GPIB interface enhances control in multi-channel power supplies

The GPIB-equipped models expand Keithley’s Series 2200 line of one-, two-, and three-channel power supplies, which complement the broad offering of instrumentation from Keithley and Tektronix.

The power supplies enhance ease of use in circuit design, university student labs, materials research, and device testing that requires the use of more than one power source. Their output levels address a wide range of sourcing requirements for characterising components, circuits, modules, and complete devices.

The Model 2230G-30-1 power supply provides two output channels, typically used for powering analogue circuits, with each channel capable of outputting up to 30V/1.5A/45W, plus a 6V/5A/30W output channel, typically used for powering digital circuits. (In contrast, the three-channel supply’s analogue outputs are limited to just 25V@1A.)

The Model 2220G-30-1 power supply provides two output channels, each capable of outputting up to 30V/1.5A/45W. These maximum output levels, combined with voltage setting and reading resolution of 1mV and current setting and reading resolution of 1mA, allow generating a wider range of output power and reading a wider range of load currents with high precision.

Remote sense terminals on each channel of the power supplies compensate for voltage drops in the power supply leads to ensure that the correct voltage is delivered to the load terminals of the DUT, enhancing overall system accuracy. They also offer superior basic current setting and readback accuracy and less than 3mVp‑p ripple and noise to ensure high quality load current measurements.

Each output channel is completely isolated, which allows the new power supplies to power two isolated circuits with different reference points, eliminating the need for a second power supply. Many competitive multi-channel power supplies do not offer isolated channel outputs and cannot properly power isolated circuits. Each channel can also be turned on or off independently, so the power supplies can be used to power up a circuit that requires turning on multiple voltage levels in a specified time sequence. A programmable timer allows setting up a test to run unattended, turning off the outputs after a specified interval.

For applications that require supplying more than 30V or 1.5A, the power supplies’ 30V outputs can be combined in a variety of configurations, such as being wired in series to produce a 60V output with a maximum current output of 1.5A or wired in parallel to produce a 3A output at 30V. When configured this way, special display modes show the actual voltage and current for the combined pair. Several features help protect fragile or experimental DUTs from damage during testing, including programmable voltage maximum values that prevent the accidental entry of a channel’s voltage above the pre-set value. These settings are in addition to the current limit setting function, which controls the level of current that can flow into the DUT, and each output channel’s limit can be set independently. In addition, all front panel controls can be locked using a user-definable password to prevent inadvertent changes during critical tests.

The combination of the new GPIB interface and an existing USB TMC-compliant device port makes it easy to control the power supplies remotely from a variety of programming environments. Standard IVI-Com and LabVIEW instrument drivers ease integration into automated test environments and provide all the tools needed for basic instrument control, data logging, and analysis.