Linear Technology has introduced a 36V step-down DC/DC converter, LT3592, designed to operate as a constant current LED driver. Its internal 36V, 900mA switch enables it to drive up to six 500mA white LED in a single string from a 36V input for industrial and LED signage applications.

LT3592 can also drive two 500mA LEDs from a 12V lead acid battery input for automotive applications. Series connection of the LEDs provides identical LED currents, resulting in uniform brightness and eliminating the need for ballast resistors. LT3592’s switching frequency can be adjusted from 400kHz to 2.2MHz via a single resistor. This enables designers to set the switching frequency above critical frequency bands such as AM radio while minimising external component size.

LED current levels of either 10 per cent or 100 per cent of the programmed value are selectable by driving LT3592’s BRIGHT pin. LT3592 utilises a fixed frequency, high side sense, current mode architecture which is said to provide fast transient response and cycle-by-cycle current limiting. Other features include: shorted and open LED protection, single wire LED capability and thermal shutdown.

LT3592EDDB and LT3592EMSE are both available in 2mm x 3mm DFN-10 or MSOP-10E packages, respectively, priced starting at $1.65 each and $1.75, respectively, in 1,000-piece quantities. For applications requiring a wider temperature range, I-grade versions, namely LT3592IDDB and LT3592IMSE, are also available. 1, 000-piece pricing starts at $1.90 each and $2.01, respectively.