resistor is connected to the enable input pin of the synchronous buck controller.
[0012] Furthermore, the synchronous buck controller is the M25116 chip.
[0013] Furthermore, the first switching circuit includes a first MOSFET; the second switching circuit includes a second MOSFET.
[0014] The first output terminal of the synchronous buck controller is electrically connected to the gate of the first MOSFET; the drain of the first MOSFET is connected to the power input voltage; the source of the first MOSFET is electrically connected to the drain of the second MOSFET and the first input terminal of the charge / discharge output circuit.
[0015] The second output terminal of the synchronous buck controller is electrically connected to the gate of the second MOSFET; the source of the second MOSFET is electrically connected to the second input terminal of the charge / discharge output circuit.
[0016] Furthermore, the operational amplifier circuit includes an operational amplifier and a linear regulator; the third output terminal of the synchronous buck controller is electrically connected to the power input terminal of the linear regulator; the output terminal of the linear regulator is electrically connected to the power input terminal of the operational amplifier; the input terminal of the operational amplifier is electrically connected to the output terminal of the sampling circuit; and the output terminal of the operational amplifier is electrically connected to the synchronous buck controller.
[0017] Furthermore, the charge / discharge output circuit includes an inductor, a fourth resistor, a fifth resistor, a sixth resistor, a second polarized capacitor, a first diode, and an output interface; the first input terminal of the charge / discharge output circuit is electrically connected to the first terminal of the fourth resistor, the output terminal of the synchronous buck controller, the first terminal of the sixth resistor, the anode of the second polarized capacitor, and the first terminal of the output interface through the inductor; the second terminal of the fourth resistor is electrically connected to the output terminal of the operational amplifier circuit, the feedback input terminal of the synchronous buck controller, and the first terminal of the fifth resistor; the second terminal of the sixth resistor is grounded through the first diode; the second terminal of the fifth resistor is grounded.
[0018] Furthermore, a filter circuit is provided between the output terminal of the operational amplifier circuit and the synchronous buck controller; the filter circuit includes a seventh resistor, a fifth capacitor, and a sixth capacitor; the output terminal of the operational amplifier circuit is electrically connected to the second terminal of the sixth capacitor, the second terminal of the fifth capacitor, and the feedback input terminal of the synchronous buck controller; the first terminal of the fifth capacitor and the first terminal of the seventh resistor are connected to the compensation pin of the synchronous buck controller; the second terminal of the seventh resistor is electrically connected to the first terminal of the sixth capacitor.
[0019] Furthermore, a second diode is connected between the output of the operational amplifier circuit and the filter circuit.
[0020] Furthermore, the sampling circuit includes a sampling resistor; the first end of the sampling resistor is grounded; the second end of the sampling resistor is connected to the output terminal of the charge / discharge output circuit and the input terminal of the operational amplifier circuit.
[0021] The beneficial effects of this utility model are: This utility model is based on a high-current DC voltage regulator circuit of power electronic devices. It controls the orderly opening and closing of the peripheral switching transistors through a synchronous step-down controller. The circuit is simple and helps to reduce the size of the equipment. It adopts control hardware with an inner current loop and an outer voltage loop. The inductor and the switching transistor have only very small conduction loss and switching loss during the operation. It has the advantages of high efficiency, low heat generation, large output current capability and stable reliability. Attached Figure Description
[0022] Figure 1 A schematic diagram of a high-current DC voltage regulator circuit for a contact resistance tester provided by this utility model;
[0023] Figure 2 This is the circuit diagram of the filter input circuit;
[0024] Figure 3 This is a partial circuit diagram of a high-current DC voltage regulator circuit for a contact resistance tester.
[0025] Figure 4 This is the circuit diagram of an operational amplifier circuit.
[0026] Icons: J1 - Voltage input interface; J2 - Output interface; U1 - Synchronous buck controller; C01 - First polarity capacitor; C02 - Second polarity capacitor; R1 - First resistor; R2 - Second resistor; R3 - Third resistor; R4 - Fourth resistor; R5 - Fifth resistor; R6 - Sixth resistor; R7 - Seventh resistor; C1 - First capacitor; C2 - Second capacitor; C3 - Third capacitor; C4 - Fourth capacitor; C5 - Fifth capacitor; C6 - Sixth capacitor; RC - Sampling resistor. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0028] As an example, see the attached document. Figure 1 As shown, in order to solve the above technical problems, this embodiment provides a high-current DC voltage regulator circuit for a contact resistance tester, including a filter input circuit, a synchronous step-down controller, a first switching transistor circuit, a second switching transistor circuit, a charge / discharge output circuit, a sampling circuit, and an operational amplifier circuit;
[0029] The input terminal of the filter input circuit is connected to the power supply input voltage; the output terminal of the filter input circuit is connected to the input terminal of the synchronous buck controller; the first output terminal of the synchronous buck controller is electrically connected to the control input terminal of the first switching transistor circuit; the input terminal of the first switching transistor circuit is electrically connected to the power supply input voltage; the output terminal of the first switching transistor circuit is electrically connected to the input terminal of the second switching transistor circuit and the first input terminal of the charge / discharge output circuit; the second output terminal of the synchronous buck controller is electrically connected to the control input terminal of the second switching transistor circuit; the output terminal of the second switching transistor circuit is electrically connected to the second input terminal of the charge / discharge output circuit.
