LT3956

• Product introduction

LT3956

80Vin, 80Vout constant current, constant voltageconverter

peculiarity

• 3000:1 True Color PWM^TMDimming
• Wide input voltage range: 4.5V to 80V
• Output voltage up to 80V
• Internal 3.3A/84V switch
• Constant current and constant voltage regulation
• 250mV high-side current sensing
• LEDs can be driven in boost, buck, buck-boost, SEPIC or flyback topologies
• Adjustable frequency: 100kHz to 1MHz
• Open circuit LED protection
• Programmable undervoltage lockout with hysteresis
• Constant voltage loop status pin
• PWM disconnect switch driver
• The CTRL pin regulates the high-side current sense threshold
• Low shutdown current:
• Programmable soft-start
• Available in a 36-pin (5mm x 6mm) QFN package

• description

  LT^®The 3956 is a DC/DC converter designed to act as a constant current source and constant voltage regulator. It is ideal for driving high-current LEDs. The device features an internal low-side N-channel power MOSFET specified for 84V at 3.3A and driven from an internally regulated 7.15V supply. The fixed-frequency, current-mode architecture enables stable operation over a wide range of supply and output voltages. A ground-referenced voltage FB pin serves as input to several LED protection circuits and also enables the converter to act as a constant voltage source. A frequency adjustment pin allows the user to set the frequency from 100kHz to 1MHz to optimize efficiency, performance, or external component size.

  LT3956 inLEDThe high side of the string senses the output current. High-side current sensing is the most flexible solution for driving LEDs, allowing boost, buck, or buck-boost mode configurations. The PWM input provides LED dimming ratios up to 3000:1, while the CTRL input provides additional analog dimming capability.

• apply

  • High power LEDs
  • Battery charger
  • Accurate current-limited voltage regulator