TPS61251

1
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
diagram schematic
Features Benefits
Resistor programmable input current limit from 100 to 1500mA with 10 accuracy _at_ 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 V Bulk 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
Applications

• Source Current Limited Applications
• Battery Backup Applications

• Li-Ion Applications
• Audio Applications

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TPS61251 3.5MHz, 1.5A current limit, 92
efficient Boost Converter for Battery Backup
Charging
Features
Benefits

• 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 mm2

• Resistor Programmable Input Current Limit from
  100 to 1500mA with 10 accuracy _at_ 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

Applications

• 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

RLIM ILIM Adjustable
VIN ILIM High limit ( 1.5A )
GND ILIM Low limit ( 100mA )
TPS61251EVM-517
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TPS61251 advantages vs comp

• Vout 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 Vout 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
• Vout lt 2.3 V and indicates the discharge of the
  capacitor.
• Vout lt 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.

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Snooze Mode

• What is it?
• Its an enhanced power save mode automatically
  activated when the load goes below 2mA.
• Vout 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 Iloadgt 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
LTC3125
TPS61251
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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
diagram schematic
Features Benefits
Resistor Programmable Input Current Limit from 100 to 1500mA with 20 accuracy _at_ 500mA Avoids overloading the power source and eliminates the need for an external load switch
100 Duty-Cycle Mode When VIN gt VOUT Output voltage is still regulated if VingtVout
Load disconnect Protects 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
Applications

• USB Host Supplies from a single cell
• Battery Backup Applications

• Current limited applications
• Audio Applications

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TPS61252 3.5MHz, 1.5A, 92 efficient Boost
Converter with adjustable input current limit
Features
Benefits

• Resistor Programmable Input Current Limit from
  100 to 1500mA with 20 accuracy _at_ 500mA
• 100 Duty-Cycle Mode When VIN gt VOUT
• Load disconnect
  
• 2x2 QFN and 1.0 µH Inductor

• Avoids overloading the power source and
  eliminates the need for an external load switch.
• Output voltage is still regulated if VingtVout
• Protects the device from reverse current
• Smallest solution size 10x7 mm2

Applications

• USB Host Supplies from a single cell Li-Ion
• Current limited applications
• Single cell Li-Ion battery power applications
• Audio Applications

RLIM ILIM Adjustable
VIN ILIM High limit ( 1.5A )
TPS61252EVM-667
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TPS61252 advantages vs comp

• 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 Vout 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

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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
• Vout lt 2.3 V and indicates the discharge of the
  capacitor.
• Vout lt 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