Super-capacitor-power-supply-for-wireless-sensors-w-charger
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7 years ago
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2.7V super capacitor charger with additional 2-channel boost converter

The device is designed to charge 4 on-board 1.5F 2.7V super capacitors from a variety of DC sources like solar panels. Super capacitors management ensure that they are not overcharged by this extracted power.

In addition to the charger, the board integrates a highly efficient, nano-power 2-channel boost converter for providing a secondary power rail to systems such as wireless sensor networks. Output voltage from this converter is set at 3.3V.

Ultra Low Power DC-DC Boost Charger

  • 300 nA Ultra-Low IQ in Low Power mode
  • Startup into Load at 0.7 V Input Voltage
  • Operating Input Voltage from 0.7 V
  • After start-up converter operates down to 200mV
  • Minimum 350 mA Switch Peak Current Limit
  • Integrated Load Switch
  • Two Modes Controlled by MODE Pin – Active Mode: Dual Outputs at Set Values – Low Power Mode: Load Switch Off; Boost Keeps On
  • Automatic Pass-Through
  • Up to 88% Efficiency at 10 µA Load from 2 V to 3.3 V Conversion (Low Power Mode)
  • Up to 93% Efficiency at 5 mA ~ 100 mA Load from 2 V to 3.3 V Conversion

Energy Storage

Energy is stored in four 1.5F 2.7V super capacitors

Mode selection

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Vsub is turned ON with a high signal on the middle pin of the mode connector. It can be connected to the High pin for continuous operation. Without any connections Vsub is in OFF state.

Storage

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Schematic

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Dimensions of the board are 39mm x 25mm x 14mm.