[0030] The output terminal of the charge / discharge output circuit is electrically connected to the input terminal of the sampling circuit; the output terminal of the sampling circuit is electrically connected to the input terminal of the synchronous buck controller through an operational amplifier circuit.
[0031] When the first switching transistor circuit is turned on, the second switching transistor circuit is turned off, and the input powers the charging and discharging output circuit; when the second switching transistor circuit is turned on, the first switching transistor circuit is turned off, and the energy of the charging and discharging output circuit is supplied to the load through the second switching transistor circuit.
[0032] This utility model is a high-current DC voltage regulator circuit based on power electronic devices. It controls the orderly opening and closing of the external switching transistors by outputting a PWM waveform through a synchronous buck controller. The circuit is simple and helps to reduce the size of the equipment. It adopts control hardware with an inner current loop and an outer voltage loop. The inductor and switching transistors have only very small conduction and switching losses during operation. Therefore, the design has the characteristics of high efficiency and low heat generation.
[0033] The internal sampling speed of the synchronous buck controller is much higher than that of the external sampling, which can achieve cycle-by-cycle control. This allows the equipment to be adjusted within a few microseconds, thereby reducing the current and electrical stress requirements of the switching transistor to maintain stable output voltage and current and ground ripple output, thus reducing the production cost of the equipment. Therefore, this invention has the characteristics of small size, low heat generation, high efficiency, low output ripple, large output current capability, and stable reliability.
[0034] Optional, as shown in the appendix Figure 2 As shown, the input terminal of the filter input circuit is connected to a voltage input interface J1; the voltage input interface J1 is electrically connected to the power input terminal of the synchronous buck controller U1 and the input terminal of the first switching transistor circuit.
[0035] Optional, as shown in the appendix Figure 2As shown, the filter input circuit includes a first polarity capacitor C0, a first capacitor C1, a first resistor R1, a second resistor R2, a second capacitor C2, a third resistor R3, a third capacitor C3, a fourth capacitor C4, and a fourth resistor R4. The first input terminal of the filter input circuit is electrically connected to the anode of the first polarity capacitor C01, the first capacitor C1, the first terminal of the first resistor R1, the first terminal of the third resistor R3, the power input terminal of the synchronous buck controller U1, and the input terminal of the first switching transistor. The second input terminal of the filter input circuit, the cathode of the first polarity capacitor C01, and the second terminal of the first capacitor C1 are grounded. The first resistor R1... The two terminals are electrically connected to the first terminal of the second capacitor C2 and the undervoltage lockout input port of the synchronous buck controller U1; the second terminal of the second capacitor C2, the second terminal of the second resistor R2, the second terminal of the third capacitor C3, the second terminal of the fourth capacitor C4, and the power ground pin of the synchronous buck controller U1 are grounded; the first terminal of the third capacitor C3 is connected to the ramp pin of the synchronous buck controller U1; the first terminal of the fourth capacitor C4 is connected to the soft-start pin of the synchronous buck controller U1; the first terminal of the second resistor R2 is connected to the synchronization input pin of the synchronous buck controller U1; the second terminal of the third resistor R3 is connected to the enable input pin of the synchronous buck controller U1.
[0036] Optionally, the synchronous buck controller is the M25116 chip.
[0037] The M25116 chip is a high-performance synchronous buck controller with a wide input voltage range: a minimum input voltage of 6V and a maximum of 42V, adapting to various input power conditions and meeting the wide voltage input requirements common in fields such as industrial control and automotive electronics. It also features high current output capability: a maximum output current of up to 20A, providing significant power support for loads and suitable for devices requiring high current supply. In contact resistance meters, it primarily provides a stable DC input voltage for the subsequent inverter circuit. Furthermore, it has low quiescent current: a typical quiescent current of 4.6mA, and total input current consumption in the off state is less than 10μA, helping to reduce system power consumption and improve energy efficiency, making it particularly suitable for battery-powered devices or low-power applications with strict power consumption requirements. Finally, it features programmable output voltage: the output voltage range is 1.215V to 36V, and the output voltage value can be flexibly set through programming to meet the specific power supply voltage requirements of different loads, increasing the flexibility of circuit design.
