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DESIGN FEATURES L High Voltage Boost / LED Controller Provides 3000 : 1 PWM Dimming Ratio by Eugene Cheung Performance , Accuracy , Versatility : LEDs and Beyond
| Content Provider | Semantic Scholar |
|---|---|
| Author | Cheung, Eugene |
| Copyright Year | 2006 |
| Abstract | Performance, Accuracy, Versatility: LEDs and Beyond The LTC3783 is a current-mode boost controller optimized for constantcurrent True Color PWMTM dimming of high-powered LEDs. Proprietary techniques provide extremely fast, true PWM load switching with no transient undervoltage or overvoltage issues. High dimming ratios of 3000:1 (at 100Hz), important for such applications as video projectors and LCD backlights, can be achieved digitally, maintaining the color integrity of white and RGB LEDs. The LTC3783 also provides an analog input for an additional 100:1 dimming (300,000:1 total). This versatile part can also be used in a boost, buck, buck-boost, SEPIC, or flyback converter, and as a constantcurrent, constant-voltage regulator. No RSENSETM operation uses a MOSFET’s on-resistance to eliminate the currentsense resistor, increasing efficiency. Applications for the LTC3783 include high voltage LED arrays and LED backlighting, as well as voltage regulators in telecom, automotive, and industrial control systems. The LTC3783 operates from input supplies ranging from 3V to 36V, and provides output overvoltage protection while regulating output current. When a sense resistor is used, the maximum output voltage is limited only by external components. The controller includes integrated drivers for power and PWM MOSFET switches, and a variable feedback voltage (0V to 1.23V) allows the designer full control over load current accuracy vs efficiency. These features make the part especially attractive for higher-power LED lighting applications. One resistor sets operating frequency from 20kHz to 1MHz, and, to reduce switching noise interference, the LTC3783 is synchronizable to an external clock. Programmable soft start limits inrush current during startup, preventing input current spikes. In addition to boost operation (VOUT > VIN), the controller offers an alternate constant-current, constant-voltage operating mode for buck-boost or buck applications. In these cases, the achievable PWM dimming ratios are generally lower. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.analog.com/media/en/technical-documentation/lt-journal-article/LTMag-V16N01-08-LTC3783-Cheung.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
