Variable clock configuration for switched op-amp circuits
First Claim
Patent Images
1. A circuit configuration in switched op-amp technology, comprising:
- at least one switchable operational amplifier having an input and an output and transistors having a switching speed;
at least one sampling capacitor connected to said input;
at least one integrating capacitor connected to said input and to said output;
a detector for detecting the switching speed of said transistors, said detector being connected to said operational amplifier;
a clock generator producing a first and a second switching signal each having switching-clock phases including an on-phase and an off-phase, the on-phases of said first and said second switching clock signal being non-overlapping;
said clock generator controlling charging of said sampling capacitor with said first switching-clock signal and switching said operational amplifier on and off with said second switching-clock signal; and
a phase-variance device varying said switching-clock phases in which said first and second switching-clock signals are in said off-phase, said phase-variance device connected to said clock generator, said phase-variance device being configured for varying a duration of said switching-clock phases in which said first and second switching-clock signals are in said off-phase dependent upon said switching speed of said transistors as detected by said detector and enlarging said duration when said switching speed is high and reducing said duration when said switching speed is low.
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Abstract
A clock configuration for driving switched op-amp circuits operated in opposite phases is presented in which a common off-phase of variable length is inserted between the on-phases of the individual operational amplifiers. The length of the off-phase can be adapted to the transient response of the operational amplifiers used. The clock configuration according to the invention can be used for further reducing the power consumption of switched op-amp circuits.
21 Citations
30 Claims
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1. A circuit configuration in switched op-amp technology, comprising:
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at least one switchable operational amplifier having an input and an output and transistors having a switching speed; at least one sampling capacitor connected to said input; at least one integrating capacitor connected to said input and to said output; a detector for detecting the switching speed of said transistors, said detector being connected to said operational amplifier; a clock generator producing a first and a second switching signal each having switching-clock phases including an on-phase and an off-phase, the on-phases of said first and said second switching clock signal being non-overlapping; said clock generator controlling charging of said sampling capacitor with said first switching-clock signal and switching said operational amplifier on and off with said second switching-clock signal; and a phase-variance device varying said switching-clock phases in which said first and second switching-clock signals are in said off-phase, said phase-variance device connected to said clock generator, said phase-variance device being configured for varying a duration of said switching-clock phases in which said first and second switching-clock signals are in said off-phase dependent upon said switching speed of said transistors as detected by said detector and enlarging said duration when said switching speed is high and reducing said duration when said switching speed is low. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A circuit configuration in fully differential circuit technology, comprising:
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at least one switchable operational amplifier having an input and an output and transistors having a switching speed; at least one sampling capacitor connected to said input; at least one integrating capacitor connected to said input and to said output; a detector for detecting the switching speed of said transistors, said detector being connected to said operational amplifier; a clock generator producing a first and a second switching signal each having switching-clock phases including an on-phase and an off-phase, the on-phases of said first and said second switching clock signal being non-overlapping; said clock generator controlling charging of said sampling capacitor with said first switching-clock signal and switching said operational amplifier on and off with said second switching-clock signal; and a phase-variance device varying said switching-clock phases in which said first and second switching-clock signals are in said off-phase, said phase-variance device connected to said clock generator, said phase-variance device being configured for varying a duration of said switching-clock phases in which said first and second switching-clock signals are in said off-phase dependent upon said switching speed of said transistors as detected by said detector and enlarging said duration when said switching speed is high and reducing said duration when said switching speed is low. - View Dependent Claims (29)
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15. A circuit configuration in switched op-amp technology, comprising:
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at least one switchable operational amplifier having an input and an output and transistors having a switching speed; at least one sampling capacitor connected to said input; at least one integrating capacitor connected to said input and to said output; a detector for detecting the switching speed of said transistors, said detector being connected to said operational amplifier; clock generator means for generating a first and a second switching signal each having an on-phase and an off-phase, the on-phases of said first and said second switching clock signal being non-overlapping; said clock generator means controlling charging of said sampling capacitor with said first switching-clock signal and switching said operational amplifier on and off with said second switching-clock signal; and phase-variance means for varying switching-clock phases in which said first and second switching-clock signals are in said off-phase, said phase-variance means connected to said clock generator means, said phase-variance means being configured for varying a duration of said switching-clock phases in which said first and second switching-clock signals are in said off-phase dependent upon said switching speed of said transistors as detected by said detector and enlarging said duration when said switching speed is high and reducing said duration when said switching speed is low. - View Dependent Claims (30)
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16. A method for clocking successive operational amplifier stages constructed in switched op-amp technology, which comprises:
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generating at least two non-overlapping switching-clock signals; switching a first operational amplifier on and off with a first signal of the two switching-clock signals;
switching a second operational amplifier on and off with a second signal of the switching-clock signals;varying switching-clock phases of the first and second signals in which the operational amplifiers are switched off; and providing a variable delay between the switching-clock phases of the first and second signals during which the operational amplifiers are switched off. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification