LM3421 and LM3423 Controllers

Texas Instruments' LM3421 and LM3423 are versatile high voltage N-channel MosFET controllers for LED drivers. They can be easily configured in buck, boost, buck-boost, and SEPIC topologies. This flexibility, along with an input voltage rating of 75V, makes the LM3421 and LM3423 ideal for illuminating LEDs in a large family of applications.

Adjustable high-side current sense voltage allows for tight regulation of the LED current with the highest efficiency possible. The LM3421 and LM3423 use predictive off-time (PRO) control, which is a combination of peak current-mode control and a predictive off-timer. This method of control eases the design of loop compensation while providing inherent input voltage feed-forward compensation.

The LM3421 and LM3423 devices include high-voltage startup regulators that operate over a wide input range of 4.5 V to 75 V. The internal PWM controller is designed for adjustable switching frequencies of up to 2.0 MHz, thus enabling compact solutions.