Voltage reference circuit, voltage detector and voltage detector system

Abstract

A voltage detector (200) for monitoring an input signal and outputting a detection signal at an output when a voltage of the input signal meets a first threshold having: an input configured for receiving the input signal; a voltage reference circuit for receiving an input voltage and producing a reference voltage having a maximum value independent of the input voltage; and a trigger configured to compare the input signal and the reference voltage and to output a detection signal to the output when the voltage of the input signal reaches the first threshold. The voltage reference circuit comprises a reset input connected to either the input or the output and is configured to reduce the reference voltage when a predetermined reset signal is received. The voltage reference circuit may include: an input for receiving the input voltage; a first current controlling element (210), such as a diode, which allows current to flow as an increasing, non-linear function of voltage at least within a first range of voltages; a second current controlling element (240), such as a transistor, which allows current to flow as an increasing, non-linear function of voltage at least with a second range of voltages; and an output at which the output reference voltage is produced. The first current controlling element and the second current controlling element are connected in series between the input and a common reference, with the second current controlling element between the first current controlling element and a common reference, the output comprises a node between the two current controlling elements, the first and second range of voltages overlap and the second current controlling element is configured to vary the function by which it allows current to flow in dependence on the input voltage.

Dependencies are inferred from the claim text.