ABLIC launches the S-821A/1B Series of 1-cell battery protection ICs for smartphones and wearable devices

— Realizing safety and reliability for metal casing batteries through high side protection —

　ABLIC (President: Seiji Tanaka, Head Office: Minato-ku, Tokyo; hereinafter “ABLIC”), a group company of MinebeaMitsumi Inc., today launched the S-821A/1B Series of 1-cell battery protection ICs which realize high side protection (*1) using Nch MOSFETs (*2).
　1-cell lithium-ion batteries are used in a wide variety of applications, including smartphones, wearable devices, and other IT devices. There has been a growing trend towards the use of higher capacity lithium-ion batteries in recent years as smartphones have become more high performance, and this has in turn resulted in an increase in lithium-ion batteries which use metal casings as they provide more battery capacity per unit volume than conventional insulated battery types. The metal casings serve as negative electrode potential for the batteries, so protection measures are required to isolate the battery's positive side current path (high side protection) in order to achieve short-circuit protection for the battery's output terminal.
　The S-821A/1B Series launched today is a protection IC for 1-cell lithium-ion batteries with the following features: (1) protective measures which isolate the current path of the battery's positive side by placing an Nch MOSFET which carries out charge-discharge control at the positive side (high side) of the lithium-ion battery and also contributes to simpler system design by making the ground levels of the battery pack and the system the same, and a built-in, industry top-class triple boost charge pump for high Nch MOSFET drive voltage and reduced Nch MOSFET on resistance; (2) 3 levels of discharge overcurrent protection with the industry's top-class level of accuracy that can isolate abnormal current in safe areas; (3) industry top-class overcharge detection voltage accuracy of ±15mV; (4) a power-saving function which can disable discharge from the battery while reducing the protection IC current consumption to a maximum of 50nA to minimize current consumed by the battery to as close to 0 as possible; and (5) the ability to configure an overheat protection function by connecting the NTC thermistor to the thermistor connection pin (TH pin).
　These features provide benefits including strengthening safety countermeasures against battery combustion and other risks, and minimizing loss of remaining capacity during storage in order to greatly contribute to improvement of overall device safety and ease of use.
Going forward, ABLIC will continue to develop lithium-ion battery protection ICs with even greater accuracy and higher performance and to release products for applications in a wide range of fields.

(*1) High side protection: Protection of circuits and devices achieved by inserting a MOSFET between the positive battery side and a negative load and having the MOSFET turn off in the event of an irregularity to isolate the current path.
(*2) MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) are switching elements which control drain current using gate-source voltage. There are 2 types, N channel (Nch) and P channel (Pch), with Nch used for AC/DC power supplies, motor control, and DC/DC converters; and Pch used for load switches, high side switches, and other applications.

Figure Example protection circuit using the S-821A Series

Major Features

Nch high side protection
Placing an Nch MOSFET which carries out charge-discharge control on the positive side (high side) of a lithium-ion battery makes the ground levels of the battery pack and the system the same, which makes system design simpler. Because the product has a built-in 3 times boost charge pump, the Nch MOSFET drive voltage can be increased and the Nch MOSFET on resistance reduced.
High degree of safety through 3 levels of discharge overcurrent protection
The product is equipped with 3 levels of discharge overcurrent protection; discharge overcurrent 1, discharge overcurrent 2, and load short-circuiting; making it possible to isolate abnormal current in safer areas. This achieves industry top-class detection voltage accuracy and improves application device safety.
Industry top-class overcharge detection voltage accuracy of ±15mV
This product achieves an industry top-class overcharge detection voltage accuracy of ±15mV. Improving the accuracy of overcharge detection voltage makes it possible to maintain safety while maximizing battery performance.
A power-saving function which can minimize current consumption
The product is equipped with a power-saving signal input pin (PS pin) which allows for the power-saving function to be operated by an external signal which can disable discharge from the battery while reducing the protection IC current consumption to a maximum of 50nA to minimize current consumed by the battery to as close to 0 as possible.
Overheat protection function configuration through connection of an NTC thermistor
An overheat protection function can be configured by connecting an NTC thermistor to the thermistor connection pin (TH pin).
Either a 100kΩ or 470kΩ NTC thermistor can be used.

Major Specifications

・Overcharge detection voltage
3.50 to 4.80V ±15mV
・Overdischarge detection voltage
2.00 to 3.00V ±50mV
・Discharge overcurrent 1 detection voltage
-3ｍV to -100mV ±1mV (S-821A Series)
-3mV to -100mV ±0.75mV (S-821B Series)
・Discharge overcurrent 2 detection voltage
-6mV to -100mV ±3mV (S-821A Series)
-6mV to -100mV ±2mV (S-821B Series)
・Load short-circuiting detection voltage
-20mV to -100mV ±5mV (S-821A Series)
-20mV to -100mV ±4mV (S-821B Series)
・Charge overcurrent detection voltage
3ｍV to 100mV ±1mV (S-821A Series)
3mV to 100mV ±0.75mV (S-821B Series)
・Charging of 0V batteries (allowed, prohibited)
・Current consumption during operation
6.0µA typ.
・Current consumption during power-down
50nA max.
・Current consumption during power-saving
50nA max.
・Max rating
28V
・Operating temperature
-40 to 85°C
・Packages
SNT-8A 1.97×2.46×t0.5mm max.
WLP-8V 1.08×1.52×t0.35mm max.