LD9102

LD9102
High Accuracy Constant Current
Off-Line High Brightness LED Driver

Features
  High accuracy constant current
  Constant frequency or constant off-time operation
  Works with high side current sensing
  Buck switch mode controller
  Internal 350V linear regulator (can be extended using external zener diodes)
  Internal 2% Voltage Reference
  High PWM dimming ratio
  Programmable MOSFET current limit
  Programmable slope compensation
  Output short circuit protection
  Output over voltage protection
  Enable & PWM dimming
  Soft start
  +0.2A/-0.4A GATE drive
  Synchronization capability
  Typical gain 1±1% (Current Monitor)
  Max. VSENSE 500mV (Current Monitor)
  Max. quiescent current 50μA (Current Monitor)

Applications
  TFT flat panel backlighting
  AC/DC LED lamp
  LED traffic light
  T5, T8 LED line bar
  MR-16 lamp
  Signage or decorative LED lamp

General Description
The LD9102 is a current mode control LED driver IC embedded with high side current monitor. It has been designed for the purpose of controlling single buck switch mode PWM converters at a fixed frequency or fixed offtime mode.
The high side current monitor is built to transfers a high side current measurement voltage to its ground referenced output with an accurate voltage gain of one.
This monitor function features with a very wide input voltage range, high accuracy of transfer ratio, and low power consumption. A peak current control scheme is used by the controller (with programmable slope compensation). It includes an internal trans-conductance amplifier to modify the output current in closed loop. This allows high output current accuracy.
For high power applications, the IC also comprises a 0.2A source and 0.4A sink GATE driver. There is an internal 9 to 350V linear regulator which powers the IC. This makes it no longer necessary to separate power supply for the IC. The LD9102 provides a TTL compatible, PWM dimming input that can accept an external control signal with a duty ratio of 0-100% and a frequency of up to a few kilohertz.
The IC has the function of a NERR output which, can be used to disconnect LEDs in the circumstance that there is a fault condition it will use an external disconnect FET. The LD9102 based LED driver ideally suited to RGB backlight applications with DC inputs. The LD9102 based LED lamp drivers can reach efficiency of more than 90%.