Controllable current source circuit and a phase locked loop equipped with such a circuit

US6734708B1 · kind B1 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Xiaopin Zhang · Munich, DE
• Stefan Herzinger · Sauerlach, DE
• Helmut Herrmann · Hersbruck, DE

Key dates

• Filing date: Jul 24, 2000
• Grant date: May 11, 2004
• Expiry date: Apr 2, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03L7/0895
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A controllable current source circuit and a phase locked loop contained such a circuit are disclosed. The current source circuit such a single switched driver stage for a switched actuation of the loop filter. A continuously switched-on driver stage is introduced into one of several paths of the current source circuit, so that a continuously weaker current is drawn by the loop filter. The currents are preferably stabilized via a current mirror circuit.