59--Development of circuitry for improved LED turn-on and turn-off

Development of circuitry for improved LED turn-on and turn-off Need: A driver for LEDs is sought that significantly improves the turn-on (rise time) and turn-off (fall time) of a pulsed illumination system. The initial intent is to determine if significant improvements over an existing system are possible. A scalable system where multiple LEDs can be combined into an LED module (luminaire) and/or multiple LED modules operated by a driver circuit and/or multiple driver circuitss controlled by a single external system is of ultimate interest. The goal of this RFI is to identify candidate sources for a driver circuit that can provide turn-on and turn-off times significantly faster than 200 nanoseconds when operated under load conditions associated with driving LEDs with a forward voltage of 3.5 volts or greater. Key parameter: The key parameter is the turn-off time of the driver. Using a definition for turn-off time as the time for output signal to decay from 90% to 10% of the quote mark on quote mark state (or a similar definition), a turn-off time of substantially less than 200 nanoseconds must be demonstrated. Specifications of system: LED turn-on and turn-off are to be controlled by 5 volt TTL pulses which will be supplied externally. The hardware and software for generating and supplying the TTL signal are not part of this RFI. The driver circuitry must provide synchronized pulsing of multiple LEDs. Operational environment is conditioned indoor (18 to 27 C; 5% to 60% RH). Adequate heat dissipation for operation under the performance specifications must be considered. When considering the physical size and configuration, the design must allow for scalability through the arrangement of multiple (possibly a dozen or more) LED modules assembled in a 2-D or 3-D array which can be several feet in each dimension and simultaneously driven by one or multiple synchronized drivers. As such, driver performance must be consistent and repeatable within a tight tolerance. Performance Specifications: Parameter Threshold Objective Relative Importance 1 Turn-off time 40 ns 20 ns Critical factor 2 Turn-on time 40 ns 20 ns Critical factor 3 Frequency range 10 Hz to 100 kHza 10 Hz up to 2 MHza Important factor 4 Pulse Width 200ns to .05 S 50 ns to .05 S Important factor 5 Pulse Width Continuously on at reduced power level Continuously on at full power level 5 LED Forward voltage 3.5 V 3.5 V Important factor 6 Max current output of driver 700 mA per LED 1200 mA per LED Important factor Notes: a TTL signal supplied externally by existing system Interested parties must provide oscillographs demonstrating the accomplishment of the critical factors of having designed a circuit which provides the necessary switching speeds as identified in the Performance Specification rows 1 and 2. The amount of current being controlled by the circuit, as well as the type of load to include part type and part number and manufacturer must be provided. Responders must also include the circuit diagram, and are encouraged to submit any other information that supports their accomplishment of having fabricated an electronic system that could meet components of the specification Contact email: contact@example.gov