LED Driver, Synchronous Boost, with PWM Dimming Interface

The FAN5340 is a synchronous constant-current LED driver capable of efficiently delivering up to 500mW to a string of up to four LEDs in series. Optimized for small form-factor applications, the 1.2MHz fixed switching frequency allows the use of chip inductors and capacitors. For safety, the device features integrated short-circuit detection plus over-voltage and thermal shutdown protections. In addition, input under-voltage lockout protection is triggered if the battery voltage is low. Brightness (dimming) control is implemented by applying a PWM signal of 300Hz to 1kHz on the EN pin. During shutdown, the FAN5340 disconnects the LED anodes from the output of the boost regulator, which holds the boost regulator’s voltage on COUT, reducing audible noise from the PWM dimming, and removing power from the LED string.