CN212134877U - Circuit for detecting charging current of wireless charger mainboard - Google Patents
Circuit for detecting charging current of wireless charger mainboard Download PDFInfo
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- CN212134877U CN212134877U CN201922237157.7U CN201922237157U CN212134877U CN 212134877 U CN212134877 U CN 212134877U CN 201922237157 U CN201922237157 U CN 201922237157U CN 212134877 U CN212134877 U CN 212134877U
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Abstract
The utility model provides a circuit that is used for wireless charger mainboard charging current to detect with low costs, small, efficient and the measuring accuracy is high. The circuit comprises a system power supply unit (1), a signal receiving and transmitting unit (2), a current collecting unit (3) and a signal processing unit (4), wherein the signal receiving and transmitting unit (2), the current collecting unit (3) and the signal processing unit (4) are sequentially connected, the current collecting unit (3) is externally connected with an electronic load (5), and the system power supply unit (1) supplies power to the signal processing unit (4) and a wireless charger mainboard to be tested. The utility model is used for wireless charger test field.
Description
Technical Field
The utility model relates to a circuit board test field especially relates to a circuit that is used for wireless charger mainboard charging current to detect.
Background
With the rapid development of electronic technology, various electronic products play an increasingly important role in the life of people. And the electronic product needs to consume electric energy to work. Various chargers matched with electronic products are produced and become more and more important. The traditional wired charger is limited by environment and interfaces, and unsafe factors such as abrasion, short circuit and the like exist, so that the wireless charging is carried out at the same time. Because the wireless charger has very high convenience and aesthetic property, it is more and more favored by people.
At present, the most mature wireless charging technology is to use the electromagnetic induction principle to carry out wireless charging. It has banned the physical connection between power supply unit and the consumer, charges for the consumer through the transmission of wireless energy. Most of electronic products such as earphones, mobile phones and computers in the market also adopt an electromagnetic induction type wireless charging scheme. The wireless chargers have various brands, but the effectiveness and stability of wireless charging are required to be ensured, and especially, the charging current control during wireless charging is particularly important. Therefore, it is very important to design a device capable of testing the charging current of the main board of the wireless charger. In the traditional method, a standard power supply, a current probe, an oscilloscope and other electronic instruments are used to form a test system to test the alternating current signal of the charging current of the mainboard of the wireless charger. However, the traditional mode has high price, huge volume and large error caused by human factors, does not conform to the efficient and stable lean production principle in large-scale automatic test production, and has complex equipment wiring and low test precision.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that overcome prior art not enough, provide a circuit that is used for wireless charger mainboard charging current to detect with low costs, small, efficient and that the measuring accuracy is high.
The utility model adopts the technical proposal that: the circuit of the utility model comprises a system power supply unit for providing a wide range of power supply for the mainboard of the wireless charger to be tested;
the signal receiving and sending unit comprises a sending coil and a receiving coil and is used for receiving a charging signal of the mainboard of the wireless charger to be tested;
the current acquisition unit is used for acquiring the current signals received by the signal receiving and transmitting unit;
the signal processing unit is used for converting the received current signal of the wireless charger to be tested into a digital signal from an analog signal and analyzing the converted digital signal to obtain a current wave crest and a current effective value;
the signal receiving and transmitting unit, the current acquisition unit and the signal processing unit are sequentially connected, the current acquisition unit is externally connected with an electronic load, and the system power supply unit supplies power to the signal processing unit and the wireless charger mainboard to be tested.
The scheme can be seen, the independent system power supply unit is used as the power supply of each part in a wide range, so that the utility model can meet the requirement of large-range current test; the current acquisition unit, the signal processing unit and the like exist in the form of an integrated circuit, so that the space is greatly saved, and the volume of the whole circuit is greatly reduced; the signal processing unit can detect the current wave crest, the current effective value and the like of the converted digital signal, so that the test efficiency is greatly improved, excessive introduction of artificial factors is avoided, the test precision is ensured, and the reliability is improved; the current acquisition unit adopts a high-bandwidth Hall device and an operational amplifier, so that the corresponding speed of the circuit is greatly improved; compare with current expensive standard instrument of adoption, the utility model discloses the cost is reduced widely, the operation flow has also been simplified, has reduced operating personnel's intensity of labour, makes the utility model discloses it is possible in the automatic test of electronic product to be applied to in large batch.