[0038] Optional, as shown in the appendix Figure 3 As shown, the first switching transistor circuit includes a first MOSFET Q1; the second switching transistor circuit includes a second MOSFET Q2.
[0039] The first output terminal of the synchronous buck controller U1 is electrically connected to the gate of the first MOSFET Q1; the drain of the first MOSFET Q1 is connected to the power input voltage; the source of the first MOSFET Q1 is electrically connected to the drain of the second MOSFET Q2 and the first input terminal of the charge / discharge output circuit.
[0040] The second output terminal of the synchronous buck controller is electrically connected to the gate of the second MOSFET Q2; the source of the second MOSFET Q2 is electrically connected to the second input terminal of the charge / discharge output circuit.
[0041] When the first MOSFET Q1 is turned on, the second MOSFET Q2 is turned off, and the input powers the inductor. When the second MOSFET Q2 is turned on, the first MOSFET Q1 is turned off, and the energy from the inductor and the external capacitor is supplied to the load through the second MOSFET Q2.
[0042] Optional, as shown in the appendix Figure 4 As shown, the operational amplifier circuit includes operational amplifier U2 and linear regulator U3; the third output terminal of the synchronous buck controller is electrically connected to the power input terminal of the linear regulator U3; the output terminal of the linear regulator U3 is electrically connected to the power input terminal of the operational amplifier U2; the input terminal of the operational amplifier U2 is electrically connected to the output terminal of the sampling circuit; and the output terminal of the operational amplifier U2 is electrically connected to the synchronous buck controller U1.
[0043] Optionally, the charge / discharge output circuit includes an inductor L, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a second polarized capacitor C02, a first diode D1, and an output interface J2. The first input terminal of the charge / discharge output circuit is electrically connected to the first terminal of the fourth resistor R4, the output terminal of the synchronous buck controller U1, the first terminal of the sixth resistor R6, the anode of the second polarized capacitor C02, and the first terminal of the output interface J2 through the inductor L. The second terminal of the fourth resistor R4 is electrically connected to the output terminal of the operational amplifier circuit, the feedback input terminal of the synchronous buck controller U1, and the first terminal of the fifth resistor R5. The second terminal of the sixth resistor R6 is grounded through the first diode D1. The second terminal of the fifth resistor R5 is grounded.
[0044] The fourth resistor and the fifth resistor form a voltage divider circuit.
[0045] Optionally, a filter circuit is also provided between the output terminal of the operational amplifier circuit and the synchronous buck controller; the filter circuit includes a seventh resistor R7, a fifth capacitor C5, and a sixth capacitor C6; the output terminal of the operational amplifier circuit is electrically connected to the second terminal of the sixth capacitor C6, the second terminal of the fifth capacitor C5, and the feedback input terminal of the synchronous buck controller U1; the first terminal of the fifth capacitor C5 and the first terminal of the seventh resistor R7 are connected to the compensation pin of the synchronous buck controller U1; the second terminal of the seventh resistor R7 is electrically connected to the first terminal of the sixth capacitor C6.
[0046] Optional, as shown in the appendix Figure 3 As shown, a second diode D2 is also connected between the output terminal of the operational amplifier circuit and the filter circuit.
[0047] Optional, as shown in the appendix Figure 3 As shown, the sampling circuit includes a sampling resistor RC; the first end of the sampling resistor RC is grounded; the second end of the sampling resistor RC is connected to the output terminal of the charge / discharge output circuit and the input terminal of the operational amplifier circuit.
[0048] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A high-current DC regulated circuit for a contact resistance tester, characterized in that, It includes a filter input circuit, a synchronous buck controller, a first switching transistor circuit, a second switching transistor circuit, a charge / discharge output circuit, a sampling circuit, and an operational amplifier circuit; The input terminal of the filter input circuit is connected to the power supply input voltage; the output terminal of the filter input circuit is connected to the input terminal of the synchronous buck controller; the first output terminal of the synchronous buck controller is electrically connected to the control input terminal of the first switching transistor circuit; the input terminal of the first switching transistor circuit is electrically connected to the power supply input voltage; the output terminal of the first switching transistor circuit is electrically connected to the input terminal of the second switching transistor circuit and the first input terminal of the charge / discharge output circuit; the second output terminal of the synchronous buck controller is electrically connected to the control input terminal of the second switching transistor circuit; the output terminal of the second switching transistor circuit is electrically connected to the second input terminal of the charge / discharge output circuit. The output terminal of the charge / discharge output circuit is electrically connected to the input terminal of the sampling circuit; the output terminal of the sampling circuit is electrically connected to the input terminal of the synchronous buck controller through an operational amplifier circuit.
