Double-gear current measuring circuit

Abstract

The utility model relates to the technical field of current measurement, in particular to a double-gear current measurement circuit which comprises an input end, an output end, a first sampling resistor, a second sampling resistor and a relay. The input end is used for being connected with the current output end of a tested product used in cooperation with the double-gear current measuring circuit, and the output end is used for being connected with other equipment used in cooperation with the double-gear current measuring circuit; the first sampling resistor and the second sampling resistor are connected in parallel between the input end and the output end; the control end of the relay is connected with a microcontroller, the relay is a double-contact switch, the normally closed contact of the relay is connected with the second sampling resistor, the normally open contact of the relay is connected with the open circuit, and the common contact of the relay is connected with the connection point of the first sampling resistor and the output end. The leakage current and the working current of the to-be-measured product can be directly measured, and manual gear switching is not needed, so that the risk of damage to measurement equipment is reduced.

Description

Technical Field

[0001] This application relates to the technical field of current measurement, and in particular to a dual-range current measurement circuit. Background Art

[0002] In today's display industry, with the continuous progress of technology, modular testing has become a key link in improving production efficiency and product quality. With the increasing complexity of circuit design, the requirements for the performance detection of circuits and their components are also getting higher and higher. Especially when the circuits and their components are exposed, the problems of electrostatic breakdown and leakage current caused by chip defects are particularly prominent. These problems not only affect the performance and stability of products, but may also pose potential safety hazards during subsequent use. Therefore, how to effectively detect these problems before normal testing to prevent product or power supply damage caused by direct power-on has become an urgent problem in the industry.

[0003] Currently, the industry mainly uses traditional current testing methods to detect the leakage current of products to be tested. These methods usually involve using measurement devices with different ranges to detect currents at the Ua level and Ma level respectively. In actual operation, engineers need to manually switch different measurement ranges according to experience to meet the current detection requirements in different ranges.

[0004] However, the existing current detection technologies have significant defects. Manually switching measurement ranges is not only inefficient, but also has the risk of operation errors. Once the range is selected improperly, it may cause damage to the measurement device or inaccurate measurement results. Summary of the Utility Model

[0005] In order to directly measure the leakage current and working current of the product to be tested without manually switching ranges, thereby reducing the risk of damaging the measurement device. This application provides a dual-range current measurement circuit. The following technical solutions are provided in this application:

[0006] A dual-range current measurement circuit includes an input terminal, an output terminal, a first sampling resistor, a second sampling resistor, and a relay; the input terminal is used to connect to the current output terminal of the product to be tested that cooperates with the dual-range current measurement circuit, and the output terminal is used to connect to other devices that cooperate with the dual-range current measurement circuit; the first sampling resistor and the second sampling resistor are connected in parallel between the input terminal and the output terminal;

[0007] The control terminal of the relay is connected to a microcontroller. The relay is a double-contact switch. The normally closed contact of the relay is connected to the second sampling resistor, the normally open contact of the relay is connected to an open circuit, and the common contact of the relay is connected to the connection point of the first sampling resistor and the output terminal.

[0008] In a specific feasible implementation, the microcontroller is an MCU.

[0009] In a specific feasible implementation, the resistance value of the first sampling resistor is greater than that of the second sampling resistor.

[0010] In a specific feasible implementation, the resistance value of the first sampling resistor is 100Ω, and the resistance value of the second sampling resistor is 0.1Ω.

[0011] In a specific feasible implementation, the first sampling resistor is connected to an mA-level operational amplifier, and the second sampling resistor is connected to a μA-level operational amplifier.

[0012] In a specific feasible implementation, the output terminals of the mA-level operational amplifier and the μA-level operational amplifier are both connected to the microcontroller through an analog-to-digital converter.

[0013] In a specific feasible implementation, a hysteresis comparator is provided between the μA-level operational amplifier and the analog-to-digital converter. The output terminal of the μA-level operational amplifier is connected to the input terminal of the hysteresis comparator. The output terminal of the hysteresis comparator is connected to a status latch, and the output terminal of the status latch is connected to the microcontroller.

