HV9903

HV9903 Initial Release White LED Driver Features ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ Power efficiency of up to 85% Drives up to 6 White LEDs 2.6V to 4.6V Supply power stage can operate at 1.8V (see page 8) Built-in Soft Start DC and PWM Dimming Control Built-in Open LED protection Open LED indicator (via RSET) 1.2MHz Fixed Switching Frequency 500nA max leakage current when disabled No leakage current path through LEDs when disabled Resistor-programmable LED Current Small 6-lead MLP (3mm x 3mm) package (similar to 6-pin SOT-23) Description The Supertex HV9903 is a fixed frequency DC-DC boost converter designed for driving Light Emitting Diodes (LEDs) with constant current where the light intensity is proportional to the current through them. The input supply voltage range into the device (VDD) is 2.6 to 4.6V. Operation of the driver at lower voltages is possible as long as a 2.6–4.6V lowcurrent supply is available for the HV9903. The device uses a single inductor and a minimum number of passive components. The device can be enabled/disabled via the SHDN pin. The HV9903 has an internal oscillator. The oscillator frequency is at fixed frequency of 1.2MHz that allows use of small value inductors. The LED current can be adjusted from 5 to 40mA by an external resistor connected between the RSET and the GND pins. The amount of current though the LED can also be adjusted via DC voltage or a pulse width modulated (PWM) signal to the RSET pin. Soft-start is implemented on-chip, minimizing inrush...