Two-channel LED drivers for High CRI professional and consumer lamps

February 20, 2013 // By Christoph Hammerschmidt
Atmel announced three two-channel solid state lighting (SSL) LED drivers that provide accurate color control for two-color LED light engines. In addition, the LED drivers deliver efficient power management, with low component count for high CRI LED lamps.

Designed for applications including general lighting, residential and commercial lighting, architectural lighting, and mood lighting, the LED drivers consist of the Atmel MSL2021, MSL2023, and MSL2024; all can be accompanied with an Atmel AVR MCU or ARM processor-based MCU for a complete system solution in a variety of luminaires and lamp configurations.

The MSL2021/23/24 LED devices have several distinct advantages when compared to existing LED drivers:

  1. The devices drive one dominant LED string with a linear controller and one color LED string with a low-side buck controller to achieve the target correlated color temperature (CCT) coordinate, and replicate the color spectrum to attain a high CRI value.
  2. The devices have a look-up table in the EEPROM so designers can program accurate profiles to follow the desired CCT compensation curve, lowering the overall bill of materials (BOM) cost.
  3. The linear controller for white LEDs in the device family adaptively controls the headroom of any AC/DC or DC/DC, isolated or non-isolated topology, while external MOSFETs give designers the flexibility of choosing LED currents and LED string lengths.
  4. There are several dimming options and I2C interface for additional flexibility and control.
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"White point control of an LED lamp is a key challenge for designing high-performance general, architectural or mood lighting," said Tushar Dhayagude, Director of LED Products, Atmel Corporation. "The MSL2021/23/24 LED devices address this key issue by enabling the control of two strings, typically comprising of white and red or amber LEDs, to provide precise white color control, while providing extraordinary power efficiency, flexibility and wide power levels for the lamps."

Key features for the three new devices include:

  1. MSL2021 — the first LED driver with integrated temperature compensation for the color LED string;
  2. MSL2023 — offering I2C serial port and internal pulse-width modulation (PWM) generators;
  3. MSL2024 — featuring individual PWM input pins.
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To accelerate a design, evaluation kits are also available through your local sales representative. The kits include