LTC3783PWM LED driver with boost, flyback and SEPIC stylescontroller
peculiarity
- True Color PWMTMProvides constant color and a dimming ratio of 3000:1
- Fully integrated load FET driver for PWM dimming control of high power LEDs
- 100:1 dimming from analog inputs
- Wide FB voltage range: 0V to 1.23V
- Constant current or constant voltage regulation
- Low shutdown current: IQ= 20µA
- Internal 1.23V voltage reference with 1% accuracy
- 2% RUN pin threshold with 100mV hysteresis
- An External Resistor Can Be Used to Set the Operating Frequency from 20kHz to 1MHz
- Can be used with one frequency up to 1.3FOSCExternal clock synchronization
- Internal 7V low dropout regulator
- Programmable output overvoltage protection
- Programmable soft-start
- Available in a sense resistor (No RSENSETM) mode (VDS
- 16-pin DFN and TSSOP packages
description
LTC®The 3783 is a current mode LED driver and boost, flyback, and SEPIC type controller that drives an N-channel power MOSFET and an N-channel load PWM switch. When an external load switch is used, the PWMIN input not only drives PWMOUT, but also enables controller GATE switch and error amplifier operation, allowing the controller to store load current information when PWMIN is low. This feature, which is under patent review, enables extremely fast, true PWM load switching without transient overvoltage or undervoltage issues; The 3000:1 LED dimming ratio can be achieved digitally, avoiding the color shift common with LED current dimming. The FBP pin provides simulated dimming of the load current, resulting in a 100:1 increase in the effective dimming ratio compared to PWM alone.
At the output load, the current must return to VIN, optional constant-current/constant-voltage regulation is used to control the output (or input) current or output voltage and provide a limit for another parameter. ILIMA 10:1 analog dimming ratio is provided.
For low- to medium-power applications, the senseless mode maximizes efficiency by utilizing the on-resistance of the power MOSFETs and eliminating the need for a current-sense resistor.
The IC can be set to operate from 20kHz to 1MHz with an external resistor and can be synchronized to an external clock using the SYNC pin.
The LTC3783 is available in 16-lead DFN and TSSOP packages.
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- An array of high-voltage LEDs
- Telecom power supplies
- 42V automotive system
- 24V industrial control
- IP phone power supply