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EETE SEP 2015

Fig. 2: LTC3106 configured as a solar harvester with primary battery backup powering a wireless network node. while creating an output voltage up to 5V from either input source. Figure 1 shows a typical schematic. The LTC3106 employs a PowerPath™ control architecture to allow the use of a single inductor to generate a user-selectable fixed regulated output voltage through seamless transition between either of the two power inputs. If input power is available (VIN) the buck-boost regulator will operate from VIN, provi-ding up to 300mA to the load. Should the VIN source become unavailable, the regulator will select VSTORE/VCAP as its input delivering up to 50mA to the load. If a rechargeable battery is used as the backup source, a low current recharge power path is also provided allowing use of excess input energy to charge the backup source if the output voltage is in regulation. User selectable upper and lower charge/discharge thresholds are available to handle multiple battery chemistries and to protect the battery from overcharge/deep discharge. Charging can be externally disabled using the PRI when a primary battery is used as the backup source. The main input voltage, VIN, can be configured to operate over a voltage range from 850mV to 5.1V without a back-up source and from 330mV to 5.1V with a back-up source, like a primary battery. This range accommodates multiple power source types including high impedance sources such as a small solar panel. To ensure maximum power extraction, the LTC3106 Fig. 3: Measured I-V and P-V curves under variable light conditions for AM-1816. Piezo Switch with raised symbols PCB-POOL® is a registered trademark of Beta LAYOUT GmbH PSE HI - Robust Piezo Switch for vandal proof use - Excellent legibility lettering - Various symbols, letters, numerals, braille pse-hi.schurter.com Flex PCB Prototypes & Small Series NEW ! Flexible PCBs: • Favourable pricing – thanks to PCB-POOL ® production • Online Calculation • Made in Germany Email: sales@pcb-pool.com www.pcb-pool.com www.electronics-eetimes.com Electronic Engineering Times Europe September 2015 31


EETE SEP 2015
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