DC1497A Analog Devices

DEMO MANUAL DC1497A LT3597 60V Triple Step-Down LED Driver Description Demonstration circuit 1497A is a 60V triple step-down LED The demo circuit pulls PWM1-3 and CTRL1-3 pins up driver featuring the LT3597. The demo board is optimized to V . The switching frequency is set to 1MHz on the REF for 9 white LEDs, 100mA output per regulator from a 48V demo circuit for best solution size. The LT3597 internal input. When different number or different color of LEDs compensation makes it a lot easier for a designer to design is used for evaluation, attentions should be given to the different application circuits. maximum output voltage setting and fault reporting. The The LT3597 data sheet gives a complete description of connections between the board and LEDs strings should the part, operation and application information. The data be as short as feasible. sheet must be read in conjunction with this quick start The circuit achieves 10,000:1 PWM dimming at 100Hz guide for demo circuit 1497A. PWM frequency. LED dimming can also be done by analog Design files for this circuit board are available at control of the CTRL1-3 pin. If dimming is not required, DEMO MANUAL DC1497A F MA s UMMAr Y (T = 25C) A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V * Input Supply 6 55 V IN V LED String Voltage 28 34 V LED V Maximum Output Voltage 38 V OUT(MAX) I Output Current R23 = R24 = R25 = 20k 98 100 102 mA OUT DIM PWM Dimming Ratio PWM Dimming Frquency = 100Hz 10,000:1 FSW Switching Frequency R22 = 33.2k 0.9 1 1.1 MHz EFE Efficiency V = 48V, V = 29V, I = 100mA, BIAS = 5V, No Dimming 87 % IN OUT OUT *Actual V range should be determined by the load. For 9 white LEDs per channel, use a 48V input for evaluation. IN dc1497af 2 nce or per