Methods and apparatus for selecting settings for circuits

A sensor circuit for selecting a function setting from multiple function settings for a component, wherein the function setting is specified according to a resistance of an external resistor connected to the component, comprising:

• a voltage source adapted to supply a substantially constant voltage to the resistor,
• wherein the constant voltage is substantially independent of the resistance of the external resistor;
• and
• a measurement sensor responsive to a current in the resistor, wherein the measurement sensor generates a control signal according to the magnitude of the current.

A method for selecting a setting for an integrated circuit adapted to operate in conjunction with a plurality of settings according to an external measurement element connected to a terminal of the integrated circuit including a functional module, comprising:

• applying a substantially constant voltage to the terminal, wherein the voltage is substantially independent of the measurement element;
• generating a control signal according to a magnitude of a current in the external measurement element, wherein the signal corresponds to the setting to be selected for the integrated circuit;
• and
• providing the control signal to the functional module of the integrated circuit, wherein the functional module implements the setting to be selected according to the control signal.