A low power consumption electronic scale

Abstract

The present invention relates to a low-power electronic scale. When the PGBA module works in the first state, it processes the initial electrical signal to obtain a first processing signal, and transmits the first processing signal to the first ADC module; the first ADC module detects and obtains a first pressure value according to the first processing signal, and transmits a first control signal to the controller when the first pressure value is greater than a first threshold value; after receiving the first control signal, the controller controls the PGBA to work in the second state, and controls the first ADC to be turned off and the second ADC to work; when the PGBA module works in the second state, it processes the initial electrical signal to obtain a second processing signal, and transmits the second processing signal to the second ADC module; the second ADC module obtains a weighing result according to the second processing signal. The present invention can greatly reduce the power consumption of the electronic scale.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a low-power electronic scale. Background Art

[0002] There is a wide demand for electronic scales, including body scales, body fat scales, table scales, kitchen scales, and so on. More and more electronic scale solutions are powered directly by batteries, so the demand for low power consumption is becoming increasingly strong. According to the working state of the electronic scale, its power consumption is usually divided into three parts: sleep standby power consumption, periodic weighing detection power consumption, and high-precision measurement power consumption. For the body scale, the high-precision measurement working state time usually accounts for a small proportion, so the average power consumption contributed by this state is very small; the sleep standby power consumption is also relatively small. In order to detect whether there is an object on the scale, the electronic scale needs to be awakened periodically (such as once every 1 second) for detection. Each wake-up detection consumes a certain amount of power. Although the energy each time is not much, due to the large number of wake-ups, the periodic weighing detection power consumption accounts for the majority of the electronic scale's power consumption. Therefore, the periodic weighing detection power consumption is the bottleneck for further reducing the power consumption of the electronic scale.

[0003] like Figure 1 As shown, in the prior art solution, the high-precision measurement technology is implemented by a low-noise programmable gain amplifier (PGA) and a low-speed high-precision Sigma Delta analog-to-digital converter (ΣΔADC); the on-scale detection solution reuses this circuit, but the ΣΔADC operates in a low-precision fast mode. However, limited by the technical characteristics of the ΣΔADC, the increase in output rate is accompanied by a rapid decline in accuracy. Therefore, in order to meet the accuracy requirements of the on-scale detection, the output rate of the ΣΔADC is generally not faster than 5ksps. Due to the low output rate of the ADC, the ADC detection takes a long time, and each detection consumes more energy. Therefore, the limitation of the ADC's output rate hinders further reduction of power consumption. Therefore, it is necessary to invent a new technical solution to optimize system power consumption. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a low-power electronic scale.

[0005] The present invention provides a low-power electronic scale, which at least includes: a pressure sensor, a PGBA module, a first ADC module, a second ADC module, and at least one controller; the conversion rate of the first ADC module is higher than the conversion rate of the second ADC module; the pressure sensor converts the collected pressure signal into an initial electrical signal and transmits it to the PGBA module; the controller controls the PGBA module to work in a first state, and controls the first ADC module to work and the second ADC module to be turned off; when the PGBA module works in the first state, the initial electrical signal is processed to obtain a first processed signal, and the first processed signal is transmitted to the first ADC module; the first ADC module detects and obtains a first pressure value according to the first processed signal, and transmits a first control signal to the controller when the first pressure value is greater than a first threshold; after receiving the first control signal, the controller controls the PGBA to work in a second state, and controls the first ADC to be turned off and the second ADC to work; the gain and bandwidth of the second state are both lower than the gain and bandwidth of the first state; when the PGBA module works in the second state, the initial electrical signal is processed to obtain a second processed signal, and the second processed signal is transmitted to the second ADC module; the second ADC module obtains a weighing result according to the second processed signal.

[0006] Furthermore, the first ADC module is a successive approximation ADC or a fully parallel ADC.

[0007] Furthermore, the second ADC module is a Sigma Delta ADC.

[0008] Furthermore, the second ADC module obtains a weighing result according to the second processed signal and then displays the weighing result on the display device.

[0009] Furthermore, the electronic scale only displays the weight results greater than the second threshold value on the display device.

[0010] Furthermore, the PGBA module includes a first-stage high-impedance input differential amplifier with controllable gain, a second-stage anti-aliasing low-pass filter with controllable bandwidth, and an output-stage high-impedance input buffer.

[0011] Furthermore, the gain of the PGBA module is not less than 300 times.

