Product category: Power Supply ICs and Controllers
News Release from: Maxim Integrated Products | Subject: MAX1682
Edited by the Electronicstalk Editorial Team on 24 August 2007
LED driver offers high brightness
The MAX16821's rapid-current-pulsing LED technology meets the demanding requirements of projection applications
Maxim Integrated Products has released the MAX16821 high-power, synchronous high-brightness LED (HB LED) driver that has rapid current pulsing and is the first to drive common-anode LEDs Its rapid-current-pulsing LED technology meets the demanding requirements of projection applications, thus making it ideal for front-projection, rear-projection TV (RPTV), and pocket-projector applications that require very fast LED dimming capabilities
This article was originally published on Electronicstalk on 13 Dec 2007 at 8.00am (UK)
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LED driver dims three strings
Devices feature three 36V-rated open-drain constant-current sink outputs capable of delivering up to 150mA to three separate strings of HB LEDs.
LED driver range covers many strings
Single-channel devices integrate a pass element with a low, 0.4V (typical) dropout voltage, thus eliminating the need for an external power transistor.
Additionally, the driver architecture of the MAX16821 allows HB LEDs to be mounted in the common-anode configuration, a necessary requirement for truly efficient thermal management that reduces system integration and assembly costs.
The MAX16821 also features a pin configuration capability that allows the device to be operated in either synchronous buck or synchronous boost mode.
Synchronous buck and synchronous boost modes allow the LED driver to operate at very high efficiencies, a performance requirement that is particularly important in high-power applications such as automotive exterior lighting and emergency lighting systems.
The wide switching frequency range (125kHz to 1.5MHz) allows small inductors and filter capacitors to be used in applications such as pocket projectors where system designers are faced with extremely tight space constraints.
For systems requiring multiple drivers, the MAX16821 also features a clock output with 180 degree phase delay that can control a second, out-of-phase LED driver.
This feature can be used to minimise LED current ripple, thereby reducing the size and cost of the input and output filter capacitors even further.
The highly integrated MAX16821 operates from 5.4V to 28V with an LED current-sense voltage of 0.03V, providing the lowest dissipation of power.
Additional features include programmable hiccup, overvoltage protection, reverse current limit, and an output-enable function.
The MAX16821 operates over the automotive temperature range of -40C to +125C and is available in a tiny, lead-free, 5 x 5 x 0.8mm, 28-pin TQFN package with an exposed pad.
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