An 3000:1PWM dimming ratio of three channel output LED driver

Ling Li (Linear Technology) published a 2.1MHz DC to DC converter (DC-DC) --LT3492, this element is designed to operate as a three channel constant current LED driver. LT3492 can be driven by 96% efficiency of thirty Ma 300 LED.

Each channel in the three group of channels is operated by an independent real color pulse width modulation (True Color PWM) signal, so that each channel can be independently adjusted with a high light rate of 3000:1. The constant frequency, current mode architecture, to ensure stable operation in a wide range of supply and output voltage range; and frequency adjustment pin also allows users to 330kHz and 2.1MHz to set the frequency, the optimal efficiency and to minimize the size of external components.

LT3492 thermally enhanced 4 mm x 5 mm QFN (or thermally enhanced TSSOP) package, more than 50 watts LED applications provide very fine solution for small footprint. The LT3492 can sense the output current at the LED high voltage side to perform the buck, boost, or boost configuration. Through the external sense resistor, the user can set the output current range for each channel, three independent driving channels each have internal 600 Ma, 60 volt NPN switch, also has a built-in gate driver to disconnect PMOS. Other features include open circuit LED protection and thermal limits.

Characteristic

True Color PWMTM dimming can provide up to 3000:1 dimming ratio

Built in gate driver for PMOS LED disconnect

Three independent driver channels with 600mA, 60V internal switches

Can work in the buck, boost, buck - boost mode

CTRL pin can be set accurately in the range of 10mV to 100mV to detect the current threshold of LED

Adjustable frequency: 330kHz to 2.1MHz

Open circuit LED protection

Wide input range:

Operating voltage range from 3V to 30V

Transient protection to 40V

Surface mount assembly

28 pin (4mm x 5mm) QFN and TSSOP package

application

RGB lighting

Billboards and large displays

Automotive and Avionics lighting

Constant current source