Wia-pa wireless intelligent meter battery voltage and ambient temperature detection circuit
By actively integrating load resistance and temperature detection into the wireless smart meter, the error problem in battery power detection was solved, enabling accurate battery voltage and temperature acquisition, improving the operational reliability of the equipment and reducing maintenance costs.
Patent Information
- Application Number
- CN202521350782.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-30
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-06-30
AI Technical Summary
In industrial applications, the battery power detection of wireless smart meters suffers from large errors and inaccuracies, especially in low-power and temperature-varying environments, leading to unstable equipment operation and data loss.
By actively connecting a load resistor during measurement to simulate the battery's operating state, and combining this with ambient temperature detection, an innovative circuit structure is used to eliminate no-load measurement errors, achieving accurate synchronous acquisition of battery voltage and temperature.
It enables accurate battery power detection in low-power and temperature-varying environments, improving the reliability and stability of equipment operation and reducing maintenance costs.
Smart Images
Figure CN224682376U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to wireless intelligent instrument field, it is a WIA - PA wireless intelligent instrument battery voltage and environmental temperature's detection circuit. BACKGROUND
[0002] With the rapid development of modern communication and internet of things technology, wireless intelligent instrument is accelerating the replacement of traditional wired instrument by virtue of its significant cost advantage, deployment flexibility and digital compatibility. However, the power supply problem becomes the main bottleneck restricting its development - as most wireless instruments cannot adopt charging technology, battery performance and power monitoring is particularly critical. Accurate battery power detection not only directly affects the maintenance planning of equipment, but also relates to the reliability of system operation: if there is no effective monitoring, sudden power failure will cause equipment to drop, data loss and other problems, and the emergency maintenance cost and production loss caused thereby are often several times more than preventive maintenance. Therefore, developing high-precision battery power detection technology has great significance for realizing predictable maintenance, reducing operation and maintenance cost and ensuring stable operation of system.
[0003] However, the current battery power detection of wireless instrument generally adopts voltage-based measurement, which has two major technical bottlenecks in industrial application scenarios: first, industrial wireless instrument is in micro-ampere level low-power consumption mode for a long time, and the battery is actually in quasi-no-load state, which causes the open-circuit voltage detection value to be higher than the real load voltage, seriously affecting the power estimation accuracy. For example, when the battery runs with 18KΩ load for 2*10 4 hours, the cumulative discharge of the battery is (3.6 / 18000)*2*10 4 =4Ah, and when the battery runs with 13.5Ω load for 0.1 hours, the cumulative discharge of the battery is (3.6 / 13.5)*0.1=0.0267Ah. It can be seen that the remaining power of the latter battery is much larger than that of the former, but the actual measured battery voltage of the former is about 3.6V, and that of the latter is about 3.1V, which is less than that of the former.
[0004] Due to the special application environment, wireless instrument is in sleep state most of the time, with low power consumption. At this time, even if the battery has entered a low power state, the measured battery voltage is still a sufficient power value, which does not trigger the low power reporting mechanism. When the device enters data transmission mode or collection mode in this state, the increased current will cause the battery voltage to drop below the normal operating voltage, so that the device cannot enter the corresponding working mode, causing data loss, communication anomaly, restart or shutdown.
[0005] Secondly, the ambient temperature can significantly change the electrochemical reaction characteristics inside the battery, affecting the service life of the battery. For example, the full battery under a 35mA load, the battery voltage measured at room temperature is about 3.45V, and the battery voltage measured at-30℃ is about 3V. The temperature drop will cause the battery power to drop.
[0006] However, the traditional voltage detection does not consider the influence of the above two cases, so that the battery voltage detection value is high, which cannot accurately reflect the device running condition, and greatly affects the normal use of the device. Invention content
[0007] In view of the above technical problems, the utility model provides a kind of WIA-PA wireless intelligent instrument battery voltage and environmental temperature detection circuit, and the active access load resistance simulation battery operating condition in measurement process of prior art is innovatively solved, and the no-load measurement error is eliminated by improving circuit structure;Realize synchronous acquisition of environmental temperature parameters. Especially suitable for wireless instrument power supply monitoring in harsh environment such as industrial internet of things.
[0008] The technical scheme adopted by the present application is:
[0009] The WIA-PA wireless intelligent instrument battery voltage and environmental temperature detection circuit includes an analog switch U1, a voltage stabilizing chip U2, a temperature measurement circuit, a load resistor R3 and a battery voltage measurement circuit built-in the WIA-PA wireless intelligent instrument.
