A circuit includes: an oscillator configured to generate an oscillation clock signal; an NMOS transistor having a source connected with a power terminal of the oscillator, and a drain connected with a first power supply line to which a first power supply voltage is supplied; an operational amplifier configured to control a gate voltage of the NMOS transistor based on a voltage of the power terminal of the oscillator; and a charge pump.

The charge pump is configured to use the oscillation clock signal or a clock signal generated from the oscillation clock signal to boost the first power supply voltage and generate a boosted power supply voltage, and to supply the boosted power supply voltage to the power terminal of the operational amplifier.

A drive circuit for a MEMS resonator can include closed loop means for detecting and amplifying a signal of the MEMS resonator, and means for feeding the detected and amplified signal as a feedback signal back to the MEMS resonator. The circuitry also comprises DC bias voltage means for generating for the MEMS resonator a first DC bias voltage, and a second DC bias voltage that is controlled according to measured amplitudes of the MEMS resonator, one of the DC bias voltages being summed into the feedback signal. The circuitry comprises also a start-up circuitry adapted to detect a start-up state, and in response to a detected start-up state change at last one of the DC bias voltages to a predefined level. The state of constant oscillation is achieved reliably and in short time.

A drive circuit for a MEMS resonator can include closed loop means for detecting and amplifying a signal of the MEMS resonator, and means for feeding the detected and amplified signal as a feedback signal back to the MEMS resonator. The circuitry also comprises DC bias voltage means for generating for the MEMS resonator a first DC bias voltage, and a second DC bias voltage that is controlled according to measured amplitudes of the MEMS resonator, one of the DC bias voltages being summed into the feedback signal. The circuitry comprises also a start-up circuitry adapted to detect a start-up state, and in response to a detected start-up state change at last one of the DC bias voltages to a predefined level. The state of constant oscillation is achieved reliably and in short time.

A trigger, includes: a first voltage input terminal; a bias voltage input terminal; a first bias transistor having a scaling of N to a first component of an external device; a comparator transistor having a scaling of N to a second component of the external device; a first switch transistor and a second switch transistor; a shunt transistor having a control terminal connected to the first voltage input terminal, a second terminal connected to the second terminal of the second switch transistor, and a first terminal connected to the first terminal of the comparator transistor. The shunt transistor has an enlarging scale of M to the comparator transistor. A voltage output terminal is respectively connected to the second terminal of the first switch transistor, the control terminal of the second switch transistor, and the second terminal of the comparator transistor.

A trigger, includes: a first voltage input terminal; a bias voltage input terminal; a first bias transistor having a scaling of N to a first component of an external device; a comparator transistor having a scaling of N to a second component of the external device; a first switch transistor and a second switch transistor; a shunt transistor having a control terminal connected to the first voltage input terminal, a second terminal connected to the second terminal of the second switch transistor, and a first terminal connected to the first terminal of the comparator transistor. The shunt transistor has an enlarging scale of M to the comparator transistor. A voltage output terminal is respectively connected to the second terminal of the first switch transistor, the control terminal of the second switch transistor, and the second terminal of the comparator transistor.

An oscillator circuit includes an oscillating circuit coupled to a vibrator, and a control circuit that controls the oscillating circuit. The oscillator circuit has a normal operation mode in which the oscillating circuit oscillates in a state where a negative resistance value is a first value, and a start mode in which the oscillator circuit shifts from a state where oscillation is stopped to the normal operation mode. In the start mode, the control circuit controls the negative resistance value to increase from a second value which is smaller than the first value.

An oscillator circuit includes an oscillating circuit coupled to a vibrator, and a control circuit that controls the oscillating circuit. The oscillator circuit has a normal operation mode in which the oscillating circuit oscillates in a state where a negative resistance value is a first value, and a start mode in which the oscillator circuit shifts from a state where oscillation is stopped to the normal operation mode. In the start mode, the control circuit controls the negative resistance value to increase from a second value which is smaller than the first value.

A continuous time linear equalizer comprises an input of a first equalizer path configured to receive a first differential input signal; an input of a second equalizer path configured to receive a second differential input signal; a first programmable load capacitor coupled to an output of the first equalizer path; a second programmable load capacitor coupled to an output of the second equalizer path; and a programmable source capacitor coupled between the first equalizer path and the second equalizer path.

A continuous time linear equalizer comprises an input of a first equalizer path configured to receive a first differential input signal; an input of a second equalizer path configured to receive a second differential input signal; a first programmable load capacitor coupled to an output of the first equalizer path; a second programmable load capacitor coupled to an output of the second equalizer path; and a programmable source capacitor coupled between the first equalizer path and the second equalizer path.

An oscillator circuit has a reconfigurable oscillator amplifier. The reconfigurable oscillator amplifier is used to be coupled to a resonant circuit in parallel. The reconfigurable oscillator amplifier supports different circuit configurations for different operation modes, respectively. The reconfigurable oscillator amplifier has at least one circuit component shared by the different circuit configurations. The reconfigurable oscillator amplifier employs one of the different circuit configurations under one of the different operation modes.