The LTC3300-1 is a key component in a high performance battery management system (BMS) for series-connected Li-Ion or LiFePO4 batteries. The device operates as a fault-protected controller IC for transformer-based bidirectional active balancing. The part utilizes a nonisolated bidirectional synchronous flyback topology to balance up to 6 series-connected cells. Charge can be transferred between a selected cell and 12 or more adjacent cells. All balancers can operate independently and simultaneously with charge/discharge currents up to 10A. Bidirectional operation and simultaneous balancing minimizes the time required to equalize stack SoC, and the parts’ high transfer efficiency (up to 92%) enables high current balancing with minimal power dissipation.
Control of each balancer is provided via a unique level-shifting SPI-compatible serial interface which enables multiple LTC3300-1 devices to be connected in series, without optocouplers or isolators. The part’s stackable architecture together with interleaved transformer connections enable efficient balancing of every cell in an arbitrarily tall string (>1000V) of series-connected batteries. All associated gate drive circuitry, precision current sensing, fault protection circuitry and a robust serial data interface with built-in watchdog timer and cyclic redundancy check (CRC) data error checking are integrated.
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The LTC3300-1 is offered in thermally enhanced surface-mount compatible packages: a low profile (0.75mm) 48-lead 7mm x 7mm QFN and a 48-pin 7mm x 7mm LQFP package. The I grade is specified for both packages, with operating junction temperature range of -40°C to +125°C. Devices are available from stock and 1,000-piece pricing starts at $5.95.