Further, the system power supply unit includes a voltage drop circuit and a voltage feedback circuit, the voltage drop circuit includes a DC-DC, a fourth capacitor, a first diode and a first inductor, the fourth capacitor is connected between the PH pin and the BOOT pin of the DC-DC, the negative electrode of the first diode is connected with the PH pin of the DC-DC, the positive electrode of the first diode is grounded, one end of the first inductor is connected with the PH pin of the DC-DC, the other end of the first inductor is used as output, the voltage feedback circuit comprises a second instrumentation amplifier and a third instrumentation amplifier which are connected in sequence, the input end of the second instrumentation amplifier is connected with the output end of the first inductor, the output end of the third instrumentation amplifier is connected with the sensor pin of the DC-DC, and the output end of the third instrumentation amplifier is also connected with the output end of the first inductor.
According to the scheme, the complete voltage reduction circuit consisting of the DC-DC, the fourth capacitor, the first diode and the first inductor accurately controls the input voltage, the voltage feedback circuit is arranged to complete the detection of voltage output, the real-time monitoring of power supply is realized, and further the voltage reaching the wireless charger end to be tested is ensured to be consistent with the set voltage under the condition of large-current output while the voltage within a wide range is output, the test precision is ensured, and the wide applicability of the circuit is also ensured.
Still further, the current collection unit comprises a hall device, and a high-pass filter, an operational amplifier and a full-differential operational amplifier which are connected in sequence, wherein one end of the high-pass filter is connected with the hall device, the high-pass filter comprises a fifteenth resistor, a sixteenth capacitor and an eighteenth resistor, one end of the fifteenth resistor is connected with a voltage output end of the hall device, the other end of the fifteenth resistor is connected with the sixteenth capacitor, the other end of the sixteenth capacitor is connected with the operational amplifier, one end of the eighteenth resistor is connected between the sixteenth capacitor and the operational amplifier, and the other end of the eighteenth resistor is grounded.
According to the scheme, the introduction of the Hall device greatly improves the testing precision; the high-pass filter can filter impurities in the signal; the operational amplifier with high bandwidth amplifies the obtained small signal, ensures the voltage input range to a post-stage circuit and the integrity of signal waveform, and ensures no distortion; the fully differential operational amplifier can avoid the interference of external signals to the circuit, and improves the test precision.
Still further, the signal processing unit comprises a high-speed analog-to-digital converter and a signal processing chip, the high-speed analog-to-digital converter is connected with the signal processing chip, and the high-speed analog-to-digital converter provides a reference voltage for the fully differential operational amplifier. Therefore, the high-speed analog-to-digital converter can greatly improve the testing precision and the processing response speed, meanwhile, the analog-to-digital conversion of a complete waveform is guaranteed, the received analog signal waveform is decomposed into digital signals through the signal processing chip to detect the current wave crest and the current effective value, so that the limit current of the wireless charger is obtained, and the reference voltage provided by the high-speed analog-to-digital converter can provide reliable reference voltage for the fully differential operational amplifier, so that the testing precision is guaranteed.
Still further, the circuit also comprises a calibrator, wherein the calibrator comprises a standard power supply for inputting current to the receiving coil, a current probe and an oscilloscope, and the oscilloscope is connected with the fully differential operational amplifier through the current probe. Therefore, alternating current signals with different amplitudes are output by a standard power supply and loaded at the end of the receiving coil, an electronic load is connected at the rear end of the receiving coil, a constant impedance mode is set for current drawing, the current acquisition unit and the signal processing unit finish the acquisition and processing of current waveforms, and an oscilloscope and a current probe are used for capturing the waveforms; will by the utility model discloses the current signal amplitude that the circuit detected the gained and the current amplitude that oscilloscope obtained use the least square method to carry out curve fitting respectively, thereby make the utility model discloses the current waveform and the standard instrument that the circuit gathered keep highly uniform, and then realize the calibration, its easy operation, and right the utility model discloses the circuit plays fabulous calibration effect.
