CN218727585U - High-precision current measuring circuit - Google Patents
High-precision current measuring circuit Download PDFInfo
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- CN218727585U CN218727585U CN202222750393.0U CN202222750393U CN218727585U CN 218727585 U CN218727585 U CN 218727585U CN 202222750393 U CN202222750393 U CN 202222750393U CN 218727585 U CN218727585 U CN 218727585U
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- oscilloscope
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- resistor
- measuring circuit
- current measuring
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Abstract
The utility model discloses a high accuracy current measurement circuit, including chip U1, chip U1's VDD pin is connected with emitting diode D1's positive pole through resistance R1, and emitting diode D1's negative pole is connected with chip U1's pin P3 through resistance R2, still includes oscilloscope, and two signal output probes of oscilloscope are connected to respectively resistance R2's both ends, oscilloscope's earth probe are connected with the earthing terminal of power. The utility model discloses use two probes of oscilloscope to measure the magnitude of voltage at firing resistor both ends respectively, avoided the interference of oscilloscope ground connection end pair original line, can improve the measuring precision.
Description
Technical Field
The utility model relates to a measuring circuit, in particular to high accuracy current measurement circuit.
Background
In the prior art, the current of the LED infrared emission lamp is measured by measuring the voltage of an emission load resistor, an oscilloscope probe is directly connected to two ends of the emission resistor, namely, an LED end and an IC output end (as shown in fig. 1), and the two ends are not grounded, and then the current value is calculated by the voltage difference. The disadvantages of this measuring circuit are: during the measurement process, the ground end of the oscilloscope is connected with the IC, so that the output of the IC is influenced, and the test interference is caused. The measurement data is not accurate.
SUMMERY OF THE UTILITY MODEL
The utility model aims at overcoming the prior art defect, providing a high accuracy current measurement circuit, using two probes of oscilloscope to measure the magnitude of voltage at firing resistor both ends respectively, avoided the interference of oscilloscope ground terminal to former circuit, can improve the measuring precision.
The purpose of the utility model is realized like this: a high-precision current measuring circuit comprises a chip U1, a VDD pin of the chip U1 is connected with an anode of a light-emitting diode D1 through a resistor R1, a cathode of the light-emitting diode D1 is connected with a pin P3 of the chip U1 through a resistor R2, the high-precision current measuring circuit further comprises an oscilloscope, two signal output probes of the oscilloscope are respectively connected to two ends of the resistor R2, and a grounding probe of the oscilloscope is connected with a grounding end of a power supply.
The utility model adopts the above technical scheme, compare with prior art, beneficial effect is: the dual probes of the oscilloscope respectively measure the voltages at two ends of the resistor R2, so that the interference of the ground end of the oscilloscope is avoided, and the voltage difference value at two ends of the resistor can be measured more accurately. When the LED current is calculated, the voltage at two ends of A and B is measured by two probes, and the difference value of A and B is automatically calculated by setting subtraction in a mathematical mode of an oscilloscope, so that the current measurement of the LED infrared emission lamp is more accurate.
In order to make the measurement result more accurate, the oscilloscope adopts a dual-probe oscilloscope.
In order to provide normal working voltage for the chip, the VDD pin of the chip U1 is connected to a power supply through a resistor R1.
Drawings
Fig. 1 is a schematic diagram of a prior art measurement circuit.
Fig. 2 is a schematic circuit diagram of the present invention.
Detailed Description
As shown in fig. 2, the high-precision current measuring circuit includes a chip U1, a VDD pin of the chip U1 is connected to a power supply through a resistor R1; the VDD pin of the chip U1 is connected with the anode of the light-emitting diode D1 through a resistor R1, the cathode of the light-emitting diode D1 is connected with one end of a resistor R2, the other end of the resistor R2 is connected with a pin P3 of the chip U1, the device also comprises an oscilloscope, two signal output probes A and B of the oscilloscope are respectively connected to two ends of the resistor R2, namely the signal output probe A is connected to the connection position where the cathode of the light-emitting diode D1 is connected with one end of the resistor R2, the signal output probe B is connected to the connection position where the pin P3 of the chip is connected with the other end of the resistor R2, and the grounding probe of the oscilloscope is connected with the grounding end of a power supply; the oscilloscope adopts a dual-probe oscilloscope; in this embodiment, the chip U1 is an SC51P03A04SC1G chip.
When the utility model works, the two probes of the oscilloscope respectively measure the voltage at the two ends of the resistor R2, thereby avoiding the interference of the ground end of the oscilloscope and more accurately measuring the voltage difference at the two ends of the resistor; and (3) calculating the current of the LED (the current of the diode D1), and automatically calculating the difference value of A-B by setting subtraction under a mathematical mode of an oscilloscope according to the voltages at the two ends of A and B measured by a double probe.
As shown in Table 1, when the circuit of the utility model is used for current test, the difference of the result is-7.3% compared with the prior art; the utility model discloses a circuit structure can accurate measurement LED's current value, avoids the IC termination to bring the interference of coming.
The present invention is not limited to the above embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some replacements and transformations for some technical features without creative labor according to the disclosed technical contents, and these replacements and transformations are all within the protection scope of the present invention.
Claims (3)
1. A high-precision current measuring circuit comprises a chip U1, wherein a VDD pin of the chip U1 is connected with an anode of a light-emitting diode D1 through a resistor R1, a cathode of the light-emitting diode D1 is connected with a pin P3 of the chip U1 through a resistor R2, the high-precision current measuring circuit is characterized by further comprising an oscilloscope, two signal output probes of the oscilloscope are respectively connected to two ends of the resistor R2, and a grounding probe of the oscilloscope is connected with a grounding end of a power supply.
2. A high accuracy current measuring circuit according to claim 1, wherein said oscilloscope is a dual probe oscilloscope.
3. A high accuracy current measuring circuit according to claim 1, wherein the VDD pin of the chip U1 is connected to the power supply via a resistor R1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222750393.0U CN218727585U (en) | 2022-10-19 | 2022-10-19 | High-precision current measuring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222750393.0U CN218727585U (en) | 2022-10-19 | 2022-10-19 | High-precision current measuring circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218727585U true CN218727585U (en) | 2023-03-24 |
Family
ID=85587880
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222750393.0U Active CN218727585U (en) | 2022-10-19 | 2022-10-19 | High-precision current measuring circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218727585U (en) |
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2022
- 2022-10-19 CN CN202222750393.0U patent/CN218727585U/en active Active
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