One of the product groups offered by TME consists of so-called programmable DC power supplies. Besides fulfilling an obvious function for a power supply, that is delivering defined, pre-set and expected voltage and current, these devices also allow, by means of special commands and buttons, programming and readout of many parameters through front panel or dedicated interface.
by Marcin Zając
Good representative of this group is a family of E364xA power supplies by AGILENT TECHNOLOGIES. Excellent technical parameters and good functional features characterise the devices. What is most important is that they have a feature, which is crucial for many users, i.e. communication with PCs through dedicated interfaces RS232 and GPIB.
On the front panel of power supplies, besides readable display, necessary regulation components are located, including buttons to set the voltage values and protection thresholds, or call up to 5 earlier pre-set and memorised values of power supply parameters from non-volatile memory. Maximum resolution for setting up voltage and current is 10mv/1mA respectively. Additionally, comfortable “analogous” knob allows rough and quick setup of voltages and currents.
When it comes to electric parameters, the power supplies offer output power from 30W to 100W at voltages up to 60V and currents up to 8A. Excellent electric parameters were reached thanks to the application of specific regulation solutions. (see Figure 1)
Above all, it is not only linear transistor that has been applied for regulating voltage and current, but also so called phase-controlled pre-regulator. Thus a wide range of output voltage regulation has been achieved at significantly reduced power dissipation at series regulation element (transistor).
On the other hand connection of series linear regulation, characterised by high precision and speed with monitoring actual output parameters (voltage feedback control) ensures very high stability of output voltage regardless of changes in power supply load. Such solution also has a very favourable impact on time characteristics of the power supply response. Short-term pulse changes of load that can affect voltage stability are compensated very quickly. Declared response of the circuit is below 50us.
Also, voltage protections have been applied that prevent damage to connected devices and protect against excessive voltage rise.
Please note that protection is carried out through short-circuiting the power supply output. Should there be another power source in supplied device, it may lead to significant rise of current that flows through the power supply.
Control by means of GPIB or RS-232 connector substantially expands power supply functionality transforming it into multifunctional workshop device.
Communication through the interface runs in two directions: readout of voltage and current and setting of these parameters is possible. This can be done by means of easy to use SCPI standard (Standard Commands for Programmable Instruments), allowing quick and effective control.
Possible applications of the interface:
• quick, earlier predefined, setting of values of power supply parameters depending on requirements of connected devices;
• measuring current and voltage characteristics (without additional measuring devices) of semi-conductor components (by means of additional software);
• studying reactions of circuits to changes in power supply with pre-programmed scenario of voltage changes when designing and starting up circuit prototypes.
These are only a few examples of possible applications. In the case of using additional VXI controllers there is an option of integration of the power supplies with other, more complex, software like LabVIEW or LabWindows by National Instruments.
It opens up the possibility to create already very complex systems dealing with control, measurements or testing newly designed equipment.
Power supplies of E364xA family are solid, state-of-the-art power supplies with excellent electric parameters, both static and dynamic, offering stable output voltages at low values of ripple and noise. Connected devices are protected against excessive voltage rise, while GPIB and RS232 interfaces allow reading and setting up power supply parameters through PC.
Described components are offered by TME at attractive prices.
We kindly invite you to have a look at our offer available on the website http://www.tme.eu where you can make purchases.