1. Field of the Invention
The present invention relates to electronic circuits, and in particular relates to a comparator circuit and an amplifier circuit.
2. Description of the Related Art
A voltage comparator compares a first input voltage to a second input voltage, and produces a digital representation, i.e., a binary 1 or 0, at the output indicating which input voltage is higher, that is, the polarity of the voltage difference between the two inputs. An offset comparator has a built-in offset voltage threshold such that the voltage difference of the first and the second inputs has to exceed this threshold in order to make the output switching the binary state.
However, the bias condition of the input differential pair limits the offset range of the built-in offset voltage. Conventionally, when the voltage difference between the two inputs is greater than a certain voltage value, the offset comparator may reach a saturation condition, wherein the built-in offset has no effect on the outcome of the comparator.