(ACTIVE) Ultra Low Power Harvester Power Management IC with Boost Charger, and Autonomous Power Multiplexor


Functional diagram


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.


  • 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
  • Programmable Maximum Power Point Tracking
    • Integrated MPPT for Optimal Energy
      Extraction From a Variety of Energy
  • Gate Drivers for Primary (Nonrechargeable) and
    Secondary (Rechargeable) Storage Element
    • Autonomous Switching Based on VBAT_OK
    • Break-Before-Make Prevents System Rail


Cell Chemistry Lead Acid^LiFePO4^NiMH^Li-Polymer^NiCd   
Charge Current (Max) (A) 0.1   
Control Topology Switch-Mode   
Primary Charge Termination Method Voltage   
Number of Series Cells Single Cell   
Battery Charge Voltage (V) Adjustable   
Features Integrated FET^Over Voltage Protection^Solar Input^Under Voltage Protection   
Operating Temperature Range (C) -40 to 125   
Pin/Package 20VQFN   

Companion Products

Technical Documents

Datasheet (1)

Application notes (1)

User guides (1)

Selection guides (1)

Solution guides (1)

White papers (1)

More literature (2)

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