Описание
The DS2786B estimates available capacity for rechargeable Li-ion (Li+) and Li+ 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 DS2786B 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 DS2786B 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. The DS2786B comes in a 10-pin, lead-free, TDFN 3mm x 3mm package with an exposed pad (EP).
- 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 4.5V Input Range
- 25µV LSB, ±51.2mV Dynamic Range
- 1.67mA LSB, ±3.4A (RSNS = 15mO)
- ±204.8mVh Range
- ±13.65Ah (RSNS = 15mO)
- 0.125°C LSB, ±3°C Accuracy
- ±8 LSB Accuracy, Ratiometric Inputs Eliminate Supply Accuracy Issues
- Active Current: 50µA (typ), 80µA (max)
- Sleep Current: 1µA (typ), 3µA (max)
