CN214201591U

CN214201591U - Dynamic current detection device of low-power consumption Internet of things equipment

Info

Publication number: CN214201591U
Application number: CN202120003918.7U
Authority: CN
Inventors: 裴晓芳; 仇李琦; 范阳; 翟介新
Original assignee: Nanjing University of Information Science and Technology
Current assignee: Nanjing Linjing New Intelligent Technology Co ltd
Priority date: 2021-01-04
Filing date: 2021-01-04
Publication date: 2021-09-14
Anticipated expiration: 2031-01-04

Abstract

A dynamic current detection device of low-power-consumption Internet of things equipment comprises a sampling resistor selection circuit, a current detection amplifier, an analog-to-digital conversion module, a main control chip and a display module, wherein the sampling resistor selection circuit is used for detecting load voltage generated by a load circuit flowing through the sampling resistor selection circuit, the current detection amplifier is used for amplifying the load voltage, the analog-to-digital conversion module is used for collecting amplified voltage signals, the main control chip is used for calculating load current data according to the load voltage, and the display module is used for displaying the load current data. The sampling resistance selection circuit, the analog-to-digital conversion module and the display module are respectively connected with the main control chip, and the current detection amplifier is respectively connected with the sampling resistance selection circuit and the analog-to-digital conversion module. The utility model discloses a dynamic current detection device low cost to can accurately detect out the dynamic current of low-power consumption thing networking device.

Description

Dynamic current detection device of low-power consumption Internet of things equipment

Technical Field

The utility model belongs to the technical field of the electric power measurement, concretely relates to dynamic current detection device of low-power consumption thing networking equipment.

Background

With the rapid development of the internet of things, various low-power-consumption internet of things products are more and more widely applied, and low power consumption also becomes a more and more focused performance in embedded equipment. In order to reduce the power consumption of the device and prolong the service time of the battery, the low-power-consumption internet-of-things product generally supports switching between an active state and a dormant state, usually only activates an operation program for a short time, and is in a deep dormant state for most of the time. Therefore, the low-power consumption internet of things equipment not only needs to perform dynamic current measurement in an activated state, but also needs to perform the same measurement in a deep sleep state. The current can reach dozens to hundreds of mA in the general activation state, and only 10uA or even lower in the deep sleep state.

In the prior art, a digital multimeter has low sampling rate, narrow bandwidth and poor current response in a wide range, and when equipment is switched in a working state, the method has the defects of non-intuition and low data precision, and is not suitable for dynamic current detection of low-power-consumption products. Current analyzers available in the market are all powered by 220V mains supply, so that the size is large, and the portability is insufficient. Although the sampling rate and accuracy are high, they are not suitable for most individual users due to their high price.

Disclosure of Invention

The utility model provides a dynamic current detection device of low-power consumption thing networking equipment with low costs, precision are high to evaluate the low-power consumption performance of thing networking equipment more in detail.

The technical proposal adopted by the utility model is that

A dynamic current detection device of low-power-consumption Internet of things equipment comprises a sampling resistor selection circuit, a current detection amplifier, an analog-to-digital conversion module, a main control chip and a display module, wherein the sampling resistor selection circuit is used for detecting load voltage generated by a load circuit flowing through the sampling resistor selection circuit;

the sampling resistance selection circuit, the analog-to-digital conversion module and the display module are respectively connected with the main control chip, and the current detection amplifier is respectively connected with the sampling resistance selection circuit and the analog-to-digital conversion module.

Furthermore, the sampling resistor selection circuit comprises a PMOS tube U12, an NMOS tube Q6, a resistor R14, a resistor R17, a resistor R20, a resistor R23 and a resistor R26, wherein one end of the resistor R23 is connected with a pin 1 of the NMOS tube Q6, one end of the resistor R26 is connected with a pin 2 of the NMOS tube Q6, and the pin 2 of the NMOS tube Q6 is grounded; the other end of each of the resistor R23 and the resistor R26 is a CH1 pin and is connected with a control pin of the main control chip;

one end of the resistor R20 is connected with a pin 3 of the NMOS tube Q6, and the other end of the resistor R20 is respectively connected with a pin G of the resistor R17 and a pin G of the PMOS tube U12; the other end of the resistor R17 is a CUR _ IN end and is connected with three pins S of a PMOS tube U12, one end of the resistor R14 is connected with four pins D of the PMOS tube U12, and the other end of the resistor R14 is a CUR _ OUT end; load current flows IN from the CUR _ IN end, passes through the PMOS tube U12 and the resistor R14, and flows OUT from the CUR _ OUT end; the load voltage is the voltage difference between two ends of CUR _ IN and CUR _ OUT.

Further, the main control chip adopts a GD32E103 single chip microcomputer.

