Stahl-electronics HS-500 User Manual

HS-500

Low Noise High Voltage Switch

HS-500_User_Manual_1_41.doc

18 - January2018

Data Sheet & User Manual

Model Number HS-500 Rev. 1.41

Typical Applications:

● piezo elements

● beam line electrodes / ion optics

● ion traps

Features:

● fast low noise switches (SPDT style)

● max. 500V switching voltage with TTL/CMOS level control

● 35ns intrinsic rise/fall time

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HS-Series User Manual HS-500, Rev 1.41

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TABLE OF CONTENTS

1. Safety Hints ………………………………….…………………………………… 3

2. General Information and Overview………………….………………………….. 4

2.1 Purpose and Description of the Device…………………………….. 4

2.2 Functional Principle and Block Diagram…………………………. 4

2.3 Device Variety……………………………………………………… 5

3. Installation ……………………………………………………………………..… 6

3.1 Mechanical and Electrical Installation……………………………… 6

4. Operation and Control Elements ……………………………………………….. 7

4.1 Elements on the front plate………………………………………… 7

4.2 Elements on the rear side..………………………………………… 7

4.3 Output Characteristics……………………………………………… 8

5. Maintenance………………………………………….…………………………. 10

6. Specifications……………………………………………………………………. 11

Declaration of Conformity………………………………………………………………. 12

HS-Series User Manual HS-500, Rev 1.41

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1. Safety Hints

Read all installation, operation, and safety
instructions

Prior to operation, thoroughly review all safety,
installation, and operating instructions accompanying

this equipment.
Rear side switch turns device completely
off

If the device is not in use for a longer time, it is

recommended to turn the mains switch at rear side off.
This equipment must be connected to an
earth safety ground

This product is grounded through the grounding

conductor of the power cord. To avoid electrical

hazard, the grounding conductor must be connected to

protective earth ground.
Do not modify the unit Do not make electrical or mechanical modifications to

this unit.
Change cabling only when device is off Changing the cabling, when voltages are present at the

outputs can lead to formation of harmful sparks.
Do not operate in wet/damp conditions To avoid electric shock hazard, do not operate this

product in wet or damp conditions. Protect the device

from humidity and direct water contact.
Beware of external magnetic fields External magnetic fields can impair, damage or even

destroy this device. A maximum external field strength

of no more than B = 5mT is admissible. Having placed

the device at any time into an external magnetic of

bigger B = 5mT (regardless if power was turned on or

off) can lead to severe overheating of the device and

severely increased hazard of fire.
Service is to be performed by qualified
service persons only

All servicing on this equipment must be carried out by

factory-qualified service personnel only.
Do not block chassis ventilation openings Slots and openings in the chassis are provided for

ventilation purposes to prevent overheating of the

equipment and must not be restricted.

All case vents should continuously be cleared in order

to prevent overheating.
Operate carefully with respect to risk of
electrical shock

This device can produce high voltages at its output

lines, which are harmful in case of direct touch with the

human body or other external circuitry. Care must be

taken to avoid unintentional touching of any output line

to the human body or any devices which might be

endangered by high voltages.
Routinely cleaning from dust After long operation, or operation in a dusty

environment it is strongly recommended to have the

internal parts of the device cleaned by the

manufacturer, or an appropriately qualified workshop

in order to reduce the hazard of overheating.
No outdoor operation Outdoor operation of the device is not admissible.

HS-Series User Manual HS-500, Rev 1.41

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2. General Information and Overview

2.1 Purpose and Description of the Device

Purpose of the HS series devices is the fast switching of piezo elements, electrodes, electrostatic lenses
or beam deflectors, etc. Unlike DC power switches, the outputs expect capacitive loads and only small
permanent (continuous) currents. The outputs are optimized for high stability, precision and very low
noise. The HS series switches are housed in standard 19-inch rack-mount cases. They are available in
single-channel or dual-channels versions. In the dual channel version two completely identical
switched are housed inside the same housing. These two switches are completely independent.

fig 2.1: front view of a HS-200/HS-500 device (DUAL version)

2.2 Functional Principle and Block Diagram

The following scheme displays a block diagram of the internal structure and illustrates the functional
principle. The control input (BNC socket on front plate) defines the position of the internal high
voltage switch, which connects either input A or input B to the output. A digital signal (TTL/CMOS
level 0V/5V) may be applied to this control input at a rate between 0Hz (static operation) to 2kHz. A
three-position manual switch on the front side allows to override the digital control signal. The high
voltage switching elements inside the device are implemented as MOSFET-transistors, allowing fast
switching transitions in the order of 100ns and less.

fig 2.2: Block diagram of a HS-200/HS-500 device. Inside the DUAL version, the scheme exists twice, i.e. there
are two independent switches.

