News - Page 20 of 23

15W floating DC-DC bipolar power supplies 1kV to 6kV – Ultravolt FLHV

Posted on 26/09/2016 by Dave McGuffog

Ultravolt FLHV 15W floating DC-DC bipolar power supply

PPM can now supply a new series of 15W enhanced floating hot-deck bipolar power supplies from Ultravolt. The FLHV high voltage power supplies provide an output that can float on a high voltage bias supply up to 5 kV above or below the input ground reference. The units are available with 1kV, 2kV, 4kV and 6kV ratings. The high input/output isolation supports floating electronics on high voltage. Notable performance characteristics include a high output stability of less than ±0.5% from no load to full load and accurate monitoring (±2.0%) of the floating bias supply output voltage and current.

Performance & Features

High output stability of less than ±0.5%
Accurate monitoring (±2.0%)
Excellent unit-to-unit repeatability
No pre-loading required
Reduced input current
Standard digital-ready, fully featured interface
Programmable output range on a fixed input
Standard enable/disable control pin

Example Applications

Electrostatic chucks (ESC)
Electron multipliers (CEM
Photo multiplier tubes (PMT)
HV bias (e-beam, i-beam, energy analyzers)
Gate supplies
Pulse generators
Amplifier rails
Other floating electronics

Product Layout

Product Range

Part Number	Max. Power (W)	Max. Voltage (V)	Current (mA)	Ripple (% rated V)	Load Regulation (% rated V)
1FLHV24-BP15	15	Multiple outputs, see datasheet	See datasheet	0.05	0.1
2FLHV24-BP15	15	Multiple outputs, see datasheet	See datasheet	0.05	0.1
4FLHV24-BP15	15	Multiple outputs, see datasheet	See datasheet	0.05	0.1
6FLHV24-BP15	15	Multiple outputs, see datasheet	See datasheet	0.05	0.1

Datasheet

FLHV Series Datasheet

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4kV fast recovery diodes now on standard release

Posted on 20/09/2016 by Dave McGuffog

Dean Technology UFHV series - high current, medium voltage, fast recovery axial lead diodes

Dean Technology have announced that the UFHV series – high current, medium voltage, fast recovery axial lead diodes are now listed as standard parts because improvements in the manufacturing process have led to the series being made more economical to produce. As a result, Dean are able to increase availability. With current ratings ranging from 350 to 550 mA, the UFHV series is very flexible. Plus, a maximum reverse recovery time of 75ns and a maximum surge current of 30A represents exceptional performance versus cost – making them a very good value choice.

The compact DO-41 package is well-suited for small to medium power applications., including power supplies and multipliers found in instrumentation, plasma displays and electrophoresis applications. Available in 2kV/850mA ,3kV/825mA and 4kV/800mA versions, the diodes are available in bulk, tape+reel and ammo box packaging and is RoHS compliant. Delivery leadtime is typically from stock to 8 weeks. Please contact sales@ppm.co.uk for more information, pricing and samples.

UFHV series – high current, medium voltage, fast recovery
Available as 2kV, 3kV or 4kV max repetitive peak reverse voltage
Max reverse recovery time 75ns
Max surge current 30A
Max reverse current 5uA

Part number	Max repetitive pk reverse voltage (V)	Max forward voltage drop (V)	Max average fwd current (mA)	Max reverse current(A)	Max surge current rating (A)	Typ junction capacitance (pF)	Max junction temp (°C)	Max reverse recovery time (nS)	Op. Temp (°C)	L (in.)	D (in.)	d (in.)	l (in.)
UFHV2K	2000	3	550	5	30	12	150	75	-55 to 150	0.2	0.1	0.034	1
UFHV3K	3000	4.1	400	5	30	8	150	75	-55 to 150	0.2	0.1	0.034	1
UFHV4K	4000	5.5	350	5	30	6	150	75	-55 to 150	0.2	0.1	0.034	1

For more information on other diodes supplied by PPM, please see the axial lead diodes product page or the high voltage diode / diode assemblies page.

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Using the programmable output pins on a Z+ power supply

Posted on 20/09/2016 by Dave McGuffog

The Z+ has two programmable output pins that can be controlled from the front panel or via a computer through the bundled graphical user interface over USB. These can be used to control isolation or polarity reversal relays, for example, without the need of a separate programmable logic controller (PLC). The programmable outputs are located on the rear of the units, with slightly different layouts for the low voltage (10V – 100V) and high voltage (160V – 650V) models.

