Supertex xx9xxxxDB1 LED Driver Demoboards include the HV9967BDB1 and HV9861ADB1 high-brightness LED driver demoboards and the AT9919BDB1 high current LED driver demoboard. HV9967BDB1 uses the Supertex's HV9967B in a buck configuration in a constant off-time mode to drive 4 LEDs in series at currents up to 350mA from a 20 - 60V DC input. Both of the high-brightness LED driver demoboards feature tight regulation of the LED current within a few milliamps over the entire range of the input voltage. The LED current accuracy is almost insensitive to the passive component tolerances, such as the output filter inductance or the timing resistor. The AT9919BDB1 uses Supertex's AT9919 hysteretic buck LED driver IC to drive one LED at 1.0A from a 9.0 - 16VDC input.
For the HV9967BDB1 and HV9861ADB1, PWM dimming can be achieved by applying a pulse-width-modulated square wave signal between the PWMD and GND pins. For the AT9919BDB1, there are two PWM dimming modes. The analog control of the PWM dimming mode allows the user to dim the LED using a 0 - 2.0V analog signal applied between the ADIM and GND pins. The digital control of PWM dimming mode allows the user to dim the LEDs using an external, TTL-compatible square wave source applied between DIM and GND.