And finally, relay switches are respectively arranged on the sending coil and the receiving coil. Therefore, the current flow direction of the coil can be conveniently changed by setting the relay switch, so that the signal receiving and transmitting unit can meet various different requirements, and the applicability of the signal receiving and transmitting unit is improved.
Drawings
FIG. 1 is a simplified schematic diagram of the present invention;
FIG. 2 is a simplified circuit schematic of the system power supply unit;
fig. 3 is a simplified circuit schematic of the signal transceiving unit;
FIG. 4 is a simplified circuit schematic of the current acquisition unit;
FIG. 5 is a simplified circuit schematic of the high speed analog to digital converter portion of the signal processing unit;
FIG. 6 is a simplified circuit schematic of the first part of the FPGA of the signal processing unit;
FIG. 7 is a simplified circuit schematic of the second part of the FPGA of the signal processing unit;
FIG. 8 is a simplified circuit schematic of a third portion of the FPGA of the signal processing unit;
fig. 9 is a simple circuit schematic diagram of a peripheral circuit portion of the signal processing unit.
Detailed Description
As shown in fig. 1 to 9, the present invention includes a system power supply unit 1, a signal transceiver unit 2, a current collection unit 3, and a signal processing unit 4. The system power supply unit 1 is used for providing a wide-range power supply for the wireless charger mainboard to be tested. The signal receiving and sending unit 2 comprises a sending coil TX and a receiving coil RX, relay switches are respectively arranged on the sending coil TX and the receiving coil RX, and the signal receiving and sending unit 2 is used for receiving a charging signal of a wireless charger mainboard to be tested. The current acquisition unit 3 is used for acquiring current signals received by the signal transceiving unit. The signal processing unit 4 is configured to convert the received current signal of the wireless charger to be tested from an analog signal to a digital signal, and analyze the converted digital signal to obtain a current peak and a current effective value. The signal receiving and transmitting unit 2, the current acquisition unit 3 and the signal processing unit 4 are connected in sequence, the current acquisition unit 3 is externally connected with an electronic load 5, and the system power supply unit 1 supplies power to the signal processing unit 4 and the wireless charger mainboard to be tested. As shown in fig. 3, the signal transceiver unit is composed of a coil, a relay, and the like. According to the law of electromagnetic induction, when the current in one coil with a core changes, the other coil generates a mutual inductance coupling phenomenon. Thus, the output signal of the wireless charger product can be received.
Specifically, the system power supply unit 1 includes a voltage drop circuit including a DC-DC U1, a fourth capacitor C4, a first diode D1, and a first inductor L1, the fourth capacitor C4 is connected between the PH pin and the BOOT pin of the DC-DC U1, the cathode of the first diode D1 is connected with the PH pin of the DC-DC U1, the anode is grounded, one end of the first inductor L1 is connected with the PH pin of the DC-DC U1, and the other end is used as an output, the voltage feedback circuit comprises a second instrumentation amplifier U2 and a third instrumentation amplifier U3 which are connected in sequence, the input terminal of the second instrumentation amplifier U2 is connected to the output terminal of the first inductor L1, the output of the third instrumentation amplifier U3 is connected to the sensor pin of the DC-DC U1, the output end of the third instrumentation amplifier U3 is also connected with the output end of the first inductor L1. As shown in fig. 2, the system power supply unit 1 is composed of devices such as a DC-DC (TPS5450), an instrumentation operational amplifier (INA826), and the like. The DC-DC U1, the fourth capacitor C4, the first inductor L1 and the first diode D1 (freewheeling diode) form a standard voltage reduction circuit; the second instrumentation amplifier U2 and the third instrumentation amplifier U3 respectively complete the remote voltage feedback and the setting of the output voltage, so that not only a wider range of voltage can be output, but also the voltage output to the product end can be ensured to be consistent with the set voltage under the condition of large current.
