An oscillator circuit comprises a crystal oscillator and an inverter. The input of the inverter is connected to the first terminal of the crystal oscillator and the output of the inverter is connected to the second terminal of the crystal oscillator, oscillator circuit is arranged to operate the inverter in its linear operating region. An amplitude regulator has an input connected to the input of the inverter, arranged to provide a first supply current I.sub.AREG to the inverter, where the magnitude of the first supply current is inversely dependent on a magnitude of a voltage at the inverter input. A digital-to-analogue converter is arranged to provide a second supply current I.sub.DAC to the inverter having a magnitude determined by a digital signal applied to a digital input of the digital-to-analogue converter.

Methods, systems, and circuitries are provided to generate clock signals of different qualities in a device. A method includes determining whether the device is operating in a mid power mode or a high power mode. In response to determining that the device is operating in the mid power mode, oscillator circuitry is controlled to cause the oscillator circuitry to consume a lower amount of power, such that the oscillator circuitry generates a lower quality clock signal. In response to determining that the device is operating in the high power mode, the oscillator circuitry is controlled to cause the oscillator circuitry to consume a higher amount of power, such that the oscillator circuitry generates a higher quality clock signal. The lower amount of power and the higher amount of power are different from one another.

Methods, systems, and circuitries are provided to generate clock signals of different qualities in a device. A method includes determining whether the device is operating in a mid power mode or a high power mode. In response to determining that the device is operating in the mid power mode, oscillator circuitry is controlled to cause the oscillator circuitry to consume a lower amount of power, such that the oscillator circuitry generates a lower quality clock signal. In response to determining that the device is operating in the high power mode, the oscillator circuitry is controlled to cause the oscillator circuitry to consume a higher amount of power, such that the oscillator circuitry generates a higher quality clock signal. The lower amount of power and the higher amount of power are different from one another.

Disclosed are an apparatuses and methods for minimum energy tracking loop that includes an oscillator to imitate a threshold path of a load system and automatically adjust a clock frequency as a supply voltage to the load system is changed, a voltage regulator configured to supply a power, an energy sensing unit which is connected to the oscillator and the voltage regulator and calculates a proportional energy proportional to a total energy consumed by the load system at a specific supply voltage, a minimum energy finder to find a minimum energy point of the load system by monitoring the calculated proportional energy proportional to the total energy at a plurality of supply voltages, a buck converter to supply a power to the load system with a supply voltage at which the load system operates with a minimum energy when the minimum energy point is found in the minimum energy finder.

Disclosed are an apparatuses and methods for minimum energy tracking loop that includes an oscillator to imitate a threshold path of a load system and automatically adjust a clock frequency as a supply voltage to the load system is changed, a voltage regulator configured to supply a power, an energy sensing unit which is connected to the oscillator and the voltage regulator and calculates a proportional energy proportional to a total energy consumed by the load system at a specific supply voltage, a minimum energy finder to find a minimum energy point of the load system by monitoring the calculated proportional energy proportional to the total energy at a plurality of supply voltages, a buck converter to supply a power to the load system with a supply voltage at which the load system operates with a minimum energy when the minimum energy point is found in the minimum energy finder.

Disclosed are an apparatuses and methods for minimum energy tracking loop that includes an oscillator to imitate a threshold path of a load system and automatically adjust a clock frequency as a supply voltage to the load system is changed, a voltage regulator configured to supply a power, an energy sensing unit which is connected to the oscillator and the voltage regulator and calculates a proportional energy proportional to a total energy consumed by the load system at a specific supply voltage, a minimum energy finder to find a minimum energy point of the load system by monitoring the calculated proportional energy proportional to the total energy at a plurality of supply voltages, a buck converter to supply a power to the load system with a supply voltage at which the load system operates with a minimum energy when the minimum energy point is found in the minimum energy finder.

Disclosed are an apparatuses and methods for minimum energy tracking loop that includes an oscillator to imitate a threshold path of a load system and automatically adjust a clock frequency as a supply voltage to the load system is changed, a voltage regulator configured to supply a power, an energy sensing unit which is connected to the oscillator and the voltage regulator and calculates a proportional energy proportional to a total energy consumed by the load system at a specific supply voltage, a minimum energy finder to find a minimum energy point of the load system by monitoring the calculated proportional energy proportional to the total energy at a plurality of supply voltages, a buck converter to supply a power to the load system with a supply voltage at which the load system operates with a minimum energy when the minimum energy point is found in the minimum energy finder.

An apparatus is disclosed for implementing multi-mode oscillation circuitry with stepping control. In an example aspect, the multi-mode oscillation circuitry comprises a resonator coupled to a first oscillator and a second oscillator. The multi-mode oscillation circuitry is configured to selectively be in a first configuration with the first oscillator in an active state and the second oscillator in an inactive state or a second configuration with the first oscillator in the inactive state and the second oscillator in the active state. The apparatus also includes a step-control circuit coupled to the multi-mode oscillation circuitry. The step-control circuit is configured to cause the first oscillator to switch from the inactive state to the active state and incrementally increase a first gain of the first oscillator based on the first oscillator being in the active state to enable the multi-mode oscillation circuitry to transition from the second configuration to the first configuration.

An apparatus is disclosed for implementing multi-mode oscillation circuitry with stepping control. In an example aspect, the multi-mode oscillation circuitry comprises a resonator coupled to a first oscillator and a second oscillator. The multi-mode oscillation circuitry is configured to selectively be in a first configuration with the first oscillator in an active state and the second oscillator in an inactive state or a second configuration with the first oscillator in the inactive state and the second oscillator in the active state. The apparatus also includes a step-control circuit coupled to the multi-mode oscillation circuitry. The step-control circuit is configured to cause the first oscillator to switch from the inactive state to the active state and incrementally increase a first gain of the first oscillator based on the first oscillator being in the active state to enable the multi-mode oscillation circuitry to transition from the second configuration to the first configuration.

An oscillator circuit comprises a crystal oscillator and an inverter. The input of the inverter is connected to the first terminal of the crystal oscillator and the output of the inverter is connected to the second terminal of the crystal oscillator, oscillator circuit is arranged to operate the inverter in its linear operating region. An amplitude regulator has an input connected to the input of the inverter, arranged to provide a first supply current I.sub.AREG to the inverter, where the magnitude of the first supply current is inversely dependent on a magnitude of a voltage at the inverter input. A digital-to-analogue converter is arranged to provide a second supply current I.sub.DAC to the inverter having a magnitude determined by a digital signal applied to a digital input of the digital-to-analogue converter.