POWER AND LINEAR IC SOLUTIONS

Constant Current Switching Regulator Optimised for LED Driving

The NCP3065 from ON Semiconductor is a monolithic switching regulator designed to deliver constant current for powering high brightness LEDs. With a wide input voltage range from 3V to 40V, it can be used with the 12VAC or 12VDC supplies commonly found in lighting applications, as well as unregulated supplies such as lead acid batteries.

The device’s characteristics make it suitable for a broad range of applications, including marine lighting, low voltage architectural lighting, driving high power LEDs and general purpose, constant-current source requirements. An automotive grade variant is available for use in applications such as vehicle lighting.



The NCP3065 includes an internal 1.5A switch and can be configured in a controller topology with the addition of an external transistor to support LED currents up to 5A. The device can be configured in step-down (buck) and step-up (boost) topologies with a minimum number of external components.

The IC has a very low feedback voltage of 235mV (nominal) which is used to regulate the average current of the LED string. The use of average current sensing, rather than peak current sense techniques, offers increased accuracy and makes the accuracy of the device independent of output LED forward voltage.

The NCP3065 includes cycle-by-cycle current limiting and uses an adjustable operating frequency of up to 250kHz. An on-chip 0.2V voltage reference allows the use of small, low-cost sense resistors, improving efficiency and thermal characteristics.

The device’s mode of operation means that no control loop compensation is required and it can be used with all ceramic output capacitors or no output capacitance. Dimming can be achieved either under digital or analogue Pulse Width Modulation (PWM) control. The NCP3065 also integrates an internal thermal shutdown feature with hysteresis.

Features

• Constant current switching regulator for LED drivers
• Integrated 1.5A switch
• Up to 5A drive current with external transistor
• Input voltage range from 3.0V to 40V
• 0.2V reference
• Low feedback voltage of 235mV
• Cycle-by-cycle current limit
• No control loop compensation required
• Frequency of operation adjustable up to 250kHz
• All ceramic output capacitors or no output capacitance
• Analogue and digital PWM dimming capability
• Internal thermal shutdown with hysteresis
• Automotive version

Applications

• Automotive and marine lighting
• High power LED driver
• Constant current source
• Low voltage LED lighting
  • (Landscape, path, solar, MR16 replacement)

For further information, including a Datasheet for the NCP3065, please click here