Stanford PS325 High Voltage DC Power Supplies, ± 2,5 kV

• High Accuracy and Low Ripple

All models have 0.001% regulation and 0.05% accuracy. Output ripple is less than 0.0015% of full scale, and the output voltage can be adjusted with 1 V resolution over the entire operating range.

• Voltage and Current Displays

Convenient front-panel LED displays indicate both the voltage and current delivered to the load at all times. Adjustable voltage and current limits prevent you from operating the instrument above safe levels, while a current trip feature shuts off the high voltage in the event the current limit is exceeded.

• Flexible Operation

Voltages can be programmed from the front panel, the optional GPIB interface, or by a rear-panel analog control signal. Rear-panel monitors provide analog signals proportional to the current and voltage output levels. Either positive or negative voltages can be selected with a rear-panel switch. For quick, convenient setup, up to nine complete instrument configurations can be stored in non-volatile memory for later recall.

• Voltage Output

All PS300 series supplies have rear-panel SHV connectors. Optional cables allow connection with standard high voltage connectors (SHV or MHV). A three-position high voltage enable switch on the front panel prevents the high voltage from being turned on under computer control unless the switch has been manually armed. A highly visible red LED always indicates when the high voltage is on

• Limits and Trips

An adjustable voltage limit prevents the high voltage from being inadvertently set above a safe level. An independent current limit lowers the voltage setting until the current drawn by the load does not exceed the limit setting. Additionally, a current trip may be set which turns off the high voltage when the current limit is exceeded. After a trip, the unit can be configured to either attempt to turn the high voltage back on, or to leave it off until a manual reset.

• Adjustable Polarity (only for PS310, PS325, PS350)

The output polarity is set with a rear-panel switch. Changing polarity must be done while the unit is off, and polarity cannot be changed via the computer interface. Output polarity is always displayed on the front panel with the voltage level.

• Voltage and Current Monitors

Two rear-panel BNC connectors provide voltage and current monitoring capabilities. These connectors provide a 0 V to 10 V output corresponding to 0% to 100% of full scale output. These outputs are capable of driving 10 mA and have a 1 Ω output impedance.

The voltage monitor output can also be configured as a voltage control input. In this mode, a 0 V to 10V signal applied at the input will cause the output high voltage to vary between 0% and 100% of full scale. The output is updated at a rate of 16 Hz. Additionally, the bandwidth of the voltage control input is limited by the overall slew rate specification of the instrument. (0% to 100% of full scale in less than 0.3 s under full load.)

PS300 Series Block Diagram

All PS300 Series power supplies operate in the same manner, differing only in maximum voltage, maximum current and output ripple.

A high voltage (HV) section converts low drive voltage into high voltage (all high voltage components in the HV section are shielded). The output voltage (V) and current (I) are sensed and fed back to high gain compensation circuitry where they are compared to the programmed values. The compensation circuit controls the output voltage by setting the level of the drive voltage. A diode crossover allows control of both voltage and current.

Programmed values for the output, limits and trips are set by the microprocessor through a D/A converter. Fast acting limit circuits check the sensed voltage and current. These work independently of the microprocessor to react quickly in protecting both the supply and load.

An A/D converter reads the sensed values for the front panel display or for reading over the GPIB interface. The A/D also reads the External Voltage Set (when enabled), to ensure that limits are functional in the analog programming mode.

• Stored Settings

All instrument settings are stored in non-volatile memory so that the instrument will remember its previous settings when powered up. For safety, the high voltage is always initially turned off. Up to nine complete instrument configurations, including limit and trip settings, can be stored in non-volatile memory for later recall. Settings can be recalled manually, or under computer control.

• Optional GPIB Interface

An optional GPIB interface allows control of all instrument functions except output polarity. The required common commands of the IEEE-488.2 (1987) standard are supported. The power supply can be configured to generate service requests (SRQ) in the event of limit or trip conditions.