DC1497A: 100mA @ 38V Max, 6 ~ 55V in, Buck

Summary

Demonstration circuit 1497A is a 60V triple step-down LED driver featuring the LT3597. The demo board is optimized for 9 white LEDs, 100mA output per regulator from a 48V input. When different number or different color of LEDs is used for evaluation, attentions should be given to the maximum output voltage setting and fault reporting. The connections between the board and LEDs strings should be as short as feasible.

The circuit achieves 10,000:1 PWM dimming at 100Hz PWM frequency. LED dimming can also be done by analog control of the CTRL1-3 pin. If dimming is not required, leave the PWM1-3 and CTRL1-3 terminals unconnected.

The demo circuit pulls PWM1-3 and CTRL1-3 pins up to VREF. The switching frequency is set to 1MHz on the demo circuit for best solution size. The LT3597 internal compensation makes it a lot easier for a designer to design different application circuits.

The LT3597 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this quick start guide for demo circuit 1497A.

Specifications

Manufacturer	Analog Devices Inc.
Category	Lighting
Sub-Category	LED Drivers - DC In
Eval Board Part Number	505-DC1497A-ND
Eval Board Supplier	Analog Devices Inc.
Eval Board	Normally In Stock
Voltage In	6 ~ 55 V
Topology	Step Down
Current Out	100 mA
Voltage Out (Max)	38 V
Outputs and Type	3 Non-Isolated
Efficiency @ Conditions	>87%, 48V in, 29V @ 100 mA
Features	Current Limit (Adj. or Fixed) Open Circuit Protection Short Circuit Protection Shutdown, Enable, Standby Soft Start Synchronizable Thermal Protection
Switching Frequency	200 kHz ~ 1 MHz
Component Count + Extras	29 + 20
Design Author	Linear Technology
Application / Target Market	Automotive LCD Backlighting LCD TV / Monitor Lighting: LED Signage Medical
Main I.C. Base Part	LT3597
Date Created By Author	2011-02
Date Added To Library	2015-06