Unlike high voltage pulse-generators the internal switch circuitry is implemented as fast static switch,
which means that the applied control input level defines the (static) switch position as illustrated in the
scheme above. The output is connected to the selected input by a (transistor based) resistor. The non­selected input is isolated from the output by a high isolation resistance.

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Note that the applied supply voltages at inputs A and B must obey a certain order: voltage at input A
always needs to be more positive than voltage at input B. In general both input voltages may float up
to +/-500V versus the case ground. However, for normal operation the voltage difference (A-B) should
not exceed 500V.

Application example:
Generation of 10µs-duration positive 500Volt-pulse

The subsequent oscilloscope screen shot shows a typical application example. A control pulse of logic
levels (high = 5V, low = 0V) is applied to the control input. High voltage inputs A and B were
provided with an external voltage of +250V and -250V respectively. At the edges of the control signal
the switch is triggered, and switches from -250V to +250V and after 10µs back. Trace 2 shows the
control signal, being used to trigger the switch (trace 2: 5V/div.). A rectangular pulse results with
steep slopes and constant-voltage static levels.

fig 2.3: Oscilloscope screen shot of a positive 500V step pulse, t = 10s duration.
The lower trace (trace 2) shows the digital control signal, trace 1 (upper trace) the output signal.

2.3. Device Variety

The following devices are currently members of the HS series device family:

HS-200 single or dual version Output voltages of maximum 200V span

1)

HS-500 single or dual version Output voltages of maximum 500V span

1)

HS-1000 single or dual version Output voltages of max. 1000V span

1)

The devices with outputs up to 500V (vs. GND) are provided by default with BNC outputs at their rear
side, the other variants with higher voltages have SHV connectors. Voltages are referenced to case
ground.

Note

1)

: span is the maximum voltage difference between positive and negative inputs A and B.

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3. Installation

3.1. Mechanical and Electrical Installation

Positioning: Provide sufficient air cooling of the device and locate in normal horizontal position to
allow for defined air convection. Rack mounting into a standard 19” rack is as well possible as resting
the device on a table. If mounted in a rack, please make sure that all case vents are permanently
cleared in order to prevent overheating.

fig. 3.1: Keep air vents always cleared to ensure sufficient ventilation

Beware of external magnetic fields:
Strong external magnetic fields can impair, damage or even destroy this device (e.g. proximity to a
superconducting magnet). A maximum external field strength of no more than B = 5mT is admissible.
Not observing this important condition can lead to severe overheating of the device and increases the
hazard of fire.

Connecting to mains power:
Connect the device to the mains power supply (either 220 to 240V ac or 100 to 115V ac, depending on
version) by using an appropriate power cord, being properly wired and providing a grounded outlet.
The power cord must be suited with respect to possible load currents and should be rated to 2A
current. The mains power input is not wide-range rated, either 100…120V or 220…240V need to be
connected.

Cabling of voltage outputs:
Always provide appropriate and safe cabling when connecting the device to other devices or
vacuum/experimental setups. Cabling is preferred using high voltage cable with proper shielding.
BNC or SHV connector cables are a suitable choice in order to ensure proper shielding against
external noise pickup and in order to provide protective ground for safety reasons. Always be aware
about the potential hazard of high electrical voltages to human beings and sensitive objects of all kind
(see also safety hints in section 1).

Please note that wiring may only be done when the device is turned off. Connecting a powered­up output to external circuitry can easily cause sparks and electrical discharges. The resulting
overvoltages can severely and permanently damage the device itself and also external circuitry.

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4. Operation and Control Elements

4.1 Elements on the front plate

mains supply Switch 1 Switch 2

switch BNC ext. / manual BNC ext. / manual

fig. 4.1: front plate elements

The front plate contains the control elements of the device. It is powered up after turning on the rear­side mains supply switch and also the power button on the front plate. The Power-on-LED (green)
indicates proper operation of the internal circuitry.

fig. 4.2: manual switch, BNC input and LED
indicators, showing the switch position and
indicating operation (voltage step detector) .

