About UsLT Releases Standalone Charge Balancing IC for 12V Lead Acid Batteries
Charge is Transferred from High Voltage Batteries to Lower Voltage Batteries to Ensure all are Charged Equally
Linear Technology (now part of Analog Devices) has released the LTC3305, a single IC, standalone multicell battery balancer for 12V lead acid batteries. Balancing works by absorbing charge from higher voltage batteries and transferring that charge to lower voltage batteries so that all are charged equally. Charge is transferred using a lower capacity battery that is sequentially connected across the batteries in the stack. Not only does this battery transfer charge, but the energy in the transfer battery adds to the total energy in the stack, thus increasing capacity. Included on the chip is sequencing, drive circuitry for high voltage external NFETs, voltage monitoring and protection.
The LTC3305 is designed for standalone operation and does not require a microprocessor or other control circuitry. With the LTC3305, one battery in the stack can be replaced and quickly balanced to the remaining batteries. The LTC3305 is ideal for applications such as telecom backup systems, home batterypowered backup systems, electric vehicles and industrial lighting systems.
The LTC3305 employs an auxiliary battery storage cell to transfer charge to or from each individual battery in the stack. A mode pin provides two operating modes: timer mode and continuous mode. In timer mode, once the balancing operation is completed, the LTC3305 goes into a low power state for a programmed time and then periodically rebalances the batteries. In continuous mode, the balancing operation continues even after the batteries are balanced to their programmed termination voltage. Further, additional devices can be stacked to balance higher voltage series battery packs.
Features of the LTC3305 include:
- Single IC Balances up to Four 12V Lead Acid Batteries in Series
- All NFET Design
- Stackable to Balance Higher Voltage Series Battery Packs
- StandAlone Operation Requires No External µP or Control Circuitry
- Continuous Mode & Timer Mode
- Balancing Current Limited by External PTC Thermistor
- Programmable UV & OV Fault Thresholds
- Programmable Termination Time & Termination Voltage
The LTC3305 is currently available in a TSSOP38 Package and can be ordered from Analog Devices in tube or reel packaging.
For more information on the LTC3305 Lead Acid Battery Charge Balancer, visit the Analog Devices website at Linear Technology LTC3305 product page.
The Analog Devices website address is www.analog.com
[Reprinted with kind permission from Linear Technology - Release Date: 27th January, 2015]