[0014] In summary, the beneficial effects of the present application at least include:

[0015] 1) By automatically controlling the state switching of the relay through the microcontroller, automatic adjustment of the current measurement range is achieved, eliminating the need for manual operation by engineers. This not only greatly improves the test efficiency but also reduces the risk of human operation errors, ensuring the accuracy and reliability of the measurement process.

[0016] 2) Two parallel sampling resistors are adopted, which are respectively suitable for measuring different current ranges. Combined with dedicated operational amplifiers, high-precision measurement can be maintained at different current ranges. This design enables the circuit to provide accurate measurement data in a wide current range from microamps to milliamps.

[0017] 3) By introducing a hysteresis comparator and a status latch, the circuit of the present application can quickly detect currents exceeding the safety threshold and immediately trigger a protection mechanism to prevent equipment damage caused by excessive current. This fast-response safety protection mechanism significantly improves the safety of the test process and reduces the risks caused by electrostatic breakdown or chip defects.

[0018] Through the first sampling resistor and the second sampling resistor connected in parallel, combined with the relay controlled by the microcontroller, the function of automatically switching the current measurement range is realized. This technology solves the problems of low efficiency and high operation risk in traditional manual switching of measurement ranges, and improves the accuracy and efficiency of current measurement. At the same time, through the design of the hysteresis comparator and the status latch, it can quickly detect and respond to currents exceeding the safety threshold, trigger the protection mechanism, thereby effectively preventing the leakage current problems caused by electrostatic breakdown and chip defects, protecting the safety of the product and the power supply, and improving the performance and stability of the product.

[0019] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly and implement it in accordance with the content of the specification, the following will be described in detail with reference to the preferred embodiments of this application and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the two-range current measurement circuit in this embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following will further describe this application in detail with reference to the accompanying drawings.

[0022] An embodiment of this application discloses a two-range current measurement circuit.

[0023] Referring to Figure 1 , the two-range current measurement circuit includes an input terminal, an output terminal, a first sampling resistor R1, a second sampling resistor R2, and a relay S. The input terminal is used to connect to the current output terminal of the product under test used in conjunction with the two-range current measurement circuit. The output terminal is used to connect to other devices used in conjunction with the two-range current measurement circuit, such as a storage device or a display device, etc. The input terminal. The first sampling resistor R1 and the second sampling resistor R2 are connected in parallel between the input terminal and the output terminal. The control terminal of the relay S is connected to a microcontroller. Optionally, the microcontroller in this application is an MCU, and other types of microcontrollers can also be used. This application does not limit the specific type of the microcontroller. The relay S is a double-contact switch in this application. The normally closed contact of the relay S is connected to the second sampling resistor R1, the normally open contact of the relay S is connected to an open circuit, and the common contact of the relay S is connected to the connection point of the first sampling resistor R1 and the output terminal. Through the above hardware settings, it is convenient to assist in realizing that the relay S is in the normally open state or the normally closed state under the control of the microcontroller. When the relay S is in the normally closed state, at this time, the first sampling resistor R1 and the second sampling resistor R2 are connected in parallel, and the current of the product under test will flow through the first sampling resistor R1 and the second sampling resistor R2 connected in parallel. When the relay S is in the normally open state, at this time, the second sampling resistor R2 is disconnected, and the current of the product under test will only flow through the first sampling resistor R1.

[0024] Reference Figure 1 , the resistance value of the first sampling resistor is greater than the resistance value of the second sampling resistor, the resistance value of the first sampling resistor R1 is 100Ω, and the resistance value of the second sampling resistor R2 is 0.1Ω, so when the relay S is in the normally closed state, the total resistance of the first sampling resistor R1 and the second sampling resistor R2 connected in parallel is about 0.99Ω, and the circuit collects mA current at this time. When the relay S is in the normally open state, the total resistance, that is, the resistance value of the first sampling resistor R1, is 100Ω, and the circuit collects uA current at this time.

