Texas Instruments' bq25570 device is specifically designed to efficiently extract microwatts (µW) to milliwatts (mW) of power generated from a variety of high output impedance DC sources like photovoltaic (solar) or thermal electric generators (TEG) without collapsing those sources. The battery management features ensure that a rechargeable battery is not overcharged by this extracted power with voltage boost, or depleted beyond safe limits by a system load. In addition to the highly efficient boosting charger, the bq25570 integrates a highly efficient, nanopower buck converter for providing a second power rail to systems such as wireless sensor networks (WSN) which have stringent power and operational demands. All the capabilities of bq25570 are packed into a small foot-print 20-lead 3.5 mm x 3.5 mm QFN package (RGR).
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- Ultra-low power DC-DC boost charger
- Cold-start voltage: VIN ≥ 330 mV
- Continuous energy harvesting from VIN as low as 100 mV
- Input voltage regulation prevents collapsing high impedance input sources
- Full operating quiescent current of 488 nA (typical)
- 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 levels
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- 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 step down regulated output (buck)
- High efficiency up to 93%
- Supports peak output current up to 110 mA (typical)
- Programmable maximum power point tracking (MPPT)
- Provides optimal energy extraction from a variety of energy harvesters including solar panels, thermal, and piezo electric generators
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