[0012] Furthermore, the electronic scale includes a reset state and a high-speed weighing detection mode; after the electronic scale enters the reset state, the controller controls the electronic scale to enter the high-speed weighing detection mode; in the high-speed weighing detection mode, the PGBA module operates in a first state, the first ADC module works and the second ADC module is turned off; the reset state is triggered manually or by a timer or a power-on reset circuit (PowerOnReset).

[0013] Furthermore, the electronic scale includes a sleep state, when the electronic scale is in the sleep state, at least the first ADC module does not work; the electronic scale enters the sleep state when not weighing; after entering the sleep state for a first time, the electronic scale automatically wakes up and enters the high-speed weighing detection mode.

[0014] In the technical solution provided by the present invention, different working modes of PGBA are used in conjunction with two different ADCs. When performing on-scale detection, a medium- and high-speed ADC is used to improve the detection efficiency, thereby achieving a technical effect of power saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 , the core circuit of traditional electronic scale solution;

[0016] Figure 2 , the low power consumption electronic scale solution of the present invention;

[0017] Figure 3 , the optimal low power consumption electronic scale circuit solution;

[0018] Figure 4 , the electronic scale solution control state switching diagram of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed by the present invention, some changes in design, manufacturing or production based on the technical content disclosed by the present invention are just conventional technical means, and should not be understood as insufficient content disclosed by the present invention.

[0021] Reference to "embodiments" in the present invention means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present invention may be combined with other embodiments without conflict.

[0022] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the common meanings understood by persons with ordinary skills in the technical field to which the present invention belongs. The words "a", "an", "a", "the" and the like used in the present invention do not indicate quantity restrictions and may indicate the singular or plural.

[0023] like Figure 2 As shown, the electronic scale of this embodiment at least includes: a pressure sensor, a PGBA module, a first ADC module, a second ADC module, and at least one controller. In order to realize the complete electronic scale function, it is obvious that the electronic scale should also include other on-chip general circuits or modules, such as an oscillator, a linear regulator, an LCD display, etc., but most of these modules are conventional modules of ordinary electronic scales, which are not the key functions of the solution of the present invention. Those skilled in the art can make conventional selections as needed, and the present invention only describes in detail the improved parts of the present invention.

[0024] The low-noise programmable amplifier is a chopper-type low-noise amplifier with controllable gain and controllable bandwidth, hereinafter referred to as a low-noise PGBA (Programmable Gain and Bandwidth Amplifier). The low-noise PGA used in the traditional solution has a controllable gain but does not have a controllable bandwidth function. In order to improve the effect of on-scale detection, the solution of the present invention needs to have a controllable bandwidth function at the same time; therefore, the PGBA is used in the solution of the present invention instead of the traditional PGA.

[0025] The gain and bandwidth of PGBA are adjustable. When PGBA is at high gain and bandwidth, it can detect a wider range of signal changes, so that the response speed of PGBA is sufficient to meet the conversion rate and accuracy requirements of the first ADC; when PGBA is at low gain and bandwidth, low bandwidth can be used for anti-aliasing filtering to filter out external noise signals and high-frequency noise of PGBA itself, thereby meeting the high-precision requirements of the second ADC. In addition, the present invention has a high gain option of more than 300 times, which is used to reduce the accuracy requirements of high-speed weighing detection ADC.

[0026] The pressure sensor is used to sense pressure and convert it into an electrical signal. The signal strength depends on the applied pressure. The pressure sensor converts the collected pressure signal into an initial electrical signal and transmits it to the PGBA module. Since the initial electrical signal is relatively weak, the PGBA module needs to amplify it within a certain bandwidth.

[0027] like Figure 2 As shown, the first ADC module is used for weighing detection, and the second ADC module is used for accurate measurement; since weighing detection only needs to know whether there is a heavy object on the scale, the accuracy requirement is low, and in order to save power, the detection rate can be increased and the duration of the detection can be reduced. Therefore, the first ADC can be a medium-to-high-speed ADC; preferably, the conversion rate of the first ADC needs to be above 100ksps, the effective resolution needs to be above 10bit, and the power consumption does not exceed 1mA. You can choose a successive approximation (SAR) or a full parallel (Flash) ADC.

[0028] The second ADC module is used to accurately weigh the weight of the object, so the second ADC can be a high-precision ΣΔADC for converting high-precision sensor signals; preferably, a ΣΔADC with a conversion rate of more than 10 sps, an effective resolution of more than 18 bits, and a power consumption of no more than 2 mA can be selected.

