Abstract: A Hall-effect sensor having a distributed array of current sources connected to an active region formed in a substrate of an integrated circuit. A corresponding array of current sinks is connected to the active region of the substrate opposite the current sources. When current flows in a path parallel to a first dimension of the active region from the current sources to the current sinks, a measurable Hall voltage develops across the active region if a magnetic field is passed through the sensor. This Hall voltage is measured by two terminals connected across a second dimension of the active region of the substrate. The measured Hall voltage sensitivity is very high according to this configuration.

Abstract: The present invention provides a switched capacitor analog-to-digital converter for the sampling of an analog input signal and conversion to an equivalent digital format utilizing a multi-slope conversion technique. The elements comprising the converter are, preferably, integrated onto a single chip using CMOS technology. The converter includes a processor for coordinating switching in the converter and generating the digital output signal. A sampling circuit having a switched capacitor controlled by the processor is included in the converter for sampling the voltage of the analog input signal and transferring charge representative of the analog input signal between an integrator and the sampling circuit. Further included in the converter is a discharge circuit for either transferring charge to the integrator or receiving charge from the integrator.

Abstract: Disclosed is apparatus and method for converting and displaying the total RMS and AC RMS values of a signal in a voltmeter. This conversion is accomplished in a system having a processor and a plurality of signal conversion stages. The first signal conversion stage comprises a low-pass filter to extract the DC component of the input signal followed by an analog-to-digital converter to convert the DC component into a digital value. The remaining signal conversion stages convert the AC component of the input signal to a series of smaller and smaller DC average values. Typically there are five of these AC conversion stages, each comprising a high-pass filter connected to a full-wave rectifier which is in turn connected to a low-pass filter followed by an analog-to-digital converter. The first AC stage high-pass filter is connected to the input signal and subsequent AC stage high-pass filters are connected to the output of the full-wave rectifier of the previous AC conversion stage.

Abstract: A Class-A complementary metal oxide semi-conductor (CMOS) operational amplifier is provided having an improved slew rate. The preferred embodiment of the invention utilizes a CMOS amplifier circuit and an external capacitor, which together exhibit relatively poor sourcing of current and hence a relatively low positive slew rate in response to an input signal being more positive than an output signal of the CMOS amplifier by a relatively large amount. The disparity between the input and output signals defines an error signal. The present invention also includes a supplemental output stage communicating with the amplifier circuitry and the external capacitor. The supplemental output stage is activated in order to supply additional sourcing current, thereby increasing the positive slew rate, when a relatively large error signal is present and is de-activated otherwise.