Transcript LED Current Source

LED Current Source
Design of the circuit to provide constant
current supply to the LED
Calibrate LED with reference to MIP
signal value
Expand the design to accommodate
multiple LEDs connected concurrently
LED Current Source
Pulse Generator
Differentiator/ Amplifier
Current
Mirror
One or more LEDs can be connected to the current mirror in the future
LED Current Source
Pulse generator includes a fast
switching logic clock (possibly a 5-5-5
timer) and logic gates
Output is a square pulse with amplitude
of 2-3V (low-voltage logic for power
conservation)
LED Current Source
Differentiator/Amplifier will be designed
using a 1Ghz fast Op-Amp
Gain factors will range from 0.1 to
about 3-4
Only positive (or negative) pulses will
be used (controlled by a fast switching
diode)
LED Current Source
Current mirror will be designed using
fast switching matched transistors
Current mirrors will be needed
particularly in multi-LED design
Later on similar mirror will be used in
the pre-amplifier design
LED Current Source
LED will be calibrated using Hamamatsu
PMT and APD, and possibly SiPM and
MRS
We are looking into components
Low-power concern is due to a
possibility of battery - powered
operations for portability of the device
(single - LED version only)
LED Current Source
Tentative schedule:
Design and simulations by next Wednesday,
also parts ordered by the end of the week
Prototype completed as parts become
available
Calibrations being a subject to availability of
the second test stand