DEMO MANUAL DC2103A LTC3107EDD Ultralow Voltage Energy Harvester and Primary Battery Life Extender Description Demonstration circuit 2103A featuring the LTC 3107 is a circuit has been set up with battery terminals to allow for highly integrated DC/DC converter designed to extend the different battery configurations to be used. Please con- life of a primary battery in low power wireless systems by sult the schematic for proper switch positioning. Space harvesting and managing surplus energy from extremely is provided, and alternate part footprints have been built low input voltage sources such as thermoelectric gen- into the PCB to allow experimentation with larger capaci- erators (TEG). The step-up topology operates from input tors and different battery types for more energy storage. voltages as low as 20mV. Refer to the data sheet for more information including The DC2103A demonstration circuit has been optimized equations to properly size the output capacitors for a for low start-up voltage with a 100:1 turns ratio trans- given application. former. For applications where it is desirable to trade-off The DC2103A demo board also incorporates a connector a higher start-up voltage for higher current, a lower turns (J1) which can be used to connect to a Dust Networks ratio transformer can be used. Refer to the LTC3107 data mote demo board sheet for more information. The LTC3107 data sheet has detailed information about The LTC3107 is designed to accumulate and manage the operation, specification, and applications of the part. energy from low voltage and low impedance sources The data sheet should be read in conjunction with this while providing battery backup with seamless transitions Quick Start Guide. between Energy Harvesting (EH) and battery power. Design files for this circuit board are available at By utilizing the EH source when it is available, the life of DEMO MANUAL DC2103A Quick s Dp Using short twisted pair leads for any power connections AA alkaline batteries can also be used. In that case, the and with all loads and power supplies off, refer to Figure 1 switches should be configured to connect the batteries in for the proper measurement and equipment setup. The series as described below for the 2 battery case. Power Supply (PS1) should not be connected to the circuit The demo board can also be powered by a power supply, until told to do so in the procedure below. or any other custom battery configuration, (the voltage The LTC3107 and therefore the demo board require a battery needs to be within 2V to 4V) by connecting the source to operate and regulate the output voltage, even if a source between VBATT and ground using the terminals provided is available at the VIN terminals. The battery provides a on the demo board (E9 and E10) reference for the output voltage regulation loop. Several NOTE: The battery voltage, at the VBATT pin, should be battery options are provided on the demo board. A coin a minimum of 2V and should not exceed 4V for proper cell battery, CR2032 can be used by populating BTH1 and operation. setting SW1 in the appropriate position (see schematic When measuring the input or output voltage ripple, care and step 2 below). A CR2032 battery is provided with the must be taken to avoid a long ground lead on the oscil- demo board. Alternatively, battery holders are provided for loscope probe. Measure the input or output voltage ripple AA size batteries. In the case of a primary battery such as by touching the probe tip directly across the VLDO or a Lithium Thionyl Chloride battery, in a AA case size, which VOUT and GND terminals. See Figure 2 for proper scope has a terminal voltage of 3.6V, a single battery should be probe technique. used and the switches configured as described below. Two Figure 1. Connection Diagram dc2103af 2 ure roce tart