Abstract: A battery charger including a battery detector at a node at which a battery is connectable. When a battery is not present, a voltage at the node fluctuates, but when a battery is present, the battery holds the voltage substantially constant. A level shifter shifts the voltage at the node. If no battery is present, the shifted voltage will fall below a predetermined threshold, but if a battery is present, the shifted voltage will remain above the predetermined threshold. A ground sense comparator detects whether or not the shifted voltage is below the predetermined threshold, and provides a battery detection signal accordingly. A controllable charge driver couples power from a power supply through to a battery, to charge the battery. An integrated circuit provides logic functions of the apparatus, including logic functioning as a charge controller.

Abstract: In an input buffer, logic level discrimination is provided by a first circuit which provides a first current to the output so that the output voltage is a hysteresis function of the input volt. To improve transient response without increasing power consumption, a second circuit is used to provide a second current to the output in support of the first current during transient periods of the input signal.

Abstract: A differential input amplifier having adjustable quiescent output voltage is provided by connecting a current means which, responsive to an adjustment voltage, can introduce current into and remove current out of one of the current paths of the amplifier.

Abstract: A level discriminating buffer, including a input stage, a latching stage, and a switching accelerator, having an improved response time. The input stage discriminates between logic states of the input signal. The latch stage acts as a logic state latch and further provides transistors in the current paths of the input and latch stages that are non-conducting during each static state of the input signal. The switching accelerator is responsive to the input stage for generating a short period signal to accelerate the logic state switching of the latch stage and thereby improve the response of the output signal to a change in an input signal logic state change.

Abstract: In a circuit for providing a bandgap voltage reference, a first current proportional to the thermal voltage V.sub.T is generated by a first current source. By means of current mirror operation, the first current induces a second current source to generate a proportional second current. The second current source is coupled to means which generates a first voltage which is proportional to the base-emitter junction of a bipolar transistor. The second current generates a second voltage which is then added to the first voltage to give the voltage reference.

Abstract: The present invention provides a precision current source wherein a reference current level is established by the inter-dependent operation of three current stages. The first stage provides first and second current paths and functions to mirror the current level through the first and second current paths. A second stage, coupled to the first and second current paths, defines a first current/voltage relationship at respective points in the first and second current paths. A third stage, also coupled to the first and second current paths, defines a second current/voltage relationship again at the respective points in the first and second current paths. In accordance with the present invention, the first and second current/voltage relationships are chosen to be mutually solvable for a discrete, non-zero pairing of voltage and current levels, thereby establishing a reference current level at the defined current set point.