Date: 12/11/2012

IC-pair from Toshiba detects charge in electric/hybrid car batteries

The electric/hybrid (ev) car requires proper monitoring of battery charge level to predict the exact mileage the vehicle can give at any given point of time. To do that Toshiba has launched a chip-set to monitor lithium-ion battery used in automotives. The battery monitor IC can manage up to 16 cells per 1 IC.

The chipset includes battery monitor IC (TB9141FG), and microcontroller (TMPM358FDTFG) to detect the remaining charge level and equalizes it among cells (cell balancing) and can also detect abnormal battery status.

The TB9141FG uses 96V high-voltage process and realizes monitoring of a 16-cell Li-ion battery with a single IC. The TB9141FG is able to communicate in a noisy environment, using differential signaling in a daisy chain communication link between two or more TB9141FGs, an important feature for automotive applications.

The TMPM358FDTFG is a 32-bit RISC microcontroller built around an ARM Cortex-M32 core and is compliant with functional safety standards (IEC61508 / ISO26262). The device achieves a battery monitor system with low power consumption, due to its back up RAM function, sleep function3 and Toshiba's original low power technologies.

Toshiba will provide a reference model mounting the TB9141FG and the TMPM358FDTFG and a software library to be compliant with functional safety standards. It allows customers to easily create their own battery monitor system.

Toshiba is promoting the battery monitor chipset business and developing products that meet all functional requirements in a market that is expected to grow with increasing demand for HEVs and EVs. The company targets a 25% market share by FY2017.

Availability: Sample and reference model shipments of this chipset will start in February and March 2013 respectively. Mass production will start in April 2014. Sample prices of TB9141FG and TMPM358FDTFG are 800 yen and 1,000 yen (include tax), respectively.

TB9141FG Battery Monitor IC Key Features
1. Monitor up to 16 cells

The TB9141FG uses 96V high-voltage process and realizes monitoring of a 16-cell Li-ion battery with a single IC. The TB9141FG will promote the development of lower cost battery monitoring systems with fewer components.

2. Noise tolerant communication

Differential configuration is introduced in daisy chain communication between each TB9141FG for stable communication even in a noisy environment, an essential quality for battery monitoring in automotive applications.
3. ±2mV (typ.) cell-voltage-measurement-accuracy

The TB9141FG realizes typical ±2mV cell-voltage-measurement-accuracy that improves the accuracy of battery state of charge (SOC) detection and contributes to effective use of the battery.

4. Voltage measurement in operating cell balancing

The TB9141FG incorporates a cell balance switch and is able to measure battery voltage while carrying out cell balancing.

5. Built-in self-test functions

The TB9141FG incorporates many self-test functions for use in ISO26262 compliant systems.

TMPM358FDTFG Microcontroller Key Features
1. Backup function in power down status of CortexTM-M32 core.

The TMPM358FDTFG incorporates a backup power supply for a 16-bit pre scalar counter, 32-bit up counter and for retaining stand-by SRAM data which contains a battery parameters. As the device can stand-by on low power when not monitoring batteries, power consumption of the total system can be reduced.

2. ECC function

ECC (Error Check & Correct) function is incorporated and secures all RAM area.

3. Built-in self-test functions

The TMPM358FDTFG incorporates many self-test functions for use in ISO26262 compliant systems.

4. Software libraries developed under ISO26262 certificated process4

Various software libraries will be developed under ISO26262 certificated process and released to facilitate development of customer software for TMPM358FDTFG.