CN215116499U - Current testing device and electronic equipment - Google Patents
Current testing device and electronic equipment Download PDFInfo
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- CN215116499U CN215116499U CN202120929758.9U CN202120929758U CN215116499U CN 215116499 U CN215116499 U CN 215116499U CN 202120929758 U CN202120929758 U CN 202120929758U CN 215116499 U CN215116499 U CN 215116499U
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Abstract
The embodiment of the application discloses a current testing device and electronic equipment, and relates to the field of electronic equipment. The current test device includes: the device comprises a sampling resistor, a primary filter circuit, a resistor selection circuit, an amplifying circuit, a secondary filter circuit and an ADC (analog to digital converter) acquisition circuit; the resistor selection circuit comprises a relay and a plurality of resistors, wherein the relay is used for controlling one resistor to be connected to the amplifying circuit; the sampling resistor is connected with the filter circuit and used for converting the acquired small current signal into a voltage signal; the first-stage filter circuit is connected with the amplifying circuit and is used for carrying out low-pass filtering processing on the voltage signal on the sampling resistor; the amplifying circuit is connected with the relay and the resistance selection circuit and used for amplifying the voltage signal input by the primary filter circuit according to the circuit accessed by the relay; the second-stage filter circuit is connected with the ADC acquisition circuit and is used for performing low-pass filtering processing on the voltage signal output by the amplifying circuit; the ADC acquisition circuit is used for carrying out analog-to-digital conversion processing on a voltage signal output by the secondary filter circuit, and the ADC acquisition circuit realizes current acquisition on a single current wire through the sampling resistor and high-precision gain adjustment through the relay.
Description
Technical Field
The utility model relates to a current test field especially relates to a current test device and electronic equipment.
Background
In mobile terminal, the application of current collection device is more and more extensive, and along with mobile terminal is towards miniaturization and convenience development, the requirement to current collection device's size and collection precision is higher and higher, therefore how to design the more compact and higher current collection device of collection precision of structure is the problem that awaits the solution at present.
SUMMERY OF THE UTILITY MODEL
The embodiment of the application provides a current testing device and electronic equipment, can solve the problems that the size of a current collecting device is large and the collecting precision is not high in the related technology. The technical scheme is as follows:
in a first aspect, an embodiment of the present application provides a current testing apparatus, including:
the device comprises a sampling resistor, a primary filter circuit, a resistor selection circuit, an amplifying circuit, a secondary filter circuit and an ADC (analog to digital converter) acquisition circuit; the resistor selection circuit comprises a relay and a plurality of resistors, wherein the relay is used for controlling one resistor in the plurality of resistors to be connected to the amplifying circuit;
the sampling resistor is connected with the filter circuit and used for converting the acquired small current signal into a voltage signal;
the primary filter circuit is connected with the amplifying circuit and is used for carrying out low-pass filtering processing on the voltage signal on the sampling resistor;
the amplifying circuit is connected with the relay and the resistance selection circuit and is used for amplifying the voltage signal input by the primary filter circuit according to the circuit accessed by the relay;
the second-stage filter circuit is connected with the ADC acquisition circuit and is used for performing low-pass filtering processing on the voltage signal output by the amplifying circuit;
and the ADC acquisition circuit is used for carrying out analog-to-digital conversion processing on the voltage signal output by the secondary filter circuit.
In a second aspect, an embodiment of the present application provides an electronic device, including: a current testing device. The electronic device may be a portable device or a fixed device.
The beneficial effects brought by the technical scheme provided by some embodiments of the application at least comprise:
first, this application is through sampling resistance collection undercurrent signal, the great problem of size that the undercurrent signal brought is gathered to use fluxgate current sensor circuit among the correlation technique has been solved, fluxgate current sensor needs the electric current to pass formation excitation magnetic field with unsettled mode, thereby realize gathering undercurrent signal's purpose, but can't realize the electric current collection of walking the line to single electric current on the circuit board, the adoption resistance of this application can establish ties and realize the electric current collection on single electric current walks the line on the circuit board in the circuit, it is more compact to improve electric current collection system simultaneously, reduce electric current collection system's size. Secondly, this application adjusts the amplification gain through the mode of relay switching resistance, solves the great problem of error that uses the analog switch chip to bring because of temperature variation among the correlation technique, and the internal resistance of the relay of this application is very little, has fine uniformity, consequently can reduce the error of the amplification gain that temperature variation brought, improves the precision of current collection.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a block diagram of a current testing apparatus according to an embodiment of the present invention;
fig. 2 is a circuit diagram of a current testing apparatus according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 1, the present invention provides a block diagram of a current testing apparatus according to an embodiment, which is hereinafter referred to as a current testing apparatus, the current testing apparatus includes: the device comprises a sampling resistor 11, a primary filter circuit 12, an amplifying circuit 13, a resistor selection circuit 14, a secondary filter circuit 15 and an ADC acquisition circuit 16. The resistor selection circuit 14 includes a plurality of resistors and a relay, and the relay selects one of the plurality of resistors to be connected to the amplifying circuit 13 in response to a control signal, so that the gain of the amplifying resistor 13 can be adjusted.