Each channel features a three-position manual switch (fig. 4.2). In upper position the output (rear side)
is connected to the high voltage input A, moved into lower position it connects the output to input B.
In center position, the control voltage applied to the BNC input, defines the switch state. A high level
connects the output with A, low level to B. Standard 5V / 0V signal may be applied to this control
input. In practical cases a PC controlled Delay-Gate generator or function generator is often connected
here. Switching rates up to 2kHz are supported. The LED indicators on the right hand side show the
switch status, indicating which input (A or B) is connected to the output. HS series switch devices
after production date dec. 2017 feature also a slope/step detector, which LED lights up upon occurence
of positive or negative output steps lager 25V, thus indicating correct functionality.

4.2 Elements on the rear side

fig. 4.3: rear side elements (a dual channel version is shown)

The rear side of the device contains the ventilation elements, 230V supply connector, power on/off
switch (with fuses) and the high voltage inputs and outputs.

fig. 4.4: BNC sockets for at inputs and output

Fig. 4.4 shows the BNC sockets for the two DC high voltage supply voltages A, and B and the switch
output OUT. Please note that the voltage on input A needs to be more positive compared to the voltage
on input B. This is indicated by the plus and minus sign “+” and “-“. In general, both input voltages
may reside in the range between -500V and +500V versus GND, but their difference should not

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exceed 500V. The fuse sockets shown in fig. 4.4 contain safety fuses for the two high voltage inputs.
In case extensive currents flow, they may blow. Nominal rating is 0.5 Ampere, fast blow.
The inputs A and B can be connected to an appropriate high voltage supply, e.g. to a device of stahl-
electronics HV-series. The output is supposed to be connected to capacitive load like switched
electrode, piezo element or ion trap. Note that excessive capacitive loads impair the switching speed
performance. Nominal loads from 0pF to 300pF can be connected (max. 1.5nF), see next section for
waveforms.

4.3 Output Characteristics

Dynamic Response

As soon as the internal switch connects either input A or B to the output, the latter assumes the voltage
on the respective input. There is a time constant related to each voltage transition, essentially given by

the internal switch resistance (approx. 145 ), the internal output current limit (approx. 1A) and the
capacitive load on the output, including all cables to an experimental setup. In case of BNC cable type
one may count about 100pF each meter cable length, therefore extensively long cables should be
avoided. The following oscilloscope screen shots show voltage step transitions observed at the output
with small (17pF) and larger capacitive loads (250pF) for further illustration.

100V step

fig. 4.5 positive and negative voltage step of 100V with small capacitive load (C = 17pF) at the output,
transient rise time (10% to 90% of voltage step size) is in the order of 40ns in each case. The green trace
shows the input trigger signal.

200V step

fig. 4.6 (left frame) positive voltage step of 200V (blue trace) with small capacitive load (C = 17pF) at the
output; (right frame) negative step of 200V with small capacitive load (C=17pF); transient rise time (10% to
90% of voltage step size) is in the order of 45ns in each case. The green trace shows the input trigger signal.

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500V step

fig. 4.7 (left frame) positive voltage step of 500V (blue trace) with small capacitive load (C = 17pF) at the
output; (right frame) negative step of 500V with small capacitive load (C=17pF); transient rise time (10% to
90% of voltage step size) is in the order of 50ns in each case. The green trace shows the input trigger signal.

500V step with large load

fig. 4.8 (left frame) positive voltage step of 500V (blue trace) with capacitive load of 250pF the output; (right
frame) negative step of 500V with same load; transient rise time (10% to 90% of voltage step size) is in the
order of 110ns in each case. The green trace shows the input trigger signal. The slower rise/fall times are mainly
caused by the internal safety current limit of approx. 1.1 Ampere

Noise and Ripple

In contrast to other devices, based on switched circuit / power switching technology, the HS series
devices feature a very low noise level. This makes them specially suited for ion traps, ion sources and
low energy beam line applications. Each output exhibits a very low broadband noise (DC to 20MHz)
of smaller than 350µV

rms

and a low ripple level (50Hz) smaller 50µV

rms

. In general the outputs are

completely free of parasitic switching spikes in the RF region.

Static Switch Behaviour

In case of low-frequency or static operation, the ‘on’-state serial resistance of input A or B to OUT
amounts to approx 190 Ohms, and increases to larger 10 MOhm in the ‘off’ state.

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5. Maintenance

The HS series high voltage switches are designed for years of reliable operation. Under normal
operating conditions, they should not require electrical maintenance, except routine cleaning of dust. If
any question should arise, please contact the manufacturer.

