Comparator

A comparator for comparing a first input voltage with a second input voltage and generating a corresponding output voltage, the comparator comprising:

• a first input terminal for receiving the first input voltage;
• a second input terminal for receiving the second input voltage;
• an output terminal for outputting the output voltage;
• a first supply rail for providing a first supply voltage;
• a second supply rail for providing a second supply voltage, the comparator further comprising:
• a follower stage comprising a first follower stage supply terminal coupled to the first supply rail, a second follower stage supply terminal coupled to the second supply rail, a follower stage input terminal coupled to the second input terminal, and a follower stage output terminal for providing a follower stage output voltage;
• and an inverter stage comprising a first inverter stage supply terminal coupled to the first supply rail, a second inverter stage supply terminal coupled to the follower stage output terminal, an inverter stage input terminal coupled to the first input terminal, and an inverter stage output terminal for providing an inverter stage output voltage and coupled to the output terminal;
• and
• signal conditioning means coupled between the inverter stage output terminal and the comparator output terminal,
• wherein the inverter stage output voltage has a first range, in use, determined by the voltage applied to the first supply rail and by the follower stage output voltage, and the signal conditioning means is adapted to generate, from the inverter stage output voltage, a comparator output voltage at the comparator output terminal having a second range, where the second range is larger than the first range, wherein said second range extends substantially from a voltage supplied to the first supply rail to a voltage supplied to the second supply rail.