BQ25773

The BQ25773 is a synchronous NVDC buck-boost battery charge controller to charge a 2- to 5-cell battery from a wide range of input sources including USB adapter, extended power range (EPR) USB-C Power Delivery (PD) sources, standard power range (SPR) USB-C Power Delivery (PD) sources and traditional adapters. The device offers a low component count, high efficiency solution for space constrained, 2- to 5-cell battery charging applications.

The NVDC configuration allows the system to be regulated based on battery voltage, but not drop below system minimum voltage. The system keeps operating even when the battery is completely discharged or removed. When load power exceeds input source rating, the battery goes into supplement mode and prevents the system from crashing.

During power up, the charger sets the converter to a buck, boost, or buck-boost configuration based on the input source and battery conditions. The charger seamlessly transits between the buck, boost, and buck-boost operation modes without host control. The TI patented quasi dual phase converter can interleave dual phase under high power buck mode helping thermal distribution and reduce each inductor size. At same time it only needs two boost side switching MOSFETs to save overall system area and cost due to limited power operation under boost mode.

In the absence of an input source, the BQ25773 supports the USB On-the-Go (OTG) function from a 2- to 5-cell battery to generate an adjustable 3V to 5V output on VBUS with 20mV resolution.

When only a battery powers the system and no external load is connected to the USB OTG port, the BQ25773 implements the latest Intel Vmin Active Protection (VAP) feature, in which the device charges up the VBUS voltage from the battery to store some energy in the input decoupling capacitors. During a system peak power spike, the energy stored in the input capacitors supplements the system, to prevent the system voltage from dropping below the minimum system voltage and causing a system crash.

The BQ25773 monitors adapter current, battery current, and system power. The flexibly programmable PROCHOT output goes directly to the CPU for throttling back when needed.

The latest version of the USB-C PD specification includes Fast Role Swap (FRS) to ensure power role swapping occurs in a timely fashion so that the device(s) connected to the dock can avoid experiencing momentary power loss or glitching. This device integrates FRS in compliance with the PD specification.

TI patented switching frequency dithering pattern can significantly reduce EMI noise over the whole conductive EMI frequency range (150kHz to 30MHz). Multiple dithering scale options are available and provide flexibility for different applications. The ditherring feature greatly simplify EMI noise filter design.

The charger operate in the TI patented Pass Through Mode (PTM) to improve efficiency over the full load range. In PTM, input power directly pass through the charger to the system. Switching losses of the MOSFETs and inductor core loss can be saved thus achieving high efficiency operation.

The BQ25773 is available in a 36-pin 4mm × 5mm WQFN package.