9/30/2019
Techanalye Co.,Ltd.
This time, I introduce the S-82B1B series, Lithium-ion Battery Protection IC with Power-saving function. ABLIC provides a wide range of Battery Protection ICs and the S-82B1B focuses on the small battery and the Power-saving function is added.
The Battery Protection ICs monitor batteries and detect overcharge, over discharge and overcurrent and protect them. The S-82B1B series has a new PS pin (input pin for power-saving signal) shown in yellow in the Fig.1. By inputting a signal to this pin, Power-saving function is started. When Power-saving function is enabled, discharge from the battery pack is stopped, current consumption of the protection circuit of the S-82B1B series is reduced to 50nA max. and current consumption of the battery becomes nearly zero.
Then, why do we need this Power-saving function?
The most important role of the feature is protecting the battery from deep discharge (See Fig.2). Deep discharge is the mode that a battery is discharged beyond the discharge cutoff voltage, the minimum voltage it can be discharged safely, and reaches very low voltage less than 1V. When the Battery Protection IC detects over discharge, it stops the discharge before any further discharge occurs. But due to leakage current of the protection circuit and self-discharge of the battery, the potential has gradually decreased. When it reaches deep discharge, it is deteriorated and if you try to recharge it, it will be in danger of an accident such as exotherm and ignition. Therefore, many products are designed to prohibit battery charge once it run down to deep discharge. However, because of this safety design, sometimes a problem happens that the battery in the product reaches deep discharge after shipping and the product cannot be charged and doesn't work at all before it is purchased.
- Reduce current consumption of the protection circuit and the product almost zero.
- No battery power consumption when instrument is off in shelf-life.
- Protect battery from deep discharge (Extend the time of the battery remaining amount to reach 0 as long as possible.)
Fig. 2 The role of the Power-saving function
You might think that it can be solved by shipping with full charged battery to avoid voltage less than discharge cutoff voltage (most of the products show battery power 0 before its battery becomes this situation). But since 2016, the guide to the lithium battery air transport regulations is revised and it requires shipping products to be at a state of charge no more than 30%. So, especially in the product which equips small and low power battery, it is possible to be deep discharge during stored in warehouses or stores after shipped by air and never work again (see Fig.3).
To avoid this problem, it is effective to prolong the battery run time to power 0 before deep discharge.
Fig.4 shows the time of the small and low power battery its capacity is 25mAh from 30% charged (7.5mAh) to power 0. The result with the S-82B1B series is 150,000 hours (more than 17 years) and it achieves an overwhelming extended time while competitive product is 2,500 hours (about 3.5 months) and ABLIC's S-8240A series which has no Power-saving function is 5,000 hours (about 7 months).
Using the Power-saving function of the S-82B1B series, it is possible to extend the small battery run time going down to power 0 more than a dozen years. The Battery Protection IC S-82B1B series is, as it were, the savior who protects the products with small battery against problems caused by deep discharging.
In the next article, I will report more about the problems occurred by deep discharge.
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Related Information
- [Application] ICs ideal for Smart Watches and Smart Bands
- [Product information/Datasheet] Battery Protection IC with Power-saving Function for 1-Cell Pack S-82B1B