Model 4906 Supercap Feather Wing
Need to transmit occasional LoRaWAN® data, or occasionally power up a high-power sensor, using a high-impedance battery like a coin cell or lithium thionyl chloride battery? The 100 mW needed for a typical transmission can overwhelm a high-impedance power supply; and many battery chemistries will give much lower life when discharged at a high rate than at a low rate.
The Model 4906 Supercap Feather Wing is designed to bridge this gap. It includes a 1 farad CAP-XX HW103 supercapacitor ("supercap"), charge-control circuitry to manage the supercap, and a 2.7 V buck regulator that operates from any 2.4 V to 5 V power supply to create a low-impedance 2.7 V power supply. In between transmissions, the charge controller trickle-charges the supercap, storing energy while keeping the instantaneous load low. Then, while your board is transmitting, the supercap provides a burst of power to allow you to do your work before going back to a low power state.
Supercaps, like batteries, store charge. Unlike batteries, supercaps store charge on the plates of a capacitor, rather than storing charge chemically. Supercaps won't hold charge nearly as long as batteries; but they charge and discharge much more efficiently, with very little energy lost to heat. They also retain their performance over many more charge / discharge cycles, and have a design life of ten years.
The output voltage drops as the supercap is discharged, and therefore this module is intended for use with Feather form-factor boards that contain integrated boost regulators, such as MCCI's Catena 4801, Catena 4612 and Catena 4618. Such boards can work with input voltages from 1.8 V to 2.7 V.
Specifications and Features
- Dimensions: 2" x 0.9"
- Input voltage 3 V nominal (2.4V to 5V)
- Input impedance: 1k ohms.
- Output voltage 2.7 V nominal, 2.75 V max
- Input connector JST-PH2
- Output connector JST-PA3 (center pin no-connect)
- Test points are provided for monitoring performance during prototyping
- Open-source hardware
- Datasheet available here
- Schematics and Gerber files available on GitHub
- Datasheet for CAP-XX HW-103 one farad supercap here
Volume discounts and custom variants are available. Contact MCCI via email (firstname.lastname@example.org) for assistance.