An oscillator using a supply regulation loop and a method of operating the oscillator are provided. The oscillator includes a reference voltage generator configured to generate reference voltages from a supply voltage, a supply regulation loop circuit including a first operational amplifier and a transistor, the first operational amplifier being configured to receive a first reference voltage of the reference voltages, and the transistor being connected to an output terminal of the first operational amplifier, and a frequency locked loop (FLL) circuit configured to generate a clock signal, based on an input voltage determined based on a current flowing in the transistor and a second reference voltage of the reference voltages, wherein the first operational amplifier may include an input terminal configured to receive the first reference voltage and to receive negative feedback from the transistor, and the output terminal being configured to generate an output voltage independent of noise of the supply voltage.

An apparatus is provided which comprises: an oscillator to generate a first clock having a first frequency; a divider coupled to the oscillator, wherein the divider is to generate a second clock having a second frequency; and a current reference generator comprising a switched capacitor circuitry which is to receive the second clock directly or indirectly.

An apparatus is provided which comprises: an oscillator to generate a first clock having a first frequency; a divider coupled to the oscillator, wherein the divider is to generate a second clock having a second frequency; and a current reference generator comprising a switched capacitor circuitry which is to receive the second clock directly or indirectly.

A clock circuit comprises an oscillator circuit and a power-on reset circuit, the oscillator circuit comprises a current generating module and a loop oscillation module connected together; the current generating module is used for outputting a control current to the loop oscillation module; the loop oscillation module is used for outputting an oscillation signal with a set frequency under action of the control current; and the power-on reset circuit is connected to the loop oscillation module and is used for providing an enabling control signal to the loop oscillation module after a power supply is powered on to the power-on reset circuit and the oscillator circuit.

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 module used with a plurality of power sources includes an oscillator unit, a clock monitor unit (CMU), a software module and a digital calibration circuit. The oscillator unit generates a clock signal. The CMU is coupled to the oscillator unit, determines whether an amplitude of the clock signal exceeds a predetermined threshold, and outputs an alarm signal if the amplitude of the clock signal is lower than the predetermined threshold. The software module is coupled to the CMU, and receives the alarm signal to output a calibration signal. The digital calibration circuit is coupled to the oscillator and the software module, and outputs a control signal in response to the clock signal and the calibration signal, adjusting the plurality of power sources to modify the clock signal.

A push-start crystal oscillator (XO), an associated electronic device and a push-start method for performing a start-up procedure of an XO are provided. The push-start XO includes an inverting amplifier and a push-start logic control circuit, wherein the inverting amplifier is coupled to a crystal load. The inverting amplifier generates a first XO signal and a second XO signal. The push-start logic control circuit receives a feedback clock from a phase locked loop (PLL), and generates a phase control clock according to the feedback clock, wherein a push phase and a settle phase are specified by the phase control clock. During the settle phase, the PLL calibrates a frequency of the feedback clock according to the second XO signal. During the push phase, the feedback clock is transmitted to the inverting amplifier in order to increase the amplitude of the first XO signal.

A semiconductor device includes: a secondary battery; a constant voltage generation circuit that is driven in accordance with the secondary battery; a control logic circuit that is driven with a constant voltage generated by the constant voltage generation circuit and controls the constant voltage generation circuit; and a starting circuit that outputs a control signal for operating the constant voltage generation circuit in correspondence to an initialization signal input from outside in a case in which the constant voltage generation circuit is stopped.

A semiconductor device includes: a secondary battery; a constant voltage generation circuit that is driven in accordance with the secondary battery; a control logic circuit that is driven with a constant voltage generated by the constant voltage generation circuit and controls the constant voltage generation circuit; and a starting circuit that outputs a control signal for operating the constant voltage generation circuit in correspondence to an initialization signal input from outside in a case in which the constant voltage generation circuit is stopped.

A system and method for calibrating a Voltage-Controlled Oscillator (VCO) having both fine-tuning control and coarse-tuning control. The VCO frequency can vary monotonically with changes in each of one or more operational conditions. The calibration method determines the coarse-tuning control setting for the VCO at system start-up. The method comprises generating frequency characterization data, generating a polynomial function from the characterization data, calculating the fine-tuning control voltage based on the polynomial function and a measurement of the operational conditions, and sweeping through ail the coarse-tuning control settings to determine the coarse-tuning control setting that generates the closest VCO frequency to a target frequency when using the calculated fine-tuning control voltage.