[0029] In summary, in order to achieve the purpose of power saving and accurate measurement, the conversion rate of the first ADC module should be higher than the conversion rate of the second ADC module; the power consumption of the first ADC module is preferably but not necessarily lower than the power consumption of the second ADC module.

[0030] In specific operation, in order to perform fast weighing detection, the controller controls the PGBA module to work in the first state, which is a high-gain, high-bandwidth mode, and controls the first ADC module to work and the second ADC module to shut down. Figure 2As can be seen from the schematic diagram, when the PGBA module works in the first state, it processes the initial electrical signal to obtain the first processed signal, and transmits the first processed signal to the first ADC module; at this time, the PGBA processes the high-gain, high-bandwidth mode, amplifies the tiny signal in a wider range, facilitates the rapid detection of the first ADC module, reduces the detection time of the first ADC module, and achieves the purpose of power saving. At this time, the second ADC module is turned off to further reduce power consumption.

[0031] When the first ADC module detects a first pressure value based on the first processed signal, a first control signal is transmitted to the controller when the first pressure value is greater than the first threshold. When the first pressure value is greater than the first threshold, it means that an object is detected on the scale. The first threshold can be set according to the type and accuracy of the electronic scale. For example, the first threshold of the human electronic scale can be set to 5kg. Only when a pressure exceeding 5kg is detected, it is considered that someone is standing on the electronic scale; if the electronic scale is a kitchen scale, the accuracy requirement is high, and the first threshold can be set to a smaller value, such as 5g. When the first ADC module detects that an object is placed on the electronic scale, its task is completed; the first ADC module is connected to the control module, and the first ADC module transmits the first control signal detected that an object is on the scale to the controller.

[0032] After receiving the first control signal, the controller controls the PGBA to work in the second state, and controls the first ADC to be turned off and the second ADC to work. When an object is weighed, the first ADC can be turned off to save power. At this time, the PGBA can be adjusted to a low gain and low bandwidth state. The low gain and low bandwidth PGBA signal has low distortion, which can facilitate the second ADC to perform accurate measurements. The PGBA continuously processes the signal of the pressure sensor and transmits the processing result to the second ADC. The second ADC analyzes the signal to obtain the precise weight of the object. After obtaining the precise weight of the object, the result can be output, such as through a display device such as an LED. In addition, if the actual object is lower than the weighing threshold, it means that the high-speed weighing detection judgment is wrong, such as accidental touch, accidental circuit noise, etc. Therefore, further, only the weighing results greater than the second threshold can be displayed on the display device.

[0033] Based on the above implementation mode, preferably, Figure 3As shown, the PGBA includes a high-impedance input differential amplifier with controllable gain in the first stage, an anti-aliasing low-pass filter with controllable bandwidth in the second stage, and a buffer with high-impedance input in the output stage. The gain is controlled by configuring the ratio of the feedback resistor network in the first stage. The maximum gain reaches more than 384 times. With the 12-bit SAR ADC, the resolution of the input signal that can be detected can reach 2uV, which meets the requirements of using common sensors to identify the 5kg weighing threshold. The bandwidth is controlled by configuring the resistance and capacitance of the low-pass filter. The high-impedance buffer is used to drive the ADC of the subsequent stage. Compared with the commonly used instrumentation amplifier, the output stage of the PGBA used is two high-input impedance buffers. The high input impedance characteristic is conducive to simplifying the controllable bandwidth filter design of the previous stage and is also conducive to driving the ADC of the subsequent stage.

[0034] Based on the above embodiments, in order to further solve the workflow of the present invention, as follows Figure 4 As shown, the working process of the electronic scale of the present invention can be divided into the following states:

[0035] State 1, reset state. After the reset is completed, the PGBA high gain and high bandwidth mode is enabled, and the first ADC is enabled to convert the output signal of the PGBA, and the system enters state 2. The reset state can be triggered manually, such as setting a reset button on the electronic scale. When the electronic scale is abnormal, the user can manually reset it. The reset state can also be triggered by a timer. For example, if the system detects that the working state of the electronic scale has been processing a certain state for a long time, it means that the electronic scale is not in a normal state, and the electronic scale can be forcibly reset. The reset state can also be triggered by a power-on reset circuit. If the circuit detects that the power supply voltage is lower than the voltage at which the digital circuit can work normally, the electronic scale can be forcibly reset.