Wherein, the connection relation among the above-mentioned each circuit includes: the sampling resistor 11 is connected with a first-stage filter circuit 12, the first-stage filter circuit 12 is connected with an amplifying circuit 13, the amplifying circuit 13 is respectively connected with a resistor selection circuit 14 and a second-stage filter circuit 15, and the second-stage filter circuit 15 is connected with an ADC (analog to digital converter) acquisition circuit.
The collecting resistor 11 is connected in series to the wire and used for converting a small current signal in the wire into a voltage signal.
The first-stage filter circuit 12 is used for low-pass filtering the voltage signal converted by the sampling resistor and eliminating high-frequency noise.
The amplifying circuit 13 is used for determining an amplification gain according to the resistance selected by the resistance selection circuit 14 and amplifying the voltage signal output by the first-stage filter circuit 12 according to the amplification gain.
The second-stage filter circuit 15 is configured to perform low-pass filtering again on the voltage signal output by the amplifying circuit 13, and filter out high-frequency noise, so as to improve accuracy of data.
The ADC acquisition circuit 16 is configured to perform analog-to-digital conversion on the voltage signal output by the secondary filter circuit 15 to obtain a digital signal, so as to perform data processing on the digital signal in the following.
In one or more possible embodiments, a first terminal of the sampling resistor is connected to the current output terminal, and a second terminal of the sampling resistor is connected to the current input terminal; the primary filter circuit comprises a first capacitor, a second capacitor C2, a second resistor and a third resistor;
the connection relationship of each device in the first-stage filter circuit 12 includes: the first end of the first capacitor is connected with the first end of the sampling resistor, and the second end of the first capacitor is connected with the second end of the sampling resistor; the first end of the first capacitor is connected with the first end of the second capacitor through the second resistor, and the second end of the first capacitor is connected through the third resistor.
Further, the amplifying circuit 13 includes an operational amplifier; and a negative input pin of the operational amplifier is connected with the first end of the second capacitor, and a positive input pin of the operational amplifier is connected with the second end of the second capacitor.
The two-stage filter circuit includes: a fourth resistor R4 and a third capacitor C3;
a first end of the fourth resistor R4 is connected to the output pin of the operational amplifier U1, a second end of the fourth resistor R4 is connected to a first end of the third capacitor C3, and a second end of the third capacitor C3 is grounded.
In one or more possible embodiments, the resistance selection circuit 14 includes a number of the plurality of resistances of two.
Further, the resistance selection circuit 14 includes: the relay, the fifth resistor and the sixth resistor;
the connection relationship of each device in the resistance selection circuit 14 is as follows: the first pin of relay connects DC power supply externally, and the second pin of relay links to each other with amplifier circuit through the fifth resistance, and the third pin of relay links to each other with amplifier circuit, and the fourth pin of relay links to each other with amplifier circuit through the sixth resistance. Optionally, the model of the operational amplifier is AD 620.
Further, the ADC acquisition circuit 16 includes: the ADC chip, a fourth capacitor, a fifth capacitor and a sixth capacitor;
the input pin of the ADC chip is connected with the first end of the third capacitor, the reference capacitor pin of the ADC chip is grounded through the fifth capacitor, the reference pin of the ADC chip U3 is grounded through the sixth capacitor, the ground pin of the ADC chip is grounded, and the voltage driving pin of the ADC chip U3 is grounded through the fourth capacitor. Optionally, the model of the ADC chip U3 is AD 7091R-8.
