In wearable devices, the battery is usually very small (for example, 100 mAh), and the device takes several days or even weeks without charging, so power consumption is a key design consideration. Therefore, high power conversion efficiency will be a key design element.
Stylish wrist-worn wearable devices need to be kept to a minimum size in order to maintain their cool features. This drives a high level of full device integration including power management ICs. In addition, the footprint and package of the power device should be as small as possible. In addition, wearable devices may use newer batteries, and some products may prefer non-contact charging. Wireless charging is included in these contactless charging.
Current design challenges for wearable battery
1. If the lithium battery is overcharged or the temperature is too high
It will cause a fire. The safety of the lithium battery is still worrying. At the same time, the charger should have almost all types of safety design, including overvoltage protection, overcurrent protection, and overtemperature. Protection, short-circuit protection, and low-temperature charging, even when the charger IC and solution size must be kept very small.
2. Because the battery in the wearable device is small
The needs for charging accuracy is increased, making charging these small batteries is not an easy task. The charger must be able to provide a smaller charge cut-off current. In other words, the accuracy of the charger should be higher, up to mA level. For example, in a smartphone system, the normal charging current of a 2,000 mAh battery is 1.2 A (0.6 C), and the charging cut-off current should be 1/10 to 1/20 of the normal charging current, that is, 120 mA to 60 mA. However, in the bracelet, since the battery capacity may be 100 mAh, the normal charging current will be 60 mA, and the charging cut-off current should be 6 mA to 3 mA. Charger devices that meet this requirement are difficult to find.
3. Wearable devices should have a long battery life
Often, consumers are not happy if they charge their devices every day. In the current situation where many of the best smartphones have to be recharged in a day or two, end users are clearly looking forward to improvements. The entire power management should be able to provide a highly efficient power conversion system, including regulator efficiency, and regulators and battery chargers should provide low quiescent current, low standby current, and low leakage current. Power management devices with very low leakage current and standby current as well as low quiescent current are more difficult to design.
4. The failure point of many products is the charging/signal connector
In wearable devices, the failure point of many products is the charging/signal connector because of the relationship between humidity and corrosion.
In response to these design challenges, Grepow batteries have taken corresponding measures to gradually solve the battery runtime requirements based on their cutting-edge battery production technology. We need to develop new batteries while using wearables. The new battery power density is increased in that it takes longer to convert to available power.
With the great success of applications such as smart shoes and Bluetooth headsets, wireless charging has become a wearable device, especially a replacement for smartwatches. Using wireless charging allows the wearable device to be sealed without the need for a connector. Wireless charging facilitates the promotion of easy-to-charge use cases with custom mounts. Wireless charging, so that wearable devices can be charged anywhere, and some battery designs are limited to size or special shape requirements require customization. Grepow’s small, irregularly shaped power solutions are a trend.
Wearable devices have the following 3 trends
Ultra-low quiescent current and small package power management single-chip is a trend.
The power management chip needs to integrate functions such as linear charging, LDO, and DC/DC. LDO and DC/DC power other modules, such as Bluetooth, sensors, MCUs, GPS, etc. For example, STNS01 is a power management chip with integrated path management, 3.1V/100mA ultra-low quiescent current LDO, linear charging and over-discharge protection. The entire chip size is only 3mm × 3mm, while standby power consumption is only 100 nA. Path management guarantees plug-and-play and reduces battery charge and discharge times to extend battery life. The 3.1V/100mA ultra-low quiescent current LDO can achieve 1nA quiescent current without load. The linear charging current can be set from 15mA to 200mA through the peripheral resistors, which can meet the charging current requirements of all kinds of wearable devices.
Solar charging and wireless charging will be widely used in smartwatches.
Solar charging is a good solution as the country’s energy-saving requirements and the outdoor sports of wearable device users are more. Wireless charging itself has a good sealing feature, especially for some outdoor sports or underwater sports wearable devices will be a good charging solution. Grepow batteries are also moving in this direction.
AMOLED screen driver chip, AMOLED screens will be widely used in smartwatches.
Compared with traditional LCD screens, AMOLED screens have higher brightness, thinner, better resolution and more power saving. STOD32W is a driver chip that can meet different size requirements.
In terms of wearable device power, Grepow has many solutions, including PMIC (Power Management IC), linear charger, and wireless charging solution, display driver chip. For example, power management chips for linear charging and over-discharge protection. LDO with the ultra-low quiescent current. In the state of no load, its quiescent current is only 1uA, and in the non-operating state, it is only 1nA.
In terms of power supply design of wearable devices, different chip platform manufacturers will launch their own different functions of wearable device solutions. Designing a power management chip suitable for different manufacturers’ platforms will be a challenge, as well as ultra-low power consumption and small size. In addition, there is currently no wireless charging for different size requirements.
Grepow wearable battery advantages
It meets power management low power consumption, small size, and low cost. The wearable device itself is a broad concept covering a wide range of product forms, including traditional portable devices (such as watches), as well as various types of sensors in non-device wearable products that become wearable devices, such as clothing shoes. Cap and so on. The functions provided by wearable devices are currently concentrated in tools (such as GPS, environment, etc.) and sports and health (such as step, sleep, heart rate, body fat analysis, and blood oxygen).
The current status of wearable devices has the following characteristics: the entire smart wearable device market is still in the start-up phase, such as the richness of functions, the practicality of the results and the service characteristics, etc., which need further improvement; many functions and performance implementations are also needed. Further technological breakthroughs, such as power consumption, size, and ease of use; more and more companies are developing wearable devices, and almost all brands of mobile phone manufacturers are investing in some form; more and more IDH (Independent Design Company) is involved in the development of related technologies, especially in software data processing.
From the perspective of the trend of wearable devices, the following points may be concerned by the industry: the macro view will be a new growth point in the electronic equipment market; the continuous increase and improvement of health care functions, and even some performance arrivals Or through medical-grade application standards; high-integration, small-volume, low-power, and low-cost sensor hardware will become more critical in future wearable device development; background data analysis and processing and feedback to end users will It is the only way to maintain the user’s continued use.
Currently, Grepow has introduced a total solution for a variety of wearable batteries. The wearable device integrates a battery-type temperature sensor (for detecting the temperature of the body surface), a light sensor (for detecting the heart rate), and the like, and other wearable device batteries. For the endurance of the product, the life of the Grepow product depends on the specific application design.