[0036] State 2, high-speed weighing detection mode. The digital processing module waits and analyzes the output data of the first ADC to determine whether there is an object that exceeds the weighing threshold. If it is determined that no object is put in, the corresponding module is turned off and the system enters state 3; if it is determined that an object is put in, the PGBA is enabled to adapt to the gain and low bandwidth mode, the first ADC is turned off, the second ADC is enabled and the output signal of the PGBA is converted, and the system enters state 4. The high-speed weighing detection mode is also the mode when the PGBA module in the aforementioned embodiment works in the first state.

[0037] State 3, periodic sleep state. After a certain period of sleep, the system is automatically awakened, the controller enables the PGBA high-bandwidth mode, and enables the first ADC, that is, enters state 2. In the sleep state, power-consuming modules can be turned off, such as the first ADC and the second ADC to reduce the overall energy consumption of the system. Of course, other modules can also be turned off at the same time, such as PGBA, LED and other modules. The technicians in this field can choose which modules to turn off.

[0038] State 4, high-precision measurement mode. The digital processing module waits and analyzes the conversion output of the second ADC to convert the actual weight of the object. If the actual object is lower than the weighing threshold, it means that the high-speed weighing detection is wrong (such as accidental touch, accidental circuit noise, etc., the probability of this happening is very low), and the corresponding module is turned off to enter state 3; if the actual object is higher than or equal to the weighing threshold, the measurement module is turned off to enter state 5. The high-precision measurement mode is the mode of controlling the PGBA to work in the second state as described in the aforementioned embodiment.

[0039] State 5, result display. Display the measurement results on LCD or other display modules. After the set display time, turn off the corresponding module and enter state 3.

[0040] It can be seen from the above process that by changing the working state of PGBA and cooperating with the first medium and high speed ADC, the speed of weighing detection can be increased, thereby reducing the power consumption of periodic weighing detection and achieving the overall power saving of the electronic scale.

[0041] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low power consumption electronic scale, characterized in that: The electronic scale comprises at least: a pressure sensor, a PGBA module, a first ADC module, a second ADC module, and at least one controller; The conversion rate of the first ADC module is higher than the conversion rate of the second ADC module; The pressure sensor converts the collected pressure signal into an initial electrical signal and transmits it to the PGBA module; The controller controls the PGBA module to operate in a first state, and controls the first ADC module to operate and the second ADC module to shut down; When the PGBA module operates in the first state, the initial electrical signal is processed to obtain a first processed signal, and the first processed signal is transmitted to the first ADC module; The first ADC module detects and obtains a first pressure value according to the first processed signal, and transmits a first control signal to the controller when the first pressure value is greater than a first threshold; After receiving the first control signal, the controller controls the PGBA to work in the second state, and controls the first ADC to be turned off and the second ADC to work; The gain and bandwidth of the second state are lower than the gain and bandwidth of the first state; When the PGBA module operates in the second state, the initial electrical signal is processed to obtain a second processed signal, and the second processed signal is transmitted to the second ADC module; The second ADC module obtains a weighing result according to the second processed signal; The PGBA module includes a first-stage high-impedance input differential amplifier with controllable gain, a second-stage anti-aliasing low-pass filter with controllable bandwidth, and an output-stage high-impedance input buffer.

2. The low power consumption electronic scale according to claim 1, characterized in that: The first ADC module is a successive approximation ADC or a fully parallel ADC.

3. The low power consumption electronic scale according to claim 1, characterized in that: The second ADC module is a Sigma Delta ADC.

4. The low power consumption electronic scale according to claim 1, characterized in that: The electronic scale includes a display device, and the second ADC module obtains a weighing result according to the second processed signal and then displays the weighing result on the display device.

5. The low power consumption electronic scale according to claim 4, characterized in that: The electronic scale only displays the weighing result greater than the second threshold on the display device.

6. The low power consumption electronic scale according to claim 5, characterized in that: The gain of the PGBA module is not less than 300 times.

7. The low power consumption electronic scale according to claim 1, characterized in that: The electronic scale includes a reset state and a high-speed weighing detection mode; after the electronic scale enters the reset state, the controller controls the electronic scale to enter the high-speed weighing detection mode; in the high-speed weighing detection mode, the PGBA module operates in a first state, the first ADC module works and the second ADC module is turned off; the reset state is triggered manually or by a timer or a power-on reset circuit.

8. The low power consumption electronic scale according to claim 7, characterized in that: The electronic scale includes a sleep state, when the electronic scale is in the sleep state, at least the first ADC module does not work; the electronic scale enters the sleep state when not weighing; after entering the sleep state for a first time, the electronic scale automatically wakes up and enters the high-speed weighing detection mode.

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