Abstract: A switched-capacitance amplifier has a common terminal and an input signal terminal for receiving an input signal voltage therebetween, and it has an inverted output signal terminal for supplying, during each of a second series of separated time intervals interleaved without overlap with a first series of separated time intervals, an output voltage that is the negative of its input signal voltage. The switched-capacitance amplifier includes first and second capacitors. The switched-capacitance amplifier also includes a differential-input amplifier, having an output connection to the inverted output signal terminal, having a non-inverting input connection to the common terminal, having an inverting input connection, and having an input port between its non-inverting and inverting input connections.

Abstract: Current mirror amplifiers are disclosed, each having first and second ports that can be interchanged as to which is input port and which is output port in response to an electric control signal. A chopper-stabilized differential amplifier that uses such a switchable current mirror amplifier as a balanced-to-single-ended signal converter for output signals is disclosed, which chopper-stabilized differential amplifier is particularly suited for the integrating amplifier in a delta-sigma analog-to-digital converter.

Abstract: An approach to A/D converter architecture is based on a "pipelined and submerged" architecture which includes a pipeline of elemental stages (10.sub.i). Each stage of the pipeline comprises a low-resolution flash A/D subconverter (12), a D/A converter (14), and a unity-gain buffer (16). To minimize converter nonlinearity due to component mismatches, a self calibration technique based on an "interpolation" scheme is used. This technique employs an on-chip delta-sigma A/D converter (32) to provide the reference for calibration and a 100-bit memory (50) to store nonlinearity information. Long term drift is corrected by a calibrator (34) in parallel with data conversion.

Abstract: A pipelined analog-to-digital converter architecture comprises three pipeline stages wherein the first stage includes a low-resolution flash A/D subconverter (10), two sample-and-hold amplifiers (12 and 14), two D/A converters (16 and 18), and two unity-gain buffers (20 and 22). Parallel-autozero analog processing is accomplished by alternately passing the analog signal through one or the other of two parallel processing channels. The sampled analog signal is delivered to the flash A/D subconverter and the D/A converters simultaneously. The residue from the D/A converters is delivered to the second stage, passing through a flash A/D subconverter (24), an additional D/A converter (26), and alternately through two comparators (28 and 30) each having a gain of eight. The second stage produces and delivers its residual voltage to the final pipeline stage comprising a flash A/D subconverter (32).

Abstract: An electronic watthour meter employs a first analog signal representing either a load current or voltage to pulse-width-modulate a second analog signal representing the other of the load current or voltage. The resulting signal contains a DC component proportional to the product of current and voltage. AC components are removed from the product signal in an integrator before applying the DC component to a threshold circuit. The threshold circuit alternates its output between positive and negative values each time the DC component of the product signal passes through a predetermined positive and negative value. This pulsed signal is transmitted to a register for integrating the energy usage. A pulse-width modulator produces a constant-frequency pulsed output whose positive and negative alternations have lengths which are proportional to the line signal it receives. At each alternation of the pulsed signal, the output of the pulse-width modulator alternates between a direct and an inverted signal.

Abstract: Apparatus for producing a pulse width modulated signal in response to a current signal related to a current or a voltage in an electric system. A series resistor in series with a signal voltage proportional to the current or voltage in the system converts the signal voltage into the current signal. An integrator includes an operational amplifier with an integrating capacitor connected between an output and a first input thereof, producing a virtual ground at an input of the integrator. The series resistor is connected to the virtual ground. A second operational amplifier has a first input receiving an output of the integrator. A first bi-polarity trigger receives the output of the second operational amplifier.

Abstract: An error signal, i.e., offset, noise or drift, is sampled in an input capacitor at an error sampling interval and held during the amplification interval. During the amplification interval, the signal is amplified offset-free. The circuit has two paths which operate alternately in such a way that the signal path is never interrupted, except for very brief intervals. Each of the two paths includes an operational amplifier, and the offset voltages of the two operational amplifiers are cancelled out automatically.

