DC/DC converter balances high voltage battery stacks

13th December 2013

Staff Reporter

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Featuring isolated balancing design and system telemetry, Linear’s LT8584 monolithic flyback DC/DC converter is designed to actively balance high voltage stacks of batteries. The active balancing offered with the DC/DC converters redistributes the charge from the stronger cells to charge the weaker cells during discharge. This enables the weaker cells to continue to supply the load, extracting 96% of the entire stack capacity where passive balancing usually extracts approximately 80%.

The converter’s isolated balancing design can return charge to the top of the battery stack or to any combination of cells in the stack. It can also return charge to a 12V battery used as an alternator replacement. The system telemetry includes current, resistance and temperature monitoring when used with the LTC680x family of parts.

Due to the integrated 6A/50V power switch, the converters enable an average discharge current of 2.5A while offering a simple and compact application circuit. The LT8584 runs off of the cell that it is discharging, removing the need for complicated biasing schemes. Via the enable pin, the LT8584 integrates with the LTC680x family monitoring ICs without any additional software. Drawing less than 20nA of quiescent current from the battery when disabled, the LT8584s can also be paralleled for applications requiring higher balancing current. It is packaged in a 16-lead TSSOP and is both FMEA and ISO 26262 compliant.

Three versions are available with the standard LT8584EFE priced at $2.95 and packaged in 16-lead TSSOP. The LT8584IFE, an industrial temperature version, operates between -40°C to 125°C and is priced at $3.25 each. The automotive temperature version, operating from -40°C to 150°C, is priced at $3.50. All versions are available and pricing is for 1,000 piece quantities.