BQ25910 Charger IC USB Charging Chip for Xiaomi

If a Xiaomi board comes into your shop with a "not charging" or "dead after flash" complaint and the charging circuit tests faulty, the BQ25910 is often the chip you're chasing. Texas Instruments designed it as an I2C-controlled three-level switch-mode charger for single-cell Li-Ion, Li-Polymer, and LiFePO4 batteries, and Xiaomi uses it in a parallel charger setup — meaning it works alongside a primary charging IC to split the charging load and push higher current into the battery faster.On boards like the Mi 5A, you'll typically find the BQ25910 paired with ICs such as the BQ24259, BQ27426, or BQ24297. This parallel-charger arrangement is why Xiaomi phones from this generation can pull higher charge currents without one IC overheating — the load gets shared. If you're diagnosing a charging fault and see one of these companion ICs on the schematic, check the BQ25910 footprint too, since a failure in the parallel charger often shows up as slow charging, intermittent charging, or the phone charging only when the primary IC is under load.The chip supports input voltages from 3.9V to 14V, with a 20V absolute maximum rating, so it tolerates a wide swing in adapter voltage without immediate damage — useful when a technician is troubleshooting a board that's already been exposed to a bad charger or reversed polarity. Input current limit is programmable from 500mA to 3.6A in 100mA steps, letting the system throttle input based on what the USB port or adapter can actually deliver. On the output side, charge current tops out at 6A and battery charge voltage regulates between 3.5V and 4.775V, with ±0.4% charge voltage accuracy — tight enough that a board with a marginal charging IC often shows voltage regulation errors before it fails outright.Switching frequency runs at 750kHz using a three-level buck topology, which TI states delivers 95.4% charging efficiency at 1.5A from a 5V input and 93.3% at 3A from a 9V input. That efficiency matters on a real board because it means less heat dissipation around the charging circuit — so if you're seeing excessive heat near the charging IC area on a Xiaomi board, it's worth checking for a shorted or degraded BQ25910 rather than assuming it's normal operation.All the switching MOSFETs, current sensing, and loop compensation are integrated inside the chip, along with a reverse-blocking FET. That means there's no external sense resistor to worry about when you're doing continuity checks around the IC — if current sensing looks off, the fault is almost always on the chip itself rather than a discrete component nearby. Standby battery leakage stays under 10µA, so a phone that drains its battery unusually fast while off could point to a leaky charging IC on the parallel charger side.For board-level work, this IC comes into play during dead-after-flash recovery, no-power diagnosis, charging port repair follow-up (after ruling out the port itself), and general "charging issue" complaints where the primary IC tests fine but the board still won't pull full current. Reflow with proper hot air temperature control, use flux generously, and confirm ball alignment before reballing — the 36-ball DSBGA package is small and easy to shift during rework if you rush the jumper or don't stabilize the board first.Always confirm the exact IC marking against your board's schematic before ordering, since Xiaomi shares charging architectures across some models but not all. KB GSM Store stocks genuine BQ25910 units for technicians across Lahore, Karachi, and Islamabad who need a reliable source for board-level charging repairs without unverified or relabeled stock.