Pinouts for low voltage (left) and high voltage (right) models

On the low voltage and high voltage models the programmable outputs are located at pins 1 and 6, with slightly different connectors on each model. Pin out diagrams are shown above. Internally the programmable outputs are controlled via open collector FETs each shunted by a 27V Zener diode. The outputs are rated to 25V maximum and can sink a maximum current of 100mA. These values should not be exceeded.

internal characteristics of Z programmable outputs

The internal characteristics of the programmable outputs

Combining programmable pins with relays

The programmable pins can be used in conjunction with relays to give additional functionality to the Z+ power supplies. Two useful examples are shown below

Example showing the use of the programmable outputs and relays to switch between local and remote sensing.

Example showing the use of the programmable outputs and relays to switch polarity at the load

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HV ceramic resistors now available as axial-leaded and slab types.

Posted on 12/09/2016 by Dave McGuffog

PPM can now supply high voltage ceramic resistors in axial leaded and slab types, manufactured by specialist Swedish manufacturer Kanthal. The 500BA ceramic slab resistors and BA100 & 200 axial-leaded ceramic resistors extend a high voltage ceramic portfolio already including tubular, disk/washer and water cooled resistors.

High peak power and high energy

Both the axial leaded and slab types provide excellent performance where high peak power or high-energy pulses must be handled in a small size. The bulk construction produces an inherently non-inductive resistor and allows energy and power to be uniformly distributed through the entire resistor body. Therefore, there is no film or wire to fail. Maximum continuous operating temperature of both types is specified at 230°C. The standard dielectric coating is recommended for use in air, and the oil-resistant coating is recommended for use in oil. Custom designs are also available.

Axial leaded resistors available with peak voltage of up to 25kV and resistance values from 2ohms to 7.5Mohm.
Slab resistors can support a peak voltage of up to 65kV and range in resistance from 1ohm to 1.8Mohm.

More information on each range can be found on the ceramic resistors page.

Typical Applications

The 500BA series of ceramic slab resistors and BA100 & 200 series of axial-leaded ceramic resistors are ideal for applications such as:

DC Coupling and Filter Cap Discharge
Voltage Balancing
Pre-charge / Inrush Limit
Voltage Divider
Filter
Snubber
Crowbar
Measuring
EMI / EFI Test

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Choosing a high voltage switch

Posted on 24/08/2016 by Dave McGuffog

Due to advances in semiconductor technologies, solid-state switches can now substitute thyratrons, ignitrons, spark gaps and electromechanical high voltage relays. TTL control input and low power electronics replace expensive heater supplies and drivers found in older systems. A high voltage switch can be chosen that meets application, system or load type criteria such as voltage, current, frequency and on-time. However, some extra work is required to ensure optimal performance of the switch in the application.

High voltage switches are composed of an array of semiconductors controlled by a sophisticated trigger mechanism. Overvoltages and high peak currents can be destructive so care must be taken when choosing a switch to ensure that specification limits are never exceeded. Also, the high dV/dt and dI/dt created by switching events requires care to be taken with circuit layout, wiring, shielding and grounding so that cross-talk and over-voltages are kept to a minimum.

How is power dissipated?

The equations below show how the power dissipated in the switch is proportional to the resistance R, capacitance CL and frequency f in each case. Typically not much can be done to escape the effects of the voltage but resistance, capacitance and frequency can be minimised to limit power losses.

Power dissipated inside a high voltage switch for frequencies <100Hz (left) and >100Hz (right)

The static on-resistance R will be given on the datasheet for each switch and the load capacitance CL should be known or estimated conservatively. The value for PD should then be compared with the value given on the datasheet.

If the value for power dissipation is greater than that given on the datasheet then additional cooling options may be needed. The power dissipation for a variety of cooling options is usually listed to help identify the correct solution.

Different types of switch

Different switch technologies suit different applications. High voltage switches supplied by PPM use four main technologies to cover 1kV – 140kV and 15A – 16kA:

MOSFET – (Metal Oxide Semiconductor Field Effect Transistor)
IGBT (Insulated Gate Bipolar Transistor
MCT (MOS-controlled Thyristor)
SCR (Silicon-Controlled Rectifier)

Critical low frequency or resistive load applications may use a low on-resistance switch to help to reduce ohmic losses. Push-pull types have two switches in a half-bridge configuration. This enables the load to be actively discharged to provide a very fast falling edge.

