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Published byLucinda Robinson Modified over 9 years ago
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Applications TPS61251 3.5MHz, 1.5A Current Limit, 92% Efficient Boost Converter for Battery Backu BOOST CONVERTER FOR BATTERY BACKUP CHARGING WITH ADJUSTABLE CONSTANT CURRENT AND SNOOZE MODE FeaturesBenefits Resistor programmable input current limit from 100 to 1500mA with 10% accuracy @ 500mA Avoids overloading the source and gives control over the charge current of the capacitor Capable to charge large capacitor (Farad Range) Enables back up solution for system current surge Snooze mode draws only 2 ́ (typ) Quiescent Current Drastic reduction (more than 90%) of Iq optimizes efficiency and allows extended battery lifetime Output voltage up to 6.5 VBulk capacitors with higher voltage rating can be used which implies bigger amount of energy for a given capacitance. 1.0 ̈ Inductor & 2x2 QFN package Smallest solution size C 10x7 mm2 diagram schematic Source Current Limited Applications Battery Backup Applications Li-Ion Applications Audio Applications
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Resistor Programmable Input Current Limit from 100 to 1500mA with ±10% accuracy @ 500mA Designed to charge large capacitor (Farad Range) Snooze mode draws only 2 μA (typ) Quiescent Current, Output voltage up to 6.5 V,, Power Good in shutdown, 2x2 QFN + 1.0 µH Inductor TPS61251 3.5MHz, 1.5A current limit, 92% efficient Boost Converter for Battery Backup Charging Current limited Applications with high peak current loads (SSDs, PCMCIA Tx bursts, Memory, GPRS/GSM Tx) Battery Backup Applications Single cell Li-Ion battery power applications Audio applications RF-PA buffer Avoids overloading the source and gives control over the charge current of the capacitor Enables back up solution for system current surge. Drastic reduction (more than 90%) of Iq optimizes efficiency and allows extended battery lifetime. Bulk capacitors with higher voltage rating can be used which implies bigger amount of energy for a given capacitance: Allows to power the follow-on circuit until the output voltage is below 2.3V maximizing the use of energy in the storage capacitor. Smallest solution size – 10x7 mm 2 R LIM I LIM = Adjustable V IN I LIM = High limit ( 1.5A ) GN D I LIM = Low limit ( 100mA ) TPS61251EVM-517
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V out up to 6.5V Higher voltage rate bulk capacitors Reduces capacitances for a given energy Reduces total solution cost. Wider programmable input current range, giving higher flexibility in terms of input energy source. TPS61251 accuracy is 10% vs 5% from LTC. We guarantee the accuracy for a much wider current window (100mA to 1500mA vs 200mA to 1000mA) Power Good function built in to indicate whether the V out reaches the programmed value & therefore the capacitor is fully charged. Operation: PG is set high if the feedback voltage reaches 95% of its nominal value. The PG comparator operates even in shut down mode when EN is set to low and/or VIN is turned off. This guaranties power good functionality until the capacitor is discharged. The PG output goes low when: ◘V out < 2.3 V and indicates the discharge of the capacitor. ◘V out < 2.0 V all internal circuitry is disabled. Therefore the PG open drain output becomes high resistive and follows the voltage the pull-up resistor is connected to. While the output capacitors are still charged the converter can be disconnected from its supply but it will still supply a follow-on circuitry with energy needed for a secured shut down. TPS61251 advantages vs comp
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Snooze Mode What is it? It’s an enhanced power save mode automatically activated when the load goes below 2mA. V out with ±2% is maintained Iq for this mode is 2uA (typ) We achieve this by switching off as many internal regulation circuits as possible. If I load > 2mA, Vout drops and the converter wakes up to recharge the cap.
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Snooze mode Allows maximum efficiency over the load range LTC3125TPS61251
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Applications TPS61252 3.5MHz, 1.5A, 92% Efficient Boost Converter with Adjustable Input Current L 3.5MHz, 1.5A, 92% efficient Boost Converter with adjustable input current limit FeaturesBenefits Resistor Programmable Input Current Limit from 100 to 1500mA with 20% accuracy @ 500mA Avoids overloading the power source and eliminates the need for an external load switch 100% Duty-Cycle Mode When VIN > VOUT Output voltage is still regulated if Vin>Vout Load disconnectProtects the device from reverse current Power Good (PG) output with wider operating window PG: - High when feedback voltage is 95% of nominal value. - Low when feedback voltage falls to 90% of nom. value. 2x2 QFN and 1.0 ̈ Inductor Smallest solution size C 10x7 mm2 diagram schematic USB Host Supplies from a single cell Battery Backup Applications Current limited applications Audio Applications
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Resistor Programmable Input Current Limit from 100 to 1500mA with ±20% accuracy @ 500mA 100% Duty-Cycle Mode When V IN > V OUT Load disconnect 2x2 QFN and 1.0 µH Inductor TPS61252 3.5MHz, 1.5A, 92% efficient Boost Converter with adjustable input current limit USB Host Supplies from a single cell Li-Ion Current limited applications Single cell Li-Ion battery power applications Audio Applications Avoids overloading the power source and eliminates the need for an external load switch. Output voltage is still regulated if Vin>Vout Protects the device from reverse current Smallest solution size – 10x7 mm 2 R LIM I LIM = Adjustable V IN I LIM = High limit ( 1.5A ) TPS61252EVM-667
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Wider programmable input current range, giving higher flexibility in terms of input energy source. Wider output voltage range up to 6.5V TPS61252 current accuracy is 20% vs 5% from LTC. We guarantee the accuracy for a much wider current window (100mA to 1500mA vs 200mA to 1000mA) Power Good function built in to indicate whether the V out reaches the programmed value PG is set high if the feedback voltage reaches 95% of its nominal value. PG is set low when the feedback voltage falls to 90% of its nominal value. TPS61252 allows for a smaller total solution size TPS61252 has a better output voltage accuracy, ±1.5% vs ±2.4% TPS61252 advantages vs comp
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TPS61251 & TPS61252 differences TPS61251 is optimized for charging bulk capacitors TPS61252 is a regular boost converter. TPS61252 current accuracy is 20% vs 10% from TPS61251 Snooze Mode only available with TPS61251 Power Good function is different for both devices: TPS61251 -PG is set high if the feedback voltage reaches 95% of its nominal value. -The PG comparator operates even in shut down mode when EN is set to low and/or VIN is turned off. This guaranties power good functionality until the capacitor is discharged. -The PG output goes low when: ◘V out < 2.3 V and indicates the discharge of the capacitor. ◘V out < 2.0 V all internal circuitry is disabled. Therefore the PG open drain output becomes high resistive and follows the voltage the pull-up resistor is connected to. While the output capacitors are still charged the converter can be disconnected from its supply but it will still supply a follow-on circuitry with energy needed for a secured shut down. TPS61252 – As described before
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