QUICK START GUIDE
Demonstration System EPC9150
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DESCRIPTION
The EPC9150 demonstration board is primarily intended to drive laser
diodes with high current pulses with total pulse widths of < 3 ns possible
(half amplitude full width). The board is shipped with a EPC2034C
enhancement mode (eGaN®) eld eect transistor (FET). The EPC2034C is
a 200 V FET capable of current pulses up to 214 A. The EPC9150 ships with
the EPC9989 interposer board. The EPC9989 has a collection of break-
away 5 mm square interposer PCBs with footprints for dierent lasers and
a collection of other footprints. The use of the interposers allows many
dierent lasers or other loads to be mounted while still being able to use
the EPC9150. The boards do not include a laser diode or load, which must
be supplied by the user.
The power stage of the EPC9150 comprises a ground-referenced eGaN
FET driven by a Texas Instruments LMG1020 gate driver. The printed
circuit board is designed to minimize the power loop inductance while
maintaining mounting exibility for the laser diode or other load. It
includes multiple on-board passive probes for voltages and discharge
capacitor current, and is equipped with high bandwidth SMA connectors
for input and sensing. In addition, the board includes a narrow pulse
generator capable of sub-nanosecond precision, or the user can simply
send the input to the gate drive directly. As shipped, the board is
designed to operate from 3.3 V logic, but is equipped with both a logic
level translator and a dierential receiver to accommodate dierent use
cases. Finally, the board can also be used for other applications requiring a
ground-referenced eGaN FET, e.g. Class E ampliers or similar. A complete
block diagram of the circuit is given in Figure 1, and a detailed schematic
in Figures 7, 8, and 9.
For more information on the EPC2034C eGaN FET, please refer to the
datasheet available from EPC at www.epc-co.com. The datasheet should
be read in conjunction with this quick start guide. In addition, EPC provides
an application note: AN027 eGaN FETs for Lidar – Getting the Most Out of
the EPC9126 Laser Driver. While the note discusses Rev. 2 of the EPC9126,
most of the methods and analysis are applicable to the EPC9150.
QUICK START PROCEDURE
The EPC9150 demonstration board is easy to set up to evaluate the
performance of the EPC2034C eGaN FET. Refer to Figure 2 for proper
connect and measurement setup and follow the procedure below:
1. Review laser safety considerations. Observe all necessary laser
safety requirements including the use of personal protection
equipment (PPE) as required. Refer to qualied safety personnel
as necessary.
2. With power o, install laser diode U2 or other load. The use of one
of the interposers from the included EPC9989 be used to mount the
laser or other load, and this is discussed in the section LASER DIODE
OR LOAD CONSIDERATIONS.
3. With power o, connect the input power supply bus to +V
BUS
(J11)
and ground / return to –V
BUS
(J11) or GND.
4. With power o, connect the logic supply (5.5-12 V
DC
) to +V
Logic
(J10)
and ground return to –V
Logic
(J10) or GND.
Table 1: Performance Summary (T
A
= 25°C) EPC9150
Symbol Parameter Conditions Min Nom Max Units
V
Logic
Gate drive and
logic supply
5.5 12
V
V
BUS
Bus Input
Voltage Range
0
160
Z
IN
Input impedance 50 Ω
V
INPUT
Input pulse range 0
5
V
T
Pin
Input pulse width 1 ns
5. With power o, connect the signal pulse generator to the input J7.
J7 is terminated with 50 Ω on the EPC9150, and is designed for a
3.3 V logic input as shipped. This can be changed as discussed in
Section OTHER FEATURES of this guide.
6. Connect the remaining measurement SMA outputs to an
oscilloscope, using 50 Ω cables and with the scope inputs set to 50
Ω impedance. See section MEASUREMENT CONSIDERATIONS
for more information, including the attenuation values for each
output.
7. Turn on the logic supply voltage to a value within the
specications.
8. Turn on the bus voltage to a value within the specication.
9. Turn on the pulse source and observe switching operation via the
outputs and any additional desired probing. Laser diode output
may be observed with an appropriate electro-optical receiver.
10. Once operational, adjust the bus voltage, input pulse width, and
pulse repletion frequency (PRF) as desired within the operating
range and observe the system behavior.
11. For shutdown, please follow steps in reverse.
LASER SAFETY WARNING: This board is capable of driving laser diodes
to generate high power optical pulses. Such pulses are capable of causing
PERMANENT VISION DAMAGE AND BLINDNESS as well as additional
injury or property damage. Laser diodes may emit infrared (IR) light that
is invisible to the user, but which can still cause PERMANENT VISION
DAMAGE AND BLINDNESS as well as additional injury or property
damage. User is fully responsible for following proper laser safety
procedures to prevent injury or damage.