Self-biased bipolar ring-oscillator phase-locked loops with wide tuning range

An apparatus comprising:

• a VCO that generates an output clock signal having a frequency;
• a quantizer that is coupled to and controlled by the VCO;
• a charge pump that is coupled to the VCO so as to provide a control signal to the VCO based on at least in part on the frequency of the output clock signal of the VCO;
• a charge pump current generator that is coupled to the charge pump so as to selectively increase a current supply to the charge pump based at least in part on the frequency of the output clock signal of the VCO, wherein the charge pump current generator includes a plurality of current paths to be selectively actuated by the quantizer;
• and
• a loop filter that is coupled to the charge pump so as to control a bandwidth of the PLL by controlling the control signal, wherein the frequency of the VCO is responsive to the control signal.

An apparatus comprising:

• a VCO to provide an output clock signal based on a control voltage, wherein the VCO includes:
• a plurality of ring-oscillator stages to generate an output voltage based on an input voltage, wherein each ring-oscillator stage comprises a plurality of gain stages to selectively generate a control current and an output current based on a comparison of the control voltage and a corresponding threshold voltage, and one gain stage to generate an output current;
• and
• a resistor ladder to provide a plurality of threshold voltages;
• a quantizer to generate digital control signals based on corresponding control currents from the gain stages, wherein the quantizer includes a plurality of current comparators corresponding to the plurality of control currents received;
• a phase/frequency detector to generate digital adjustment signals based on a comparison of a reference clock and a feedback clock that is based on the VCO output clock;
• a loop filter to adjust the control voltage to the VCO based on the digital control signals;
• a charge pump to supply a charge pump current to the loop filter based on a charge pump source current and the digital adjustment signals from the phase/frequency detector;
• and
• a charge pump current generator to generate the charge pump source current based on the digital control signals, wherein the charge pump current generator includes a plurality of switching elements to selectively increase the charge pump source current based on the digital control signals.

An apparatus comprising:

• a phase/frequency detector that receives a reference signal and a feedback signal;
• a charge pump that is coupled to the phase/frequency detector;
• a loop filter that is coupled to the charge pump;
• a VCO that is coupled to the loop filter, wherein the VCO generates an output signal;
• a divider that is coupled to the VCO and the phase/frequency detector, wherein the divider generates the feedback signal at least in part from the output signal;
• a quantizer that is coupled to the VCO, wherein the VCO controls the quantizer;
• and
• a charge pump current generator that is coupled to the charge pump and the quantizer, wherein the charge pump provides a current to the charge pump, and wherein the magnitude of the current is controlled by the quantizer.