BQ25756RRVR

The BQ25756 is a wide-input-voltage, switch-mode buck/boost lithium-ion, lithium-polymer, or lithium-iron-phosphate battery charging controller with bidirectional power flow support. This device not only provides precise charging current and charging voltage regulation but also offers automatic pre-charging regulation, charging termination, and charging status indication, enabling efficient battery charging over a wide voltage range. The device integrates all loop compensation functions of the buck/boost converter, thus providing an easy-to-use, high-density solution. In reverse mode, the device draws power from the battery and regulates the input terminal voltage through an added constant current loop to achieve protection, thereby supporting USB-PD EPR power profiles. In addition to the I2C host-controlled charging mode, the device also supports an independent charging mode through resistor-programmable limits. The input current, charging current, and charging voltage regulation targets can be set via the ILIM_HIZ, ICHG, and FB pins respectively.

Applications

• E-kick scooters, e-bikes
• Cordless power tools, garden tools
• Robotic lawn mowers
• Portable power stations
• Cordless vacuum cleaners, robotic vacuum cleaners
• Solar chargers
• USB-PD EPR (Extended Power Range)

Key features

• Wide battery voltage operating range: up to 70V, supporting multi-chemistry batteries: 1-cell to 14-cell Li-ion charging profile, 1-cell to 16-cell LiFePO₄ charging profile
• Synchronous buck/boost charging controller with NFET drivers
• Adjustable switching frequency: 200kHz to 600kHz
• Optional external clock synchronization
• Integrated loop compensation with soft-start
• Optional gate driver supply input for improved efficiency
• Automatic MPPT for solar charging
• Buck-only mode
• Bidirectional converter operation (reverse mode) supporting USB-PD EPR
• Adjustable input voltage (VAC) regulation range: 3.3V to 65V in 20mV steps
• Adjustable input current regulation (RAC_SNS) using 5mΩ resistor: 400mA to 20A in 50mA steps
• ±0.5% charge voltage regulation
• ±3% charge current regulation
• ±3% input current regulation
• I2C control for superior system performance with per-battery programmable options
• Hardware-adjustable input and output current limits
• Integrated 16-bit ADC for voltage, current, and temperature monitoring
• Adjustable input overvoltage and undervoltage protection
• Battery overvoltage and overcurrent protection
• Charge safety timer
• Battery short-circuit protection
• Thermal shutdown
• Status outputs: adapter present status (PG), charger operating status (STAT1, STAT2)
• 36-pin 5mm × 6mm QFN package