The HV9910BDB1 demoboard is an offline, high current LED driver designed to drive a 40V LED string at 1.4A from a 110V input. The demoboard uses HV9910B LED driver IC to drive a buck converter. The HV9910BDB1 has a typical full load efficiency of 88%, with the buck converter efficiency (excluding the diode bridge rectifier and EMI filter) at 93%. The demoboard also meets CISPR-15 conducted EMI standards. 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 0.1A (note: zero output current can be obtained only by PWM dimming).