ANALOG DEVICES DC1666A Demonstration Board, 1 Output, 60 V in, 2 A/25.5 V Out, Synchronous Buck-Boost, Analogue/PWM

DC1666A demonstration circuit is a synchronous four switch buck-boost LED driver controller. It accepts an input voltage from 4.7V to 60V, and drives up to 25V of LEDs at 2A. DC1666A features both PWM and analogue dimming of the LED string. It has an OPENLED flag that indicates when the LED string has been removed and it has a SHORTLED flag that indicates that the output has been shorted to GND. In both cases, the IC remains in control and well protected. DC1666A features very high efficiency at 300KHz switching frequency and continuous conduction mode (CCM). The synchronous four-switch topology both steps up and steps down voltage while regulating up to 50W of constant LED output current at efficiencies up to 98%. The circuit can be altered for applications requiring over 100W of LEDs. An optional SYNC terminal is provided for synchronizing to an external clock and CLKOUT terminal provides a source to sync another converter to the internal clock of the LT®3791.

• 2.0A ILED current (CTRL = Float, 7V < PVIN < 57.6V)
• 9.5V < VLED < 25.5V VLED range (R7 = 1M, R9 = 44.2k)
• 28.3V open LED voltage (R7 = 1M, R9 = 44.2k)
• 11A peak switch current limit boost region (RS = 0.004ohm)
• 10A valley switch current limit buck region (RS = 0.004ohm)
• Simple PWM dimming