Analysing and modelling the system

The final choice may come down to factors that only become apparent when analysing the entire system. Modelling the entire system using software such as PLECS or SPICE will enable you to optimize parameters and finalise your switch selection. For example, inductive loads or large stray inductance will generate reverse voltages which could damage the switch. Using freewheeling diodes can protect the semiconductors within the switch from these events.

Avoiding damage to the switch

The values specified by the manufacturer should not be exceeded as this may destroy the internal MOSFETs or the trigger circuit. Particular care must be taken with cable routing and shielding as large voltage and current transients on the high voltage circuit can induce significant instantaneous voltages on low level control lines. Subtle overcurrent and overvoltage events should be identified initially at low voltages so as not to create long term reliability issues in the full system at full load. Initial system testing should be done at low voltages to check there are no obvious issues. Overvoltages will scale with voltage – checks should be done to ensure low and high voltage signals remain in the correct limits determined by the switch or other components. Tests should be done at low operating voltages first before increasing to the full high voltage value.

PPM supply fixed on-time switches, variable on-time switches and pulsed power switch assemblies. The full range offered by PPM can be found in the high voltage switches section.

Fixed On-Time Switches

	On-Time Description	Maximum Voltage	Maximum Current	Switch On-time
Fixed thyristor/SCR switches	Current Depending	4 - 150 kV	1 - 16 kA	> 35 us
General Purpose Fixed MOSFET Switches	Fixed	4 - 150 kV	15 - 200 A	100 - 300 ns
Low Impedance MOSFET Switches	Fixed	0.5 - 40 kV	70 - 1600 A	150 ns
Ultra-Fast MOSFET Switches	Fixed	3 - 12 kV	60 - 200 A	120 - 200 ns
Low On-Resistance Fixed MOSFET Switches	Fixed	3 - 24 kV	60 - 1040 A	150 - 250 ns

Variable On-Time Switches

	On-Time Description	Maximum Voltage	Maximum Current	Switch On-time
General Purpose Variable MOSFET Switches	Variable	0.5 - 36 kV	12 - 640 A	> 50 ns
High di/dt MOSFET Switches	Variable	3 - 36 kV	200 - 3200 A	> 300 ns
Low Capacitance MOSFET Switches	Variable	3 - 140 kV	30 - 800 A	> 60 ns
Low On-Resistance Variable MOSFET Switches	Variable	0.5 - 21.6 kV	125 - 3750 A	> 150 ns
AC MOSFET Switches	Variable	1.2 - 36 kV	12 - 130 A	> 50 ns
General Purpose IGBT Switches	Variable	3 - 36 kV	800 - 9600 A	> 0.2 us
Push-Pull MOSFET Switches	Variable	2x 1.2 - 140 kV	2x 12 - 200 A	> 50 ns
High Voltage Pulse Generators	Variable	(2x) 3 - 12 kV	(2x) 15 - 80 A	> 50 ns

Pulsed Power Switch Assemblies

	On-Time Description	Maximum Voltage	Maximum Current	Current Rise Rate
Pulsed Power Stacks	Variable	30 kV	20 - 50 kA	10 - 30 kA/us

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NEW high voltage programmable power supplies from HiTek Power

Posted on 23/08/2016 by Dave McGuffog

Series OLS10K 10kW high voltage power supplies

HiTek Power have released four new series of high voltage programmable power supplies: 400W, 600W, 3kW and 10kW. These products are available in 1U-4U rack mount units, depending on the power rating. Each product series ranges in output voltage from 1kV to 80kV*. The units are available in positive and negative polarities and feature arc count and extinguish (ACE) functionality

Local or remote control
Current or voltage control
Current ripple of <0.5%
Voltage ripple of <0.1%

OL400W / OL600W

OL3000

Series-OLS10K-10kW-high-voltage-power-supplies-01

OLS510K

The OL400W and OL600W series provide a single 400W/600W output suitable for electron/ion beam systems, x-ray systems and ion/chemical vapour deposition equipment. These units are available in 1U or 2U rack units and can be used in the most severe of electrical environments. Using air as the primary insulation method these units provide a power density of approximately 1W / cubic inch. The OL3000 and OLS10K series provide a single 3kW/10kW output suitable for x-ray, lab systems and heavy industrial electron beam welding and ion implantation. These are available in 3U or 4U rack units.

