Abstract: A switch mode power amplifier circuit apparatus comprises a fixed gain amplifier, modulator and a filter circuit electrically configured so as to direct a feedback signal for reducing clock ripple and improving signal fidelity at an output takeoff point in the amplifier circuit. An amplifier output is directed to the modulator and a modulator output is directed into an inductor of the filter circuit. The feedback signal is directed from the filter circuit to an amplifier input.

Abstract: A floating current mirror circuit is disclosed which achieves high open loop gain without additional voltage gain stages leading to frequency compensation and increased power dissipation. The output of the circuit has only a first pole and is designed to be coupled to a second current source, a base coupled to the first terminal of the diode, and an emitter coupled to the floating node. A second bipolar transistor has a base coupled to the collector of the first transistor, and emitter coupled to the floating node.

Abstract: A high voltage constant current source circuit includes first transistor biased as a constant current source and a second transistor connected in series with the first transistor. The second transistor has a punch-through voltage that is substantially less than any breakdown voltage of the second transistor. The emitter of the second transistor is connected to the collector of the first transistor. The collector of the second transistor supplies the constant current, provides an increased high output impedance, and allows low voltage operation if the collector-to-emitter voltage of the second transistor is less than its punch-through voltage. If its punch-through voltage is exceeded, that punch-through voltage adds to the collector-to-emitter breakdown voltage of the first transistor, allowing high voltage operation.