The DS2786G-C29+T estimates available capacity for rechargeable Li-Ion and Li-Ion Polymer batteries based on the cell voltage in the open-circuit state following a relaxation period. The open-circuit voltage (OCV) is used to determine relative cell capacity based on a lookup table stored in the IC. This capability makes accurate capacity information available immediately after a battery pack is inserted. During periods of moderate to high rate discharging, which preclude OCV measurements, the DS2786G-C29+T uses coulomb counting as a secondary means of estimating relative capacity. Remaining capacity is reported in percent, along with cell voltage, current and temperature information. Cell characteristics and application parameters used in the calculations are stored in on-chip EEPROM. The DS2786G-C29+T is intended for use on the host side of portable devices, though it can also be mounted within a battery pack. Measurement and estimated capacity data are accessed through an I2C interface. Temperature data is available from an on-die sensor. Resistance measurements of a pack identification resistor and pack thermistor are supported by ratiometric measurements on two auxiliary inputs.
Feature
- Relative Capacity Calculated from Combination Coulomb Counter and Open-Circuit Cell Voltage (OCV) Battery Model
- Accurate Warning of Low Battery Conditions Even On First Cycle (No Learn Cycle Needed)
- 12-Bit Battery Voltage Measurement:
- ±10mV Accuracy
- 1.22mV LSB, 0V to 5V Input Range
- 11-Bit Bidirectional Current Measurement:
- 25μV LSB, ±51.2mV Dynamic Range
- 1.67mA LSB, ±3.4A (RSNS = 15mΩ)
- Current Accumulation Measurement Resolution:
- ±204.8mVh Range
- ±13.65Ah (RSNS = 15mΩ)
- Internal Temperature Measurement:
- 0.125°C LSB, ±3°C Accuracy
- Two 11-Bit Aux Input Voltage Measurements:
- ±8 LSB Accuracy, Ratiometric Inputs Eliminate Supply Accuracy Issues
- VOUT Pin Drives Resistive Dividers, Reduces Current Consumption
- 2-Wire Interface
- Low Power Consumption:
- Active Current: 50μA typ, 80μA max
- Sleep Current: 1μA typ, 3μA max
Applications
- 3G Multimedia Wireless Handsets
- Digital Audio (MP3) Players
- Digital Still Cameras
