Patent ID: 6388481
Filing Date: 2002-05-14
Classification: H03L

Abstract:
An apparatus including oscillator control circuitry for a phase lock loop, comprising:phase detection circuitry, responsive to a reference signal, an oscillator feedback signal and a charge pump feedback signal, that provides first and second phase signals indicative of a phase difference between said reference and oscillator feedback signals with respective assertion states responsive to said phase difference and respective deassertion states responsive to said charge pump feedback signal; control signal generator circuitry, coupled to said phase detection circuitry and responsive to said first and second phase signals, that provides a first pump control signal with assertion and deassertion states corresponding to and time-delayed from said first phase signal assertion and deassertion states, a first bias control signal with assertion and deassertion states responsive to said first phase signal and said first pump control signal, a second pump control signal with assertion and deassertion states corresponding to and time-delayed from said second phase signal assertion and deassertion states, and a second bias control signal with assertion and deassertion states responsive to said second phase signal and said second pump control signal; bias control circuitry, coupled to said control signal generator circuitry and responsive to said first and second bias control signals, that provides first and second bias enablement signals with assertion and deassertion states; and charge pump circuitry, coupled to said bias control circuitry and said control signal generator circuitry and responsive to said first and second bias enablement signals and said first and second pump control signals, that provides a composite output current signal and said charge pump feedback signal, wherein said composite output current signal includes an output source current component substantially coincident with said first bias enablement and pump control signal assertion states and includes an output sink current component substantially coincident with said second bias enablement and pump control signal assertion states, and said charge pump feedback signal includes an assertion state responsive to a coincidence of said output source and sink current components.