Renesas Electronics Extends Battery Life for Tablets and Notebook PCs with High-Precision Battery Fuel Gauge IC
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Renesas Electronics Extends Battery Life for Tablets and Notebook PCs with High-Precision Battery Fuel Gauge IC

IC Combines Remaining Battery Capacity Detection and Charging Functionality on a Single Chip, Enabling Charging Control Tailored to the Battery Characteristics

SANTA CLARA, Calif. — (BUSINESS WIRE) — July 23, 2015 — Renesas Electronics Corporation (TSE:6723), a premier supplier of advanced semiconductor solutions, today announced its new lithium-ion (Li-ion) battery fuel gauge IC, the RAJ240500, designed to extend battery life for connected mobile devices such as tablets, notebook PCs and smartphones. Leveraging its extensive design expertise in fuel gauge and charging ICs for mobile devices, Renesas has developed a single-chip device that delivers high-precision battery charge measurement and control that reduces the burden on the battery and contributes to longer device battery life. In addition, in order to facilitate the development using this product, Renesas is offering sample codes and evaluation tools as solutions, including the reference card circuit diagram.

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Battery life has become an important decision factor for consumers purchasing mobile devices such as tablets and notebook PCs, creating strong demand for efficient battery charging and control technologies. In the past, battery control circuits had to treat the battery as being at ‘zero charge’ even when there was still some capacity remaining, and as ‘fully charged’ even when charging was not yet complete, in order to assure the safety of the battery. The resulting design challenge was a shorter battery life relative to charge capacity.

Battery degradation is another challenge. Li-ion batteries suffer from reduced capacity after repeated charge-discharge cycles due to deterioration of the materials they are made from. Repeated control when not fully charged or fully discharged reduces the number of charge-discharge cycles over the service life of the battery, which for many devices is equivalent to the service life of the device. To extend the usable battery duration and enable longer battery life while accounting for typical wear-and-tear changes, designers require charge control that decreases the burden placed on the battery and that reduces degradation as far as possible.

About the RAJ240500 fuel gauge IC:

The new Renesas fuel gauge IC addresses these design challenges with a two-in-one solution that combines advanced algorithmic fuel gauge IC functionality with charger IC functionality in a single device. Integrating battery charge measurement, or fuel gauge, and charging functionality on a single chip allows designers to achieve high-precision charging control that closely matches the battery status. This enables them to utilize the battery’s capacity to the fullest extent to maximize the battery life per charge as well as reduce the battery load and degradation rate to extend service life.

Additional feature highlights include:

Pricing and Availability

Samples of the RAJ240500 are now available, priced at US$10 per unit. Mass production of the RAJ240500 is scheduled to begin in October 2015 and is expected to reach a volume of 10,000,000 units per month in October 2016. (Pricing and availability are subject to change without notice.)

(Note 1) NVDC (Narrow VDC) is a high-efficiency power architecture provided by Intel Corporation ®. By limiting the input voltage range of the system load, it aims to improve the power efficiency of the system.

(Note 2) Dynamic Battery Power Technology (DBPT) is an advanced system operation technology provided by Intel Corporation® and utilizes battery condition information to maximize system performance. To maximize the system performance, this technology leverages information such as the remaining battery capacity and the battery’s characteristics.

About Renesas Electronics Corporation

Renesas Electronics Corporation (TSE: 6723), the world’s number one supplier of microcontrollers, is a premier supplier of advanced semiconductor solutions including microcontrollers, SoC solutions and a broad-range of analog and power devices. Business operations began as Renesas Electronics in April 2010 through the integration of NEC Electronics Corporation (TSE:6723) and Renesas Technology Corp., with operations spanning research, development, design and manufacturing for a wide range of applications. Headquartered in Japan, Renesas Electronics has subsidiaries in 20 countries worldwide. More information can be found at

(Remarks) All registered trademarks or trademarks are the property of their respective owners.

Product Specifications of the RAJ240500

Product name   RAJ240500 DNP
Part name   RAJ240500 A20DNP
Supply voltage   VCC_FG: 2.0 V - 25.0 V

VCC_CHG: 4.0 V - 25.0 V




-20 - +85 °C


CPU Core   RL78
Number of cells supported   1 - 3 cells
Built-in memory   CPU: Flash (Code:128 KB + Data: 4 KB)/ SRAM(5.5 KB)
Communication   UART、I2C-BUS(SMBus)
Voltmeter   15 bit sigma-delta AD converter
Ammeter   18 bit sigma-delta AD converter


  Supporting NVDC and JEITA guideline
FET driver   Built-in High side N channel FET driver, supporting pre-charge function

All registered trademarks or trademarks are the property of their respective owners.


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