An oscillator capable of quick startup is provided. A transistor is provided between an output terminal of a certain stage inverter and an input terminal of the following stage inverter included in the voltage controlled oscillator. With the use of the on resistance of the transistor, the oscillation frequency of the clock signal is controlled. While supply of the power supply voltage is stopped, a signal that is input to the input terminal of the inverter just before supply of the power supply voltage is stopped is stored by turning off the transistor. This operation makes it possible to immediately output a clock signal that has the same frequency as that before supply of the power supply voltage is stopped at the time when the power supply voltage is supplied again.

The disclosure concerns an oscillator circuit (10) for a signal transmitter, the oscillator circuit (10) comprising: a resonant circuit (12) comprising a resonant inductor (LR) and a resonant capacitor (CR) parallel to the resonant inductor (LR) or comprising a crystal device, a driving branch (14) comprising a pump capacitor (CP) connected to the resonant circuit (12), a feedback branch (20) connected to the resonant circuit (12), a phase shifting circuit (22) connected to the resonant circuit (12) via the feedback branch (20), a comparator circuit (24) connected to the feedback branch (20) via the phase shifting circuit (22) and a driver circuit (28) connected to an output of the comparator circuit (24) and operable to charge the pump capacitor (CP).

The disclosure concerns an oscillator circuit (10) for a signal transmitter, the oscillator circuit (10) comprising: a resonant circuit (12) comprising a resonant inductor (LR) and a resonant capacitor (CR) parallel to the resonant inductor (LR) or comprising a crystal device, a driving branch (14) comprising a pump capacitor (CP) connected to the resonant circuit (12), a feedback branch (20) connected to the resonant circuit (12), a phase shifting circuit (22) connected to the resonant circuit (12) via the feedback branch (20), a comparator circuit (24) connected to the feedback branch (20) via the phase shifting circuit (22) and a driver circuit (28) connected to an output of the comparator circuit (24) and operable to charge the pump capacitor (CP).

A relaxation oscillator includes a start-up circuit. During the start-up period of the relaxation oscillator, two output signals from the relaxation oscillator are controlled to be complementary signals by the start-up circuit according to a control signal. Consequently, the relaxation oscillator can be started up successfully. The relaxation oscillator can generate periodic square wave signals. Moreover, during the start-up period of the relaxation oscillator, the generation of the deadlock situation can be avoided.

A relaxation oscillator includes a start-up circuit. During the start-up period of the relaxation oscillator, two output signals from the relaxation oscillator are controlled to be complementary signals by the start-up circuit according to a control signal. Consequently, the relaxation oscillator can be started up successfully. The relaxation oscillator can generate periodic square wave signals. Moreover, during the start-up period of the relaxation oscillator, the generation of the deadlock situation can be avoided.

An oscillator capable of quick startup is provided. A transistor is provided between an output terminal of a certain stage inverter and an input terminal of the following stage inverter included in the voltage controlled oscillator. With the use of the on resistance of the transistor, the oscillation frequency of the clock signal is controlled. While supply of the power supply voltage is stopped, a signal that is input to the input terminal of the inverter just before supply of the power supply voltage is stopped is stored by turning off the transistor. This operation makes it possible to immediately output a clock signal that has the same frequency as that before supply of the power supply voltage is stopped at the time when the power supply voltage is supplied again.

Systems and methods are disclosed for wide frequency range voltage controlled oscillators. For example, an apparatus includes a Voltage Controlled Oscillator (VCO) including a delay cell which includes first and second current sources provided in parallel with one another. The first current source is controlled by a voltage control input connected to a voltage control terminal and the second current source is controlled by a bias voltage input connected to a bias voltage terminal. The first current source provides an alternate current path in the delay cell when the second current source is off. The delay cell is operable to receive an input and produce an output using the alternate current path.

Systems and methods are disclosed for wide frequency range voltage controlled oscillators. For example, an apparatus includes a Voltage Controlled Oscillator (VCO) including a delay cell which includes first and second current sources provided in parallel with one another. The first current source is controlled by a voltage control input connected to a voltage control terminal and the second current source is controlled by a bias voltage input connected to a bias voltage terminal. The first current source provides an alternate current path in the delay cell when the second current source is off. The delay cell is operable to receive an input and produce an output using the alternate current path.

An example semiconductor chip includes analog circuits, digital circuits, and a digital input port. The digital input port is to receive an input signal. The analog circuit is to receive the input signal from the digital input port and produce a digital signal based on the input signal.

An example semiconductor chip includes analog circuits, digital circuits, and a digital input port. The digital input port is to receive an input signal. The analog circuit is to receive the input signal from the digital input port and produce a digital signal based on the input signal.