The current collecting unit 3 comprises a hall device U4, and a high-pass filter, an operational amplifier U5A and a full-differential operational amplifier U6 which are connected in sequence, wherein one end of the high-pass filter is connected with the hall device U4, the high-pass filter comprises a fifteenth resistor R15, a sixteenth capacitor C16 and an eighteenth resistor R18, one end of the fifteenth resistor R15 is connected with a voltage output end of the hall device U4, the other end of the fifteenth resistor R15 is connected with the sixteenth capacitor C16, the other end of the sixteenth capacitor C16 is connected with the operational amplifier U5A, one end of the eighteenth resistor R18 is connected between the sixteenth capacitor C16 and the operational amplifier U5A, and the other end of the eighteenth resistor R18 is grounded. As shown in fig. 4, the current collecting unit 3 is composed of a hall chip (ACS70331E) and its peripheral circuit, a remote computing amplifier (AD8066), a differential operational amplifier (THS 4551), and other devices. The high-bandwidth and high-precision Hall chip outputs a voltage in proportion to current according to Hall effect (when the current passes through a semiconductor in a direction perpendicular to an external magnetic field, a carrier deflects, an additional electric field is generated in a direction perpendicular to the current and the magnetic field, so that potential difference is generated at two ends of the semiconductor), the output voltage is amplified by three times through a high-pass filter and a high-bandwidth operational amplifier to ensure that the input range and the waveform integrity of a rear-stage circuit are achieved, and a single-ended signal is converted into a differential signal through a fully differential operational amplifier and is sent to a signal processing unit to avoid the interference of other signals of the circuit.
The signal processing unit 4 comprises a high-speed analog-to-digital converter ADC and a signal processing chip FPGA, the high-speed analog-to-digital converter ADC is connected with the signal processing chip FPGA, and the high-speed analog-to-digital converter ADC provides a reference voltage Vref for the fully differential operational amplifier U6. As shown in fig. 5, the signal processing unit 4 is constituted by a high-speed ADC (ADS 5231) and an FPGA (ZYNQ 7010). The high speed ADC has a 50nS sampling rate and 2^12 resolution to ensure analog to digital conversion of the complete waveform. The operational amplifier (AD 8639) follows the reference voltage outputted by the ADC and outputs the reference voltage to the fully differential operational amplifier (THS 4551) for reference. The collected current signals are processed by the FPGA, so that parameters such as current spikes, effective values and the like can be obtained. The limiting current is known from these parameters.
The circuit further comprises a calibrator which comprises a standard power supply for inputting current to the receiving coil RX, a current probe and an oscilloscope, wherein the oscilloscope is connected with the fully differential operational amplifier U6 through the current probe. The calibration procedure was as follows: the standard power supply is used for outputting alternating current signals with different amplitudes to be loaded at a receiving coil end, the alternating current signals are connected with an electronic load at the rear end, a constant impedance mode is set to pull current, a current acquisition unit and a signal processing unit are used for acquiring and processing current waveforms, and an oscilloscope and a current probe are used for capturing the waveforms; will by the utility model discloses the current signal amplitude that the circuit detected the gained uses the least square method respectively with the current amplitude that oscilloscope obtained to carry out curve fitting, thereby makes the utility model discloses the current waveform and the standard instrument that the circuit gathered keep highly uniform, and then realize the calibration.
The utility model discloses response speed is fast, and the circuit is simple, and is with low costs, and the reliability is high, but among the applicable electric current signal acquisition test scheme, can be applied to in electronic product automated current test equipment in batches.
