Patent ID: 7049877

Claim:
Switched level-shift circuit for a signal-switch which is provided for switching an applied analog input signal, wherein the switched level-shift circuit comprises: a) an input terminal for the analog input signal applied to the signal-switch; b) a control input terminal for a control signal; c) an analog level-shift circuit which adds a constant voltage to the analog input signal to generate a level-shifted analog output signal when the control signal is in a first logical state, the analog level-shift circuit comprising: i) a first current source which is switched on when the control signal is in the first logical state; ii) at least one resistor connected in series with the current source wherein the resistor generates a constant voltage drop when the first current source is switched on; and iii) a MOS-FET connected in series to the resistor, wherein the MOS-FET has a gate connected to the signal input terminal, a source and a drain connected to the resistor, wherein the generated constant voltage drop of the resistor and the gate source voltage of the MOS-FET form the constant voltage added to the analog input signal to generate the level-shifted analog output signal; and d) an output terminal for the generated level-shifted analog output signal which is connected to a gate terminal of said signal-switch.