[0010] One end of the analog switch U1 is connected to the positive terminal of the WIA-PA wireless intelligent instrument battery to be measured. The other end of the analog switch U1 is connected to the voltage stabilizing chip U2, the load resistor R3 and the battery voltage measurement circuit.
[0011] The voltage stabilizing chip U2 is connected to the temperature measurement circuit and the battery voltage measurement circuit, respectively.
[0012] The analog switch U1, the temperature measurement circuit and the battery voltage measurement circuit are also connected to the single-chip microcomputer of the WIA-PA wireless intelligent instrument.
[0013] The temperature measurement circuit includes a low-temperature drift high-precision resistor R1, a thermistor NTC, an operational amplifier U3 and a first RC low-pass filter circuit.
[0014] The voltage stabilizing chip U2 is grounded through the low-temperature drift high-precision resistor R1 and the thermistor NTC in sequence. The lead wire between the low-temperature drift high-precision resistor R1 and the thermistor NTC is connected to the non-inverting input terminal of the operational amplifier U3. The inverting input terminal of the operational amplifier U3 is connected to the output terminal of the operational amplifier U3. The output terminal of the operational amplifier U3 is connected to the single-chip microcomputer of the WIA-PA wireless intelligent instrument through the first RC low-pass filter circuit.
[0015] The first RC low-pass filter circuit comprises a low-temperature drift high-precision resistor R6 and a capacitor C1; the output end of the operational amplifier U3 is grounded through the low-temperature drift high-precision resistor R6 and the capacitor C1, and a lead wire between the low-temperature drift high-precision resistor R6 and the capacitor C1 is connected to the single-chip microcomputer of the WIA-PA wireless intelligent instrument.
[0016] The battery voltage measurement circuit comprises low-temperature drift high-precision resistors R4 and R5, an operational amplifier U4 and a second RC low-pass filter circuit.
[0017] The voltage stabilizing chip U2 is grounded through the low-temperature drift high-precision resistors R4 and R5 in sequence; a lead wire between the low-temperature drift high-precision resistors R4 and R5 is connected to the non-inverting input end of the operational amplifier U4, the inverting input end of the operational amplifier U4 is connected to the output end of the operational amplifier U4, and the output end of the operational amplifier U4 is connected to the second RC low-pass filter circuit and then connected to the single-chip microcomputer of the WIA-PA wireless intelligent instrument.
[0018] The second RC low-pass filter circuit comprises a low-temperature drift high-precision resistor R7 and a capacitor C2; the output end of the operational amplifier U4 is grounded through the low-temperature drift high-precision resistor R7 and the capacitor C2, and a lead wire between the low-temperature drift high-precision resistor R7 and the capacitor C2 is connected to the single-chip microcomputer of the WIA-PA wireless intelligent instrument.
[0019] The display screen circuit further comprises: the VDD pin of the liquid crystal drive chip U4 is connected to a direct current power supply +3.3V, the direct current power supply +3.3V is filtered through the capacitor C5, and the VDD pin is further connected to the VLCD / SEG 39 pin through the resistor R36; the SDA pin of the liquid crystal drive chip U4 is connected to the LCD_SDA pin of the single-chip microcomputer through the resistor R32, and the LCD_SDA pin is further connected to the direct current power supply +3.3V through the pull-up resistor R34; the SCL pin of the liquid crystal drive chip U4 is connected to the LCD_SCL pin of the single-chip microcomputer through the resistor R33, and the LCD_SCL pin is further connected to the direct current power supply +3.3V through the pull-up resistor R35; the COM0 to COM3 and SEG0 to SEG23 pins of the liquid crystal drive chip U4 respectively output the LCD_COM0 to LCD_COM3 and LCD_SEG0 to LCD_SEG23 signals to connect the COM0 to COM3 and SEG0 to SEG23 pins of the LCD liquid crystal screen U2.
[0020] The resistors are patch resistors, and the capacitors are patch capacitors.
[0021] Beneficial technical effects and advantages:
[0022] 1. The utility model fundamentally solves the major technical problems in the field of industrial wireless instrument: for the low-power instrument of one-time power supply, the utility model actively applies working load during measurement, so that the battery enters high-load state for voltage measurement, and the problem of power error caused by open-circuit voltage method due to no-load measurement is completely overcome.
