DC-DC High Voltage Power Supplies

Form, Fit and Function Design: 

Spellman’s UM Series of printed circuit board mountable, high voltage modules offer a form, fit and function replacement for presently available commercially made units, while providing additional features and benefits at competitive pricing. Utilizing proprietary power conversion technology and Spellman's six decades of high voltage experience, these SMT based high voltage modules provide improved performance/reliability and easier system integration at a lower cost when compared to the competition.

Advanced Power Conversion Topology:

UM converters use a proprietary zero voltage switching power conversion topology providing exceptional efficiency and inherent low noise and ripple. Radiated emissions are reduced compared to conventional switching topologies, minimizing or even eliminating the need to shield the unit from adjacent circuitry. 

The high voltage output is generated using a ferrite core high voltage step up transformer which feeds a half wave Cockcroft-Walton voltage multiplier to obtain the specified high voltage output. 
Due to the fixed, high frequency conversion rate the output capacitance is small resulting in minimal stored energy. Through the use of generously rated surge limiting resistors and a fast acting current loop, all units are fully arc and short circuit protected.

Control and Regulation:

The actual output voltage generated is sampled via a high impedance divider to create a voltage feedback signal. A current feedback signal is created via a current sense resistor in the low end return of the high voltage output circuitry. These two accurate ground referenced feedback signals are used to precisely regulate and control the units in addition to external monitoring purposes. 

Due to the UM’s unique converter topology it can provide full current into low impedance loads or even a short circuit. Standard units limit at 103% of maximum rated output current.

Standard Interface:

The Spellman UM Series interface provides current programming capability and positive polarity, buffered, low output imped­ance voltage and current monitor signals (zero to +4.64Vdc equals zero to full scale rated). A voltage programming input is provided where 0 to +4.64Vdc equals 0 to 100% of rated voltage. 

Current programmability allows the user to set where the unit will current limit, anywhere from 0 to 100% of maximum rated current. This feature is beneficial where less than full output current is desired, like in the case of protecting a sensitive load. 

The buffered low impedance voltage and current monitor signals can drive external circuitry directly, while minimizing loading and pickup effects. These features save the user the expense and implementation of external interface buffering circuitry while improving overall signal integrity.  

This standard interface is made available via a row of 13 pins with 0.1. pin spacing. A legacy interface (7 pins on a 0.2. spacing) that is compatible with presently available commercially made units can be provided by ordering the “L” option.

Mechanical and Environmental Considerations:

The UM Series are solid encapsulated, printed circuit board mountable, plastic cased converters. All units are encapsulat­ed using a silicon based potting material which is consider­ably lighter in weight than epoxy. Isolated, non grounded 2-56 machine screws thread into the module to securely mount it to the printed circuit board, relieving any stress on the interface pins. Mounting plates, brackets and flanged mounting options are also available. High voltage output is provided via a 36. (914.4mm) minimum length of appropriately rated high volt­age wire. 

Regulatory Approvals: 

Compliant to EEC EMC Directive. Compliant to EEC Low Voltage Directive. UL/CUL recognized, File E227588. RoHS Compliant.

Specifications

^{(Rev. 128074-001 REV. P)}

Input Voltage: 

12Vdc for 4W, 24Vdc for 15W and 30W 

Nominal Voltage Range: 

11Vdc to 30Vdc for 4W, 23Vdc to 30Vdc for 15W and 30W 4W units can operate at 24Vdc input with no deratings or damage to unit 

Input Current: (typical) 

Disabled: 10mA @ 24Vdc

Full output, no load: 160mA @ 24Vdc, 300mA @ 12Vdc

Full output, full load: 

4 watt units: 330mA @ 24Vdc, 640mA @ 12Vdc

15 watt units: 850mA @ 24Vdc

30 watt units: 1590mA @ 24Vdc 

Voltage Regulation: 

Line: <0.01% Load: <0.01% 

Current Regulation: 

Line: <0.01% Load: <0.01% 

Stability: 

0.01% per 8 hours, 0.02% per day after 30 min. warmup 

Accuracy: 

2% on all programming and monitoring, except I Sense 10% 

Temperature Coefficient: (typical) 

Standard: 100ppm/°C 

Optional: 25ppm/°C (T Option)

Environmental: 

Temperature Range: 

Operating: -40°C to 65°C case temperature 
Storage: -55°C to 105°C, non operational

Humidity: 10% to 90%, non-condensing. 

Cooling: 

Convection cooled, typical. 30 watt units operating at full power might require additional cooling to maintain case temperature below 65°C. Methods may include: forced air cooling, use of heat sink or metal case, etc. It is the user’s responsibility to maintain the case temperature below 65°C. Damage to the power supply due to inadequate cooling is considered misuse and repairs will not be covered under warranty.  

