Environmental sensor board demonstrates IoT PMICs
The board measures ambient temperature, humidity, air-pressure and illuminance. Data collected by the board is sent from the MCU by Bluetooth (BLE) to an app on smartphones or tablets.
RIOT-001 has various PMICs which feature ultra-low supply current and low output noise level. A PV cell powers the sensor board, and energy is initially collected by the R1800 Buck DC/DC Converter and stored in Nichicon’s 0.35 mAh Small Lithium-Ion secondary Battery (SLB). The R1800 has reverse current protection preventing charging loss. Using a PV cell according to the specifications of the RIOT-001 board makes battery-free operation possible.
The RP604 Buck-Boost DC/DC converter regulates the SLB battery voltage as it is charging and discharging to provide stable power to the MCU, Bluetooth (BLE) transmitter and sensors. It has a wide operating voltage from 1.8 V to 5.5 V and high efficiency operation in both standby and active modes.
The SLB battery voltage is measured by an advanced battery monitor embedded in a RP124 LDO. The RP124 has a built-in resistor divider and voltage follower as a buffer to minimise measurement losses. The device has a lower current flow to ground and the output is compatible with the input impedance of the A/D converter.
An alternative power source is available in the form of the RIOT-C01 (sold separately) add-on board with a CR2032 coin battery that can be connected to the main board. A second reason the use the RIOT-C01 is to shorten the initial charging time of the SLB battery as it can take a while for a PV cell to charge the battery.
More information
Related news
PMIC halves size while extending battery life for wearables
Easy-to-use single-chip solution safeguards sensitive data
Renesas denies Maxim acquisition talks
IoT E-Book looks at opportunities and obstacles for IIoT
If you enjoyed this article, you will like the following ones: don't miss them by subscribing to :