LED driver for high power machine vision flash
Machine vision systems use very short glare flashes to produce high-speed images for various data processing applications. For example, fast-moving conveyor belts use machine vision systems for rapid labeling and defect detection. Infrared and laser LED flashes are commonly used in machine vision for short-range and motion detection. The security system emits high-speed, imperceptible LED flashes to detect movement, capture and store security images.
A challenge that all these systems have is to generate very high current and short-term (microsecond) LED camera flash waveforms, which may spread out over a long period of time, such as 100 ms to more than 1 s. It is not easy to generate short-term LED flash square waves with longer intervals. When the driving current of the LED (or LED string) rises above 1 A, and the LED turn-on time is shortened to a few microseconds, the challenge is further increased. Many LED driver with high-speed PWM capabilities may not be able to effectively handle long off-time and short-time high currents without degrading the quality of the square wave required to properly process high-speed images.