[0025] Reference Figure 1 , the first sampling resistor R1 is connected to a mA-level operational amplifier, and the second sampling resistor R2 is connected to a uA-level operational amplifier. The above two operational amplifiers of different levels respectively sample currents in different ranges and amplify the voltage drop signals generated by them, which is convenient for subsequent processing. By using two different sampling resistors and corresponding operational amplifiers, the circuit can achieve more accurate measurements in different current ranges. Large currents and small currents are processed by different amplifiers respectively, which avoids the accuracy loss that may occur when a single amplifier processes a wide range of currents as much as possible. The output end of the operational amplifier is connected to the microcontroller MCU through the analog-to-digital converter ADC. After the operational amplifier outputs the analog signal, the analog-to-digital converter ADC converts the analog signal into a digital signal and transmits it to the microcontroller MCU for processing.

[0026] Reference Figure 1 A hysteresis comparator is provided between the uA-class operational amplifier and the analog-to-digital converter ADC. The output of the uA-class operational amplifier is connected to the input of the hysteresis comparator. The output of the hysteresis comparator is connected to a state latch. The output of the state latch is connected to the microcontroller MCU. The hysteresis comparator can quickly detect whether the current exceeds the safety threshold and immediately trigger the protection mechanism when it exceeds the threshold. When the hysteresis comparator detects a high current, it will send a signal, which will be passed to the state latch. The state latch will latch this state, that is, record the occurrence of a high current event, and keep this state until it is read and processed by the microcontroller MCU. The microcontroller MCU switches the current gear by changing the state of the relay S to achieve the purpose of protecting the circuit.

[0027] In summary, the present application proposes a two - gear current measurement circuit. Through the first sampling resistor and the second sampling resistor connected in parallel, combined with the relay controlled by the microcontroller, the function of automatically switching the current measurement gear is realized. This technology solves the problems of low efficiency and high operation risk of traditional manual switching of measurement gears, and improves the accuracy and efficiency of current measurement. At the same time, through the design of the hysteresis comparator and the state latch, it can quickly detect and respond to currents exceeding the safety threshold, trigger the protection mechanism, thereby effectively preventing the leakage current problems caused by electrostatic breakdown and chip defects, protecting the safety of the product and the power supply, and improving the performance and stability of the product.

[0028] The above are all preferred embodiments of the present application. The protection scope of the present application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A dual-position current measurement circuit, characterized in that: It includes an input end, an output end, a first sampling resistor, a second sampling resistor and a relay; the input end is used to connect with the current output end of the product under test used in conjunction with the dual-speed current measurement circuit, and the output end is used to connect with other equipment used in conjunction with the dual-speed current measurement circuit; the first sampling resistor and the second sampling resistor are connected in parallel between the input end and the output end; The control end of the relay is connected to a microcontroller, the relay is a double-contact switch, the normally closed contact of the relay is connected to the second sampling resistor, the normally open contact of the relay is connected to the open circuit, and the common contact of the relay is connected to the connection point of the first sampling resistor and the output end.

2. The dual-speed current measurement circuit according to claim 1, characterized in that: The microcontroller is MCU.

3. The dual-speed current measurement circuit according to claim 1, characterized in that: The resistance value of the first sampling resistor is greater than the resistance value of the second sampling resistor.

4. The dual-speed current measurement circuit according to claim 3, characterized in that: The resistance value of the first sampling resistor is 100Ω, and the resistance value of the second sampling resistor is 0.1Ω.

5. The dual-speed current measurement circuit according to claim 1, characterized in that: The first sampling resistor is connected to a mA-level operational amplifier, and the second sampling resistor is connected to a uA-level operational amplifier.

6. The dual-speed current measurement circuit according to claim 5, characterized in that: The output ends of the mA-level operational amplifier and the uA-level operational amplifier are both connected to the microcontroller via an analog-to-digital converter.

7. The dual-speed current measurement circuit according to claim 6, characterized in that: A hysteresis comparator is provided between the uA-class operational amplifier and the analog-to-digital converter, the output end of the uA-class operational amplifier is connected to the input end of the hysteresis comparator, the output end of the hysteresis comparator is connected to a state latch, and the output end of the state latch is connected to the microcontroller.

Images