A feedback stage for an integrator circuit is provided. The integrator receives a first input current and a second input current that include respective measurement current components and an offset current component. The integrator integrates the first input current and the second input current and generates a first output voltage and a second output voltage. The feedback stage including a transconductance amplifier detects a difference between the first output voltage and the second output voltage and sinks or sources a first output current and a second output current based on the difference between the first output voltage and the second output voltage. The first output current is additively combined with the first input current and the second output current is additively combined with the second input current to mitigate the offset current component at an input of the integrator.

A cascade of amplifier stages has a differential input and a differential output. The cascade of amplifier stages includes at least one differential amplifier circuit including first and second transistors, at least one of the first and second transistors having a control terminal and a body terminal. A mismatch between the first and second transistors generates an input offset. A feedback network couples the differential output to the body terminal in order to cancel the input offset. The feedback network includes a low-pass filter and a differential amplifier stage.

The invention provides a Low-voltage Differential Signaling (LVDS) receiver circuit that comprises a folded-cascode operational transconductance amplifier (OTA) that includes a pair of input branches and a pair of output branches. The pair of input branches of the folded-cascode OTA includes a p-channel metal-oxide semiconductor (PMOS) input transistor pair connected to a first supply voltage domain. The pair of output branches includes an output circuit connected to a second supply voltage domain. The LVDS receiver circuit further includes a common-mode feedback circuit connected to the pair of output branches of the folded-cascode OTA that controls the second supply voltage domain. The LVDS receiver circuit further includes a regenerative buffer circuit connected to the pair of output branches of the folded-cascode OTA and an output generated from the pair of output branches of the folded-cascode OTA directly operates the regenerative buffer circuit to produce a distortion-free output signal.

An electronic circuit including: a differential multiplier circuit with a first differential input and a second differential input and a differential output; and a phase locked loop (PLL) circuit including: (1) a balanced differential mixer circuit with a first differential input electrically connected to the differential output of the differential multiplier circuit, a second differential input, and an output; (2) a loop filter having an output and an input electrically connected to the output of the balanced differential mixer circuit; and (3) a voltage controlled oscillator (VCO) circuit having an input electrically connected to the output of the loop filter and with an output electrically feeding back to the second differential input of the balanced differential mixer circuit.

A feedback stage for an integrator circuit is provided. The integrator receives a first input current and a second input current that include respective measurement current components and an offset current component. The integrator integrates the first input current and the second input current and generates a first output voltage and a second output voltage. The feedback stage including a transconductance amplifier detects a difference between the first output voltage and the second output voltage and sinks or sources a first output current and a second output current based on the difference between the first output voltage and the second output voltage. The first output current is additively combined with the first input current and the second output current is additively combined with the second input current to mitigate the offset current component at an input of the integrator.

Described herein is an apparatus and system of a low-impedance reference voltage generator. The apparatus comprises: a voltage-control loop including a first transistor to provide an output voltage; and a current-control loop to sense current through the first transistor, relative to a reference current. The node having the output voltage is a low-impedance node.

An operational amplifier includes: a first amplifier stage, configured to generate first output voltages according to first input voltages; a second amplifier stage, configured to generate second output voltages according to the first output voltages; a second output stage circuit, configured to replicate an equivalent or a scaled-down version of the first output stage circuit; a first common-mode feedback circuit, configured to keep an output common-mode voltage of the second output stage circuit at a predetermined value; a logic loop circuit configured to, when the operational amplifier operates in a direct current calibration phase, adjust a difference between the first output voltages; a bias circuit, configured to generate a voltage close to a common mode voltage of the first output voltages produced after the operational amplifier is turned on, the voltage serving as a reference voltage of a second common-mode feedback circuit.

A circuit system including an operational amplification circuit is disclosed. The operational amplification circuit includes N stages of operational amplification units that are cascaded, an input terminal of the 1.sup.st stage of operational amplification unit is an input terminal of the operational amplification circuit, and an output terminal of the N.sup.th stage of operational amplification unit is an output terminal of the operational amplification circuit; an output terminal of the i.sup.th stage of operational amplification unit is connected to an input terminal of the (i+1).sup.th stage of operational amplification unit, so as to provide an input signal for the (i+1).sup.th stage of operational amplification unit; and there is a feedback channel from the output terminal of the N.sup.th stage of operational amplification unit to an input terminal of each of the 1.sup.st stage of operational amplification unit to the N.sup.th stage of operational amplification unit.

An electronic circuit including: a differential multiplier circuit with a first differential input and a second differential input and a differential output; and a phase locked loop (PLL) circuit including: (1) a balanced differential mixer circuit with a first differential input electrically connected to the differential output of the differential multiplier circuit, a second differential input, and an output; (2) a loop filter having an output and an input electrically connected to the output of the balanced differential mixer circuit; and (3) a voltage controlled oscillator (VCO) circuit having an input electrically connected to the output of the loop filter and with an output electrically feeding back to the second differential input of the balanced differential mixer circuit.

The invention provides a Low-voltage Differential Signaling (LVDS) receiver circuit that comprises a folded-cascode operational transconductance amplifier (OTA) that includes a pair of input branches and a pair of output branches. The pair of input branches of the folded-cascode OTA includes a p-channel metal-oxide semiconductor (PMOS) input transistor pair connected to a first supply voltage domain. The pair of output branches includes an output circuit connected to a second supply voltage domain. The LVDS receiver circuit further includes a common-mode feedback circuit connected to the pair of output branches of the folded-cascode OTA that controls the second supply voltage domain. The LVDS receiver circuit further includes a regenerative buffer circuit connected to the pair of output branches of the folded-cascode OTA and an output generated from the pair of output branches of the folded-cascode OTA directly operates the regenerative buffer circuit to produce a distortion-free output signal.