Linear Technology, LTC3105, Linear Tech
400mA Synchronous Step-Up DC/DC Converter with Maximum Power Point Control & 250mV Start Up for Energy Harvesting Applications
News Release from:
Linear Technology (UK) Limited
19 January 2011
Linear Technology has announced the LTC3105, a high performance, synchronous boost converter that incorporates maximum power point control (MPPC) and starts up with inputs as low as 250mV. The LTC3105 operates over an extremely wide input range of 0.2V to 5V, making it ideal for harvesting energy from high impedance alternative power sources, including photovoltaic cells, thermoelectric generators (TEGs) and fuel cells. The LTC3105's internal 400mA synchronous switches maximize efficiency while its Burst Mode operation offers quiescent current of only 22uA, further optimizing converter efficiency overall operating conditions. A user-programmable MPPC set point maximizes the energy that can be extracted from any power source without collapsing its internal voltage.
The LTC3105 is ideally suited to power wireless sensors and data acquisition applications. Surplus or ambient energy can be harvested and then used to generate system power in lieu of traditional wired or battery power, which may be expensive or impractical. Typically, these applications require very low average power, but require periodic pulses of higher load current. For example, the LTC3105 can be used in wireless sensor applications where the power load is extremely low when the sensor is in standby mode, interrupted by periodic high load bursts, when the circuitry is powered up to take measurements and transmit data.
The LTC3105 offers an auxiliary LDO that delivers up to 6mA of output current to power external microcontrollers and sensors while the main output is charging. Once fully charged, the main output can deliver voltages as high as 5.25V with up to 100mA of output current. It can also regulate VOUT even when VIN is greater than or equal to VOUT, offering further design flexibility. In shutdown, the LTC3105 offers output disconnect, isolating VIN from VOUT, requiring only 4uA of quiescent current. The combination of the LT3105's 3mm x 3mm DFN package (or MSOP-12) and very small external components offers a very compact solution for energy harvesting applications.
Summary of Features of the LTC3105:
* Low Start-Up Voltage: 250mV
* Maximum Power Point Control for High Impedance Sources
* Wide VIN Range: 0.2V to 5V
* Auxiliary 6mA LDO Regulator
* Burst Mode Operation: IQ = 22uA
* Output Disconnect & Inrush Current Limiting
* VIN > VOUT Operation
* Anti-Ringing Control
* Soft Start
* Automatic Power Adjust
* Power Good Indicator
* 10-Lead 3mm x 3mm DFN or MSOP-12 Package