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LTC3588-1 - Piezoelectric Energy Harvesting Power Supply

LTC3588-1 - Piezoelectric Energy Harvesting Power Supply
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LTC3588-1 - Piezoelectric Energy Harvesting Power Supply - 1

LTC3588-1 1 35881fa TYPICAL APPLICATION DESCRIPTION Piezoelectric Energy Harvesting Power Supply The LTC®3588-1 integrates a low-loss full-wave bridge rectifi er with a high effi ciency buck converter to form a complete energy harvesting solution optimized for high output impedance energy sources such as piezoelectric transducers. An ultralow quiescent current undervoltage lockout (UVLO) mode with a wide hysteresis window allows charge to accumulate on an input capacitor until the buck converter can effi ciently transfer a portion of the stored charge to the output. In regulation, the LTC3588-1 enters a sleep state in which both input and output quiescent currents are minimal. The buck converter turns on and off as needed to maintain regulation. Four output voltages, 1.8V, 2.5V, 3.3V and 3.6V, are pin selectable with up to 100mA of continuous output current; however, the output capacitor may be sized to service a higher output current burst. An input protective shunt set at 20V enables greater energy storage for a given amount of input capacitance. L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. 100mA Piezoelectric Energy Harvesting Power Supply FEATURES APPLICATIONS n 950nA Input Quiescent Current (Output in Regulation – No Load) n 450nA Input Quiescent Current in UVLO n 2.7V to 20V Input Operating Range n Integrated Low-Loss Full-Wave Bridge Rectifi er n Up to 100mA of Output Current n Selectable Output Voltages of 1.8V, 2.5V, 3.3V, 3.6V n High Effi ciency Integrated Hysteretic Buck DC/DC n Input Protective Shunt – Up to 25mA Pull-Down at VIN 20V n Wide Input Undervoltage Lockout (UVLO) Range n Available in 10-Lead MSE and 3mm × 3mm DFN Packages n Piezoelectric Energy Harvesting n Electro-Mechanical Energy Harvesting n Wireless HVAC Sensors n Mobile Asset Tracking n Tire Pressure Sensors n Battery Replacement for Industrial Sensors n Remote Light Switches n Standalone Nanopower Buck Regulator 35881 TA01 PZ1 VIN CAP VIN2 PZ2 SW VOUT PGOOD D0, D1 LTC3588-1 MIDE V21BL GND 1ìF 6V 4.7ìF 6V CSTORAGE 25V 47ìF 6V OUTPUT VOLTAGE SELECT VOUT 10ìH 2 LTC3588-1 3.3V Regulator Start-Up Profi le TIME (s) 0 VOLTAGE (V) 22 20 18 8 4 10 12 14 16 6 2 0 200 35881 TA01b 400 600 VIN VOUT PGOOD = LOGIC 1 CSTORAGE = 22ìF, COUT = 47ìF NO LOAD, IVIN = 2ìA

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LTC3588-1 - Piezoelectric Energy Harvesting Power Supply - 3

LTC3588-1 3 35881fa E LECTRICAL CHARACTERISTICSThe l denotes the specifi cations which apply over the full operating junction temperature range, otherwise specifi cations are for TA = 25°C. (Note 2) VIN = 5.5V unless otherwise specifi ed. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VIN Input Voltage Range Low Impedance Source on VIN l 18.0 V IVIN VIN Quiescent Current UVLO Buck Enabled, Sleeping Buck Enabled, Sleeping Buck Enabled, Not Sleeping VIN = 2.5V, Not PGOOD VIN = 4.5V VIN = 18V ISW = 0A (Note 4) 450 950 1.7 150 700 1500 2.5 250 nA nA ìA ìA VUVLO VIN Undervoltage Lockout Threshold...

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LTC3588-1 - Piezoelectric Energy Harvesting Power Supply - 4

LTC3588-1 4 35881fa TYPICAL PERFORMANCE CHARACTERISTICS IVIN in UVLO vs VIN IVIN in Sleep vs VIN UVLO Rising vs Temperature UVLO Falling vs Temperature VSHUNT vs Temperature Total Bridge Rectifi er Drop vs Bridge Current TEMPERATURE (°C) –55 UVLO RISING (V) 5.2 5.0 4.6 4.2 4.8 4.4 4.0 3.8 –15 25 65 105 35881 G03 –35 5 45 85 125 D1 = D0 = 1 D1 = D0 = 0 TEMPERATURE (°C) –55 UVLO FALLING (V) 4.2 4.0 3.6 3.2 3.8 3.4 3.0 2.8 –15 25 65 105 35881 G04 –35 5 45 85 125 D1 = D0 = 1 D1 = D0 = 0 D1 = 1, D0 = 0 BRIDGE CURRENT (A) VBRIDGE (mV) 35881 G06 1800 1600 1400 1200 1000 800 600 400 200 0 1ì 10ì...

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LTC3588-1 - Piezoelectric Energy Harvesting Power Supply - 7

LTC3588-1 7 35881fa PIN FUNCTIONS PZ1 (Pin 1): Input connection for piezoelectric element or other AC source (used in conjunction with PZ2). PZ2 (Pin 2): Input connection for piezoelectric element or other AC source (used in conjunction with PZ1). CAP (Pin 3): Internal rail referenced to VIN to serve as gate drive for buck PMOS switch. A 1ìF capacitor should be connected between CAP and VIN. This pin is not intended for use as an external system rail. VIN (Pin 4): Rectifi ed Input Voltage. A capacitor on this pin serves as an energy reservoir and input supply for the buck regulator. The VIN...

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LTC3588-1 - Piezoelectric Energy Harvesting Power Supply - 8

LTC3588-1 8 35881fa The LTC3588-1 is an ultralow quiescent current power supply designed specifi cally for energy harvesting and/or low current step-down applications. The part is designed to interface directly to a piezoelectric or alternative A/C power source, rectify a voltage waveform and store harvested energy on an external capacitor, bleed off any excess power via an internal shunt regulator, and maintain a regulated output voltage by means of a nanopower high effi ciency synchronous buck regulator. Internal Bridge Rectifi er The LTC3588-1 has an internal full-wave bridge rectifi er...

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LTC3588-1 - Piezoelectric Energy Harvesting Power Supply - 9

LTC3588-1 9 35881fa OPERATION UVLO falling threshold before the output voltage reaches regulation, the buck converter will shut off and will not be turned on until the input voltage again rises above the UVLO rising threshold. During this time the output voltage will be loaded by less than 100nA. When the buck brings the output voltage into regulation the converter enters a low quiescent current sleep state that monitors the output voltage with a sleep comparator. During this operating mode load current is provided by the buck output capacitor. When the output voltage falls below the...

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LTC3588-1 - Piezoelectric Energy Harvesting Power Supply - 10

LTC3588-1 10 35881fa OPERATION The D0/D1 inputs can be switched while in regulation as shown in Figure 3. If VOUT is programmed to a voltage with a PGOOD falling threshold above the old VOUT, PGOOD will transition low until the new regulation point is reached. When VOUT is programmed to a lower voltage, PGOOD will remain high through the transition. Energy Storage Harvested energy can be stored on the input capacitor or the output capacitor. The wide input range takes advantage of the fact that energy storage on a capacitor is proportional to the square of the capacitor voltage. After the...

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