US 7,126,415 B2Granted

Switched-capacitor circuits with reduced finite-gain effect

AssigneeTexas Instruments Incorporated

InventorsFranco Maloberti, Martin K. Kinyua

Life of this patent

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Abstract

Operational amplifier circuits (20, 30) including error capacitors (C3, C13) for storing finite gain effect error voltages for correction of output voltages of the circuits (20, 30), are disclosed. The circuits (20, 30) are operated in a sample clock phase to produce an approximation of the output voltage, using negative polarity versions of the input voltages to the circuit. The approximate output voltage is used to produce and store an error voltage, corresponding to the differential voltage at the input of the operational amplifier (15, 25), relative to virtual ground. This error voltage is then subtracted from the input voltage applied in the operate clock phase, to correct for the finite gain effect. A pipelined analog-to-digital converter (50) using the disclosed operational amplifier circuits (20, 30) is also disclosed.

Claims8

Dependent claims

A switched-capacitor operational amplifier circuit, comprising:

an operational amplifier, having an input and an output;
a first sampling capacitor;
an error capacitor, connected to the first sampling capacitor at a first node, and connected to the input of the operational amplifier;
a second sampling capacitor;
a feedback capacitor, connected to the second sampling capacitor at a second node;
a grounding switch for connecting the first node to a ground potential responsive to a first clock phase;
first and second sampling switches, for connecting the first and second sampling capacitors to complementary input voltages responsive to the first clock phase;
sampling feedback switches, for connecting the feedback capacitor between the input and output of the operational amplifier through the second node responsive to the first clock phase;
a feedback switch, for connecting the output of the operational amplifier to the first sampling capacitor responsive to a second clock phase;
and
grounding switches, for connecting the feedback capacitor to ground potential responsive to the second clock phase.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/287,411Filed 23 Nov 2005 · division
Priority: 31 Dec 2003
Published: US 2006/0071709 A16 Apr 2006
Granted: 24 Oct 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

H03F 3/45977
By using a feedback circuit: using switching means, e.g. sample and hold
H03F 3/005
Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements: using switched capacitors, e.g. dynamic amplifiers;…
H03F
Amplifiers

Family

Application10/750,508Parent of this division · filed 31 Dec 2003
US 2006/0071709 A1Pre-grant publication · published 6 Apr 2006
US 7,068,203 B2Parent of this division
US 2005/0140433 A1Published application
US 7,126,415 B2This patent

From the US filing history. Foreign family members aren’t listed.