LTC3337 Nanopower Primary Battery SoH Monitor

Analog Devices' LTC3337 is the lowest I_Q SoH (state of health) monitor and coulomb counter with infinite dynamic range. It is accurate across all load profiles and measures all the important state of health variables (Q, V, Z, T). The LTC3337 is battery-friendly by presenting the battery with a load profile that allows it to deliver its maximum capacity, independent of the actual load.

The demonstration circuit DC2973A shows the LTC3337 primary battery state of health (SoH) monitor with precision coulomb counter operating with a configurable peak current limit. The LTC3337 supports input voltages from 1.8 V to 5.5 V and a peak current up to 100 mA with a quiescent current of 100 nA. Coulomb count, battery voltage, and battery series resistance (BSR) are measurable and can be used to quantify the charge state and health of a battery.

DC2973A demonstrates a simple layout for the highest-power configuration of the LTC3337. The circuit can be reduced for lower I_PEAK levels. The demo board can be connected directly to a PC using a micro USB cable to run a GUI and configure a simple battery state of charge (SOC) monitor. Source code for the GUI is available and can be used as a starting point for LTC3337 firmware development.

Features

• Ultra-low quiescent current of 100 nA gives longer battery run times, helpful in remote locations where access is minimal or difficult
• Infinite dynamic range is accurate across all load profiles
• Allows battery to run at maximum capacity by presenting the battery an optimized load profile

Applications

• General purpose: low power primary battery-powered systems (for example, 1 - LiSOCl2, 2 - 3x alkaline)
• Consumer: electronic door locks
• Industrial automation: remote industrial sensors (meters, alarms, and others), asset trackers