JAJSQP6B December 2022 – March 2024 BQ25758
PRODUCTION DATA
To set the maximum input current using the IIN pin, a pull-down resistor to PGND is used. When using a 2-mΩ RAC_SNS resistor, the input current limit is controlled by: IAC_MAX = KILIM / RIIN.
The actual input current limit is the lower value between IIN pin setting and register setting (IAC_DPM). For example, if the register setting is 20 A, and IIN pin has a 5-kΩ resistor (KILIM = 50 A-kΩ) to ground for 10 A, the actual input current limit is 10 A. IIN pin can be used to set the input current limit when EN_IIN_PIN bit is set to 1. The device regulates the pin at VREF_ILIM_HIZ. If pin voltage exceeds VREF_ILIM_HIZ, the device enters input current regulation. Entering input current regulation through the pin sets the IAC_DPM_STAT and FLAG bits, and produces an interrupt to host. The interrupt can be masked via the IAC_DPM_MASK bit.
The IIN pin can also be used to monitor input current. When not in input current regulation, the voltage on IIN pin (VIIN) is proportional to the input current. Pin voltage can be used to monitor input current with the following relationship: IAC = KILIM x VIIN / (RIIN x VREF_ILIM_HIZ).
For example, if the pin is set with 5-kΩ resistor, and the pin voltage is 1.0 V, the actual input current is between 4.8 A to 5.2 A (based on KILIM specified).
If IIN pin is shorted, the input current limit is set by the IAC_DPM register. If hardware input current limit function is not needed, it is recommended to short this pin to GND. If IIN pin is pulled above VIH_ILIM_HIZ, the device enters HIZ mode (refer to Section 6.3.3.6). The IIN pin function can be disabled by setting the EN_IIN_PIN bit to 0. When the pin is disabled, input current limit and monitoring functions as well as HIZ mode control via the pin are not available.