Ami Semiconductor, Inc.

Bernard Robert Gregoire, Jr

A switched capacitor voltage reference circuit that has a transconductance circuit that receives the output of the amplifier, and then outputs a current that depends on its input voltage. This may be accomplished using a charge pump that is controlled by the amplifier output. The transconductance circuit provides a reference voltage at the output terminal of the switched capacitor generation circuit. A capacitor capacitively couples the output terminal of the switched capacitor circuit to the inverting terminal of the amplifier during the generation phase. By adjusting the capacitances of the various capacitors, the level and temperature dependence of the generated reference voltage may be controlled. Also, the charge pump often allows for reference voltages that are greater than the supply voltage.

Switched capacitor voltage reference circuits using transconductance circuit to generate reference voltage

An enhanced output impedance current mirror in which the operational amplifier includes a set of four MOSFETs having a common gate that is connected to a drain terminal of one of the differential pairs. Two of the MOSFETs reside in parallel in the current path of each of the MOSFETs of the differential pair. The differential pair MOSFET that has its drain terminal connected to the common gate also has a gate terminal that is connected to the common node between the two other MOSFETs in its current path.

Low voltage enhanced output impedance current mirror

A bandgap reference that generates a temperature stable DC voltage by using a corrective current. The corrective current is generated by a series of differential pairs that are controlled by both positive temperature shift gate voltage on one transistor, as well as a negative temperature shift gate voltage on the other transistor. As temperature changes and crosses the crossing point at which the current is split evenly through both transistors, the current change is more abrupt. The crossing points of each of the differential pairs may be appropriately selected so as to generate a high resolution corrective current. The various current contributions are summed to form the total corrective current, which tends to be quite accurate due to the abrupt crossing points. The corrective current is then fed back into the circuit so as to compensate for much of the temperature error.

Bandgap voltage reference using differential pairs to perform temperature curvature compensation

A bandgap voltage reference uses multiple PTAT voltage reference circuits (also called PTAT sources) coupled in series to generate a final PTAT voltage. A current-biased base-emitter region of a bipolar transistor is coupled between the final PTAT voltage and an output terminal of the bandgap voltage reference so as to add the base-emitter voltage to the final PTAT voltage to thereby generate a stable bandgap voltage reference. By using multiple PTAT voltage reference in series, the need for a resistor ratio is reduced (or even eliminated) thereby reducing the size of the resistors that generate the resistor ratio (or eliminate the need for the resistors entirely).

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Bozeman, MT, United States of America

Bernard Robert Gregoire, Jr