University of Bristol

Sensor Driven Ltd.

Bernard Stark

Guang Yang

Salah Adami

Chunhong Zhang

Plamen Proynov

Mark Volanthen

An electronic circuit for detecting a change in a property of interest, the circuit comprising a voltage detector having an input and a device for providing a bias current to the input of the voltage detector, wherein the circuit is arranged such that a change in the property of interest modifies the current received at the input of the voltage detector. A change in the property of interest may modify the current by adding or subtracting a current to the bias current. The property of interest may be a signal which is combined with the bias current thereby to alter the current at the input of the voltage detector. The signal may be capacitively coupled into the bias current. The signal may be provided by a sensor, which may be a voltage generating sensor and could be an antenna, rectenna, microphone or any other suitable sensor.

Electronic circuits comprising voltage detectors

A voltage detector () 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 (), 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 (), 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.

Voltage reference circuit, voltage detector and voltage detector system

A voltage detector comprising: a first voltage reference generator for generating a first voltage reference signal; a second voltage reference generator for generating a second voltage reference signal, wherein the second voltage reference signal is higher than the first voltage reference signal; a trigger, powered by an input signal to the voltage detector, and having an input for receiving either the first or second voltage reference signal and an output for generating a detection signal; and a switch for selectively, connecting the input of the trigger to the first or second voltage reference signal, wherein the switch is operative to connect the input of the trigger to the first voltage reference signal when the detection signal output by the voltage detector is low and is operative to connect the input of the trigger to the second voltage reference signal when the detection signal output by the voltage detector is high, and a voltage detector system for monitoring an input signal and outputting a detection signal when a voltage of the input signal meets a first threshold, the voltage detector system comprising: a first voltage detector having an input for receiving the input signal and an output for outputting a detection signal, wherein the first voltage detector is configured to output the detection signal when the voltage of the input signal meets a first rising input voltage threshold; a second voltage detector having an input for receiving the input signal and an output for outputting a detection signal, wherein the second voltage detector is configured to output the detection signal when the voltage of the input signal meets a second rising input voltage threshold which is higher than the first threshold, wherein the output of the second voltage detector controls a connection between the input signal and the input of the first voltage detector such that when the voltage the input signal meets the second rising input voltage threshold the connection between the input and the input of the first voltage detector is inhibited or disconnected.

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Bristol, United Kingdom

Bernard Stark