Showing papers on "Switched capacitor published in 1973"

Control of Overvoltages on Energizing Capacitor Banks

Abstract: Transient voltage phenomena occurring during the energization of shunt capacitor banks, due to prestrike and temporary interruption in the switching device of inrush currents have been considered. An analysis is made of a generalized capacitance circuit and energization transient voltage pattems are shown for a range of circuit permutations. An application guide is discussed for reduction of overvoltages during capacitor bank energization by proper choice of circuit elements. The influence of circuit resistance on the bus voltage patterns is reviewed.

Tunable RC-active filters using periodically switched conductances

Abstract: The realization of electronically tunable RC-active filters is achieved by the use of periodically switched conductances within the filter. A method of analysis of RC networks containing periodically switched conductances is given, which is based on the impulse response of the network at a capacitance. The use of periodically switched conductances to tune RC-active filters has several practical advantages, such as eliminating the need to carefully match independently adjustable network elements and being able to control a transfer function with one timing waveform. This method of electronically tuning RC-active filters is illustrated by several designs.

Temperature stable relaxation oscillator having controllable output frequency

Abstract: The disclosed oscillator configuration is suitable for being provided in monolithic integrated circuit form and provides a sawtooth output signal having a repetition rate which is controllable and which is substantially independent of temperature variation. The oscillator circuit includes a comparator which senses the voltage across a discrete timing capacitor and switches states to control the charge and discharge of the capacitor. The oscillator configuration insures that no conductive semiconductor devices are connected to the timing capacitor during the relatively long charge time of the capacitor and that all transistors connected to the capacitor during the short discharge time are saturated to minimize the effects of the thermal changes of the active devices on the capacitor charge and discharge times. Moreover, the oscillator circuit requires only two power supply levels and one timing control terminal to facilitate its use in minimum lead integrated circuit packages including other circuits.

Frequency converter circuit with integrated injection capacitor

Abstract: In a signal converter circuit having a mixer circuit with an input terminal for receiving radio frequency (RF) signals and locally oscillated signals, by way of an injection or coupling capacitor, from the output of a local oscillator circuit, such injection or coupling capacitor is formed between a pair of terminals of a capacitor element provided on a semiconductor substrate on which at least portions of the mixer and local oscillator circuits are also formed, and the capacitor element is connected with the mixer and local oscillator circuits so that the stray capacitor appearing between one of the capacitor element terminals and the substrate is at the mixer circuit side of injection capacitor rather than at the local oscillator side of the latter.

A high-speed p-channel random access 1024-bit memory made with electron lithography

Abstract: A switched capacitor, p-channel, 1024-- bit random access memory has been made with electron lithography. The circuit was the same as that described by Boll and Lynch (IEDM, 1972) but with halved lateral dimensions. For a given cell the gate length of the switching transistor was 4µm, and the chip size was 1.2×1.8mm. In order to fabricate the device, a 1µm alignment accuracy was required. Even with the modest shrinking of feature size, the minimum access time of the memory was reduced to less than 50 ns.

Circuit for measuring an unknown resistance by using a voltage ratio

Abstract: A reference source is AC coupled to a converter for selectively providing both positive and negative reference signals to the converter. A reference signal potential is selectively applied to a first side of a first capacitor via a sequence of switches and a second side of the first capacitor is selectively connected to a common signal through a return switch. A first signal is presented at the second side of the first capacitor when a first switch of the sequence of switches and the return switch are closed. A second signal is presented at the second side of the first capacitor when the first and return switches are opened and a second switch of the sequence of switches is closed. The second signal presented at the second side of the first is the reference signal having a given polarity with respect to the common signal. Automatic zeroing of an offset voltage generated by an integrator and a comparator of the analog to digital converter is provided by a second capacitor serially connected between an input terminal of the integrator and the common signal, the integrator and comparator being connected in a closed loop configuration. A voltage ratio measurement by the analog to digital converter, the ratio of the voltage across a first resistor having a known resistance to the voltage across a second resistor having an unknown resistance, represents the resistance value of the second resistor.

Analysis of a Forced Commutation Circuit for Design of a Class or Thyristor Inverters

Abstract: The literature contains a variety of inverter circuits with forced commutation. In general, the auxiliary circuit for switching off the load current carrying thyristors is composed of a number of energy storage components and semiconductor switches which are affected by losses. These circuits demonstrate specific advantages under certain conditions. The analysis of a forced commutated inverter with a series LC-resonant circuit is presented in this article. The peak capacitor voltage depends on the quality of the resonant circuit and the ratio of the peak capacitor current vs. the maximum load current. This can cause high stresses on all the components of the inverter circuit. The set of equations for the circuit is established and used for the computation of results. The peaks of stored energy and the losses in the commutation circuit are calculated and given in a normalized form. Design parameters in normalized form are derived therefrom and presented in this article.

A Bilevel Thin Film Hybrid Circuit Containing Crossovers, Resistors, Capacitors, and Integrated Circuits

Abstract: Here is a discussion on the fabrication, characterization, and economic considerations of a set of complex hybrid integrated circuits being used in exploratory switching applications. Several approaches to fabrication are discussed. One approach is unique in that it includes four distinct technologies in addition to simple thin film interconnections. They are (1) beam crossovers, (2) thin film resistors, (3) thin film capacitors, and (4) metallized via holes to a backplane. Alternate approaches including discrete capacitor elements are also discussed.

Determination of autotransformer-capacitor phase converter parameters

Abstract: An analytical approach is described for determining the parameters for an autotransformer-capacitor phase converter that allows matching of the converter to a specific motor for a given load. Equations are developed for the capacitor size and autotransformer turns ratio that will give balanced operation of a three-phase motor. Predicted values are compared with the experimental results.