A circuit or associated system or apparatus includes a first transistor, a second transistor, a first switch, a second switch, a first current source, and a third switch. The first transistor is configured to sample a first current of a control line. The second transistor is configured to apply a second current to the control line. The second transistor is also configured to match the second current to the first current. The first switch is connected in series between a control terminal of the first transistor and a control terminal of the second transistor. The second switch is connected in series between the second transistor and the control line. The third switch is connected in series between the first current source and the control line.