LED Driver with Dynamic Headroom Control and Thermal Control Interfaces from the PowerWise® Family

National Semiconductor LM3464

Features

  • Wide input voltage range (12V-80V)
  • Dynamic Headroom Control ensures maximum efficiency
  • 4 output channels with individual current regulation
  • High channel to channel accuracy
  • Digital PWM/Analog dimming control interface
  • Resistor programmable dimming frequency & minimum duty cycle (analog dimming mode)
  • Direct interface to thermal sensor
  • Fault detection
  • Over temperature protection
  • Thermal shutdown
  • Under voltage lockout
  • Thermal enhanced eTSSOP-28 package

National Semiconductor - LM3464

Description

The LM3464 is a 4-channel high voltage current regulator that provides a simple solution for LED lighting applications. The LM3464 provides four individual current regulator channels and works in conjunction with external N-channel MOSFETs and sense resistors to give accurate driving current for every LED string. Additionally, the Dynamic Headroom Control (DHC) output can be interfaced to the external power supply to adjust the LED supply voltage to the lowest level that is adequate to maintain all the string currents in regulation, yielding the optimal overall efficiency.

 

Digital PWM or analog voltage signals can be used to control the duty cycle of the all the channels. When analog control is used, the dimming frequency can be programmed via an external capacitor. A minimum duty cycle control is provided in the conditions that the analog dimming is configured as thermal feedback.

Protection features include VIN under-voltage lock-out, LED open/short circuit and over-temperature fault signaling to the system controller.

Applications

  • Streetlights
  • Solid State Lighting Solutions

Typical connection diagram

LED Driver with Dynamic Headroom Control and Thermal Control Interfaces from the PowerWise® Family
Click to enlarge

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