16-Channel LED Driver Offers 5000:1 True Color PWM Dimming

1st February 2008

ES Admin

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Linear Technology has announced the LT3595, a 45V 2MHz DC/DC buck mode converter designed to operate as a 16-channel constant current LED driver. Each channel of the LT3595 can drive up to ten 50mA LEDs in series, enabling the LT3595 to drive up to 160 50mA LEDs while delivering efficiencies up to 92%. Its multichannel capability makes it ideal for large TFT-LCD backlighting applications. Each of the 16 channels is independently operated and can be dimmed to ratios as high as 5000:1.

A 2MHz fixed frequency, current mode architecture offers stable operation over a wide range of input and output voltages while minimizing the size of the external components. Power switches, Schottky diodes and compensation components are all internal, providing a very small solution footprint while minimizing component cost. Its thermally enhanced 5mm x 9mm QFN package ensures a very compact solution footprint, driving up to 30Watts of LEDs.

The LT3595 uses 100mA, 45V internal switches. An external resistor sets the LED current for all 16 channels and dimming is then controlled for each channel using individual PWM pins. The relative current matching among the 16 drivers is 8%, ensuring uniform LED brightness. The LT3595 also enables LEDs to be disconnected in shutdown, open LED and thermal protection.