Patent classifications
H03F3/45192
Operational amplifier offset trim
An integrated circuit (IC) includes first, second, third, and fourth transistors, first and second current source devices, and a trim circuit. The first transistor has a first control input and a first current terminal. The second transistor has a second control input and a second current terminal. The third transistor had a third control input and third and fourth current terminals. The fourth transistor has a fourth control input and fifth and sixth current terminals. The first current source is coupled between a first power supply node and the third current terminal. The second current source is coupled between the first supply node and the fifth current terminal. The trim circuit is coupled between the fourth current terminal and a second power supply node, and is coupled between the sixth current terminal and the second power supply node. The trim circuit includes a resistive digital-to-analog converter (RDAC) circuit.
Class AB buffer with multiple output stages
A class AB buffer includes an output stage and an input stage. The output stage includes a first output transistor and a second output transistor. The second output transistor is coupled to the first output transistor. The input stage is coupled to the output stage. The input stage includes a first cascode transistor, a first switch, a second cascode transistor, and a second switch. The first switch is coupled to the first cascode transistor and the first output transistor. The second switch is coupled to the first switch, the second cascode transistor, and the first output transistor.
Output pole-compensated operational amplifier
A circuit includes a first transconductance stage having an output. The circuit further includes an output transconductance stage, and a first source-degenerated transistor having a first control input and first and second current terminals. The first control input is coupled to the output of the first transconductance stage. The circuit also includes a second transistor having a second control input and third and fourth current terminals. The third current terminal is coupled to the second current terminal and to the output transconductance stage.
Differential amplifier circuitry
Differential amplifier circuitry including: first and second main transistors of a given conductivity type; and first and second auxiliary transistors of an opposite conductivity type, where the first and second main transistors are connected along first and second main current paths passing between first and second main voltage reference nodes and first and second output nodes, respectively, with their source terminals connected to the first and second output nodes, respectively, and with their gate terminals controlled by component input signals of a differential input signal; and the first and second auxiliary transistors are connected along first and second auxiliary current paths passing between first and second auxiliary voltage reference nodes and the first and second output nodes, respectively, with their drain terminals connected to the first and second output nodes, respectively, and with their gate terminals controlled by the component input signals of the differential input signal.
NONLINEAR FREQUENCY COMPENSATION SYSTEM
A device comprises a voltage limiter, two capacitors, a resistor, and a voltage follower buffer. The voltage limiter has a first input coupled to a reference voltage rail, a second input coupled to a supply voltage rail, and two voltage limiter outputs. The first capacitor is coupled between a device output and the first voltage limiter output, and the resistor is coupled between the first and second voltage limiter outputs. The voltage follower buffer has an input coupled to the first voltage limiter output and a voltage follower buffer output. The second capacitor is coupled between a device input and the voltage follower buffer output. In some implementations, a resistance of the resistor is greater than a capacitance of the first capacitor. In some implementations, a third capacitor is coupled between the device input and the device output.
Fully differential rail-to-rail output amplifier with inverter-based input pair
A fully differential rail-to-rail-output amplifier includes a differential input inverter pair, folded cascode pair, class AB control pair, and class AB output rail-to-rail pair. A drain associated with the folded cascode pair is operatively coupled to the class AB control pair, and the drain associated with the folded cascode pair is unconnected to the current source associated with the class AB control pair. A method of providing fully differential rail-to-rail-output amplification includes coupling a folded cascode pair operatively to a differential input inverter pair, coupling a drain associated with the folded cascode pair operatively to a class AB control pair, and coupling a class AB output rail-to-rail pair operatively to the class AB control pair.
AMPLIFIER CAPACITIVE LOAD COMPENSATION
An amplifier includes a first stage and a second stage. The first stage is configured to amplify a received signal. The second stage is coupled to the first stage. The second stage includes a source follower and a compensation network. The source follower includes an input and an output. The compensation network is coupled to the input of the source follower and the output of the source follower. The compensation network is configured to modify a magnitude and phase response of the first stage based on a load capacitance coupled to the output of the source follower.
Load Regulation for LDO with Low Loop Gain
Circuits and methods for maintaining loop stability and good load regulation in low loop gain LDO regulator circuits. Embodiments encompass LDO regulator circuits that include an offset error correction circuit that generates an opposing voltage V.sub.OFFSET as a function of load current to substantially cancel out variations in V.sub.OUT that would otherwise occur due to load regulation limitations of the LDO regulator circuits. Embodiments use V.sub.OFFSET to imbalance currents in differential paths in a last-stage LDO error-amplifier so that an offset is propagated to a pair of inputs to the error-amplifier, thereby altering the output voltage V.sub.OUT to a corrected value. Benefits include improved LDO load regulation even when feedback loop gain is low, the available of both digital and analog implementations, high LDO accuracy and less variation of the output voltage V.sub.OUT, and suitability for implementation in integrated circuits for applications such as high precision power supplies.
HIGH-FREQUENCY HIGH-LINEAR INPUT BUFFER DIFFERENTIAL CIRCUIT
A high-frequency high-linear input buffer includes a first MOS transistor, a second MOS transistor, a third MOS transistor, and a signal panning unit. A gate terminal of the first MOS transistor is used as an input terminal of the buffer. A current input terminal of the first MOS transistor is connected to a current output terminal of the second MOS transistor. A current output terminal of the first MOS transistor is connected to a current input terminal of the third MOS transistor. A current input terminal of the second MOS transistor is connected to a gate terminal of the third MOS transistor. An input terminal of the signal panning unit is connected to an input terminal of the buffer. An output terminal of the signal panning unit is connected to a gate terminal of the second MOS transistor. An output terminal of the third MOS transistor is connected to ground.
Receiver front-end circuit and operating method thereof
A receiver front-end circuit and an operating method thereof are disclosed. The receiver front-end circuit includes a common-mode suppression circuit and a rear-stage circuit. The common-mode suppression circuit is used to receive an external input common-mode voltage signal and perform common-mode noise suppression processing on the external input common-mode voltage signal, and then output an internal input common-mode voltage signal. The rear-stage circuit is coupled to the common-mode suppression circuit and used to receive the internal input common-mode voltage signal. The dynamic swing of the internal input common-mode voltage signal is smaller than the dynamic swing of the external input common-mode voltage signal.