Abstract: An electronic energy consumption measuring circuit capable of being fabricated on a single integrated circuit chip employs a switched-capacitor integrator for integrating the product of first and second voltages which are proportional, respectively, to load voltage and current in an electrical system to provide a measure of the energy being consumed, and a hysteresis comparator for converting the integrator output into a pulse train wherein each pulse represents a predetermined amount of energy. The output pulses may be accumulated and displayed to provide an indication of total energy consumed. A divider at the hysteresis comparator output enables the capacitor ratio in the switched-capacitor integrator to be reduced substantially so that the capacitor values are approximately the same order of magnitude. This reduces the chip area necessary for fabricating the capacitors and improves the matching between the capacitors, thereby affording higher integration accuracy.

Abstract: Transient offset error voltages due to charge injection by MOS analog switches in switched-capacitor integrators of electronic metering circuits are compensated by use of a continuous switched input capacitor network on the inverting input of the integrator amplifier. Any residual charge injection not cancelled by the switched capacitor network is compensated by employing another switched capacitor network on the non-inverting input of the amplifier and by matching the geometries of the switches in the two networks so that the charge injected into each input of the amplifier is the same.

Abstract: A switched-capacitor integrator is employed in an electronic watthour measurement device for integrating the average component of a product signal formed by pulse-width modulating an analog signal proportional to one of a load current and voltage at a pulse duty ratio proportional to the other of the load current and voltage. A hysteresis comparator forces the direction of integration to alternate between positive and negative limits for balancing out offset voltages in the integrator and comparator. A triangular-wave generator employed as part of the pulse-width-modulation technique is also implemented using a switched-capacitor integrator. The switched-capacitor integrators permit fabrication of the circuit with the required accuracy without needing external, discrete time-constant-determining resistances and capacitances. Measurement accuracy is determined by the ratio of capacitances of two on-chip capacitors, the accuracy to a clock signal and two reference voltages.

Abstract: A transformerless, self-contained, low cost, small size, light weight solid state electronic watthour meter is described which employs thin film ferromagnetic current sensors of the type which are magnetically coupled to power conductors whose current flow is to be sensed and metered and which provides electrical isolation between the power conductors and the sensing and metering circuitry. The meter is self-contained in that it draws its operating direct current supply potential required to operate the meter directly from the power conductors being metered and does not require a separate battery or transformer coupled direct current power source. The entire meter circuitry, including the thin film ferromagnetic current sensors which can be fabricated by thin film technology and the direct current power supply and the watthour meter circuitry, all are susceptible of fabrication on a single substrate using semiconductor integrated circuit fabrication techniques.

Abstract: Transient offset error voltages due to charge injection by MOS analog switches and DC offsets of multipliers in switched-capacitor integrators of electronic metering circuits are compensated by the common mode rejection of a differential switched-capacitor integrator. To cancel internal DC offset voltages of the integrator amplifier, a series capacitor connected to the inverting input of the amplifier is charged, during the autozero phase of the clock cycle, to a voltage equal to the internal DC offset voltage of the amplifier and subsequently, during the integration phase of the clock cycle, this voltage is applied to the inverting input of the amplifier.

Abstract: A switched-capacitor integrator is employed in an electronic watthour measurement device for integrating the average component of a product signal formed by pulse-width modulating an analog signal proportional to one of a load current and voltage at a pulse duty ratio proportional to the other of the load current and voltage. A hysteresis comparator forces the direction of integration to alternate between positive and negative limits for balancing out offset voltages in the integrator and comparator. A triangular-wave generator employed as part of the pulse-width-modulation technique is also implemented using a switched-capacitor integrator. The switched-capacitor integrators permit fabrication of the circuit with the required accuracy without needing external, discrete time-constant-determining resistances and capacitances. Measurement accuracy is determined by the ratio of capacitances of two on-chip capacitors, the accuracy to a clock signal and two reference voltages.

