Stability-compensated operational amplifier

An integrated-circuit precision-current source comprising:

• an operational amplifier comprising:
• an inverting node to which a reference potential is applied;
• a non-inverting node to which a feedback potential is applied;
• a first differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means of the first differential amplifier having an output node, and having means for producing on the output node an output potential that, with reference to a predetermined potential, defines an output signal having a magnitude that is a function of the magnitude of the difference between the reference potential and the feedback potential;
• a second differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means for having means for producing a compensation signal;
• and
• capacitance means for coupling the compensation signal to the non-inverting node;
• resistance-loaded signal-inverting MOSFET means defining a first current flow path, and biased by the output potential for controlled current flow through the first flow path to produce the feedback potential;
• and
• signal-inverting MOSFET means biased by the output potential to produce a current in a second path in parallel with the first path.

An integrated-circuit precision-current source comprising:

• an operational amplifier comprising:
• a pair of nodes defining an inverting node and a non-inverting node, to one of which a reference potential is applied and to the other of which a feedback potential is applied;
• a first differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means of the first differential amplifier having an output node, and having means for producing on the output node an output potential that, with reference to a predetermined potential, defines an output signal having a magnitude that is a function of the magnitude of the difference between the reference and feedback potentials;
• a second differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means for having means for producing a compensation signal;
• and
• capacitance means for coupling the compensation signal to the node to which the feedback potential is applied;
• resistance-loaded MOSFET means defining a first current flow path, and biased by the output potential for controlled current flow through the first flow path to produce the feedback potential;
• and
• MOSFET means biased by the output potential to produce a current in a second path in parallel with the first path.