Loop filter used in PLL, and PLL
AssigneeSocionext Inc.
InventorsTaku Toshikawa, Heiji Ikoma, Naoshi Yanagisawa
Life of this patent
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Abstract
A loop filter includes: an input terminal and an output terminal mutually connected via a first node; a filter unit; and a low pass filter provided between a second power supply terminal and a third power supply node. One or more of at least one first resistive element and at least one first capacitive element constituting the filter unit are provided between the first node and a first power supply terminal via a switch part, and at least either the resistance value or the capacitance value of the filter unit is variable with on/off of the switch part. The switch part is constituted by transistors, and the backgate of at least one of the transistors is connected to the third power supply node.
Claims11
A loop filter used for a PLL, comprising:
- an input terminal and an output terminal mutually connected via a first node;
- a filter unit provided between the first node and a first power supply terminal, the filter unit including at least one first resistive element, at least one first capacitive element, and a switch part;
- and
- a low pass filter provided between a second power supply terminal and a third power supply node,
- wherein
- one or more of the at least one first resistive element and the at least one first capacitive element are provided between the first node and the first power supply terminal via the switch part, and at least either a resistance value or a capacitance value of the filter unit is variable with on/off of the switch part, and
- the switch part is constituted by transistors, and a backgate of at least one of the transistors is connected to the third power supply node.
Dependencies are inferred from the claim text.