Abstract: Near field communication (NFC) devices may be required to operate at low power and so process small signals which are more susceptible to corruption by noise. An NFC device 100 is described having an antenna 10 which can be adapted to receive signal from a further NFC device. When a signal is received by the antenna, an input voltage is generated. A variable resistance element 12 is connected in series between the antenna 10 and an amplifier 14, which is adapted to increase the input resistance with increasing input voltage. By increasing the resistance when the input voltage is increased, the current drawn from the coil is reduced. This results in a lower overall power consumption of the device while maintaining reliable performance, because the higher input signal level is less susceptible to corruption by the noise generated by the variable resistance element 12, and the amplifier 14.

Abstract: A thermally-compensated oscillator has a current reference with an output current which relates to an ambient temperature with a first relationship, a ring oscillator having an operating frequency which relates to the ambient temperature with a second relationship, and which receives the output current of the current reference and outputs an oscillator signal, and a level shifter which receives the oscillator signal from the ring oscillator and outputs a corresponding voltage-regulated clock signal.

Abstract: Near field communication (NFC) devices may be required to operate at low power and so process small signals which are more susceptible to corruption by noise. An NFC device 100 is described having an antenna 10 which can be adapted to receive signal from a further NFC device. When a signal is received by the antenna, an input voltage is generated. A variable resistance element 12 is connected in series between the antenna 10 and an amplifier 14, which is adapted to increase the input resistance with increasing input voltage. By increasing the resistance when the input voltage is increased, the current drawn from the coil is reduced. This results in a lower overall power consumption of the device while maintaining reliable performance, because the higher input signal level is less susceptible to corruption by the noise generated by the variable resistance element 12, and the amplifier 14.

Abstract: A thermally-compensated oscillator has a current reference with an output current which relates to an ambient temperature with a first relationship, a ring oscillator having an operating frequency which relates to the ambient temperature with a second relationship, and which receives the output current of the current reference and outputs an oscillator signal, and a level shifter which receives the oscillator signal from the ring oscillator and outputs a corresponding voltage-regulated clock signal.