说明

The TPS61251 device provides a power supply solution for products powered by either a three-cell, NiCd or NiMH battery, or a one-cell Li-Ion or Li-polymer battery. The wide input voltage range is ideal to power portable applications like mobile phones, solid state drives (SSD) and wireless modems. The converter is designed to charge large capacitors in the Farad range to support battery back up applications. During capacitor charging the TPS61251 is working as a constant current source until V_OUT has reached its programmed value. The charge current can be programmed by an external resistor R_ILIM and provides a ±10% accuracy for the average input current limit.

The TPS61251 in combination with a reservoir capacitor allows the converter to provide high current pules that would exceed the capability of the suppling circuit (PC slot, USB) and keeps the slot power safely within its capabilities.

特性

• Resistor Programmable Input Current Limit
  • ±10% Current Accuracy at 500mA over Full Temperature Range
  • Programmable from 100mA up to 1500mA
• Snooze Mode Draws Only 2 µA (typ.) Quiescent Current
• Designed to Charge Large Capacitor Values in the Farad Range
• Up to 92% Efficiency
• Power Good Indicates Appropriate Output Voltage Level even in Shut Down
• V_IN Range from 2.3V to 6.0V
• Adjustable Output Voltage up to 6.5V
• 100% Duty-Cycle Mode When V_IN > V_OUT
• Load Disconnect and Reverse Current Protection
• Short Circuit Protection
• Typical Operating Frequency 3.5 MHz
• Available in a 2×2-mm QFN-8 Package
• APPLICATIONS
  • Current Limited Applications With High Peak Power Loads
    (SSD, PCMCIA Tx Bursts, Memory, GPRS/GSM Tx)
  • Li-Ion Applications
  • Battery Backup Applications
  • Audio Applications
  • RF-PA Buffer