J Series

Electrical Characteristics & Description
Model J Series power supplies provide up to 3 watts of high voltage power in a package of just 3.6 cubic inches. The J Series units are extremely versatile, allowing the user to float the high voltage up to 5 kVDC above the input line. These power supplies are ideal for photomultiplier, CRT, image intensification and other electro-optical applications.

The input voltage range is +25 to +31 VDC, drawing just under 250 mA at full rated 3-W output. The input current at no load is less than 70 mA.

The output voltage adjustment is accomplished via a 10-turn slotted screwdriver potentiometer located on the top surface of the unit. The output voltage may also be adjusted by using a remotely located trim pot of 20 k Ohm 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 3% is provided for half to full load variations. Load regulation for NO LOAD to FULL LOAD is less than 20%. Output ripple is 1% max at full output power.

Each J 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 temperature. 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 J 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. In the voltage mode, 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 3-W limit. The current limit circuitry internal to the J high voltage power supply has a reaction time constant of less than 0.1.