Tyre pressure monitoring system

Claim 2

A tyre monitoring system according to claim 1 wherein each remote unit comprises: a plurality of energy receiving circuits for mounting along an annular path within the tyre, each having an antenna for receiving the first RF signal, a converter for converting the first RF signal to a voltage, and an output for providing the voltage; a power regulating means coupled to receive the voltage from the outputs of the plurality of energy receiving circuits, coupled to receive a power enable signal and coupled to provide a regulated voltage when the power enable signal is received; a hysteresis circuit coupled to receive the voltage from the outputs of the plurality of energy receiving circuits, having an output for providing a hysteresis high output signal when the voltage from the outputs of the plurality of energy receiving circuits is greater than a predetermined high voltage, and for providing a hysteresis low output signal when the voltage from the outputs of the plurality of energy receiving circuits is less than a predetermined low voltage; a pressure sensor circuit coupled to receive the regulated voltage from the output of the power regulating means, having a pressure sensor for detecting the pressure and for generating a pressure signal indicative of the detected pressure, and an output for providing the pressure signal; a comparator circuit coupled to receive the regulated voltage and the pressure signal from the pressure sensor circuit, having a comparator for comparing the pressure signal with a predetermined pressure signal, and an output for providing a pressure high output signal when the pressure signal is greater than the predetermined pressure signal, and for providing a pressure low output signal when the pressure signal is less than the predetermined pressure signal; a coupling means having a corresponding plurality of inputs, each input coupled to the output of one of the plurality of energy receiving circuits for receiving the first RF signal from at least one of the plurality of energy receiving circuits, and having an output for providing the received first RF signal; an RF transmission circuit coupled to receive the second RF signal and a transmit enable signal from the logic circuit, and having an antenna for transmitting the second RF signal upon receipt of the transmit enable signal; and a logic circuit coupled to receive the voltage from the outputs of the plurality of energy receiving circuits, coupled to receive the first RF signal from the output of the coupling means, coupled to the outputs of the hysteresis circuit and the comparator circuit, coupled to provide the power enable signal to the power regulating means, coupled to provide the second RF signal and a transmit enable signal, wherein the logic circuit provides the power enable signal in response to receiving the hysteresis high output signal from the hysteresis circuit, and wherein the logic circuit provides the transmit enable signal in response to receiving the pressure high output signal from the comparator circuit.

Claim 3

A tyre pressure monitoring system according to claim 1 wherein the controller comprises: a memory for storing data and an executable program; a plurality of outputs, each output coupled to the input of one of the plurality of remote energy transmitting circuits for providing the activate signal thereto; a plurality of inputs, each input coupled to an output of one of the plurality of remote receivers to receive the output signal therefrom; a display having an input coupled to receive data and, for displaying the received data; and a processor coupled to the memory, the plurality of outputs, the plurality of inputs, and the input of the display, the processor being arranged for executing the program in the memory to sequentially cause the one of the plurality of inputs to provide the activate signal, to monitor the plurality of inputs for receipt of the output signal, and when the output signal is not received after the predetermined time from providing the activate signal, providing data to the display to indicate that there is a fault with the pressure detection of at least one of the plurality of tyres.

Claim 4

A tyre pressure monitoring system according to claim 1 wherein each remote receiver comprises: a frequency selective circuit having an input for coupling to the antenna, and an output, the frequency selective circuit being arranged for primarily coupling the second RF signal from the input to the output; a RF amplifier coupled to receive the second RF signal from the output of the frequency selective circuit and coupled to provide an amplified second RF signal; and a demodulator coupled to receive the amplified second RF signal from the RF amplifier, demodulate the amplified second RF signal to produce the output signal, and coupled to provide the output signal.

Claim 5

A tyre pressure monitoring system according to claim 1 wherein each remote energy transmitting circuit comprises: a RF signal generator coupled to the input for receiving the activate signal, for generating the first RF signal in response to receiving the activate signal, and coupled to the antenna for providing the first RF signal thereto.

Claim 6

A tyre pressure monitoring system according to claim 2 wherein the converter comprises a bridge rectifier.

Claim 7

A tyre pressure monitoring system according to claim 2 wherein the coupling means comprises an OR logic gate.