*60kV for OL3000 series

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Power electronics simulator PLECS v4.0 released

Posted on 21/07/2016 by Dave McGuffog

New functionality included in PLECS 4.0

Version 4.0 of power electronics simulation platform PLECS® has now been released by Swiss developer Plexim GmbH. The latest version now includes the following additional capabilities:

New state machine block allows a modelling environment to support finite state machines that respond to discrete events.

Extended PLECS coder for PLECS Standalone can now produce code for a specific hardware target. The new External Mode enables you tune parameter values on the hardware target and display captured data on the host computer. The first supported target is the new PLECS RT Box; more targets will follow.
Automatic Initialization of Thermal States – PLECS can now automatically calculate initial temperatures for thermal capacitances based on their surrounding temperature.

New and Enhanced Library Components:

The electrical machines library has been extended with two new synchronous machine models based on look-up tables that can be imported from an FEM tool.
The Induction Machine with Saturation now features a Full VBR implementation, in which both the stator and the rotor are modeled as voltages behind variable reactances.
The mechanical library has been extended with a Planetary Gear Set model.

Extended Processor-in-the-Loop (PIL) framework – now supports STM32 F0, F1, F2 and F3 MCUs.

Reduction of algebraic loops with PLECS Blockset – Continuous inputs of a circuit block that do not have an immediate effect on any output are marked as non direct feedthrough inputs. This helps reduce the occurrence of algebraic loops in Simulink if you feed the output of a circuit block back to its input, e.g. to model a mechanical load.

Support for High-DPI Displays – the graphical user interface of PLECS now supports high-DPI displays on Windows and Mac OS X.

About PLECS

The PLECS® product family has been specifically developed to assist engineers with the design and implementation of complex power electronics systems. PLECS tools facilitate the selection of power-conversion topologies, allow for the sizing of components and thermal management systems and expedite the conception and realisation of sophisticated control algorithms.

PLECS Product Range:

PLECS Blockset
PLECS Standalone
PLECS Coder
PLECS PIL
PLECS Web-based Simulation

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EBG release 2kW thick film resistor UXP2000

Posted on 18/07/2016 by Dave McGuffog

UXP2000 ultra high power resistor from EBG

EBG have released an ultra-high power resistor with a rated at 2000W*

The UXP2000 has an operating temperature range of -55°C to +150°C and a maximum working voltage of 5kV DC. Higher voltages and other temperature coefficients are available on request. Resistance tolerance is+/- 5% to +/-10%.

The datasheet is available to view via the PPM high power thick film resistors page.

About EBG resistors

EBG has been a leading manufacturer of non-inductive thick film resistors since 1977. The manufacturing process is state-of-the-art, producing precision resistors for high voltage, high power, and pulse loading applications. EBG offer:

Resistances 0.0005 – 30 GOhm;
Voltage range 1 – 96kV;
Power ratings of 1 – 1700 Watts
Tolerances of +/-0.1% to +/- 10%.

Normal lead time for standard or custom products is 8 weeks or less.

The EBG product range consists of over 350 standard and custom models of high voltage resistors, power resistors, pulse resistors, current sense resistors, load resistors, high power resistors, and matched divider resistor sets. Form factors available include cylindrical, flat, TO220, TO247, SOT227 and many custom power footprints.

*2000W at 125°C bottom case resp. 60°C heat sink temperature

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New ultra-stable HV thick film resistor +/-5ppm over temperature

Posted on 18/07/2016 by Dave McGuffog

Austrian manufacturer EBG have released a thick film, high voltage resistor which delivers exceptional stability of only +/- 5ppm over a temperature range +25degC to +65degC. The SHP52 is available in the range 100Mohm to 250Mohm and has a maximum operating voltage of 10kV DC. EBG is a leading manufacturer of standard and customised high voltage and high power resistors. EBG thick film resistors are available with voltage ratings up to 100kV and power ratings up to 2kW. The company have been manufacturing resistors for over thirty years for applications such as smart grid, drives, aerospace, medical and industrial applications.

The SHP52 is part of PPM’s range of high voltage thick film resistors.

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High power resistors down to short lead-times

Posted on 06/07/2016 by Dave McGuffog

Many of the standard high power resistors manufactured by Austrian company EBG are currently available on short leadtimes for small quantities. Metal film and thick film resistors for high power, high voltage and current shunt applications can be sourced in the UK via PPM. Custom products remain on a standard leadtime. Visit the PPM Resistors page…

Current Shunt – Thick Film
High Voltage – Thick Film
Metal Film Resistors
Power – Thick Film