Referring to fig. 2, a circuit diagram of a current testing apparatus according to an embodiment of the present application is provided, where the current testing apparatus includes: the circuit comprises a sampling resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, an operational amplifier U1, a relay U2 and an ADC chip U3.
Wherein, the connection relation of the above-mentioned devices includes: the first end of the sampling resistor R1 is connected with the current output end I _ out, the second end of the sampling resistor R1 is connected with the current input end I _ in, the first end of the first capacitor C1 is connected with the first end of the sampling resistor R1, and the second end of the first capacitor C1 is connected with the second end of the sampling resistor R1. A first terminal of the first capacitor C1 is connected to a first terminal of the second capacitor C2 through a second resistor R2, and a second terminal of the first capacitor C1 is connected to a second terminal of the second capacitor C2 through a third resistor R3. A first terminal of the second capacitor C2 is connected to the positive input pin IN + of the operational amplifier U1, and a second terminal of the second capacitor C2 is connected to the positive input pin of the operational amplifier U1.
An external resistor pin RG (pin number 1) of the operational amplifier U1 is connected to the third pin 3 of the relay U2, and the other external resistor pin RG of the operational amplifier U1 is connected to the second pin2 of the relay U2 via a fifth resistor R5 and to the fourth pin 4 of the relay via a sixth resistor R6.
The ground pin GND and the reference pin REF of the operational amplifier U2 are grounded, the power pin VDD is externally connected to a dc power supply, the output pin OUT is connected to the first end of the third capacitor C3 and the input pin VIN0 of the ADC chip through the fourth resistor R4, and the second end of the third capacitor C3 is grounded.
The reference capacitor pin REGCAP of the ADC chip U3 is grounded through the fifth capacitor C5, the reference pin REF is grounded through the sixth capacitor, the ground pin GND is grounded, the voltage driving pin VDRIVE is grounded through the fourth capacitor C4, and is connected to the driving voltage source VDRIVE.
The working process of the current testing device comprises the following steps: in a sampling link, a sampling resistor R1 converts a small current signal on a lead into a voltage signal; the small current signal has a small amplitude and is easily influenced by high-frequency noise, and the R2, the R3, the C1 and the C2 form a primary filter circuit to perform low-pass filtering on a voltage signal output by the sampling resistor R1. The operational amplifier U1 adjusts the gain through the external fifth resistor R5 or the sixth resistor R6, the RELAY U2 selects the fifth resistor R5 or the sixth resistor R6 to be connected to the operational amplifier U1 through the input CONTROL signal RELAY CONTROL, because the RELAY is a mechanical switch, the internal resistance of the RELAY can be almost ignored, the RELAY has good consistency and is not influenced by temperature, extra errors cannot be introduced into the gain adjustment of the operational amplifier U1, the system precision can be improved, if the gain gear is increased, the RELAY, namely the external resistor, can be increased, and the good expansibility is achieved. The operational amplifier U1 amplifies the voltage signal output from the first-stage filter circuit. The two-stage filter circuit is composed of R4 and C3, and performs low-pass filtering processing on the voltage signal output by the operational amplifier U1. The ADC chip performs analog-to-digital conversion on the analog voltage signal input by the secondary filter circuit, and transmits the analog voltage signal to other equipment for processing through SPI interfaces (pin1, pin20, pin21 and pin 22).
The utility model provides a current test device specifically following technological effect: first, this application is through sampling resistance collection undercurrent signal, the great problem of size that the undercurrent signal brought is gathered to use fluxgate current sensor circuit among the correlation technique has been solved, fluxgate current sensor needs the electric current to pass formation excitation magnetic field with unsettled mode, thereby realize gathering undercurrent signal's purpose, but can't realize the electric current collection of walking the line to single electric current on the circuit board, the adoption resistance of this application can establish ties and realize the electric current collection on single electric current walks the line on the circuit board in the circuit, it is more compact to improve electric current collection system simultaneously, reduce electric current collection system's size. Secondly, this application adjusts the amplification gain through the mode of relay switching resistance, solves the great problem of error that uses the analog switch chip to bring because of temperature variation among the correlation technique, and the internal resistance of the relay of this application is very little, has fine uniformity, consequently can reduce the error of the amplification gain that temperature variation brought, improves the precision of current collection.
An embodiment of the present application further provides an electronic device, which includes the current testing apparatus described above, and may further include: a casing for accommodating the current testing device, a display screen, an input device (such as a keyboard, a mouse or a touch screen), and the like.
