National Semi Announces LED Drivers With Wide Input Voltage Range
National Semiconductor Corp. added two new light-emitting diode (LED) drivers to its PowerWise® energy-efficient product family. National’s LM3401 and LM3405A LED drivers power 1 to 5W, high-brightness LEDs found in industrial and automotive applications as well as general illumination applications such as solid state and signage. Each offers a wide input voltage range and provides a constant current to regulate the LED brightness and low feedback voltage to minimize power dissipation.
Featuring a voltage range from 4.5 to 35V, National’s LM3401 LED driver includes a scalable current drive of greater than 3A and a 100% duty cycle. A low feedback voltage of 0.2V and accuracy within 3% provides a constant current to provide constant color output from an LED.
The LM3405A LED driver features a voltage range from 3 to 22V and is able to regulate from a loosely coupled 12V ac rail found in industrial and commercial lighting applications. TThe company claims that the small SOT-23 package allows LEDs to be placed into small-form factor light bulbs to offer higher efficiency versus the traditional halogen and incandescent sources for illumination.
The LM3401 is a high-efficiency hysteretic PFET switching controller that provides a high-performance, constant current drive to a string of LEDs resulting in a constant color output. An adjustable hysteretic window allows for flexibility in component selection and overall design simplicity. No external compensation is required. The regulated LED current is sensed and is compared to the reduced feedback of 0.2V for current sensing which eliminates the need for an output capacitor. Offered in an 8-pin mini SOIC package, the LM3401 has programmable over current voltage protection and a DIM input pin for PWM inputs to control dimming.
The new LM3405A extends the voltage range of National’s previously announced LM3405 up to 22V. Offered in a tiny 6-pin SOT-23 package, the LM3405A constant-current buck regulator delivers up to 1A of current to drive 3W or 5W LEDs. With a 0.2V reference voltage for constant-current feedback control, internal compensation and a fixed 1.6 MHz switching frequency, the LM3405A provides a simple, highly-efficient solution for driving LEDs. The LM3405A also includes an EN/DIM pin for pulse-width-modulation (PWM) dimming. The LM3405A drives general illumination for industrial and commercial lighting applications from the 12Vac and 12Vdc rail.
Available now, the LM3401 is priced at $0.75 each and the LM3405A is $1.30 in 1,000-unit quantities.
