For the first time, the first SOTB embedded controller will allow powerful, connected applications to source energy from the environment. For this reason, it includes an integrated energy harvesting controller on chip.
This unique peripheral is designed to allow the microcontroller to start from an energy harvesting source and also to manage external rechargeable batteries or super capacitors to provide a power reservoir.
There are many issues that must be resolved when designing an energy harvesting application. For example, one of the biggest problems when using a normal microcontroller is managing the start-up current, as an energy source can normally only supply a small amount of current at any time. Yet a normal microcontroller will typically use significantly more current than is available from the energy source during the start-up phase.
The energy harvesting controller on the R7F0E017 manages this start up current along with the whole start up sequence, so thmicrocontroller starts up reliably and safely.
Figure 5 shows the energy harvesting controller implemented on the R7F0E017.
The R7F0E017 is able to run safely from a pure energy harvesting power source due to the operation of the Energy Harvesting Controller. The device can operate from a wide range of potential energy sources including solar power, vibration, pressure and temperature difference, and many others. The integrated energy harvesting controller, supported by very few inexpensive external components, completely manages the cyclic wake-up sequence of the microcontroller, only using the extremely low energy harvesting source current. The energy harvesting controller includes internal ‘inrush-current’ protection and can operate at very low voltage level to avoid malfunctions during the start-up phase.