Patent
Bias circuit for switched capacitor applications
Ion E. Opris,Laurence D. Lewicki +1 more
TLDR
In this article, an adaptive bias circuit for switched capacitor applications that compensates for temperature and process variations by maintaining a constant settling time of CMOS operational amplifiers is introduced, which allows a dynamic trade-off between the slew-rate and the gain bandwidth product which allows the output of the operational amplifier to settle within a certain predetermined precision.Abstract:
An adaptive bias circuit for switched capacitor applications that compensates for temperature and process variations by maintaining a constant settling time of CMOS operational amplifiers is introduced. To this end, the adaptive bias circuit allows a dynamic trade-off between the slew-rate and the gain bandwidth product which allows the output of the operational amplifier to settle within a certain predetermined precision. A first aspect of the invention includes a current source providing a same current to a pair of transistors having different effective current densities. A resistor is coupled between the pair of transistors while from one end of the resistor, a constant bias current is drawn. In this manner, a voltage difference develops across the resistor which effectively indicates the change in the transconductance of the pair of transistors with respect to temperature and process variations. Another aspect of the invention allows the bias circuit to minimize the body effect, the back bias effect, the channel length modulation effect, as well as the dependence of circuit performance upon the power supply voltage.read more
Citations
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References
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Journal ArticleDOI
Relationship between frequency response and settling time of operational amplifiers
TL;DR: In this article, the effects of pole zero pairs (doublets) on the frequency response and settling time of operational amplifiers were explored using analytical techniques and computer simulation, and it was shown that doublets which produce only minor changes in circuit frequency response can produce major changes in settling time.
Journal ArticleDOI
A quad CMOS single-supply op amp with rail-to-rail output swing
TL;DR: In this article, the realization of a commercially viable, general-purpose quad CMOS amplifier is presented, along with discussions of the tradeoffs involved in such a design, and the amplifier features an output swing that extends to either supply rail, together with an input commonmode range that includes ground.
Patent
Temperature compensated complementary metal-insulator-semiconductor oscillator
TL;DR: In this paper, a temperature compensated complementary metal-insulator-semiconductor oscillator receives a temperature independent reference voltage from an external source, attenuated and summed with a threshold voltage in order to bias a gate electrode of MOSFET.
Patent
Constant-current circuit operating in saturation region
TL;DR: In this paper, a constant-current circuit with four MOS transistors is presented, where the first and second transistors are driven at a constant current ratio corresponding to a ratio of gatewidth and gate-length ratios of the third and fourth transistors.
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Comparator with built-in hysteresis
TL;DR: In this article, a comparator with a built-in hysteresis is described, which has a differential input stage, an output stage, and a bias circuit with a hystresis circuit.