Further, the current sense amplifier is of type AD 8418.

Further, the model of the analog-to-digital conversion module is AD 9220.

Further, the display module adopts an LCD display screen.

The beneficial effects of the utility model reside in that:

the utility model discloses a dynamic current detection device low cost to can accurately detect out the dynamic current of low-power consumption thing networking device.

Drawings

Fig. 1 is a block diagram of the module connection of the dynamic current detection device of the present invention;

FIG. 2 is a circuit diagram of a GD32E103 single chip microcomputer;

FIG. 3 is a circuit diagram of a sampling resistor selection circuit;

fig. 4 is a circuit diagram of the current sense amplifier AD 8418;

fig. 5 is a circuit diagram of the analog-to-digital conversion module AD 9220;

FIG. 6 is a diagram showing a state object displayed on an LCD screen.

Detailed Description

The dynamic current detection device of the low power consumption internet of things device of the present invention is further described in detail with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1, a dynamic current detection apparatus for a low-power consumption internet of things device includes a sampling resistor selection circuit for detecting a load voltage generated by a load circuit flowing through, a current detection amplifier for amplifying the load voltage, an analog-to-digital conversion module for collecting an amplified voltage signal, a main control chip for calculating load current data according to the load voltage, and a display module for displaying the load current data.

Specifically, as shown in fig. 3, the sampling resistor selection circuit includes a PMOS transistor U12, an NMOS transistor Q6, a resistor R14, a resistor R17, a resistor R20, a resistor R23, and a resistor R26, one end of the resistor R23 is connected to a pin 1 of the NMOS transistor Q6, one end of the resistor R26 is connected to a pin 2 of the NMOS transistor Q6, and a pin 2 of the NMOS transistor Q6 is grounded. The other end of each of the resistor R23 and the resistor R26 is a CH1 pin and is connected with a control pin of the main control chip.

One end of the resistor R20 is connected with a pin 3 of the NMOS tube Q6, and the other end of the resistor R20 is connected with a pin G of the resistor R17 and a pin G of the PMOS tube U12 respectively. The other end of the resistor R17 is a CUR _ IN end and is connected with three pins S of the PMOS tube U12, one end of the resistor R14 is connected with four pins D of the PMOS tube U12, and the other end of the resistor R14 is a CUR _ OUT end. The load current flows IN from the CUR _ IN terminal, passes through the PMOS tube U12 and the resistor R14, and flows OUT from the CUR _ OUT terminal. The load voltage is the voltage difference between two ends of CUR _ IN and CUR _ OUT.

Fig. 3 is a 0.18 Ω sampling resistor selection circuit, and VBA2107 is a PMOS transistor with ultra-low on-resistance, typically less than 6 milliohms. When a pin CH1 outputs a low level, the NMOS transistor Q6 is disconnected, the Vgs of the PMOS transistor U12 is 0V, the PMOS transistor U12 is disconnected, and the current of load equipment cannot pass; when the pin CH1 outputs a high level, the NMOS transistor Q6 is conducted, when Vgs is smaller than-1V, the PMOS transistor U12 is conducted, and load current flows IN from the pin CUR _ IN, passes through the sampling resistors of the PMOS transistors U12 and R14 and flows OUT from the pin CUR _ OUT. The load current flowing through is calculated by detecting the voltage difference across CUR _ IN and CUR _ OUT.

The total number of sampling resistors is six, and the corresponding measuring range relationship is shown in table 1.

TABLE 1 relationship between sampling resistance and measuring range

In this embodiment, the main control chip adopts a GD32E103 single chip microcomputer (GD32E103RBT6, megachange company), as shown in fig. 2. The single chip microcomputer adopts an ARM Cortex-M4F inner core, and integrates a complete DSP instruction set, parallel computing capability and a special single-precision floating point operation unit. 128KB of embedded Flash and 32KB of SRAM are provided. And by matching with a built-in hardware acceleration unit, the working performance under the highest main frequency can reach 120 DMIPS.

The current sense amplifier is model AD8418, as shown in fig. 4. The AD8418 is a high-voltage and high-resolution current detection amplifier. The initial gain is set to be 20V/V, the maximum gain error in the whole temperature range is +/-0.15%, and the input common-mode rejection performance is excellent when the input common-mode voltage is in a range of-2V to + 70V. In this embodiment, a unidirectional mode is employed, with the output set to the negative supply rail. The differential voltage value of the inputs of IN + and IN-of the AD8418 is output by the OUT pin after 20 times of gain. D6 is a TVS bi-directional diode that clamps the voltage to 2V when the differential voltage exceeds 2V, acting as a protection circuit.