Routine cleaning

All ventilation openings should be checked periodically and kept free of dust and other obstructions. A
vacuum cleaner may be used to clean these vents when the unit and external voltage sources are
powered off. The front panel may be cleaned periodically with a clean cloth and mild alcohol solution,
when the unit is powered off. It is recommended to send the device to the manufacturer routinely in 5­year intervals for internal cleaning from dust.

Fire hazard

Please note, that excessive accumulation of dust inside the case of the device can lead to overheating.
This, together with possible discharges increases the risk of fire, caused by electrical sparks. Routinely
cleaning the device from dust minimizes this risk. It is therefore recommended to send the device to
the manufacturer routinely in 5-year intervals for internal cleaning from dust, or to have it cleaned by
an accordingly qualified electronical workshop. Environmental conditions containing oil mists (e.g. in
proximity to a vacuum pump or mechanical machines) place a severe danger, since inflammable
substances may enter the device through the ventilation holes. If in doubt, cleaning by an accordingly
qualified electronical workshop or the manufacturer is strongly recommended.
An increased hazard of fire can also occur if the device has been (permanently or temporarily) located
in proximity to a strong (e.g. superconducting) magnet. A maximum external field of no more than B
= 5mT is admissible and must not be exceeded at any time.

6. Specifications

typ. max. Conditions and remarks

Control Input

required drive level 0V and 5V -2V to +6V

vs. GND

TTL/ HC-MOS compatible

threshold 2.4V
input impedance vs. GND

2k // 6pF

drive rate / switching rate 2kHz device will inhibit control signals with

considerably higher rates

Output Switch

static resistance
from A or B to OUT
“on”-state

180 200

I

OUT

< 200mA

isolation resistance from
A or B to OUT

>10M

voltage differences from A or B to
OUT smaller or equal 500V

leakage currents from
A or B to OUT 40nA* 200nA*

voltage differences from A or B to

OUT smaller or equal 500V
intrinsic switch capacitance
on OUT terminal

80pF

Noise 350µV

rms

f = DC to 10MHz
admissible DC current 140mA continuous current
admissible pulsed current 1.7A

t < 1.5ms, repetition rate <= 2 Hz
internal current limit,
shortly at switching instant

1.1A 1.7A

t < 700µs

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Transfer characteristics

delay from control input to
output response 240ns

200V to 500V output step size

(positive or negative going)
delay jitter 0.4ns rms T = 25°C +/-1°C
max. pulse duration infinite
min. pulse duration 6.6µs

35ns capacitive load of 17pF (probehead)Output rise or fall time,

10% to 90% step size

110ns capacitive load of 250pF

Input Voltage Rating

Input A or B vs. GND +/-500V both polarities may be applied vs.

GND
Voltage difference
from A to B 500V

input A always needs to be on more

positive potential with respect to B
Fuse rating 500mA fast fuse replaceable on rear side

Environmental
Conditions

Magnetic Field max. 5 mT
Storage Temperature -55 C° to +85

C°
Operating Humidity &
Temperature

noncondensing relative humidity up to 95% between temperatures of
+10°C and +35°C.
Outdoor operation of the device is not admissible.

Power Supply

AC input voltage 230VACat 50Hz/60Hz or alternatively 110VAC.

The power entry module is EMI/RFI-filtered.

Fuse: medium fast blow 1.0A

Note: Supply voltage needs to be defined at time or ordering.

Power supply input is not wide-range rated (either 230V or 110V).

Power Consumption 2.7W 3.6W

Case Dimensions

19.00” wide x 10” deep x 1 height unit. Front-panel mounting holes are
dimensioned for M6 rack configurations

weight approximately 1.2kg

Note *): Inputs A and B feature 1 G resistors to ground for protection against parasitic charge up.
Currents through these protection resistors add to the numbers mentioned above.

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DECLARATION OF CONFORMITY

Manufacturer's Name: Dr. Stefan Stahl

- Electronics for Science and Research -

Manufacturer's Address: Kellerweg 23

67582 Mettenheim
Germany.

Declares, that the product

Product Name: HS series high voltage switch
Model Number: HS-200, HS-500

Product Options: This declaration covers all options of the above product(s)

Conforms with the following European Directives:

The product herewith complies with the requirements of the:

1. Low Voltage Directive 73/73EEC;

2. EMC Directive 89/336/EEC (including 93/68/EEC) and carries the CE Marking
accordingly

Mettenheim, 25. Jan. 2017, Dr. Stefan Stahl, CEO