SIGLENT’s testing solutions for wearables

In recent years, wearable devices have gradually become a hot word. From smart bracelets to fitness wristbands to VR glasses, these products present the most cutting-edge technology in the digital intelligence era before us. Its development dates back to 1975, the year Hamilton Watch introduced the Pulsar calculator watch. But today, the technical challenges of wearable devices have not been overcome for a long time, and the unfriendly user experience caused by poor battery life has not been substantially improved.

SIGLENT’s testing solutions for wearables

Hamilton Watch launched the Pulsar calculator watch, and then US President Gerald Ford wanted one

Can we continue to optimize the design?

As we all know, battery life is mainly determined by two factors, namely battery capacity and device power consumption. Unfortunately, until new battery technologies or materials emerge, there is very limited room for improvement in battery capacity. Open source and reduce expenditure, then this “source” cannot be further explored in a short time, so the pressure falls on how to reduce power consumption.

Most wearable manufacturers focus more on this. .

For most R&D, the correct thinking for low-power design is:

First of all, select low-power devices (including modules and main control ICs, many products have to meet the requirements of small size under the premise of low power consumption due to the limitation of board area)

Then, the software algorithm is optimized.

Finally, the power consumption test is also a gatekeeper.

Compared with other Electronic products, wearable devices have stricter control over single component and system power consumption. Almost all internal hardware structures must be accurately measured before the product leaves the factory, such as chips, sensors, wireless modules, etc. The low power consumption measurement of smart wearable devices mainly measures the power consumption of the device in the standby sleep state. The ultra-long standby time of the device, the current value as low as μA level, and the extremely harsh power supply conditions are all difficult to test, so the related industry development It is very important that the developer can design a low-power system and test equipment.

Low-power test and measurement equipment needs to meet the following requirements:

High accuracy: high measurement accuracy and power supply accuracy in different ranges

Wide dynamic range: Accurately capture the peak value of the measured current pulse

High stability: ensure stable supply voltage and adapt to transient changes

High adaptability: Graphical operation interface, clearly and vividly present the state of signal changes, and analyze signals accurately and in real time

Steps:

Generally, products with wireless communication will also emit pulse current in standby conditions, so the low power consumption of such products also includes pulse current components. Except for the bright screen measurement, other measurement items are after entering a certain condition state,The average current obtained in about 10 minutes.

Device connection:

Use SPD3303X DC stabilized power supply to output 4V voltage at constant voltage, with low output voltage ripple, no overshoot and fast response, accurately supply power to smart watches, and connect SDM3065X six-and-a-half-digit multimeter in series in the power supply circuit to measure the performance of smart watches in each current in a standby condition. Below is the test device connection diagram.

SIGLENT’s testing solutions for wearables

The low power consumption measurement of wearable devices mainly tests the standby part. We selected the following typical standby scenarios for testing.

During the test, we used the EasyDMM host computer software unique to SDM3065X, which integrates the functions of data analysis and saving, and a graphical Display operation interface. Compared with the operation on the multimeter side, the operation on the PC side is more practical and convenient.

SIGLENT’s testing solutions for wearables

1. The first thing to measure is the idle screen standby in the 4GLTE networked state. This state occupies more than 70% of the battery life of the entire watch, so this test is very important.

SIGLENT’s testing solutions for wearables

We used the measurement statistics function of the multimeter when we were measuring for a long time when the screen was on standby. From the statistical table below, we can directly see that the average current is 12.952mA, the peak value is 431.784mA, and the minimum value is 3.702mA. At the same time, choose to open the trend graph to see the current change in the entire 10-minute measurement interval, and you can clearly observe the abnormal current that occasionally jumps out.

SIGLENT’s testing solutions for wearables

4GLTE network information screen standby current test chart

After the measurement, we select the histogram Display mode for the data, analyze the current measured in the entire standby interval, and output the percentage of the current value. It can be seen that the data from 3.702 to 40mA accounts for 96.86% of the 10-minute measurement data. This feature makes data analysis very convenient.

2. The next step is to measure the power consumption of the screen under the WIFI network

SIGLENT’s testing solutions for wearables

SIGLENT’s testing solutions for wearables

Screen current when connected to WiFi

The current when the WIFI screen is connected to standby is about 11mA, which is almost 1mA smaller than that of the screen under 4G network. This is because 4G networks need to transmit and receive signals from base stations. Due to the large radiation range and high construction cost, the base stations are built in open areas such as the top of the mountain, and the mobile phone receives signals from the top of the mountain, which naturally consumes more power. If the signal is not good, it will consume more power to transmit a stronger signal to search the network. And WiFi is much easier, transmitting signals through wireless routing. To achieve close coverage in a fixed environment, the signal fluctuation is not large, and the mobile phone consumes less power in a stable state!

