DEI PVX-4140 B User manual

PVX-4140 B
±3500 V Pulse Generator
Operating Manual
Directed Energy, Inc.
1609 Oakridge Dr., Suite 100
Fort Collins, CO80525
[phone]
[e-mail]
https://directedenergy.com
Document #7650-0038 Rev A1. © Copyright 2019 Directed Energy, Inc. All rights reserved.

TABLE OF CONTENTS
1.0 GENERAL DESCRIPTION .............................................................................4
2.0 SPECIFICATIONS..........................................................................................4
3.0 SAFETY..........................................................................................................4
3.1 Power Source............................................................................5
3.2 Grounding .................................................................................5
3.3 General Operating Precautions.................................................5
4.0 OPERATING CONSIDERATIONS .................................................................5
4.1 Output Cabling .....................................................................................5
4.2 Load Simulation ...................................................................................6
4.3 Gate Input ............................................................................................6
4.4 High Voltage Inputs..............................................................................6
4.5 Output Pulse Considerations ...............................................................6
4.6 Controls and Indicators ........................................................................7
4.6.1 Power Switch and LED...........................................................7
4.6.2 Enable Button and LED..........................................................7
4.6.3 Gate Connector......................................................................7
4.6.4 Gated LED .............................................................................7
4.6.5 Over Current LED...................................................................7
4.6.6 Control Error LED...................................................................8
4.6.7 Current Monitor ......................................................................8
4.6.8 Voltage Monitor ......................................................................8
4.7 Remote Control .......................................................................10
5.0 PREPARATION FOR USE ...........................................................................12
5.1 General ..............................................................................................12
5.2 Initial Inspection ............................................................................12
5.3 Electrical Installation ..........................................................................12
5.3.1 Input Power Cord .................................................................12
5.4 Electrical Check .................................................................................12
5.4.1 Power-Up .............................................................................12
6.0 OPERATING INSTRUCTIONS.....................................................................14
6.1 Power-Up Procedures........................................................................14
6.2 Power-Down Procedures ...................................................................14
7.0 TROUBLESHOOTING..................................................................................15
7.1 Troubleshooting Procedures..............................................................15
7.1.1 Fuses ...................................................................................15
8.0 SYSTEM FAILURE MODES.........................................................................15
8.1 Over-Current Failure ..........................................................................15
9.0 WARRANTY .................................................................................................16
10 Factory Service..............................................................................................17

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Document #7650-0038 Rev A1. © Copyright 2019 Directed Energy, Inc. All rights reserved.
1.0 GENERAL DESCRIPTION
The DEI PVX-4140 B is a solid-state high-voltage pulser designed to drive capacitive
loads such as grids and deflection, reflection and acceleration plates.
The instrument features an output voltage swing of up to 3500 V, peak current of up
to 25 A, and continuous current of up to 0.1 A. It can output DC as well as very flat
voltage pulses into a capacitive load.
The PVX-4140 B generates single-ended output pulses from ground to +3500 V or
from ground to -3500 V; it can also generate pulses originating from a voltage offset
from ground. The offset can range from -3500 V to +3500 V with a maximum
differential of 3500 V.
2.0 SPECIFICATIONS
Reference the PVX-4140 B datasheet on the website for the specifications:
https://directedenergy.com
3.0 SAFETY
The high voltage capability of this instrument dictates caution when operating it. The
following is a summary of general safety precautions that must be observed during all
phases of operation of the PVX-4140 B.
WARNING
•Risk of lethal electric shock. Do not touch the output or load while the PVX-
4140 B is operating. This instrument produces LETHAL levels of electric
current at its output.
•DO NOT OPERATE THIS INSTRUMENT UNLESS ANOTHER PERSON,
CAPABLE OF RENDERING FIRST AID OR RESUSCITATION, IS PRESENT.
•SAFE AND PROPER OPERATION OF THIS INSTRUMENT IS THE
RESPONSIBILITY OF THE USER.
•The cover should NEVER be removed. There are NO user-serviceable items
inside.
•Always turn the high voltage power supplies and the PVX-4140 B OFF prior to
working with the load or input and output cables.
•Do not remove the input or output cables while the instrument is in operation. Never
short-circuit the output. Failure to observe these precautions can result in potential
electric shock to personnel, arcing, and damage to the connectors and the
instrument.

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•Pulsed power systems are capable of random triggering via transients. Whenever
the PVX-4140 B is turned on, or voltage is present in the chassis, assume a pulse
can appear on the output connector.
Directed Energy, Inc. (DEI) provides information on its products and associated
hazards, but it assumes no responsibility for the after-sale operation and safety
practices.
3.1 Power Source
The PVX-4140 B is designed to operate from a power source that will not apply more
than 240 volts AC between the supply conductors or between either supply conductor
and ground.
A protective grounding connection by way of the grounding conductor in the AC power
cord is essential.
3.2 Grounding
The PVX-4140 B is grounded through the grounding conductor of the AC power cord.
To avoid electrical shock, plug the PVX-4140 B into a properly wired receptacle
before making connection to any input or output connectors. Use only a power
cord that is in good condition.
3.3 General Operating Precautions
Do not remove the input or output cables while the instrument is in operation. Never
short-circuit the output. Failure to observe these precautions can result in potential
electric shock to personnel, arcing, and damage to the connectors and the instrument.
4.0 OPERATING CONSIDERATIONS
4.1 Output Cabling
The PVX-4140 B is designed to drive capacitive loads with fast rise times. Since the
output current is limited, increasing the load capacitance lengthens the rise time. If the
load is fixed, only the type and length of the interconnecting cable will vary the output
capacitance.
The instrument is supplied with a 6-foot length of RG-59 coaxial cable that has a
capacitance of 21.5 pF per foot. The instrument is series-terminated in the
characteristic impedance of the cable (75 Ω). DEI recommends using the shortest
possible cable to ensure the fastest rise times and best pulse fidelity.

