Patent attributes
A current source is provided with two resistor banks, and digital potentiometers are used to control how much each resistor bank affects the resulting output current. Furthermore, when the digital potentiometers are at a particular setting such that a particular resistor bank does not affect the resulting output current (i.e., the resistor bank is “inactive”), the resistance of that resistor bank can be switched without affecting the output current, thus minimizing or eliminating discontinuities in the output current during a current sweep operation. Thus, for example, when a resistor bank meets its threshold and becomes inactive, the resistance of the inactive resistor bank may be switched, and then the digital potentiometer setting may be changed to facilitate smoothly reactivating that resistor bank, with the new resistance.