3. Then the standby power consumption measurement under VoLTE network

SIGLENT’s testing solutions for wearables

SIGLENT’s testing solutions for wearables

Power consumption measurement in Volte mode

VoLTE is a high-definition voice call mode under the 4G network, and VoLTE is an IMS-based voice service. It is an IP data transmission technology that does not require 2G/3G network, and all services are carried on the 4G network, which can realize the unification of data and voice services under the same network. The 4G network not only provides high-speed data services, but also provides high-quality audio and video calls. The latter requires VoLTE technology to achieve. To put it bluntly, VoLTE is actually a 4G phone. We measured and found that the standby current in this mode and the current in the 4G network standby mode are very small, only a few hundred microamps.

4. The last thing we do is the deep sleep measurement. The current of the smart watch is measured without the SIM card inserted, and the main measurement is the minimum standby current.

SIGLENT’s testing solutions for wearables

SIGLENT’s testing solutions for wearables

Residual current measurement during sleep phase

It can be seen that the average current measured in the sleep phase is 9.304mA, which is 3mA less than the standby mode in 4G network and Volte mode, and 2mA less than the standby mode in WIFI mode. In this function, we generally focus on low current. We can also intuitively see that the minimum current is 3.365mA in the statistical function. This statistical function does help a lot in data analysis.

For the above typical scenarios, we have measured multiple sets of data, which need to be saved and analyzed. The data saving function on the SDM3065X host computer software can save the measurement data in the computer, especially for long-term deep sleep measurement, up to 1 million sets of data can be saved. At the same time, without using the host computer, the multimeter end also has 1GB of storage space to support saving data in the internal memory. Of course, an external U disk is also possible.

SIGLENT’s testing solutions for wearables

SIGLENT’s testing solutions for wearables

Data save picture

able to pass”Graph” button to perform trend graph and histogram analysis on any saved data, and you can also use “Export” button to export data to CSV file format, which are two very useful functions.

Through the above measurements, the power consumption of the smart watch in each standby situation can be obtained.

SIGLENT’s testing solutions for wearables

The above is the actual power consumption of the smart wearable watch we measured in different standby states, all of which meet the design requirements. The high-precision SDM3065X 6.5-digit multimeter and the SPD3303X programmable linear DC power supply can improve the reliability of the test results and facilitate wearable device design engineers to make appropriate optimization solutions.

Nowadays, smart wearable devices are more and more sought after by everyone, and with it, the public has higher and higher requirements for the endurance of wearable devices. Under the current trend that the functions of smart wearable devices tend to be unified, battery life almost determines the vitality of products, so major smart wearable device manufacturers have spared no effort in battery life. Dingyang Technology’s high-precision testing solutions for smart wearable devices will help smart wearable device manufacturers to accurately understand the power consumption of products under various usage conditions, so as to formulate corresponding power consumption optimization solutions. In the smart wearable product industry maintain strong competitiveness.

For more technical documents, please pay attention to Dingyang Hardware Think Tank.

SIGLENT’s testing solutions for wearables

For more information about Dingyang Technology, please pay attention to Dingyang Technology’s public account:

About Dingyang

SIGLENT is a company specializing in general electronic test and measurement instruments and related solutions.

Since the launch of the first digital oscilloscope product in 2005, Dingyang Technology has been the fastest growing digital oscilloscope manufacturer in the world for more than 10 years. After years of development, Dingyang products have expanded to digital oscilloscopes, handheld oscilloscopes, function/arbitrary waveform generators, spectrum analyzers, desktop multimeters, DC power supplies and other general-purpose test and measurement instruments. In 2007, Dingyang established a global strategic partnership with LeCroy, a leader in high-end oscilloscopes. In 2011, Dingyang developed into a leading digital oscilloscope manufacturer in China. In 2014, Dingyang released China’s first smart oscilloscope SDS3000 series, leading the trend of “one per hand” laboratory using oscilloscopes to transition from functional oscilloscopes to smart oscilloscopes. In 2017, Dingyang released SDG6000X series pulse/arbitrary waveform generators and SDG6000X-E series function/arbitrary waveform generators, which broke the monopoly of the industry and broke through domestic technical bottlenecks in many parameters. The output bandwidth is up to 500MHz. At present, Dingyang has established branches in Cleveland, USA and Hamburg, Germany, and its products are exported to more than 70 countries around the world. SIGLENT is gradually becoming a world-renowned brand of testing and measuring instruments.

The Links:   KCS057QV1AJ-G20 VI-2W1-EY

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