Abstract: An electronic solid state Q-hour meter for measuring leading and lagging VARS quantities of electric power over a defined range of power factor. The Q-hour meter comprises first and second time division/pulse width-amplitude modulated/analog multiplier circuits. First and second current transformers are coupled to first and second phases of a multi-phase power supply to be monitored for deriving first and second analog circuit indicating signals which are supplied to respective analog current input terminals of the analog multipliers. First and second potential transformers are coupled across the first and second phases of the multi-phase power supply for deriving first and second analog voltage indicating signals that are supplied to respective input terminals of the first and second analog multiplier circuits.

Abstract: An improved solid state semiconductor integrated circuit electronic watt/watthour meter circuit having analog and high frequency digital outputs with automatic error correction. The meter comprises first and second transformers for developing first and second voltage and current indicating signals for supply to a multiplier circuit that multiplies the two signals together and derives an output analog product signal representative of the instantaneous power being supplied by a source of electric energy. A multiplier low pass filter circuit is coupled to the output from the multiplier circuit for deriving from the product signal an average value power signal V. An analog-to-pulse rate converter is supplied with the average value power signal V and serves to convert it into a high frequency train of output signal pulses wherein each output signal pulse represents a predetermined quantized amount of electric energy.

Abstract: An electronic watt and kilowatt hour measuring circuit susceptible of being fabricated for the most part in solid state semiconductor monolithic integrated circuit form is provided. The electronic measuring circuit uses an active load terminated current transformer sensor for sensing alternating load current and a voltage transformer for sensing the alternating current voltage supplied from a source of alternating current electric energy being monitored. The output of the active load terminated current sensor transformer has an inherent DC-offset error voltage added to the alternating voltage which is proportional to the current being measured. This DC-offset error voltage is caused by the operational amplifier employed in the active load terminated current transformer sensor.

Abstract: A sensor for measuring large magnitudes of A.C. current utilizes a conductive member having a higher-resistance element parallelled by a pair of elements with lower, and substantially equal, resistance and so arranged as to cause cancellation of magnetic field effects upon the higher-resistance element due to a flow of current through the lower-resistance elements. Thermal-effect compensation of the higher-resistance element of the sensor is also disclosed. Active load termination of a current-sensing transformer, positioned about the higher-resistance element, is used.

Abstract: An improved solid state semiconductor electronic combined watthour and watt meter circuit providing both analog and digital outputs and having automatic error correction comprising first and second input transformers for developing first and second signals proportional respectively to the voltage and current being supplied from a source of electrical energy to a consumer. The first and second signals are supplied to a multiplier circuit for developing pulse-width-modulated and amplitude modulated product output signals representative of instantaneous watts. This product signal is supplied to a summing analog-to-pulse rate circuit for developing an output pulse train wherein each output pulse represents a predetermined quantized amount of energy and which is used to reverse polarity of the multiplier switches to accomplish automatic error correction.

Abstract: An electronic wattmeter in the form of an electronic watt-transducer circuit requiring a minimum number of components that can be fabricated by monolithic semiconductor integrated circuit manufacturing techniques and which provides a direct current output signal that is proportional to watts. The electronic watt transducer circuit comprises a first transformer for developing a first voltage related signal proportional to the input voltage to be measured and a second current transformer for developing a second current related signal proportional to the input current to be measured. A pulse width modulator is connected to receive the first voltage related signal and an input repetitive sampling signal for producing repetitive pulse width modulated output pulses having instantaneous pulse width proportional to the corresponding instantaneous amplitude of the first voltage related signal.

Abstract: A sensor comprising a member of ferromagnetic ferrite material having anistropic magneto-resistive properties wherein the resistivity characteristics of the ferrite member vary in response to variations in strength of a magnetic field applied longitudinally with respect to a selected longitudinal axis of the ferrite member. A magnetic field is impressed across the ferrite member with the magnetic lines of flux extending along the longitudinal axis of the ferrite member which exhibits variable magneto-resistive properties. A flow of electric current through the ferrite member along a current path that extends in the same direction or opposite to the direction of the magnetic lines of flux and changes in the value of the electric current flow through the ferrite member are measured as an indication of the value of a physical phenomena being sensed by the sensor.