Self Powered Active Load

The TBOH02 is a precision self powered active load. It does not need a separate supply voltage and operates as low as 2V. Its features include constant resistance and constant current mode. A 10 turn potentiometer with dial, a range switch and a precision reference enable accurate setting of current or resistance. Furthermore it can be controlled by an external voltage.

The design is fully analog. Supply noise measurements using the TBOH02 as load will not be superimposed with additional noise in contrary to such measurements carried out with digitally controlled active loads.

The TBOH02 can not only be used as active load for power supply measurements, but also as current sink or current source for power LED testing and similar applications. It also comes handy when carrying out tests in the field, where no external power is available.

The TBSOH02 operates from 2V to 70V. The maximum current is up to 10A, however it has to be taken care that the maximum power without additional cooling is limited to 25W. A fan accessory which can be clipped onto the heat sink increases the maximum power rating to 100W.

The design is based on the EDN, August 2005 article Precision active load operates as low as 2V by Joel Setton

By courtesy of Joel Setton, Crolles, France