TI BQ25792RQMR

The BQ25792 is a fully integrated switching-mode buck/boost charger suitable for 1 - 4 cell lithium-ion and lithium-polymer batteries. This integration includes 4-switch MOSFETs (Q₁, Q₂, Q₃, Q₄), input and charging current detection circuits, a battery FET (Q_BAT), and loop compensation for the buck/boost converter. It uses NVDC power path management to regulate the system voltage to a level slightly higher than the battery voltage, but it will not drop below the configurable minimum system voltage. When the system power exceeds the input source rating, the battery supplement mode supports the system without overloading the input source.

The BQ25792 supports the full input and output (OTG) voltage range for USB Type-C and USB Power Delivery (USB-PD) applications. The charger supports narrow-range VDC power path management, regulating the system voltage to a level slightly higher than the battery voltage, but it will not drop below the minimum system voltage. Even when the battery is fully discharged or removed, the minimum system voltage allows the system to operate. When the system power exceeds the input source rating, the battery supplement mode supports the system power requirements without overloading the input source.

The device charges the battery from various input sources, such as traditional USB adapters, high-voltage USB PD adapters, and traditional barrel adapters. Without host control, the charger automatically sets the converter to buck, boost, or buck-boost configuration based on the input voltage and battery voltage. The dual-input source selector manages the power inflow from two different input sources. Input selection is controlled by the host via I2C, with default source 1 (VAC1) as the primary input and source 2 (VAC2) as the auxiliary input.

To support fast charging via an adjustable high-voltage adapter, the device provides a D+/D- handshake mechanism. The device complies with USB 2.0 and USB 3.0 power transfer specifications and has input current and voltage regulation functions. Additionally, the input current optimizer (ICO) can detect the maximum power point of an unknown input source.

In addition to the I2C host-controlled charging mode, this charger also supports the automatic charging mode. After power-on, charging is enabled using the default register settings. This device can complete the charging cycle without software intervention. It detects the battery voltage and charges the battery in different stages: trickle charging, pre-charging, constant current (CC) charging, and constant voltage (CV) charging. At the end of the charging cycle, when the charging current is lower than the preset limit (termination current) in the constant voltage stage, the charger automatically terminates. When the entire battery voltage drops below the recharge threshold, the charger will automatically start another charging cycle.

Without an input source, this device supports the USB On-the-Go (OTG) function, discharging the battery to generate an adjustable 2.8V to 22V voltage on VBUS in 10mV steps, complying with the Programmable Power Supply (PPS) characteristics defined by the USB PD 3.0 specification.

The charger provides various safety features for battery charging and system operation, including battery negative temperature coefficient thermistor monitoring, trickle charging, pre-charging, and fast charging timers, as well as overvoltage/overcurrent protection on the battery and input. When the junction temperature exceeds the programmable threshold, thermal regulation reduces the charging current. The device's STAT output reports the charging status and any fault conditions. When a fault occurs, the INT pin immediately notifies the host.

The device also provides a 16-bit analog-to-digital converter (ADC) for monitoring the charging current and input/battery/system (VAC, VBUS, BAT, SYS, TS) voltages. It comes in a 29-pin 4mm × 4mm QFN package.

• High power density, highly integrated buck-boost charger for 1–4 cell batteries, supporting any USB PD 3.0 profile
• Integrated four-switch MOSFETs, BATFET
• Integrated input and charge current sensing
• High efficiency
• 750kHz or 1.5MHz switching frequency
• 5A charge current with 10mA resolution
• Up to 96.5% efficiency: charging a 16V battery from 20V input at 3A
• Wide input source support
• 3.6V to 24V wide input operating voltage range, 30V absolute maximum rating
• Maximum power tracking, VINDPM up to 22V, IINDPM up to 3.3A
• Detects USB BC1.2, SDP, CDP, DCP, HVDCP, and non-standard adapters
• Dual-input power multiplexer controller for source selection (optional)
• Narrow voltage DC (NVDC) power path management
• USB OTG: powering USB port from battery
• 2.8V to 22V OTG output voltage with 10mV resolution, supporting USB-PD PPS
• OTG output current regulation up to 3.32A with 40mA resolution
• Flexible autonomous and I²C modes for superior system performance
• Integrated 16-bit ADC for voltage, current, and temperature monitoring
• Low battery quiescent current
• 21μA in battery-only operation
• 600nA in charger ship mode
• High accuracy
• 2S–4S battery charge voltage regulation: +0.65% to -0.85%
• Charge current regulation: ±5%
• Input current regulation: ±5%
• Safety
• Thermal regulation and thermal shutdown
• Input/battery OVP and OCP
• Converter MOSFET OCP
• Charge safety timer
• Package: 29-pin, 4mm × 4mm QFN

• Video doorbells, smart home control
• Data concentrators, robotic lawn mowers, robotic vacuum cleaners
• Asset tracking, mobile POS
• Multi-parameter patient monitors, ECG, ultrasonic smart probes