D Series

Electrical Characteristics & Description
Model D Series power supplies provide up to 20 watts of high voltage power in a package of just 6.4 cubic inches. They offer full floating output and very tight line and load regulation. D Series units are extremely versatile, allowing the user to float the high voltage up to 1 kVDC above the input line. These power supplies are ideal for photomultiplier, CRT, image intensification and other electro-optical applications. Their high efficiency switching circuitry and constant power attributes are well suited for capacitor charging applications.

The input Voltage range is 25 to 31 VDC, drawing just under 950 mA at the full rated 20-watt output. The input current at no load is less than 100 mA.

The output voltage adjustment is via a 10-turn slotted trimpot potentiometer located on the top surface of the unit. The output voltage may also be adjusted by using a remotely located trimpot of 20 kOhm connected between pins 2 and 3 or by means of an external voltage of up to 5 volts applied at pin 3 with respect to ground. Pin 2 provides a reference output voltage of 5.0 VDC. Load regulation of less than 2% is provided for no load to full load variations. Output ripple is 1% max at full output power.

Each D unit is encapsulated in an anodized aluminum case which provides electrostatic shielding and heat removal. The calculated MTBF is 70,000 hours at 85 deg C case.  Mounting is by 4 corner eyelet holes that allow the use of a #6 diameter screw. Units may be stacked on top of each other with this arrangement.

The D Series high voltage power supplies are regulated by virtue of Pulse Width Modulation topology. The normal input voltage of 28 VDC is stepped up by resonant action to a high voltage output which is floating with respect to the input ground. The output voltage is sensed using a unique patented circuit to allow fully floating operation with no Galvanic connection to the input power side of the power supply.

The output voltage may be controlled in two different ways. For voltage programming, a control voltage between 0 - 5 VDC will adjust the output between 0 and full output. In the resistance programming mode, a resistor placed between Pin 2 (5.0-V reference output) and Pin 3 (Vcontrol) will set the output to a voltage which depends on the value of the resistance used. Typically a 10 KOhm resistor will set the output voltage to 50%. Zero resistance yields full output.

The maximum output current ability is set for each unit to be 120% above the nominal value determined by the 5-W limit. The current limit circuitry internal to the D high voltage power supply has a reaction time constant of less than 0.1 second which triggers a “try again” circuit whose duty cycle is typically 2 seconds to begin SLO-start reset.