• Ultra Low-Power With High-Efficiency DC-DC Boost Charger
  • Cold-Start Voltage: VIN ≥ 330 mV
  • Continuous Energy Harvesting From Input Sources as Low as 100 mV
  • Ultra-Low Quiescent Current of 325 nA
  • Input Voltage Regulation Prevents Collapsing High-Impedance Input Sources
  • Ship Mode With < 5 nA From Battery
• Energy Storage
  • Energy can be Stored to Rechargeable Li-Ion Batteries, Thin-Film Batteries, Super-Capacitors, or Conventional Capacitors
• Battery Charging and Protection
  • Internally Set Undervoltage Level
  • User-Programmable Overvoltage Level
• Battery-Good Output Flag
  • Programmable Threshold and Hysteresis
  • Warn Attached Microcontrollers of Pending Loss of Power
  • Can be Used to Enable or Disable System Loads
• Programmable Maximum Power Point Tracking (MPPT)
  • Integrated MPPT for Optimal Energy Extraction From a Variety of Energy Harvesters
• Gate Drivers for Primary (Nonrechargeable) and Secondary (Rechargeable) Storage Element Multiplexing
  • Autonomous Switching Based on VBAT_OK
  • Break-Before-Make Prevents System Rail Droop

• Energy Harvesting
• Solar Chargers
• Thermal Electric Generator (TEG) Harvesting
• Wireless Sensor Networks (WSN)
• Industrial Monitoring
• Environmental Monitoring
• Bridge and Structural Health Monitoring (SHM)
• Smart Building Controls
• Portable and Wearable Health Devices
• Entertainment System Remote Controls

The bq25505 device is specifically designed to efficiently extract the microwatts (µW) to miliwatts (mW) of power generated from a variety of DC energy harvesting, high-impedance sources like photovoltaic (solar) or thermal electric generators (TEGs) without collapsing those sources. The battery-management features of the bq25505 ensure that a secondary rechargeable battery is not overcharged by this extracted power, with voltage boosted, nor depleted beyond safe limits by a system load. The integrated multiplexer gate drivers autonomously switch the system load to a primary nonrechargeable battery if the secondary battery voltage falls below the user-defined VBAT_OK threshold.