POWERELECTRONICS
Lowpower components for IoT and energy harvesting
Ricoh introduces new products to help lower power consumption, improve features and power without batteries or mains
A
common trend in semiconductor design has always been to design products as
small as possible and with a minimum of power consumption, typical features intended for portable devices. Today, these features are extremely important for those applications intended to work independently, powered by photovoltaic cells or other alternative power sources. In this article we would like to introduce a
few products to give you the inspiration to develop your next application with a minimum of current consumption, great features and powered without batteries or mains power.
Energy Harvesting The R1810 Boost DC/DC Converter is a smart solution designed for powering low current consuming IoT devices by extracting energy from Photovoltaic cells.
Autonomous operating wireless devices
significantly reduce the cost and labour of regularmaintenance to replace batteries. However, photovoltaic cells usually supply a voltage which is way below the desired operating voltage of the application, therefore a special circuit is required that collects, converts and stores energy in an external energy storage capacitor, followed by regulation of the output voltage to the required level. The R1810 is especially tailored for this
purpose and starts up with only 9µW provided froma single cell photovoltaic element, the start-up voltage is only 0.5V and once started, the operation continues even if the input voltage drops until 0.2V. The advanced R1810 has an internally fixed maximumpower point voltage (VMP output voltage setting (VSET
) and ) to optimise the performance of the electrical circuit with
respect to the selected energy harvester type. Once sufficient energy available on the input and increases above the VMP level, the boost DC/DC Converter will be enabled to transfer energy frominput to the output. When the amount of transferred power exceeds the supplied power fromthe photovoltaic cell, the input voltage decreases below VMP and the DC/DC converter stops switching. Twomonitoring circuits indicate the status
of the conversion process on respective outputs. The Input Power Good function becomes active when the output voltage level falls below the VOUTUVLO
voltage and
whether the DC/DC converter stops switching for at least 1.5 seconds. Another Output Power Good function indicates that the output voltage level drops below 50 to 80% of its nominal level, this threshold is internally set and specified by the product version. A built-in reverse current protection is
enabled to prevent a current flow from output to input when light on the photovoltaic cell is blocked. As soon as the input voltage drops below the output voltage, the high side MOSFET transistor is turned off to avoid a reverse current draining the energy storage capacitor.
Buck-Boost DC/DC Converter Another RP605 Buck-Boost DC/DC converter, with a wide operating voltage from1.8 to 5.5V, is used to regulate the fluctuating storage voltage as it is charged and
24 SEPTEMBER 2021 | ELECTRONICS TODAY
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