Patent ID: 7020793

Claim:
A circuit for aligning a signal with a reference signal, said circuit comprising: a phase-adjusting circuit for adjusting a phase of a signal in accordance with a control signal received at a control signal input, said phase-adjusting circuit outputting an adjusted signal; a first control circuit coupled to said phase-adjusting circuit, for outputting a first voltage signal in accordance with a phase difference between a first input signal and a second input signal, said first control circuit receiving a reference signal as the first input signal and the adjusted signal as the second input signal, the first voltage signal also reflecting a static phase offset due to asymmetries in components of said first control circuit; a second control circuit which is a replica of said first control circuit and has the same static phase offset as said first control circuit, said second control circuit receiving the reference signal as two input signals and outputting a second voltage signal reflecting the same static phase offset; and a tuning circuit coupled to said first and second control circuits, said tuning circuit comparing the first and second voltage signals and tuning a bias current in said first and second control circuits such that the static phase offsets of said first and second control circuits become zero in a steady state.