The LTC3783 is a current mode LED driver and boost, flyback and SEPIC controller that drives both an N-channel power MOSFET and an N-channel load PWM switch. When using an external load switch, the PWMIN input not only drives PWMOUT, but also enables controller GATE switching and error amplifier operation, allowing the controller to store load current information while PWMIN is low. This feature (patent pending) provides extremely fast, true PWM load switching with no transient overvoltage or undervoltage issues; LED dimming ratios of 3000:1 can be achieved digitally, avoiding the color shift normally associated with LED current dimming. The FBP pin allows analog dimming of load current, further increasing the effective dimming ratio by 100:1 over PWM alone.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.