US 8,274,320 B2Granted

Signal processing circuit with improved linearity

AssigneeMStar Semiconductor, Inc.

InventorsWei-Hsiu Hsu, Shuo Yuan Hsiao

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Abstract

A signal processing circuit includes a differential input circuit, a first DC filter, a second DC filter, a differential transconductance circuit, and a differential converting circuit. The differential input circuit includes first and second input circuits respectively for receiving first and second input signals to generate first and second processed signals. The first DC filter and the second DC filter, respectively coupled to the first and the second input circuits, receive the first and the second processed signals and output first and second voltage signals. The differential transconductance circuit includes first and second transconductance circuits, respectively coupled to the first and the second DC filters, for converting the first and the second voltage signals to first and second current signals. The differential converting circuit includes first and second converting circuits, respectively coupled to the first and the second transconductance circuits, for mixing the first and the second current signals with first and second clock signals to generate first and second output signals.

Claims13

Dependent claims

A signal processing circuit, comprising:

a differential input circuit comprising a first input circuit and a second input circuit for receiving a first input signal and a second input signal to generate a first processed signal and a second processed signal respectively;
a first reference current generating circuit for providing a first reference current to control an allowable swing amplitude of the first input signal and the second input signal;
a first DC filter and a second DC filter, respectively coupled to the first and the second input circuits, for receiving the first and the second processed signals to output a first voltage signal and a second voltage signal:
a differential transconductance circuit comprising a first transconductance circuit and a second transconductance circuit, respectively coupled to the first and the second DC filters, for converting the first and the second voltage signals to first and second current signals;
and
a differential converting circuit comprising a first converting circuit and a second converting circuit, respectively coupled to the first and the second transconductance circuits, for mixing the first and the second current signals with first and second clock signals to generate first and second output signals;
wherein the first and the second input signals are a differential signal pair, the first and the second clock signals are a differential signal pair, and the first and the second output signals are a differential signal pair.

4 more elements

A signal processing circuit, comprising:

a first input circuit for receiving a first input signal to generate a first voltage, comprising
a first impedance component, comprising a first end for receiving the first input signal and a second end;
a first operational amplifier, comprising a first input end coupled to the second end of the first impedance component, a second input end coupled to a first reference voltage, and an output end;
and
a third transconductance circuit, comprising an input end coupled to the output end of the first operational amplifier, and an output end coupled to the second end of the first impedance component;
a second input circuit for receiving a second input signal to generate a second voltage signal, comprising
a second impedance component, comprising a first end coupled to the second input signal and a second end;
a second operational amplifier, comprising a first input end coupled to the second end of the second impedance component, a second input end coupled to the first reference voltage, and an output end;
and
a fourth transconductance circuit, comprising an input end coupled to the output end of the second operational amplifier, and an output end coupled to the second end of the second impedance component;
a differential transconductance circuit comprising first and second transconductance circuits, respectively coupled to the output end of the first and the second operational amplifiers, for converting the first and the second voltage signals to first and second current signals;
and
a differential converting circuit comprising first and second converting circuits, respectively coupled to the first and the second transconductance circuits, for mixing the first and the second current signals with first and second clock signals to generate a first and a second output signals;
wherein the first and the second input signals are a differential signal pair, the first and the second clock signals are a differential signal pair, and the first and the second output signals are a differential signal pair, and
wherein the first input circuit further comprises a first reference current generating circuit, coupled to the second end of the first impedance component, for providing a first reference current, and the second input circuit further comprises a second reference current generating circuit, coupled to the second end of the second impedance component, for providing a second reference current.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/838,658Filed 19 Jul 2010
Priority: TW 98125885 A31 Jul 2009
Published: US 2011/0025417 A13 Feb 2011
Granted: 25 Sep 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H03F 3/45183
Using MOSFET transistors as the active amplifying circuit: long tailed pairs
H03F 3/45636
In differential amplifiers with FET transistors as the active amplifying circuit: by using feedback means
H03F 2200/375
Indexing scheme relating to amplifiers: circuitry to compensate the offset being present in an amplifier
H03F 2200/78
Indexing scheme relating to amplifiers: a comparator being used in a controlling circuit of an amplifier