JAJSHF0B February 2019 – November 2019 BQ25887
PRODUCTION DATA.
For safe operation, the BQ2588x has an additional hardware pin on ILIM to limit maximum input current. The maximum input current is set by a resistor from ILIM pin to ground as:
The actual input current limit is the lower value between ILIM pin setting and register setting (IINDPM). For example, if the register setting is 3.3 A (0x1C), and ILIM has a 820-Ω resistor (KILIM = 1276 max) to ground for 1.55 A, the input current limit is 1.55 A. ILIM pin can be used to set the input current limit rather than the register settings when EN_ILIM bit is set. The device regulates ILIM pin at 0.8 V. If ILIM voltage exceeds 0.8 V, the device enters input current regulation (refer to section). Entering IINDPM through ILIM pin sets the IINDPM_STAT and FLAG bits, and produces and interrupt to host. The interrupt can be masked via the IINDPM_MASK bit.
The ILIM pin can also be used to monitor input current when EN_ILIM is set. The voltage on ILIM pin is proportional to the input current. ILIM can be used to monitor input current with the following relationship:
For example, if ILIM pin is set with 820-Ω resistor, and the ILIM voltage 0.5V, the actual input current is 0.795 A to 0.973 A. If ILIM pin is open, the input current is limited to zero since ILIM voltage floats above 0.8 V. If ILIM pin is shorted, the input current limit is set by the register.
The ILIM pin function can be disabled by setting the EN_ILIM bit to 0. When the pin is disabled, both input current limit function and monitoring function are not available.