Apple Inc.

Ramy A Ahmed

Jafar Savoj

Bruno Werner Garlepp

Amr A Hafez

A circuit for sensing local operating properties of an integrated circuit is disclosed. The circuit may include one or more sensor circuits configured to sense the local operating properties of the integrated circuit. The sensor circuits may receive a supply voltage with a magnitude in a limited range from a digital power supply that is different from the digital power supply that provides power to functional circuits in the integrated circuit. Level shifters may be coupled to the sensor circuits to shift output signals from the sensor circuits to levels that correspond to the digital power supply that provides power to functional circuits in the integrated circuit. Counters and a shift register may be coupled to the level shifters to receive the shifted output signals, the values of which may be used to determine the local operating properties of the integrated circuit as sensed by the sensor circuits.

Integration of analog circuits inside digital blocks

A circuit that produces an output signal having a frequency that is proportional to absolute temperature (PTAT) is disclosed. In one embodiment, the circuit includes a ring oscillator and a bias current circuit coupled thereto. The ring oscillator and the bias current circuit are implemented in close proximity to one another. During operation, the bias current circuit generates a bias current that is provided to the ring oscillator. The amount of bias current generated is dependent upon the temperature of the circuit. In turn, the frequency of an output signal provided by the ring oscillator is dependent on the amount of bias current received from the bias current circuit. Accordingly, the frequency of the ring oscillator output signal is dependent on the temperature of the circuit.

PTAT ring oscillator circuit

A sensor circuit and integrated circuit having the same is disclosed. In one embodiment, a sensor circuit includes first and second ring oscillators having different circuit topologies. A first counter is coupled to receive an output signal from the first ring oscillator, while a second counter is coupled to receive an output signal from the second ring oscillator. The sensor circuit further includes a local clock circuit that provides a clock signal to the first and second counters. Furthermore, the local clock circuit is coupled to provide the clock signal exclusively to circuitry within the sensor circuit, the circuitry including the first and second counters.

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Cupertino, CA, United States of America

Ramy A Ahmed