Operational amplifier arrangement including a quiescent current control circuit
First Claim
1. An operational amplifier arrangement comprising:
- a differential output stage having input terminals coupled to respective output terminals of a preceding stage, said operational amplifier arrangement further including;
a quiescent current control circuit coupled to respective output terminals of said output stage and said preceding stage, said quiescent current control circuit controlling the quiescent current of said differential output stage by commonly and simultaneously tuning respective input offset voltages of said preceding stage, wherein said quiescent current control circuit digitally and off-line tunes said respective input offset voltages of said preceding stage, said quiescent current control circuit including;
a digital control module adapted to control the common tuning of said input offset voltages, based on at least one signal received from a current sense and comparison module included in said quiescent current control circuit and coupled between said output stage and said digital control module, whereby said current sense and comparison module is adapted to measure the output currents in two series branches of said output stage, to compare them individually with a predetermined reference current, and to generate said at least one signal to said digital control module indicative of the result of said comparison.
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Abstract
An operational amplifier arrangement (OAA) includes a differential output stage (OS), input terminals of which are coupled to respective output terminals of a preceding stage (A2, A3), said operational amplifier arrangement (OAA) further includes a quiescent current control circuit (QCCC) coupled between said output stage (OS) and said preceding stage (A2, A3) and adapted to control the quiescent current of said differential output stage (OS) by commonly and simultaneously tuning respective input offset voltages (VoffA2, VoffA3) of said preceding stage (A2, A3), is characterised in that said quiescent current control circuit (QCCC) is adapted to digitally and off-line tune said input offset voltages of said preceding stage.
74 Citations
19 Claims
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1. An operational amplifier arrangement comprising:
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a differential output stage having input terminals coupled to respective output terminals of a preceding stage, said operational amplifier arrangement further including;
a quiescent current control circuit coupled to respective output terminals of said output stage and said preceding stage, said quiescent current control circuit controlling the quiescent current of said differential output stage by commonly and simultaneously tuning respective input offset voltages of said preceding stage, wherein said quiescent current control circuit digitally and off-line tunes said respective input offset voltages of said preceding stage, said quiescent current control circuit including;
a digital control module adapted to control the common tuning of said input offset voltages, based on at least one signal received from a current sense and comparison module included in said quiescent current control circuit and coupled between said output stage and said digital control module, whereby said current sense and comparison module is adapted to measure the output currents in two series branches of said output stage, to compare them individually with a predetermined reference current, and to generate said at least one signal to said digital control module indicative of the result of said comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14)
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10. An operational amplifier arrangement comprising:
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an amplifier stage comprising a first and second operational amplifiers;
a differential output stage having input terminals coupled to respective output terminals of said amplifier stage;
a quiescent current control circuit coupled to said amplifier stage and to respective output terminals of said output stage, said quiescent current control circuit controlling the quiescent current of said differential output stage by individually tuning input offset voltages of said first and second operational amplifiers, wherein said quiescent current control circuit digitally and off-line tunes said input offset voltages of said first and second operational amplifiers. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification