Back to results
US 5,936,466 AGranted
Differential operational transconductance amplifier
AssigneeInternational Business Machines Corporation
InventorsHajime Andoh, Denny Duan Lee Tang
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeInternational Business Machines Corporation
InventorsHajime Andoh, Denny Duan Lee Tang
Estimating the term…
A low-power dual-g.sub.m differential operational transconductance amplifier (OTA) having a differential input for improved common-mode noise rejection, a high transconductance for power savings, and circuitry for controlling its output conductance. The OTA includes a pair of input inverters for receiving differential input signals, a common-mode voltage control circuit for controlling the DC voltage levels of the inverters, and a Q-control circuit for adjusting the OTA's output conductance. The common-mode voltage control circuit has a pair of compensating current sources and a feedback loop acting as a high-gain amplifier. The high-gain amplifier has a pair of comparators for respectively comparing the DC voltage levels of the inverter outputs with a reference voltage. The Q-control circuit includes a current source coupled to a crossed-coupled NMOS transistor pair such that the OTA's output conductance may be controlled by adjusting the current source.
A differential operational transconductance amplifier (OTA) for amplifying a differential input having positive and negative input signals, the OTA having positive and negative outputs and an output conductance, comprising:
An electronically tunable filter comprising a plurality of integrators connected in series, each integrator including first and second differential operational transconductance amplifiers (OTAs) and first and second capacitors, each OTA having positive and negative inputs and outputs, for each integrator, the positive and negative outputs of the first OTA being connected respectively to the positive and negative inputs of the first OTA of the next integrator, the positive and negative inputs of the first OTA being connected to the negative and positive outputs of the second OTA and to the first and second capacitors, respectively, each OTA having an output conductance and comprising:
Dependencies are inferred from the claim text.