SLUSG46 March 2026 BQ25785
PRODUCTION DATA
The CELL_BATPRES pin is biased with a resistor divider from REGN_A/B to GND. After REGN_A/B ramps up or CELL_BATPRES pin ramps up, the device detects the battery configuration through CELL_BATPRES pin bias voltage after 2ms delay time. No external capacitor is allowed at the CELL_BATPRES pin. When the CELL_BATPRES pin is pulled down to GND at the beginning of device start up process, CHARGE_VOLTAGE(), SYSOVP, VSYS_MIN() and VRECHG() follow the battery removal row in Battery Cell Configuration.
After device start up, when the battery is removed, the CELL_BATPRES pin must be pulled low through external MOSFET shown in application diagram. If the CELL_BATPRES pin is pulled lower than VCELL_BATPRES_FALL for 1ms deglitch time, then the device disables charge by resetting CHARGE_CURRENT()=000h and EN_AUTO_CHG=0b; at the same time, CHARGE_VOLTAGE(), SYSOVP, VSYS_MIN() and VRECHG() are not changed. When the REGN_A/B voltage rises up or the CELL_BATPRES pin is increased higher than VCELL_BATPRES_RISE, the device must re-read the cell configuration again with a 2ms delay time: CHARGE_VOLTAGE(), SYSOVP, VSYS_MIN() and VRECHG() must be re-detected to corresponding cell setting default value if the values are not changed by EC before; if any of CHARGE_VOLTAGE(), SYSOVP, VSYS_MIN() and VRECHG() are changed by EC before this re-detection then the value must not be influenced by the new detection process anymore. This is needed to avoid EC writing target value back and forth. Refer to Table 7-6 for the CELL_BATPRES pin configuration typical voltage for swept cell count. Note if the device is in learn mode (EN_LEARN=1b). Pulling the CELL_BATPRES pin low clears EN_LEARN bit to 0b and forces device to exit learn mode.
When the CELL_BATPRES pin is pulled to ground, battery removal is indicated. Since there is no battery supplement, the charger can automatically disable IIN_DPM by setting EN_IIN_DPM to 0 to minimize VSYS voltage drop. This function can be enabled through setting IIN_DPM_AUTO_DISABLE=1b. The host can re-enable IIN_DPM function later by writing EN_IIN_DPM bit to 1.
| CELL COUNT | PIN VOLTAGE WITH RESPECT TO REGN_A/B | CHARGE_VOLTAGE() | SYSOVP | VSYS_MIN | VRECHG |
|---|---|---|---|---|---|
| 5S | 100% | 21.000V | 27V | 15.4V | 500mV |
| 4S | 75% | 16.800V | 22V | 12.3V | 400mV |
| 3S | 55% | 12.600V | 17V | 9.2V | 300mV |
| 2S | 40% | 8.400V | 12V | 6.6V | 200mV |
| Battery removal | 0% | 8.400V | 27V | 6.6V | 200mV |