The HV9910BDB3 demoboard is a high current LED driver designed to drive one LED or two LEDs in series at currents up to 1.0A from a 10 – 30VDC input. The demoboard uses HV9910B Universal LED driver IC to drive a buck converter. The HV9910BDB3 can be configured to operate in either a constant frequency mode (for driving a single LED) or in a constant off-time mode (for driving two LEDs). The output current can be adjusted in two ways – either with linear dimming using the onboard potentiometer or with PWM dimming by applying a TTL – compatible square wave signal at the PWMD terminal. Using linear dimming, the output current of the HV9910DB1 can be lowered to about 0.01A (note: zero output current can be obtained only by PWM dimming).