Patent ID: 7576572

Claim:
A comparator, comprising: at least one current stage for providing a first current proportional to a difference between first and second comparator inputs, the first current being provided to an amplifier input; an amplifier for amplifying a current provided to the amplifier input and providing a comparator output; an apparatus for introducing hysteresis, comprising at least one of a current source and a current sink, the current source being arranged to selectively source a source current to the amplifier input such that the comparator output changes from a first state to a second state when a difference between the first and second inputs rises above a first value, and the current sink being arranged to selectively sink a sink current from the amplifier input such that the comparator output changes from the second state to the first state when the difference between the first and second inputs falls below a second value; and apparatus for controlling at least one of the source current and the sink current to be proportional to a bias current of the current stage.