Ultra Low Power Boost Converter with Battery Management for Energy Harvester | Nano-Power Management - BQ25504

BQ25504 (ACTIVE)

Ultra Low Power Boost Converter with Battery Management for Energy Harvester | Nano-Power Management


Special note

See how the BQ25504 and other TI products combine to create a unique Chemical/Gas Sensor SOLUTION

Description

The bq25504 device is the first of a new family of intelligent integrated energy harvesting nano-power management solutions that are well suited for meeting the special needs of ultra low power applications. The device is specifically designed to efficiently acquire and manage the microwatts (µW) to miliwatts (mW) of power generated from a variety of DC sources like photovoltaic (solar) or thermal electric generators. The bq25504 is the first device of its kind to implement a highly efficient boost converter/charger targeted toward products and systems, such as wireless sensor networks (WSNs) which have stringent power and operational demands. The design of the bq25504 starts with a DC-DC boost converter/charger that requires only microwatts of power to begin operating.

Once started, the boost converter/charger can effectively extract power from low-voltage output harvesters such as thermoelectric generators (TEGs) or single- or dual-cell solar panels. The boost converter can be started with VIN as low as 330 mV, and once started, can continue to harvest energy down to VIN = 80 mV.

The bq25504 also implements a programmable maximum power point tracking sampling network to optimize the transfer of power into the device. Sampling the VIN_DC open-circuit voltage is programmed using external resistors, and held with an external capacitor (CREF).

For example solar cells that operate at maximum power point (MPP) of 80% of their open-circuit voltage, the resistor divider can be set to 80% of the VIN_DC voltage and the network will control the VIN_DC to operate near that sampled reference voltage. Alternatively, an external reference voltage can be provide by a MCU to produce a more complex MPPT algorithm.

The bq25504 was designed with the flexibility to support a variety of energy storage elements. The availability of the sources from which harvesters extract their energy can often be sporadic or time-varying. Systems will typically need some type of energy storage element, such as a rechargeable battery, super capacitor, or conventional capacitor. The storage element ensures that constant power is available when needed for the systems. The storage element also allows the system to handle any peak currents that cannot directly come from the input source.

To prevent damage to a customer’s storage element, both maximum and minimum voltages are monitored against the user programmed undervoltage (UV) and overvoltage (OV) levels.

To further assist users in the strict management of their energy budgets, the bq25504 toggles the battery good flag to signal an attached microprocessor when the voltage on an energy storage battery or capacitor has dropped below a preset critical level. This warning should trigger the shedding of load currents to prevent the system from entering an undervoltage condition. The OV, UV, and battery good thresholds are programmed independently.

All the capabilities of bq25504 are packed into a small-footprint, 16-lead, 3-mm × 3-mm VQFN package.

Features

  • Ultra Low-Power With High-Efficiency DC-DC
    Boost Converter/Charger
    • Continuous Energy Harvesting From Low-Input
      Sources: VIN ≥ 80 mV
      (Typical)
    • Ultra-Low Quiescent Current: IQ < 330 nA
      (Typical)
    • Cold-Start Voltage: VIN ≥ 330 mV (Typical)
  • Programmable Dynamic Maximum Power Point
    Tracking (MPPT)
    • Integrated Dynamic Maximum Power Point Tracking
      for Optimal Energy Extraction From a Variety of
      Energy Generation Sources
    • Input Voltage Regulation Prevents Collapsing Input
      Source
  • Energy Storage
    • Energy Can be Stored to Rechargeable Li-ion
      Batteries, Thin-film Batteries, Super-Capacitors, or
      Conventional Capacitors
  • Battery Charging and Protection
    • User Programmable Undervoltage and Overvoltage
      Levels
    • On-Chip Temperature Sensor With Programmable
      Overtemperature Shutoff
  • Battery Status Output
    • Battery Good Output Pin
    • Programmable Threshold and Hysteresis
    • Warn Attached Microcontrollers of Pending
      Loss of Power
    • Can be Used to Enable or Disable System
      Loads

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Parametrics Compare all products in Energy Harvesting & Solar Charging

 
Cell Chemistry
Charge Current (Max) (A)
Control Topology
Primary Charge Termination Method
Switching Frequency (kHz)
# Series Cells
Battery Charge Voltage (V)
Special Features
Operating Temperature Range (C)
Pin/Package
Approx. Price (US$)
BQ25504
Li-Ion
SuperCap
Lead Acid
LiFePO4
NiMH
Li-Polymer
NiCd    
0.1    
Switch-Mode    
Voltage    
1000    
Single Cell    
Adjustable    
Integrated FET
Over Voltage Protection
Solar Input
Under Voltage Protection    
-40 to 85    
16QFN    
2.10 | 1ku    
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