The disclosure discloses an RC oscillating circuit. A first end of a capacitor is grounded, a second end of the capacitor is connected to a charging path, a discharging path and a comparator, A first input end of a comparator is connected to first reference voltage. An output end of the comparator outputs a first output signal and is connected to a control end of the discharging path. The first reference voltage provides the flipped voltage of the comparator The first output signal forms an output clock signal. A first regulating circuit is configured to regulate the magnitude of the charging current and realize coarse frequency tuning. A second regulating circuit is configured to regulate the magnitude of the first reference voltage and realize fine frequency tuning. The disclosure has the advantages of low power consumption, fast start, high precision and wide tuning range.

The disclosure discloses an RC oscillating circuit. A first end of a capacitor is grounded, a second end of the capacitor is connected to a charging path, a discharging path and a comparator, A first input end of a comparator is connected to first reference voltage. An output end of the comparator outputs a first output signal and is connected to a control end of the discharging path. The first reference voltage provides the flipped voltage of the comparator The first output signal forms an output clock signal. A first regulating circuit is configured to regulate the magnitude of the charging current and realize coarse frequency tuning. A second regulating circuit is configured to regulate the magnitude of the first reference voltage and realize fine frequency tuning. The disclosure has the advantages of low power consumption, fast start, high precision and wide tuning range.

An oscillator includes a first current source, a second current source, a first chopper circuit, a resistive component, a capacitive component, and a processing circuit. The first current source provides a first current. The second current source provides a second current. The first chopper circuit includes a first terminal coupled to the first current source, a second terminal coupled to the second current source, a third terminal coupled to the resistive component, and a fourth terminal coupled to the capacitive component. The processing circuit generates an output clock in response to a first voltage across the resistive component and a second voltage across the capacitive component. The first chopper circuit couples the first terminal and the second terminal to the third terminal and the fourth terminal, respectively and alternately. The resistive component and the capacitive component receive the first current and the second current, respectively and alternately.

An oscillator includes a first current source, a second current source, a first chopper circuit, a resistive component, a capacitive component, and a processing circuit. The first current source provides a first current. The second current source provides a second current. The first chopper circuit includes a first terminal coupled to the first current source, a second terminal coupled to the second current source, a third terminal coupled to the resistive component, and a fourth terminal coupled to the capacitive component. The processing circuit generates an output clock in response to a first voltage across the resistive component and a second voltage across the capacitive component. The first chopper circuit couples the first terminal and the second terminal to the third terminal and the fourth terminal, respectively and alternately. The resistive component and the capacitive component receive the first current and the second current, respectively and alternately.

Methods and systems are described for generating multiple phases of a local clock at a controllable variable frequency, using loop-connected strings of active circuit elements. A specific embodiment incorporates a loop of four active circuit elements, each element providing true and complement outputs that are cross-coupled to maintain a fixed phase relationship, and feed-forward connections at each loop node to facilitate high frequency operation. A particular physical layout is described that maximizes operating frequency and minimizes clock pertubations caused by unbalanced or asymmetric signal paths and parasitic node capacitances.

Methods and systems are described for generating multiple phases of a local clock at a controllable variable frequency, using loop-connected strings of active circuit elements. A specific embodiment incorporates a loop of four active circuit elements, each element providing true and complement outputs that are cross-coupled to maintain a fixed phase relationship, and feed-forward connections at each loop node to facilitate high frequency operation. A particular physical layout is described that maximizes operating frequency and minimizes clock pertubations caused by unbalanced or asymmetric signal paths and parasitic node capacitances.

An oscillator acceleration circuit, configured to accelerate the start-up of an oscillator, wherein the oscillator has an input terminal and an output terminal. The oscillator acceleration circuit includes an inverting amplifier, a feedback resistor and an acceleration circuit; the inverting amplifier has an input terminal and an output terminal correspondingly coupled to the input terminal and the output terminal of the oscillator. The feedback resistor is coupled between the input terminal and the output terminal of the oscillator, and the acceleration circuit is coupled between the input terminal and the output terminal of the oscillator. The acceleration circuit is configured to provide a transfer function, wherein the transfer function is the same as the transfer function provided by a resistor and a capacitor connected in parallel; wherein the resistance of the resistor is less than zero.

An oscillator acceleration circuit, configured to accelerate the start-up of an oscillator, wherein the oscillator has an input terminal and an output terminal. The oscillator acceleration circuit includes an inverting amplifier, a feedback resistor and an acceleration circuit; the inverting amplifier has an input terminal and an output terminal correspondingly coupled to the input terminal and the output terminal of the oscillator. The feedback resistor is coupled between the input terminal and the output terminal of the oscillator, and the acceleration circuit is coupled between the input terminal and the output terminal of the oscillator. The acceleration circuit is configured to provide a transfer function, wherein the transfer function is the same as the transfer function provided by a resistor and a capacitor connected in parallel; wherein the resistance of the resistor is less than zero.

Disclosed are an on-chip RC oscillator, a chip, and a communication terminal. The on-chip RC oscillator comprises a stabilized voltage supply module, an RC core oscillator module, a frequency sampling and conversion module, and a frequency trimming module. By means of the frequency sampling and conversion module, the clock frequency of the oscillator is sampled and detected in real time, and the sampled clock frequency is converted into a voltage signal, and then analog-to-digital conversion is performed to obtain a corresponding digital code, so that when the clock frequency changes, the frequency trimming module circuit converts said digital code into a control signal; a voltage having a suitable temperature coefficient is outputted for the RC core oscillator; also, a zero temperature coefficient current of a suitable magnitude is outputted for the RC core oscillator module, so as to precisely calibrate the clock frequency.

Disclosed are an on-chip RC oscillator, a chip, and a communication terminal. The on-chip RC oscillator comprises a stabilized voltage supply module, an RC core oscillator module, a frequency sampling and conversion module, and a frequency trimming module. By means of the frequency sampling and conversion module, the clock frequency of the oscillator is sampled and detected in real time, and the sampled clock frequency is converted into a voltage signal, and then analog-to-digital conversion is performed to obtain a corresponding digital code, so that when the clock frequency changes, the frequency trimming module circuit converts said digital code into a control signal; a voltage having a suitable temperature coefficient is outputted for the RC core oscillator; also, a zero temperature coefficient current of a suitable magnitude is outputted for the RC core oscillator module, so as to precisely calibrate the clock frequency.