High-efficiency bidirectional multicell battery balancer extends addressability options

August 16, 2013 // By EDN
A data sheet from Linear Technology describes the company's latest cell balancing IC for multi-cell lithium ion or LiFePO4 battery packs.

The LTC 3300-2 is a fault-protected controller IC for transformer-based bidirectional active balancing of multi-cell battery stacks. All associated gate drive circuitry, precision current sensing, fault detection circuitry and a robust serial interface with built-in watchdog timer are integrated. Each LTC 3300-2 can balance up to six series-connected battery cells with an input common mode voltage up to 36V. Charge from any selected cell can be transferred at high efficiency to or from 12 or more adjacent cells. Each LTC 3300-2 has an individually addressable serial interface, allowing up to 32 LTC 3300-2 devices to interface to one control processor. Fault protection features include readback capability, cyclic redundancy check (CRC) error detection, maximum on-time volt-second clamps, and overvoltage shutoffs. The related LTC 3300-1 offers a serial interface that allows the serial ports of multiple LTC 3300-1 devices to be daisy-chained without opto-couplers or isolators.

You might use the part, Linear suggests, in electric vehicles and plug-in hybrids (Evs/HEVs), for high-power uninterruptible power supplies, and in general purpose multicell battery installations.

Features include; bidirectional synchronous flyback balancing with up to 10A balancing current; up to 92% charge-transfer efficiency, and a stackable architecture that enables systems of over 800V; use of simple 2-winding transformers; a 1-MHz serial interface with 4-bit CRC; and 5-bit addressing.

Linear Technology; http://cds.linear.com/docs/en/datasheet/33002f.pdf