Data sensing apparatus of a read only memory device

A data sensing apparatus for sensing the status of a signal source, comprising:

• a first load element having a first end connected to a voltage source;
• a second load element having a first end connected to the voltage source;
• a switching element having a first end connected to a second end of the first load element and a second end of the second load element such that the first load element and the second load element are connected in parallel, the switching element providing a path for a sensing current of the signal device;
• a switch controller having an output connected to an input of the switching element and an input connected to the signal source, said switch controller controlling the switching element in response to the signal source;
• an amplifier having an input connected to the switching element and an output that provides an amplified indication of the sensing current of the signal source;
• and
• a voltage level detector connected to the voltage source and having an output connected to an input of the second load element, said voltage level detector detecting the voltage level of the voltage source and disabling the second load element when the voltage level of the voltage source is higher than a predetermined value.