[0023] 2. The technical breakthrough of the utility model lies in the original load control technology, which realizes accurate voltage measurement under the load state of the circuit without affecting the normal working power consumption of the instrument, and the modular hardware design is compatible with the existing instrument circuit architecture.
[0024] 3. The technology has great economic value in industrial Internet of Things deployment. This breakthrough not only fills the technical gap of industrial primary battery power monitoring, but also provides a new technical path for the reliability improvement of intelligent instruments. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 is the circuit block diagram of the utility model embodiment 1.
[0026] Figure 2 is the overall block diagram of the utility model embodiment 2.
[0027] Figure 3 is the display screen circuit diagram of the utility model embodiment 2. DETAILED DESCRIPTION
[0028] In order to make the above-mentioned purpose, features and advantages of the utility model more obvious and easy to understand, the specific embodiments of the utility model will be described in detail below. In the following description, a lot of specific details are set forth in order to fully understand the utility model. However, the utility model can be implemented in many other ways different from the description herein, and those skilled in the art can make similar improvements without departing from the connotation of the utility model, so the utility model is not limited by the specific implementation disclosed below.
[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the utility model belongs. The terms used in the specification of the utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the utility model.
[0030] The utility model is a WIA-PA wireless intelligent instrument battery voltage and environmental temperature detection circuit, which can be used for battery power detection of low-power equipment. When the intelligent wireless instrument works in a low-power state, its battery is approximately in an idle condition, and the existing voltage detection method will cause the voltage detection value to be too high. In addition, battery power is significantly affected by temperature, especially in the outdoor environment where the instrument is widely used, low-temperature working conditions will reduce the service life of the battery. In view of the double technical problems of load and temperature influence, the utility model proposes a detection circuit scheme.
[0031] Embodiment 1:
[0032] Figure 1The circuit composition of this utility model is described. This utility model proposes an innovative hardware circuit architecture scheme, including an analog switch U1, a voltage regulator chip U2, a temperature measurement circuit, a load resistor R3, and a battery voltage measurement circuit. The analog switch U1, the temperature measurement circuit, and the battery voltage measurement circuit are also connected to a microcontroller.
[0033] Figure 1 The analog switch U1 is used to enable the detection circuit. This circuit itself consumes more power than the average power consumption of the device during normal operation, so it is only turned on when detection is performed and turned off at other times. Figure 1 The voltage regulator chip U2 has two functions in this circuit: first, to provide a reference for the temperature acquisition circuit, and second, to serve as a power supply for the operational amplifier.
[0034] Figure 1 The temperature measurement circuit consists of voltage divider resistors (R1 and NTC), an operational amplifier, and a first RC low-pass filter circuit. The low-temperature-drift, high-precision resistor R1 and the NTC thermistor form a temperature voltage divider circuit. The NTC thermistor, also known as a negative temperature coefficient thermistor, has a resistance that decreases as temperature rises. The voltage regulator chip outputs voltage V1, and the temperature detection voltage is V2. According to the series resistor voltage divider formula, V2 = V1 * NTC / (R1 + NTC). The relationship between the NTC resistor value and temperature is determined by the characteristics of the device itself. Operational amplifier U3 acts as a voltage follower to stabilize the signal. The low-temperature-drift, high-precision resistor R6 and capacitor C1 form the first RC low-pass filter circuit to filter out interference signals.
[0035] Figure 1 R3 is the load resistor, used to provide the test current required by the system. Its resistance value is determined based on the battery type and the series / parallel connection method.
[0036] Figure 1 The battery voltage measurement circuit consists of voltage divider resistors (R4 and R5), operational amplifier U4, and a second RC low-pass filter circuit. The low-temperature drift, high-precision resistors R4 and R5 form the battery voltage divider circuit. According to the series resistor voltage divider formula, V3 = battery voltage * R5 / (R4 + R5). Operational amplifier U4 acts as a voltage follower to stabilize the signal. The low-temperature drift, high-precision resistor R7 and capacitor C2 constitute the second RC low-pass filter circuit to filter out interference signals.
[0037] Resistors R1, R6, R4, R5, and R7 are surface mount resistors, and capacitors C1 and C2 are surface mount capacitors.
