Showing papers on "Converters published in 1972"

Low-frequency characterization of switched DC-DC converters

Abstract: Averaging techniques are developed here to represent buck, boost, and buck-boost types of switched dc-dc converters by approximate continuous models. Simple analytical expressions in terms of the circuit components are derived for the characteristic transient and frequency responses of timeaveraged (continuous) power-stage models for use in designing and understanding the behavior of corresponding switched power stages. Novel conclusions include the dependence of effective circuit component values upon switch duty ratio and the existence of a real positive zero in certain transfer functions. Responses from analog computer simulations of the switched and averaged power stages agree well and, in turn, confirm the analytic predictions. High-order systems can be analyzed by the averaging technique without a commensurate increase in complexity.

Serially-connected converters having multiple regulation modes for use in supplying serially-connected loads on long lines

Abstract: These serially connected converters have multiple regulation modes including a new normal mode in which the current-versus-voltage characteristic has a substantial negative slope. This mode produces better load sharing among the serially connected converters than would a constant-current mode of operation and provides more stable operation of the remote repeaters serially supplied along a communication line by the converters than would a constant-voltage mode of regulation of the converters, especially in the presence of disturbances on the line. In the event that a converter is turned on into a line presenting an abnormally high load impedance, the converters are shut down. In the dual-line communication link, the neutral point at the floating end is grounded in the presence of sufficient voltage inbalance and then is ungrounded when the line currents are near balance.

Floating negative-impedance converters

Abstract: Two floating negative-impedance converters (FNICs) using operational amplifers are proposed. Each circuit uses a common-grounded power supply and can simulate floating negative elements. The stability properties of the two circuits are examined. In line with other published grounded NICs, one of the ports is found to be short-circuit stable and the other open-circuit stable. The application of the FNICs for the design of two-directional constant-resistance amplifiers is considered.

Self-Oscillating Regulated DC-to-DC Converter

Abstract: A transformer-coupled dc-to-dc converter, in which the voltage-regulation feedback loop also serves to establish the self-oscillations required for dc-to-ac inversion, is described in this paper. This results in improved circuit economy as compared to conventional converters in which regulation and inversion are separate functions.

Asdtic duty-cycle control for power converters

Abstract: The application of analog signal to discrete interval converter (ASDTIC), a hybrid micromodule, two loop control subsystem, to a switching, stepdown dc to dc converter is described in this paper. The power circuitry, interface and ASDTIC subsystems used in this switching regulator were developed to exhibit the improved regulation, transient performance, regulator stability and freedom from the effects of variations in parts characteristics due to environmental changes and aging. ASDTIC can be used with other types of power circuits that use duty-cycle control techniques by simple changes in the interface subsystem-1-. The circuitry and performance characteristics of a +10V dc switching converter as well as that of the ASDTIC micromodule are described. Realization of the ASDTIC hybrid micromodule has been accomplished with a hermetically sealed, beam-lead, bonded/deposited nichrome thin film resistors, discrete capacitors and integrated circuits on dilithic, glazed alumina substrates using 22 feed through terminals in an integrated package.

On the Performance and Design of Self-Oscillating DC-to-DC Converters

Abstract: Simplified design equations are presented based on a general and exact analysis of self-oscillating dc-to-dc converters. Converters with and without transformer coupling can be designed using these simplified equations. A discussion is presented which shows the relationship between circuit parameters and such performance characteristics as switching frequency, duty cycle, regulation, and peak-to-peak ripple bounds. The general performance and inherent limitations are then predicted for various circuit configurations. It is shown that most of the disadvantages usually ascribed to this class of circuit can be eliminated by proper circuit design. An approximate design procedure is presented and illustrated with a comparison of calculated and measured performance data.

Multi-speed digital to synchro converters

Abstract: A reversible counter is used in conjunction with a plurality of gates and an impedance network to develop a staircase output having a phase corresponding to the count initially registered. This output is then converted into an AC signal of corresponding phase for use in controlling synchros and the like. By overlapping the output of these converters, one is able to achieve greatly increased resolution in the same manner that multi-speed synchro systems are employed.

Electronic Method with Direct Time Encoding for Precision Measurement of Electric Power over a Wide Range of Frequency

Abstract: The principle of power measurement by thermal means has the advantage of a very large bandwidth and gives the possibility to realize time or frequency encoding in a simple way. The new method described is based on a known operation using special thermal converters with several heaters. The multiple heating, however, is done by a multiplexing operation on single-heater converters. It is shown that, by means of this principle, a power meter can be set up enabling precision measurement in a wide range of frequency. The measurement of real power in polyphase systems is another application of the same principle.

A Pulsewidth-Modulated Dc-to-Dc Converter That Utilizes a Small Number of Components

Abstract: In general, circuit reliability can be enhanced by either incorporating redundancy or by minimizing a circuits component count. Conventional nonregulating converters generally require two active devices, whereas in regulating converters or switching regulators as many as 10 transistors, either integrated or discrete, is not uncommon. A regulating dc-to-dc converter which provides useful regulation and which can be constructed with either two or three transistors is described.