TIBQ25504 Ultra-Low Power Energy Harvesting Battery Boost Converter Design Solution

TI’s BQ25504 is a latest integrated nanometer intelligent energy harvesting power management solution, which is very suitable for ultra-low power consumption applications with special needs. This product is specifically designed to efficiently capture and manage microwatts and milliwatts of electricity, typically from a variety of photovoltaic solar DC sources or thermal motor generators. The BQ25504 is the first implementation of a high-efficiency converter or charger for products and systems such as radio sensor networks where operating power consumption is critical. A DC-DC boost converter/charger designed with the BQ25504 requires only milliwatts of power to operate. This article summarizes the characteristics of the BQ25504 device, introduces the device, characteristics, application direction and internal structure block diagram, and gives a reference design example schematic diagram, board diagram and component list.

The bq25504 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 product 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 (WSN) which have stringent power and operational demands. The design of the bq25504 starts with a DCDC boost converter/charger that requires only microwatts of power to begin operating.

Main features of BQ25504:

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 – 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 Re-Chargeable 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/Disable System Loads

BQ25504 Application:

• Energy Harvesting
• Solar Charger
• Thermal Electric Sources 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

TIBQ25504 Ultra-Low Power Energy Harvesting Battery Boost Converter Design Solution
Figure 1. BQ25504 Block Diagram

Main features of the BQ25504 reference design:

• Evaluation module for bq25504
• Ultra low power boost converter/charger with battery management for energy harvester applications
• Resistor-programmable settings for under voltage, over voltage providing flexible battery management;
POTs Included for fine tuning the settings (not populated)
• Programmable push-pull output Indicator for battery status (VBAT_OK)
• Test points for key signals available for testing purpose – easy probe hook-up.
• Jumpers available – easy to change settings

BQ25504 design schematic diagram:

Figure 2. BQ25504 Design Schematic

BQ25504 Design Scheme Bill of Materials:

PCB component layout:

The Links:   MBRT60045 7MBP100NA060