Li-ion battery protection ICs target E-Bikes, power tools and electrical vehicles

Li-ion battery protection ICs target E-Bikes, power tools and electrical vehicles

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Rohm Semiconductor released a broad line-up of ICs providing all functions needed for controlling, monitoring and protecting systems using multiple-cell series-connected Li-ion battery packs.
By eeNews Europe


These rechargeable battery packs are commonly used in hybrid electric vehicles or electric vehicles (HEV/EV), Power Tools and E-Bicycles, application areas which are expected to rapidly grow over the next few years. The ML5207, ML5208, ML5235 and ML5237 Li-ion battery management ICs are low consumption current protector ICs compatible with multiple-cell series-connected Li-ion battery packs (five to ten respectively 13 cells), detecting the over-charge or over-discharge and over-current of each cell. They also integrate the Gate driver for an automatic On/Off control of the external PMOS-FET or N-ch FET (depending on the version) for the charge and discharge. Based on the results of the voltage control of each cell or the entire battery pack, as well as the monitoring of the charge and discharge current, an external MCU can perform corresponding actions to protect the batteries and to prevent the system to get into an irregular state. For a complete protection solution, Rohm also offers the MCU ML5227 which can be used in combination with the battery monitoring IC. The monitoring IC can supply 3.3V power supply to the MCU so that no external voltage regulator is needed. The MCU is an 8bit high-performance controller based on the low power Microcontroller series ML610Q4xx with integrated Flash memory to store the register settings.

Another chip, the ML5218 is a Li-ion battery monitoring IC for packs of four to 14 cells especially designed for the use in automotive applications. It features a highly accurate voltage measurement function to detect overcharge/over-discharge, passive cell balancing and the possibility of four temperature measurements with externally connected sensors. In addition the IC also includes some self-diagnosis functions, which are activated and analysed by the external MCU. So it is possible to detect open and short cell connections as well as communication errors between the MCU and the IC. With its high voltage process ML5218 is able to withstand a maximum input voltage of over 80V. If more than 14 cells are needed because of the high power needed for electrical vehicles, up to 32 ICs can be controlled via a multistage connection so that in total up to 448 cells can be supported.

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