The first key challenge for LED lighting in medical applications is the large LED forward current and the limited number of LED drivers that can output the large current needed to meet requirements in market. For example, in an endoscope application, a design can potentially require an LED driver to output high current (up to 40A) to compensate optical attenuation by fiber. The second challenge is high linearity for LED current and no ripple current, especially in small LED current situations. This is especially true for IVD applications. The third challenge is a high PWM frequency (potential higher than 10kHz) to dim LEDs without the banding effect, as required in operating rooms.