ltc3105 400ma step-up dc/dc converter

8/8/2019 LTC3105 400mA Step-Up DC/DC Converter

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© 2005 Linear Technology

Linear TechnologyCorporation

October 2010

Tony ArmstrongDirector of Product Marketing, Power Products

© 2005Linear Technology

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• 400mA Step-Up DC/DC Converter with Maximum Power Point ControlEnergy Harvesting Power Supply

• Low Start-Up Voltage: 250mV

• Auxiliary 6mA LDO Regulator

• Burst ModeR Operation: IQ = 22µA

LTC3105: What Is It?





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LTC3105 : Key Features

• Low Start-Up Voltage: 250mV

• Maximum Power Point Control

• Wide VIN Range: 0.2V to 5V

• Auxiliary 6mA LDO Regulator

• Burst Mode Operation: IQ = 22µA

• Output Disconnect and Inrush Current Limiting

• VIN > VOUT Operation

• Antiringing Control

• Soft Start• Automatic Power Adjust

• Power Good Indicator


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LTC3105: Example Low Voltage Power SourcesMicroPelt ThermoElectric Generator Single PhotoVoltaic Cell

ESR ~=350 ohms

MPP ~ = 75% of Voc





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LTC3105: PhotoVoltaic Reference Data

Energy Available at Various Light Conditions Relative to Full Sun

100% Ful l sun-panel square to sun

71% Ful l sun-panel at 45 degree angle to sun

60-80% Light overcast

20-30% Heavy overcast

91% Inside window, single pane, double strength glass,

window and module square to sun

84% Inside window, double pane, double strength glass,

window and module square to sun

64% Inside window, single pane, double strength glass,

window module at 45 degree angle to sun

0.4% Indoor office light -at desk top

1.3% Indoor light -s tore lighting

0.2% Indoor light – home

This information came from the following link:

http://www.oksolar.com/pv/calculations_key_concepts.htm

Indoor Light has 500x lessavailable energy than direct

Sunlight!


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LTC3105 – Typical Application





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LTC3105 – Output Current vs VSOURCE ofTypical Application


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LTC3105 – Start-Up Sequence

Typical Converter Start-Up Sequence





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LTC3105: Block Diagram Review

Power Good

MPPC Setpoint

Shutdown InputMain Output

LDO Output

VAUX

Low Voltage Start Up circuitryLTC3525 type Boost Engine


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Integrated MMPC-Why is it Important?

MPPC Enables Maximum Energy Collection Without CollapsingSource Voltage





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LTC3105: Simple Maximum Power Point Control

• Maximum Power PointControl circuit servo’s Vin toequal V(MPPT)

• V(MPPT) = 5uA x R(MPPT)

• Optimal V(MPPT) = ~ 75% ofVoc for Solar Cell and 50%of Voc for Voltage source

with ESR

V(MPPT)


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LTC3105 Package Options





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Typical Market Applications•Wireless Sensor Networks

•Solar Powered Battery/Supercapacitor Chargers

• TEG Energy Harvesting

•Remote Industrial Sensors

•Cell Phone, MP3, PMP and GPS AccessoryChargers

ltc3105 400ma step-up dc/dc converter

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