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4.2 Load Simulation
The PVX-4140 B was tested with a 50 pF capacitive load connected to the output via
6 feet of RG-59 coaxial cable.
4.3 Gate Input
A logic level of +5 V ±1 V into 50 Ωwith a rise time of <20 ns is required to gate the
PVX-4140 B. Departure from these values can result in a loss of performance. These
requirements are met by any high-quality, logic-level pulse generator. The source
should be configured to +5 V ±1 V into 50 Ωbefore the cable is attached to the PVX-
4140 B Gate input. The amplitude of the gate pulse should be set using a 50 Ωload
(e.g., a 50 Ωscope input) before connecting it to the PVX-4140 B. If the gate pulse is
greater than +5 V into 50 Ω, pulse stretching can occur.
4.4 High Voltage Inputs
The absolute maximum rating for the high voltage inputs is ±3500 V. In addition, the
+HV Input must never be greater than +3500 V above the -HV Input. Precautions
should be taken to ensure that these maximum voltages are not exceeded.
4.5 Output Pulse Considerations
The PVX-4140 B can generate single-ended output pulses from ground to +3500 V or
from ground to -3500 V. It can also generate pulses originating from a voltage offset
from ground. This offset can be from -3500 V to +3500 V, but the +HV Input should
always be equal to or greater than the -HV Input and never greater than +3500 V
above the -HV Input.
If the instrument is operated with a single power supply for unipolar pulses, the unused
high voltage input must be grounded.
When the Gate input is high, the +HV Input is switched to the output. When the Gate
input is low, the -HV Input is switched to the output. The PVX-4140 B can generate a
negative-going pulse by logically inverting the Gate input so that the Gate input is high
until a pulse is generated. When the Gate input goes low, the -HV Input is switched to
the output, thereby generating a negative going pulse (see the figure below).

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Generating a Negative Pulse with the PVX-4140 B
4.6 Controls and Indicators
4.6.1 Power Switch and LED
The power switch on the rear panel controls all AC power in the instrument. The
Power LED on the front panel illuminates when AC power is turned on.
4.6.2 Enable Button and LED
The Enable button enables and disables the pulse output. The Output Enabled
LED illuminates when the output is enabled.
4.6.3 Gate Connector
Logic-level pulses at the Gate input control the output. The input requirements are
+5 V into 50 Ωwith a rise time less than 20 ns. The output pulse follows the Gate
input signal’s pulse width and frequency.
4.6.4 Gated LED
The Gated LED illuminates when a gate signal of the appropriate amplitude and
width is received. If the Gated LED is not illuminated, the PVX-4140 B will not
generate an output pulse.
4.6.5 Over Current LED
The Over Current LED illuminates if the output pulse current exceeds either the
positive or negative current limit value.
Input Gate:
+5
V
Ground
Output Pulse:
V
high
V
low

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NOTE: Depending on the value of high voltage, the over current limit may or may
not be exceeded even when the load is shorted.
If the Over Current LED illuminates when the PVX-4140 B is in Auto Reset mode
(see Section 4.7), the pulse output will be inhibited for 6 to 7 milliseconds. If Auto
Reset is not enabled, the instrument must be manually reset. (A manual reset is
accomplished by pressing the Enable button twice: Once to reset the fault, and the
second time to enable the output. The instrument may also be reset via the remote
reset function. See section 4.7.)
If the Over Current LED illuminates continuously, the cause of the over current
fault should be corrected before attempting to operate the instrument.
4.6.6 Control Error LED
To permit burst mode operation, the Control Error LED is not used in this
instrument model.
4.6.7 Current Monitor
The Current Monitor BNC connector provides a 10 A per V scaled version of the
output current for display on an oscilloscope. The scope input impedance should
be 50 Ω.
4.6.8 Voltage Monitor
The Voltage Monitor BNC connector provides a 1 V per 1000 V scaled version of
the output pulse voltage for display on an oscilloscope. The scope input
impedance should be 1 MΩ.

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4.7 Remote Control
The PVX-4140 B can be operated via remote control. The following table provides
the pinout of the Remote Interface connector (DA-15 socket) on the rear panel.
PIN
FUNCTION
DESCRIPTION
1
GND
Ground
2
GND
Ground
3
GND
Ground
4
GND
Ground
5
GND
Ground
6
Enable Status
Output: Active low, open drain, 24 mA
maximum ON, 24 V DC maximum OFF
7
Control Error Status
Output: Active low, open drain, 24 mA
maximum ON, 24 V DC maximum OFF (not
used)
8
Power Status
Output: Active low, open drain, 24 mA
maximum ON, 24 V DC maximum OFF
9
Enable
Input: Low-to-high transition to enable, disable,
reset
10
Invert
Input: Pull low to invert the Gate input
11
Remote
Input: Pull low for remote operation
12
Interlock
Input: Pull low to satisfy the interlock
13
Auto Reset
Input: Pull low to enable auto reset
14
Over Current Status
Output: Active low, open drain, 24 mA
maximum ON, 24 V DC maximum OFF
15
Gated Status
Output: Active low, open drain, 24 mA
maximum ON, 24 V DC maximum OFF