Berkeley Nucleonics Corporation
2955 Kerner Blvd., San Rafael, CA 94901 ° Tel (415) 453 9955 ° Fax (415) 453 9956 ° www.berkeleynucleonics.com
3. Leave the PCO-6131 connected to the +24 VDC input with the voltage turned
off and with all connectors in place for approximately one minute to bleed off
the stored energy.
4. Disconnect the DC support power to the unit.
6.0 Laser Diode Interconnection Inductance
Application of the PCO-6131 requires an attention to detail to prevent problems
with inductance in the leads and load. BNC has tested the PCO-6131 with laser
diodes to determine how best to apply high current pulses to laser diodes, and the
result of this investigation is presented below.
A stripline is very integral to obtaining good fidelity of current pulses. The strip line
shown in the figures in this note is the stripline supplied with the PCO-6131 and is
available from BNC.
When a stripline is used and connected directly to the laser diode, the fall time was
in the range of 500 ns. When the laser diode was connected to the stripline with
about 6 inches of wire, the fall time degraded to about 6 microseconds. Inductance
negatively affects fall time, and the performance seen with these two
interconnection topologies is consistent with the inductance introduced into the
circuit by the wire interconnections.
For all tests, the laser diode was driven at approximately 50 Amperes. A diode
forward voltage of about 2.4 V was measured, confirming that the laser diode was
correctly wired into the circuit. The repetition frequency was limited to a few Hertz,
eliminating the need to heatsink the laser diode.