DC2257A

DC2257A demonstration circuit features the LTM®8005, a 38VIN, 38VOUT boost μModule® LED driver that can disconnect the output to protect against faults and provides spread spectrum switching to simplify emissions compliance. The demo circuit requires application of an external voltage to the PWM terminal for operation. The external voltage can be a DC level or an appropriate PWM dimming signal. Common frequencies for PWM dimming are 100Hz or higher. Analog dimming is achieved using CTRL inputs. DC2257A allows adjustments to output voltage, output current, input current, switching frequency, frequency modulation rate including disable, feedback loop compensation, EN/UVLO threshold, OVLO threshold, soft start period, and fault latch-off or hiccup. In most cases, adjustment is made by modifying the appropriate resistor or capacitor components.

• DC2257A is an LED driver with an input range for normal operation from 6V to 27V
• OVLO becomes active for inputs above 29V and the maximum input voltage is 38V
• LED current is 1.2A and the base switching frequency is 350kHz
• Efficiency is 92% when the input is 12V with a 35V LED load
• 35V is the maximum LED voltage