Constant Off Time PWM Current-Mode Controller for LED Applications

The NCL30105 is a peak current controlled fixed off time controller
designed for LED driver applications in which the LEDs are operated
in deep Continuous Conduction Mode (CCM) without requiring slope
compensation. Featuring an adjustable off time generator, the
controller can drive a MOSFET up to a 500 kHz switching frequency.
A dedicated dimming pin enables the use of a pulse−width
modulated logic signal to dim the LEDs directly. The soft−start pin
creates a startup sequence that slowly ramps up the peak current and
enables the adjustment of the peak current setpoint for analog
dimming control. The device features robust protection features to
detect switch overcurrent faults and to detect maximum on time
events.
Features
• Constant Off Time Current−Mode Control Operation
• Adjustable Off Time (0.5 s to 10 s)
• Internal Leading Edge Blanking
• Source 250 mA / Sink 500 mA Peak Drive Capability
• ±3.2% Current Sense Accuracy at 25°C
• Internal Startup Delay
• 3.3 V Logic Level Dimming Input
• This is a Pb−Free Device
Safety Features
• Thermal Shutdown
• Maximum On Time Protection
• Overcurrent Protection
Typical Application
• LED Backlight Drivers for LCD Panels
• LED Light Bars
• LED Street Lighting
• LED Bulbs