Method and apparatus for precision phase skew generation

A phase skew generator, comprising:

• a phase detector configured to detect a phase error between an input signal and an output signal of the phase skew generator;
• a charge pump, coupled to the phase skew generator, the charge pump have a pre-charge current path and a normal operation current path, wherein the pre-charge current path is configured to conduct a unit current I during a first time period, and the normal operation current path is configured to conduct a current K×I during a second time period following the first time period, where K is an integer greater than 1;
• a sample and hold circuit, coupled to the capacitor, configured to sample a voltage level reflecting the phase error at predetermined times and provide an output voltage during a third time period following the second time period;
• and
• a voltage controlled delay line (VCDL), coupled to the sample and hold circuit, configured to output the output signal, wherein the VCDL comprises M delay line stages each configured to output a signal having a phase skew offset from a signal output of an immediately preceding or succeeding delay line stage, and a last delay stage provides the output signal, where M in an integer greater than or equal to 2.

A method of generating a plurality of signals, the method comprising:

• providing a first current during a first time period;
• providing a second current during a second time period following the first time period, wherein the second current is larger than the first current;
• sampling a voltage level representative a phase error between an input signal and an output signal to provide a sampled voltage (VS) during a third time period following the second time period;
• determining a difference between VS and a target VS value;
• adjusting a delay of an output clock signal based on the difference;
• and
• determining the phase error based on the difference.