LED driver for industrial and medical displays

Linear Technology has launched the LT3596, a 60V, 1MHz step-down DC/DC converter designed to operate as a constant-current LED driver for up to 30 LEDs in billboards, industrial displays and more.

From a 48V input, the LT3596 can drive up to three strings of LEDs, each with up to 10 100mA LEDs in series, delivering efficiencies of more than 90 per cent.

The LT3596's multichannel capability makes it suitable for medical displays.

Its input voltage range of 6V to 60V makes it suitable for automotive and industrial applications.

The LT3596 offers +1.5 per cent LED current matching to ensure uniform display brightness and True Color PWM dimming offers dimming ratios as high as 10,000:1.

A programmable 200kHz to 1MHz fixed frequency operation and current-mode architecture ensures stable operation over a range of supply and output voltages, minimising the size of external components.

Additionally, the switching frequency is synchronisable to an external clock.

The LT3956's thermally enhanced 5 x 8mm QFN package provides a compact solution footprint for LED backlighting applications.

The LT3596 uses a single 800mA, 60V internal switch to provide a step-down constant-current source.

The internal buck converter uses an adaptive feedback loop to regulate the output voltage slightly higher than the required LED voltage to ensure maximum efficiency.

If any of the LED strings experience an open or short-circuit, it will continue to regulate the other strings and signal the fault pin.

Additional features include LED current de-rating based on junction temperature and/or LED temperature and LED disconnect in shutdown.

The LT3596EUHG is available in a 39-lead 5 x 8mm QFN package.

An industrial-grade version, the LT3596IUHG is tested and guaranteed to operate from a -40C to 125C operating junction temperature.

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