ROHM – ML5233 – New Li-Ion Battery Monitoring IC
LAPIS Semiconductor, a ROHM Group company, has recently announced the development of a 10-cell lithium-ion battery monitoring LSI that provides a current consumption of only 25μA (typ.), the lowest in the industry, making it ideal for battery protection systems in cordless vacuum cleaners, electric tools, and other portable equipment.
The ML5233 also features an industry-low 0.1μA (typ.) current consumption during power down, minimizing the effects on battery capacity – even during long-term storage – and contributing to more eco-friendly products with virtually no loss of charged battery power.
In addition, built-in temperature and short-circuit current detection circuits enable detection of not only over-charge/discharge and overcurrent, but also abnormal (high) temperatures during discharge along with battery pack short-circuits – all without an MCU. This decreases footprint by 20% and reduces the number of external components from four to one, leading to smaller battery protection systems and lighter development load.
The demand for battery-driven cordless vacuum cleaners and electric tools utilizing secondary lithium-ion batteries is increasing worldwide every year due to their greater convenience and ease-of-use. Reducing weight to improve portability and other design factors are also considered important.
Secondary lithium-ion batteries feature greater energy efficiency per volume and weight compared to nickel-cadmium and nickel-metal hydride batteries, making it possible to reduce both size and weight. However, one drawback is that they must be continuously monitored and controlled to prevent fire, explosion, and/or reduced battery life, increasing the demand for compact, low consumption battery monitoring LSIs.
Going forward, LAPIS Semiconductor will continue to meet the needs in the consumer and industrial equipment markets for higher voltage battery monitoring systems by offering low-power multi-cell lithium-ion battery monitoring LSIs.
1. Industry-low current consumption
- During operation
Current consumption is reduced to an industry-low 25uA, 50% less than conventional products, contributing to greater energy savings for the entire system. - During power-down
Current consumption during power down is also the lowest in the industry (0.1µA typ.), posing little to no effect on battery capacity even during prolonged storage and ensuring minimal loss of charged battery power
2. Superior detection accuracy increases charging efficiency by 7%
- High overcharge detection accuracy (±15mV per each cell) increases charging efficiency by 7% over conventional products that feature ±50mV accuracy.
3. Multiple abnormality detection and protection features implemented
without a microcomputer reduces footprint by 20%
- Built-in temperature and short-circuit current detection circuits enable the detection of abnormal (high) temperatures and battery pack short-circuits without an MCU, decreasing mounting area by 20% and reducing the number of external components from four to one. In addition, configuring a hardware-based system utilizing an external MOSFET, current detection shunt resistor, and thermistor contributes to smaller protection systems and reduced development load.
4. Scalable multi-stage series connection supports systems with more than 10 cells
High-voltage processes support 4-10 cells in series using a single LSI, ensuring compatibility with electric tools and other equipment in the 14V to 36V range.
- In addition, the versatile design enables scalability to support a wider range of applications. For example, two LSIs can be combined to support up 20 cells in series and up to 72V, making them suitable for pedal-assisted bicycles, ride-on carts, and other high voltage applications.
Applications
- Cordless vacuum cleaners, electric tools and similar applications
Specifications
| Parameter | Specifications |
|---|---|
| No. of Cells Supported | 10 cells (in series) (Scalable via multi-stage series connection) |
| Overcharging/Overdischarging Detection Accuracy | ±15mV (Max. RT)/±50mV (Max. RT) |
| Charge/Discharge Overcurrent Detection Accuracy | ±10mV (Max. RT)/±15mV (Max. RT) |
| Short-Circuit Current Detection Accuracy | ±15mV (Max. RT) |
| Temperature Detection Accuracy | Discharge prohibiting temperature: 75ºC or more Charge prohibiting temperature: 55ºC or more When NTC (10kΩ, B=3435) and 4.7kΩ resistance are connected externally |
| External Charge/Discharge FET Control | Built-in NMOS-FET driver circuit |
| Current Consumption (During Operation) | 25μA (typ.), 60μA (Max.) |
| Current Consumption (During Power Down) | 0.1μA (typ.), 1μA (Max.) |
| Operating Supply Voltage Range | +5 to +60V |
| Operating Temperature Range | -40 to 85ºC |
| Package | LQFP32 (9mm x 9mm – including terminals) |