[0038] The detection principle is as follows: The microcontroller controls the analog switch to close, the test circuit to open, and the voltage regulator chip outputs a reference voltage V1, simultaneously powering the operational amplifier. The NTC resistor adjusts its resistance value according to the current ambient temperature, and then outputs the voltage value at test point V2 according to the series voltage divider formula. After signal conditioning by the operational amplifier and the first RC low-pass filter circuit, the voltage is input to the microcontroller's AD pin. Under the test current provided by the load resistor R3, the battery voltage decreases. The battery voltage is divided by R4 and R5, which is the voltage at test point V3. After signal conditioning by the operational amplifier and the first RC low-pass filter circuit, the voltage is input to the microcontroller's AD pin, thus completing the battery voltage acquisition. After acquisition, the microcontroller controls the analog switch to open, causing the device to re-enter low-power mode.
[0039] Example 2:
[0040] Based on Embodiment 1, the present invention can further expand the structure of the display circuit, such as... Figure 2 The diagram shown is a block diagram of the entire system. A microcontroller serves as the main control unit to coordinate system operation; sensor expansion interfaces enable data acquisition from multiple sensor types; and the display circuit utilizes I / O pins. 2 The C-bus connection enables real-time display of acquired data and device parameters; the battery voltage and ambient temperature detection circuit is used to acquire battery status.
[0041] like Figure 3 The diagram shows the circuit diagram of the display screen. U4 in the diagram is the LCD driver chip, which is connected to I... 2 The C bus connects to the microcontroller and provides control levels for the LCD screen U2.
[0042] The display circuit includes: the VDD pin of the LCD driver chip U4 is connected to a DC power supply of +3.3V. This +3.3V power supply is filtered by capacitor C5. The VDD pin is also connected to the VLCD / SEG39 pin via resistor R36 (used to adjust the output voltage). The SDA pin of the LCD driver chip U4 is connected to the microcontroller via resistor R32 for I / O. 2 For C-type communication data transmission and reception, resistor R34 provides a pull-up signal. The SCL pin of the LCD driver chip U4 is connected to the microcontroller via resistor R33 to receive I / O signals from the microcontroller. 2 The clock signal of the C bus is pulled up by resistor R35. The COM0~COM3 and SEG0~SEG23 pins of the LCD driver chip U4 output LCD_COM0~LCD_COM3 and LCD_SEG0~LCD_SEG23 signals respectively, which are connected to the COM0~COM3 and SEG0~SEG23 pins of the LCD screen U2.
[0043] Resistors R32, R33, R34, R35, and R36 are surface mount resistors, and capacitor C5 is a surface mount capacitor.
[0044] The LCD driver chip U4 uses the HT16C22A model. The LCD screen uses 4*24 segment dynamic scanning, meaning it has 24 segment electrodes (SEG) and 4 common electrodes (COM). The displayed content is controlled by the common electrodes (COM) and segment electrodes (SEG). The segment codes are divided into 4 groups, each group containing segments 0-23. Segment codes within a group are connected to the same common electrode (COM), and the common electrodes of the 4 groups are connected to COM0-COM3 respectively. The 24 segment codes are connected to segment electrodes SEG0-SEG23 respectively, and the segment electrodes of the 4 groups are shared according to their numbers. During display, the common electrodes (COM) and segment electrodes (SEG) are scanned in a time-division manner. Taking a 1 / 3 bias voltage as an example, COM0-COM3 are activated sequentially. The selected segment's COM and SEG voltages are inverted (voltage difference = ±VCC), and the voltage difference of the unselected segment is ±1 / 3VCC (insufficient to trigger display). Each time one group is refreshed, when the LCD's refresh rate per second exceeds the human eye's recognition frame rate, all segment codes appear to be displayed simultaneously.
[0045] The detection principle is as follows: the microcontroller collects the battery voltage, calculates the remaining battery power, determines which of the five segments corresponding to the battery power level need to be lit, and transmits the lighting information through I / O. 2 The C(SDA,SCL) bus transmits data to the LCD driver chip U4, which then controls the LCD screen display.
[0046] In summary, this invention can achieve accurate detection of battery power in intelligent wireless instruments.
[0047] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the present utility model. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present utility model shall still fall within the protection scope of the present utility model.
