PCO-6131 FIXED PULSED/CW LASER
DIODE DRIVER MODULE
•
Economical OEM Module
•
0A to 125A Output
•
2.5kW Maximum Average Output
Power
•
20V Maximum Output Voltage
•
User Adjustable Rise Time
•
<100nS to DC Pulse Width
•
Repetition Frequency Single Shot
to 500kHz
•
Current Monitor Output (Optional)
The PCO-6131 is a compact, OEM-style high
power pulsed current source designed to drive
diode lasers, bars and arrays in pulsed, QCW or
CW modes. It delivers output current variable
from 1A to 125A, pulse widths variable from
<100ns to DC, and pulse repetition frequencies
variable from single-shot to 500KHz at duty
cycles up to 100%.
The PCO-6131 features a user-adjustable
variable rise time control. This innovative feature
allows the user to adjust the rise time within a
range of <30ns to >2.5µs by means of a PCB
mounted potentiometer, to optimize the driver’s
rise time for the user’s application.
The PCO-6131 is based on a hysteretic, average
current, switch-mode regulator. This type of
regulator is a variable frequency, variable pulse
width design which maintains current in an
energy storage inductor between a minimum and
maximum level. The ripple is limited to the
minimum and maximum current determined by
the hysteretic controller. The regulator is started
when the TTL "enable" line is taken high and runs
as long as the enable is high. The use of the
hysteretic regulator provides a large input range
and high efficiency.
A shunting switch shorts the output of the
regulator until output current is needed. The
pulse is generated by opening the shunt switch
for the length of the input pulse.The pulse rise
and fall times are then limited only by the stray/
parasitic capacitance and inductance of the
shunting switch and output leads.
No power is dissipated in the driver until it is
enabled. When enabled, at 125A maximum
output approximately 75W is continuously
dissipated in the driver to maintain the current in
the energy storage inductor (see note #1 on
next page for more information).
The PCO-6131 requires user-supplied +24VDC
support power, a CMOS (+5V) gate signal, and a
TTL-level enable/ disable signal. The high current
output is derived from the +24VDC DC input. The
output pulse width and frequency are controlled
by the gate signal. The output current amplitude
is controlled by a PCB-mount potentiometer.
A current monitor output may be viewed with an
oscilloscope, providing a straight-forward means
to observe the diode current waveform in real-
time.
To protect the laser diode and the driver, circuitry
is incorporated into the driver that disables the
output if the +24VDC support power drops below
18V. Clamp diodes are incorporated into the
output network to protect the laser diode against
reverse voltage conditions.
The rugged, compact design and high power
capability of the PCO-6131 make it an excellent
OEM choice for driving high power laser diodes.
PARAMETER VALUE
PULSE OUTPUT CURRENT
Amplitude Range 0A to 125A
Means Of Adjustment Trimpot Mounted on PCB
or External Analog Voltage
Program. Jumper Selectable
Output Polarity Positive
Pulse Rise Time Variable From <30nS to >2.5uS
(10% to 90%) User Adjustable
Through Trimpot Mounted on PCB
Pulse Width <100nS to DC
Pulse Recurrence Frequency
Range
Single Shot to 500kHz
Maximum Duty Cycle 100%
Output Pulse Ripple/Droop ~2A (<2% at 125A)
Jitter <3nS First Sigma
Efficiency >75% at 50% Duty Cycle 125A
Output *
Output Connector High Current DSUB PCB Mounted
DIODE FORWARD VOLTAGE
Amplitude 20V Maximum
GATE INPUT
Type Positive Edge Trigger
Gate Input +5V CMOS
CURRENT MONITOR OUTPUT
Current Monitor (PCA-9155
Optional)
1000A/1V Terminated Into 50Ω
+3% Of The Actual Current
Current Monitor Connector BNC
CONTROL FUNCTIONS
Output Enable/Disable TTL Input High = Enabled
GENERAL
Input Power +24VDC Unregulated *
Operating Temperature 0ºC to 40ºC
Cooling Air Cooled
Dimensions (D X W X H) 6.5” x 8” x 3.3” (16.51cm x 20.3cm
x 8.4cm)
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Specifications
*The idle power consumption (power consumed when the driver is enabled but
not pulsing) varies non-linearly with output current, and can be approximated by
the formula P
IDLE
=I² x 0.023 where I is the output current setpoint. When pulsing,
the switching losses (P
SW
) are about 30W. Therefore the 24VDC power
requirements can be approximated by the formula P
SW
+ [I
OUT
V
OUT
+ I
OUT
²
(0.030)]DC + P
IDLE
(1-DC) where V
OUT
is the diode forward voltage and DC is
the duty cycle. For example, at 40A output current, 10V diode voltage and 30%
duty cycle, the power consumption is 30W + [40A x 10V + 40A² x 0.03].3 + [40A²
x 0.023](1-.3) = 190W. The +24VDC support power should be sized to provide
this average power.