Dimensions: 

8kV-12kV: 3.700. L X 1.500. W X 0.990. H (93.98mm X 38.10mm X 25.03mm)

15kV-20kV: 4.700. L X 1.500. W X 0.990. H (119.38mm X 38.10mm X 25.03mm)

25kV-40kV: 6.960. L X 1.600. W X 1.14. H (176.78mm X 40.84mm X 28.87mm) 

Weight: 

8kV-12kV:  5.7 ounces (162 grams), typical  
15kV-20kV:  7.2 ounces (204 grams), typical  
25kV-40kV:  13.1 ounces (371 grams), typical

Output Cable:

UM8, UM10, UM12, UM15: TV20 (min. length, 36. (914.4mm)

UM20, UM25: TV30 (min. length, 36. (914.4mm)

UM30, UM35, UM40: TV40 (min. length, 36. (914.4mm)

See product PDF for more specification and features.

UM 4W, 8kV TO 40kV SELECTION TABLE

UM 15W, 8kV TO 40kV SELECTION TABLE

UM 30W, 8kV TO 40kV SELECTION TABLE

STANDARD INTERFACE

Grayed out signals are provided for backward legacy compatibility and their use is not required.

Power Ground Return, Signal Ground and HV Ground Return are connected internally. For best performance they should not be connected externally.

LEGACY INTERFACE (L OPTION)

Power Ground Return, Signal Ground and HV Ground Return are connected internally. For best performance they should not be connected externally.

Standard Interface Connections
Fifteen (15) gold plated 0.025˝ (0.64mm) square pins suitable for direct PCB mounting.

Legacy Interface Connections
Nine (9) gold plated 0.025˝ (0.64mm) square pins suitable for direct PCB mounting.

See mechanical drawing for location and spacing details

Programming and Monitor Signals
Voltage and current programming is done via positive polarity, high input impedance, 0 to 4.64Vdc signals.
Voltage and current monitors are positive polarity, buffered low output impedance 0 to 4.64Vdc signals.

I Mon
The I Mon signal is a true output current monitoring signal. All internal offsets due to feedback divider currents have been compensated for.

Signature Resistor
A unique identifying signature resistor for each type of unit is connected from Pin 1A to ground. Details if desired are available upon request.

I Sense Signal
The polarity of the I Sense signal is opposite of the polarity of the output voltage of the unit that generated it. So a positive output polarity unit creates a negative polarity current monitor signal; while a negative output polarity unit creates a positive polarity current monitoring signal. This signal is clamped to ground internally via a bidirectional transient protection device and the signal is made available via a series connected 47kΩ isolation resistor. Internal HV dividers create a small,
linear offset voltage on this current monitor signal that can be compensated for.

OT Output
The unit is protected by an internal thermostat that will shut the unit off if the case temperature exceeds 65°C. The OT Output signal will change states indicating an over temperature fault has occurred. In order to clear the OT signal and re-enable the unit, the temperature has to drop below 55 degrees C and input power needs to be recycled. For details on unit cooling requirements and the OT Output signal please see the operator’s manual.

Tables & Diagrams

UM8-40 OPTIONS
T Option
Low Temperature Coefficient-
The T Option offers the UM with an improved temperature coefficient. The standard voltage feedback divider is replaced with one having a superior temperature coefficient, resulting in a unit with 25ppm/C° (typical) temperature coefficient.

PHYSICAL INTERFACING

B Option
Terminal Block-
The B Option provides terminal block connections for both the customer interface and high voltage output/return.
This feature can be helpful in situations where frequent wiring changes are anticipated, as in a testing or prototype environment.

SHIELDING OPTIONS

S Option
RF Tight Shielded Can-
The S Option mounts the UM module inside of a flanged RF tight aluminum can.

SHIELDING OPTIONS (CONT)

M Option
Mu Metal Shield-
UM modules can be fitted with an adhesive backed Mu Metal foil shield to help protect sensitive adjacent circuitry.

Same as standard unit.

CHASSIS MOUNTING OPTION

E Option
Eared Mounting Plate-
An eared mounting plate is affixed to the top surface of the UM module allowing simple chassis mounting of unit.

DIMENSIONS: in.[mm]

15 PIN - Standard Interface

9 PIN - Legacy Interface

ORDERING INFORMATION

STANDARD UNIT ORDERING EXAMPLE

OPTION ORDERING INFORMATION

Frequently Asked Questions

What Is a Safe Level of High Voltage?
Where Can I Obtain Information on High Voltage Safety Practices?
What Kind of High Voltage Connector Do You Use on Your Supplies?
What Do You Mean That the Output Side of the High Voltage Cable on Most Standard Products Is “Unterminated”?
How Should I Ground Your Supply?
Why Is Arcing an Issue for a High Voltage Power Supply?