Claims
1. A WIA-PA wireless smart meter's battery voltage and ambient temperature detection circuit, characterized in that, Includes an analog switch U1, a voltage regulator chip U2, a temperature measurement circuit, a load resistor R3, and a battery voltage measurement circuit built into the WIA-PA wireless smart meter; One end of the analog switch U1 is connected to the positive terminal of the battery of the WIA-PA wireless smart meter being tested; the other end of the analog switch U1 is connected to the voltage regulator chip U2, the load resistor R3, and the battery voltage measurement circuit. The voltage regulator chip U2 is connected to the temperature measurement circuit and the battery voltage measurement circuit, respectively. The analog switch U1, temperature measurement circuit, and battery voltage measurement circuit are also connected to the microcontroller of the WIA-PA wireless smart instrument.
2. The detection circuit for battery voltage and ambient temperature of the WIA-PA wireless smart meter according to claim 1, characterized in that, The temperature measurement circuit includes: a low-temperature drift high-precision resistor R1 and a thermistor NTC, an operational amplifier U3, and a first RC low-pass filter circuit; The voltage regulator chip U2 is grounded sequentially through a low-temperature drift high-precision resistor R1 and a thermistor NTC; the lead wire between the low-temperature drift high-precision resistor R1 and the thermistor NTC is connected to the non-inverting input terminal of the operational amplifier U3, the inverting input terminal of the operational amplifier U3 is connected to the output terminal of the operational amplifier U3, and the output terminal of the operational amplifier U3 is connected to the first RC low-pass filter circuit and then to the microcontroller of the WIA-PA wireless smart instrument.
3. The detection circuit for battery voltage and ambient temperature of the WIA-PA wireless smart meter according to claim 2, characterized in that, The first RC low-pass filter circuit includes a low-temperature drift high-precision resistor R6 and a capacitor C1; the output terminal of the operational amplifier U3 is grounded through the low-temperature drift high-precision resistor R6 and the capacitor C1, and the lead wire between the low-temperature drift high-precision resistor R6 and the capacitor C1 is connected to the microcontroller of the WIA-PA wireless smart instrument.
4. The detection circuit for battery voltage and ambient temperature of the WIA-PA wireless smart meter according to claim 1, characterized in that, The battery voltage measurement circuit includes: low-temperature drift high-precision resistors R4 and R5, operational amplifier U4, and a second RC low-pass filter circuit. The voltage regulator chip U2 is grounded sequentially through low-temperature drift high-precision resistors R4 and R5; the lead wire between the low-temperature drift high-precision resistors R4 and R5 is connected to the non-inverting input terminal of operational amplifier U4, the inverting input terminal of operational amplifier U4 is connected to the output terminal of operational amplifier U4, and the output terminal of operational amplifier U4 is connected to the second RC low-pass filter circuit and then connected to the microcontroller of WIA-PA wireless intelligent instrument.
5. The detection circuit for battery voltage and ambient temperature of the WIA-PA wireless smart meter according to claim 4, characterized in that, The second RC low-pass filter circuit includes a low-temperature drift high-precision resistor R7 and a capacitor C2; the output terminal of the operational amplifier U4 is grounded through the low-temperature drift high-precision resistor R7 and the capacitor C2, and the lead wire between the low-temperature drift high-precision resistor R7 and the capacitor C2 is connected to the microcontroller of the WIA-PA wireless smart instrument.
6. The detection circuit for battery voltage and ambient temperature of the WIA-PA wireless smart meter according to any one of claims 1 to 5, characterized in that, It also includes a display circuit: the VDD pin of the LCD driver chip U4 is connected to a DC power supply of +3.3V. The +3.3V DC power supply is filtered by capacitor C5, and the VDD pin is also connected to the VLCD / SEG39 pin through resistor R36; the SDA pin of the LCD driver chip U4 is connected to the LCD_SDA pin of the microcontroller through resistor R32, and the LCD_SDA pin is also connected to the DC power supply of +3.3V through pull-up resistor R34; the SCL pin of the LCD driver chip U4 is connected to the LCD_SCL pin of the microcontroller through resistor R33, and the LCD_SCL pin is also connected to the DC power supply of +3.3V through pull-up resistor R35; the COM0~COM3 and SEG0~SEG23 pins of the LCD driver chip U4 output LCD_COM0~LCD_COM3 and LCD_SEG0~LCD_SEG23 signals respectively, which are connected to the COM0~COM3 and SEG0~SEG23 pins of the LCD screen U2.
7. The detection circuit for battery voltage and ambient temperature of the WIA-PA wireless smart meter according to claim 6, characterized in that, The resistors and capacitors are both surface-mount resistors and surface-mount capacitors.