The model of the analog-to-digital conversion module is AD9220, as shown in FIG. 5. The AD9220 is a single-chip 12-bit analog-to-digital converter, the sampling rate is 10MSPS, and an on-chip programmable reference voltage source or an external reference voltage can be selected. A multi-stage differential pipeline architecture is adopted, digital output error correction logic is built in, 12-bit precision can be provided at a rated data rate, and no code loss is ensured in the whole working temperature range. A single clock input is used to control all internal transitions. The digital output data format is standard binary. The over-range (OTR) signal indicates an overflow condition and may be determined by the most significant bit as to whether it is an underflow or overflow. The AD9220 supports both single-ended and differential input modes. In the embodiment, a single-ended input mode is adopted, a voltage reference chip REF3120 generates a reference voltage of 2.048V, and the input voltage range of the AD9220 is 0-4.096V.

The display module adopts an LCD display screen. As shown in fig. 6, the upper part is a block diagram showing current data; the lower part is a waveform diagram which displays the dynamic current waveform diagram of the product of the Internet of things to be tested.

The utility model discloses a dynamic current detection device's working process does:

after the device is powered on, the main control chip starts an initialization function for the peripheral module, and initializes the timer and the analog-to-digital conversion module. The analog-to-digital conversion module AD9220 is a 12-bit parallel output ADC chip, and can simultaneously transmit 12-bit data to a single chip microcomputer through an IO port, wherein the reference voltage is 4.096V, and the unit resolution is 1 mV. And the GD32E103 reads an ADC sampling value every 500ns through an internal timer, stores the ADC sampling value into the ring buffer array and waits for data processing.

The single chip microcomputer reads 32 sampling points of the annular cache data every 16us, and performs data mean filtering to obtain effective ADC sampling data. Then, data judgment is carried out, if the sampling value is less than 200, the current is small, and the sampling resistance needs to be increased; if the sampling value is larger than 3800, the current is larger, and the sampling resistance needs to be reduced.

If the current sampling resistor is 0.18 omega, the ADC sampling value is X, the actual input voltage value of the ADC is XmV, the voltage difference between two ends of the sampling resistor is (X/20) mV, and the current value is I ═ X/3.6 mA. And calculating real-time current through the relation between the sampling resistor and the ADC sampling value, calculating the consumed electric quantity by integrating the real-time current with time, and calculating the operation time of the consumed electric quantity to obtain the average power consumption of the whole machine.

The device uses the GD32E103 single chip microcomputer as a main control chip, and the design of the dynamic current detection device for the low-power-consumption Internet of things equipment is completed. The analog-to-digital converter AD9220 is adopted to realize signal acquisition, the 6-gear sampling resistor is adopted to realize range self-adaptive switching, the high-resolution current detection amplifier AD8418 is adopted to realize distortion-free amplification of weak voltage, and parameter display of instantaneous current, average current, power consumption and the like can be realized on an LCD screen.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It should be understood by those skilled in the art that the present invention is not limited to the embodiments described above, but rather is described in the embodiments and the description only to illustrate the principles of the invention and that various changes and modifications may be made without departing from the spirit and scope of the invention, the scope of which is defined by the appended claims, the description and the equivalents thereof.

Claims

1. A dynamic current detection device of low-power consumption Internet of things equipment is characterized by comprising a sampling resistor selection circuit, a current detection amplifier, an analog-to-digital conversion module, a main control chip and a display module, wherein the sampling resistor selection circuit is used for detecting load voltage generated by a load circuit flowing through the sampling resistor selection circuit;

2. The dynamic current detection device of the low-power consumption internet of things equipment as claimed in claim 1, wherein the sampling resistor selection circuit comprises a PMOS tube U12, an NMOS tube Q6, a resistor R14, a resistor R17, a resistor R20, a resistor R23 and a resistor R26, one end of the resistor R23 is connected with a pin 1 of the NMOS tube Q6, one end of the resistor R26 is connected with a pin 2 of the NMOS tube Q6, and the pin 2 of the NMOS tube Q6 is grounded; the other end of each of the resistor R23 and the resistor R26 is a CH1 pin and is connected with a control pin of the main control chip;

3. The dynamic current detection device of the low-power consumption internet of things equipment as claimed in claim 2, wherein the main control chip adopts a GD32E103 single chip microcomputer.

4. The dynamic current detection device of the low-power consumption internet of things equipment as claimed in claim 1, wherein the model of the current detection amplifier is AD 8418.

5. The dynamic current detection device of the low-power consumption internet of things equipment as claimed in claim 1, wherein the model of the analog-to-digital conversion module is AD 9220.

6. The dynamic current detection device of the low-power consumption internet of things equipment as claimed in claim 1, wherein the display module adopts an LCD display screen.