The above-described embodiments do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the above-described embodiments should be included in the protection scope of the technical solution.
Claims (10)
1. A current testing device, characterized by: the method comprises the following steps:
the device comprises a sampling resistor, a primary filter circuit, a resistor selection circuit, an amplifying circuit, a secondary filter circuit and an ADC (analog to digital converter) acquisition circuit; the resistor selection circuit comprises a relay and a plurality of resistors, wherein the relay is used for controlling one resistor in the plurality of resistors to be connected to the amplifying circuit;
the sampling resistor is connected with the filter circuit and used for converting the acquired small current signal into a voltage signal;
the primary filter circuit is connected with the amplifying circuit and is used for carrying out low-pass filtering processing on the voltage signal on the sampling resistor;
the amplifying circuit is connected with the relay and the resistance selection circuit and is used for amplifying the voltage signal input by the primary filter circuit according to the circuit accessed by the relay;
the second-stage filter circuit is connected with the ADC acquisition circuit and is used for performing low-pass filtering processing on the voltage signal output by the amplifying circuit;
and the ADC acquisition circuit is used for carrying out analog-to-digital conversion processing on the voltage signal output by the secondary filter circuit.
2. The apparatus of claim 1,
the first end of the sampling resistor R1 is connected with the current output end, and the second end of the sampling resistor R1 is connected with the current input end;
the primary filter circuit comprises a first capacitor C1, a second capacitor C2, a second resistor R2 and a third resistor R3;
a first end of the first capacitor C1 is connected to a first end of the sampling resistor R1, and a second end of the first capacitor C1 is connected to a second end of the sampling resistor R1;
a first terminal of the first capacitor C1 is connected to a first terminal of the second capacitor C2 through the second resistor R2, and a second terminal of the first capacitor C1 is connected to the third resistor R3.
3. The apparatus of claim 2, wherein the amplification circuit comprises an operational amplifier U1;
the negative input pin of the operational amplifier U1 is connected to the first end of the second capacitor C2, and the positive input pin of the operational amplifier U1 is connected to the second end of the second capacitor C2.
4. The apparatus of claim 3, wherein the two-stage filtering circuit comprises: a fourth resistor R4 and a third capacitor C3;
a first end of the fourth resistor R4 is connected to the output pin of the operational amplifier U1, a second end of the fourth resistor R4 is connected to a first end of the third capacitor C3, and a second end of the third capacitor C3 is grounded.
5. The apparatus of claim 1, 2, 3 or 4, wherein the resistance selection circuit comprises a number of the plurality of resistors of two.
6. The apparatus of claim 4, wherein the resistance selection circuit comprises: a relay U2, a fifth resistor R5 and a sixth resistor R6;
a first pin of the relay U2 is externally connected with a direct current power supply, a second pin of the relay U2 is connected with the amplifying circuit through the fifth resistor R5, a third pin of the relay U2 is connected with the amplifying circuit, and a fourth pin of the relay U2 is connected with the amplifying circuit through the sixth resistor R6.
7. The apparatus of claim 3, 4 or 6, wherein the model of the operational amplifier is AD 620.
8. The apparatus of claim 4, wherein the ADC acquisition circuit comprises: the ADC chip U3, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6;
an input pin of the ADC chip U3 is connected to the first end of the third capacitor C3, a reference capacitor pin of the ADC chip U3 is grounded through the fifth capacitor C5, a reference pin of the ADC chip U3 is grounded through the sixth capacitor C6, a ground pin of the ADC chip U3 is grounded, and a voltage driving pin of the ADC chip U3 is grounded through the fourth capacitor C4.
9. The device of claim 8, wherein the ADC chip U3 is AD7091R-8 in model number.
10. An electronic device comprising the current testing apparatus according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120929758.9U CN215116499U (en) | 2021-04-30 | 2021-04-30 | Current testing device and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120929758.9U CN215116499U (en) | 2021-04-30 | 2021-04-30 | Current testing device and electronic equipment |
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| Publication Number | Publication Date |
|---|---|
| CN215116499U true CN215116499U (en) | 2021-12-10 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202120929758.9U Active CN215116499U (en) | 2021-04-30 | 2021-04-30 | Current testing device and electronic equipment |
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| CN (1) | CN215116499U (en) |
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- 2021-04-30 CN CN202120929758.9U patent/CN215116499U/en active Active
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