2. The high-current DC voltage regulator circuit for a contact resistance tester according to claim 1, characterized in that, The input terminal of the filter input circuit is connected to a voltage input interface; the voltage input interface is electrically connected to the power input terminal of the synchronous buck controller and the input terminal of the first switching transistor circuit.
3. The high-current DC voltage regulator circuit for a contact resistance tester according to claim 1, characterized in that, The filter input circuit includes a first polarized capacitor, a first capacitor, a first resistor, a second resistor, a second capacitor, a third resistor, a third capacitor, a fourth capacitor, and a fourth resistor. The first input terminal of the filter input circuit is electrically connected to the anode of the first polarized capacitor, the first capacitor, the first end of the first resistor, the first end of the third resistor, the power input terminal of the synchronous buck controller, and the input terminal of the first switching transistor. The second input terminal of the filter input circuit, the cathode of the first polarized capacitor, and the second end of the first capacitor are grounded. The second end of the first resistor is electrically connected to the first end of the second capacitor and the undervoltage lockout input port of the synchronous buck controller. The second ends of the second capacitor, the second ends of the second resistor, the second ends of the third capacitor, the second ends of the fourth capacitor, and the power ground pin of the synchronous buck controller are grounded. The first end of the third capacitor is connected to the ramp pin of the synchronous buck controller. The first end of the fourth capacitor is connected to the soft-start pin of the synchronous buck controller. The first end of the second resistor is connected to the synchronization input pin of the synchronous buck controller. The second end of the third resistor is connected to the enable input pin of the synchronous buck controller.
4. The high-current DC voltage regulator circuit for a contact resistance tester according to claim 1, characterized in that, The synchronous buck controller is the M25116 chip.
5. The high-current DC voltage regulator circuit for a contact resistance tester according to claim 1, characterized in that, The first switching circuit includes a first MOSFET; the second switching circuit includes a second MOSFET. The first output terminal of the synchronous buck controller is electrically connected to the gate of the first MOSFET; the drain of the first MOSFET is connected to the power input voltage; the source of the first MOSFET is electrically connected to the drain of the second MOSFET and the first input terminal of the charge / discharge output circuit. The second output terminal of the synchronous buck controller is electrically connected to the gate of the second MOSFET; the source of the second MOSFET is electrically connected to the second input terminal of the charge / discharge output circuit.
6. The high-current DC voltage regulator circuit for a contact resistance tester according to claim 1, characterized in that, The operational amplifier circuit includes an operational amplifier and a linear regulator; the third output terminal of the synchronous buck controller is electrically connected to the power input terminal of the linear regulator; the output terminal of the linear regulator is electrically connected to the power input terminal of the operational amplifier; the input terminal of the operational amplifier is electrically connected to the output terminal of the sampling circuit; and the output terminal of the operational amplifier is electrically connected to the synchronous buck controller.
7. The high-current DC voltage regulator circuit for a contact resistance tester according to claim 1, characterized in that, The charge / discharge output circuit includes an inductor, a fourth resistor, a fifth resistor, a sixth resistor, a second polarized capacitor, a first diode, and an output interface. The first input terminal of the charge / discharge output circuit is electrically connected to the first terminal of the fourth resistor, the output terminal of the synchronous buck controller, the first terminal of the sixth resistor, the anode of the second polarized capacitor, and the first terminal of the output interface through the inductor. The second terminal of the fourth resistor is electrically connected to the output terminal of the operational amplifier circuit, the feedback input terminal of the synchronous buck controller, and the first terminal of the fifth resistor. The second terminal of the sixth resistor is grounded through the first diode. The second terminal of the fifth resistor is grounded.
8. The high-current DC voltage regulator circuit for a contact resistance tester according to claim 7, characterized in that, A filter circuit is also provided between the output terminal of the operational amplifier circuit and the synchronous buck controller; the filter circuit includes a seventh resistor, a fifth capacitor and a sixth capacitor; the output terminal of the operational amplifier circuit is electrically connected to the second terminal of the sixth capacitor, the second terminal of the fifth capacitor and the feedback input terminal of the synchronous buck controller; the first terminal of the fifth capacitor and the first terminal of the seventh resistor are connected to the compensation pin of the synchronous buck controller; the second terminal of the seventh resistor is electrically connected to the first terminal of the sixth capacitor.
9. The high-current DC voltage regulator circuit for a contact resistance tester according to claim 7, characterized in that, A second diode is also connected between the output of the operational amplifier circuit and the filter circuit.
10. The high-current DC voltage regulator circuit for a contact resistance tester according to claim 1, characterized in that, The sampling circuit includes a sampling resistor; the first end of the sampling resistor is grounded; the second end of the sampling resistor is connected to the output terminal of the charge / discharge output circuit and the input terminal of the operational amplifier circuit.