Host controlled 2-4 cell Buck battery charge controller with system power selector with low Iq

The bq24751A is a high-efficiency, synchronous battery charger with integrated compensation and system power selector logic, offering low component count for space-constrained multi-chemistry battery charging applications. Ratiometric charge current and voltage programming allows very high regulation accuracies, and can be either hardwired with resistors or programmed by the system power-management microcontroller using a DAC or GPIOs.

The bq24751A charges two, three, or four series

Li+ cells, supporting up to 10A of charge current, and is available in a 28-pin,

5x5-mm thin QFN package.

The bq24751A controls external

switches to prevent battery discharge back to the input, connect the adapter to the

system, and to connect the battery to the system using 6V gate drives for better

system efficiency. For maximum system safety, inrush-power limiting provides

instantaneous response to high input voltage multiplied by current. This AC

Over-Power protection (ACOP) feature limits the input-switch power to the programmed

level on the ACOP pin, and latches off if the high-power condition persists to

prevent overheating.

The bq24751A features Dynamic Power

Management (DPM) and input power limiting. These features reduce battery charge

current when the input power limit is reached to avoid overloading the AC adapter

when supplying the load and the battery charger simultaneously. A highly-accurate

current-sense amplifier enables precise measurement of input current from the AC

adapter to monitor the overall system power.