Claims (6)
1. The utility model provides a circuit that is used for wireless charger mainboard charging current to detect which characterized in that: the circuit comprises
The system power supply unit (1) is used for providing a wide-range power supply for the mainboard of the wireless charger to be tested;
the signal transceiving unit (2) comprises a sending coil (TX) and a receiving coil (RX), and is used for receiving a charging signal of a mainboard of the wireless charger to be tested;
the current acquisition unit (3) is used for acquiring the current signals received by the signal receiving and transmitting unit;
the signal processing unit (4) is used for converting the received current signal of the wireless charger to be tested into a digital signal from an analog signal and analyzing the converted digital signal to obtain a current wave crest and a current effective value;
the signal receiving and transmitting unit (2), the current acquisition unit (3) and the signal processing unit (4) are connected in sequence, the current acquisition unit (3) is externally connected with an electronic load (5), and the system power supply unit (1) supplies power to the signal processing unit (4) and the wireless charger mainboard to be tested.
2. The circuit for detecting the charging current of the main board of the wireless charger according to claim 1, wherein: the system power supply unit (1) comprises a voltage reduction circuit and a voltage feedback circuit, wherein the voltage reduction circuit comprises a DC-DC (U1), a fourth capacitor (C4), a first diode (D1) and a first inductor (L1), the fourth capacitor (C4) is connected between a PH pin and a BOOT pin of the DC-DC (U1), the negative electrode of the first diode (D1) is connected with the PH pin of the DC-DC (U1), the positive electrode of the first diode is grounded, one end of the first inductor (L1) is connected with the PH pin of the DC-DC (U1), and the other end of the first inductor is used as an output, the voltage feedback circuit comprises a second instrument amplifier (U2) and a third instrument amplifier (U3) which are sequentially connected, the input end of the second instrument amplifier (U2) is connected with the output end of the first inductor (L1), and the output end of the third instrument amplifier (U3) is connected with a sor of the DC-DC (U1), the output of the third instrumentation amplifier (U3) is also connected to the output of the first inductor (L1).
3. The circuit for detecting the charging current of the main board of the wireless charger according to claim 1, wherein: the current acquisition unit (3) comprises a Hall device (U4), a high-pass filter, an operational amplifier (U5A) and a full-differential operational amplifier (U6), wherein the high-pass filter, the operational amplifier (U5A) and the full-differential operational amplifier are sequentially connected, one end of the high-pass filter is connected with the Hall device (U4), the high-pass filter comprises a fifteenth resistor (R15), a sixteenth capacitor (C16) and an eighteenth resistor (R18), one end of the fifteenth resistor (R15) is connected with a voltage output end of the Hall device (U4), the other end of the fifteenth resistor (R15) is connected with the sixteenth capacitor (C16), the other end of the sixteenth capacitor (C16) is connected with the operational amplifier (U5A), one end of the eighteenth resistor (R18) is connected between the sixteenth capacitor (C16) and the operational amplifier (U5A), and.
4. The circuit for detecting the charging current of the main board of the wireless charger according to claim 3, wherein: the signal processing unit (4) comprises a high-speed analog-to-digital converter (ADC) and a signal processing chip (FPGA), the high-speed analog-to-digital converter (ADC) is connected with the signal processing chip (FPGA), and the high-speed analog-to-digital converter (ADC) provides reference voltage (Vref) for the fully differential operational amplifier (U6).
5. A circuit for detecting charging current of a main board of a wireless charger according to claim 1 or 3, wherein: the circuit further comprises a calibrator comprising a standard power supply for inputting current to the receiving coil (RX), a current probe and an oscilloscope, wherein the oscilloscope is connected with a fully differential operational amplifier (U6) through the current probe.
6. The circuit for detecting the charging current of the main board of the wireless charger according to claim 1, wherein: and the transmitting coil (TX) and the receiving coil (RX) are respectively provided with a relay switch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922237157.7U CN212134877U (en) | 2019-12-13 | 2019-12-13 | Circuit for detecting charging current of wireless charger mainboard |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922237157.7U CN212134877U (en) | 2019-12-13 | 2019-12-13 | Circuit for detecting charging current of wireless charger mainboard |
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| Publication Number | Publication Date |
|---|---|
| CN212134877U true CN212134877U (en) | 2020-12-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922237157.7U Active CN212134877U (en) | 2019-12-13 | 2019-12-13 | Circuit for detecting charging current of wireless charger mainboard |
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| Country | Link |
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| CN (1) | CN212134877U (en) |
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