Abstract: A comparator has a differential input stage, a current source coupled to the differential input stage for providing a tail current to one side of the differential input stage, and a differential load coupled to the differential pair and having at least one diode coupled load transistor per differential side. A load current through either one of the at least one diode coupled load transistor on either differential side is mirrored with a current mirror configuration to provide a current be fed to a respective node, each node being coupled to a respective variable biasing current source and a respective other side of the differential input stage, so as to provide a variable positive feedback to the differential input stage.

Abstract: A transponder device comprises an integrated CMOS circuit with a semiconductor substrate. A first rectifying diode (DS) is formed by the substrate diode of the CMOS circuit. A first MOS transistor structure (DR1) and a second MOS transistor structure (DR2) have their channels connected in series such that they function as a second rectifying diode, the cathode of the first rectifying diode being connected to the anode of the second rectifying diode. The first MOS transistor structure (DR1) and the second MOS transistor structure (DR2) are spaced from each other such that a distance between the two MOS transistor structures is large enough that a parasitic npn-structure formed within the substrate by the first and the second MOS structures has a negligible current gain.

Abstract: A power management circuit for a system that has combined power supplies from an inductively coupled circuit and from a battery comprises voltage sensing circuitry for sensing the voltage of each of the power supplies. A switching arrangement selectively connects one of the power supplies with a user or with plural users. The switching arrangement is controlled by appropriate control circuitry in response to outputs from the voltage sensing circuitry. The power management makes the best use of energy received over the inductive interface to preserve battery lifetime.

Abstract: A power management circuit for a system that has combined power supplies from an inductively coupled circuit and from a battery comprises voltage sensing circuitry for sensing the voltage of each of the power supplies. A switching arrangement selectively connects one of the power supplies with a user or with plural users. The switching arrangement is controlled by appropriate control circuitry in response to outputs from the voltage sensing circuitry. The power management makes the best use of energy received over the inductive interface to preserve battery lifetime.