A current-limited differential entry stage compares an input signal to a reference voltage generated by a current-limited transistor or diode configuration. Current limiters comprise a D-mode feedback transistor having a gate-source junction. The D-mode transistor is not conducting between the source and the drain if a gate-source voltage is more negative than a negative threshold voltage, and conducting between the source and the drain, otherwise a feedback connection connects the source of the D-mode feedback transistor to its gate via a component that generates a voltage drop.