Linear LED driver without external diode cost

Corporation (Linear), before the introduction of high efficiency, constant current white LED driver using LT3491 SC70 package. The LT3491 chip is integrated with a Schottky diode, which eliminates the need for an external diode, thereby saving cost and space. The unique high voltage side LED current sensing topology enables the LED cathode to be connected directly to the ground, resulting in a single line current source.

LT3491 to more than 75% efficiency, from a single lithium-ion battery drive up to 6 white LED. The switching frequency of 2.3MHz, allowing the use of tiny inductors and capacitors, while maintaining switching noise outside key RF band. LT3491 has a high efficiency, low noise and minimal total solution for the board area, making it very suitable for handheld applications requiring up to 6 white LED.

LT3491 is used as a constant current source, regardless of the LED forward voltage changes with temperature, manufacturing tolerance and aging, it provides the same current for each white LED. This ensures that the brightness of the LED is consistent. LT3491 uses true color PWM (True Color PWM) dimming to provide a wide dimming range of up to 300:1. The Internal Overvoltage circuit protects the device when the LED is disconnected.