Common mode input control for switched capacitor amplifier in pipeline analog-to-digital converter
AssigneeLinear Technology Corporation
InventorDave Thomas
Life of this patent
Estimating the term…
Abstract
A common mode bias circuit may include a weak common mode bias generator and a common mode bias capacitance. During a first state of the common mode bias circuit, the weak common mode bias generator may be coupled to the common mode bias capacitance and may impart to them a predefined common mode signal level. During a second state of the common mode bias circuit, the common mode bias capacitance may be coupled to differential inputs of an amplifier in a manner that establishes an input common mode level for the amplifier.
Claims6
A common mode bias circuit comprising:
- a common mode bias generator;
- and
- a common mode bias capacitance,
- wherein the common mode bias circuit is configured such that:
- during a first state of the common mode bias circuit, the common mode bias generator is coupled to the common mode capacitance and imparts to it a predefined common mode signal level, and
- during a second state of the common mode bias circuit, the common mode bias capacitance is coupled to differential inputs of an amplifier in a manner that establishes an input common mode level for the amplifier.
A method of setting an input common mode level of a differential amplifier comprising:
- using a common mode bias generator and a common mode bias capacitance to establish a predefined signal level during a first state;
- and
- using the common mode bias capacitance during a second state to transfer a predefined signal level to differential inputs of the amplifier.
Dependencies are inferred from the claim text.