Abstract: A power delivery circuit for supplying load current to a load includes a current switch connected on the high potential side of a load. In order to detect a current condition, such as an over-current condition in the load, a current sensing and detection circuit preferably cooperates with the current switch wherein such switch comprises a multicellular device with a plurality of terminals. Such terminals include a first main current terminal connected to a source of high potential, a second main current terminal connecting a majority of device cells to the load, a first auxiliary terminal connected at one end to a minority of device cells so as to provide a current generally proportional to the main device current, and a second auxiliary terminal connected at one end to a majority of device cells.
Abstract: An embodiment of the present invention is a switching power supply with high voltage positive and negative power inputs, a system ground, a sensing resistor placed between the negative power input and system ground, first and second load outputs with the first load output connected to the positive power input, and a comparator having first and second comparison inputs and a comparison output with the second comparison input connected to the system ground. A constant-current source is connected to the first comparison input of the comparator. A power MOSFET switch transistor has its drain connected to the second load output, its source connected to the system ground, and its gate controlled by the comparison output of the comparator. And a control resistor is connected between the second power input and said first comparison input of the comparator.
Type:
Grant
Filed:
February 7, 1992
Date of Patent:
September 14, 1993
Assignee:
Power Integrations, Inc.
Inventors:
Balu Balakrishnan, Leif O. Lund, Richard A. Keller
Abstract: An improved power supply adapter is provided for plug-in connection to a standard AC power supply receptacle, and to provide a DC voltage to an associated electronic instrument. The power supply adapter comprises a relatively compact case having an end face with a plurality of conductive prongs protruding therefrom for plug-in connection to an AC receptacle, such as one socket of a standard duplex or quad wall outlet or the like. An AC adapter assembly is mounted within the adapter case with the components of the AC adapter assembly arranged generally in-line between the conductive prongs and a power cord adapted for connection to the associated electronic instrument. This in-line geometry permits the adapter case to have a relatively narrow width and low profile height conforming with a single electrical socket, whereby plug-in connection of the adapter to an electrical socket does not obstruct access to adjacent sockets.
Abstract: Disclosed is a device to obtain a DC voltage V.sub.p that is adjustable in a wide range of values. To a rectifying and filtering circuit, there are applied AC pulses. The quantity of electricity of these AC pulses is constant for each pulse, and their frequency F varies as a function of the voltage V.sub.p to be obtained. To this effect, a DC/AC converter of the hyporesonant type is used. The device can be used for providing bias for a focusing element of an X-ray tube.
Abstract: A high-voltage power supply and regulator circuit for an X-ray tube which utilizes solid-state switching devices with feedback control for real time monitoring and protection against failure due to excess current or voltage spikes. The apparatus includes a DC supply circuit utilizing a first feedback control loop and silicon controlled rectifiers to regulate the output of a high-voltage transformer. The apparatus further includes a regulator circuit utilizing a second feedback control loop and a series of FETs to product a continuous or pulsed output of precise magnitude and phase. Shielded voltage dividers are provided to accurately measure the voltage outputs and produce feedback control signals. Discharge modules on the high-voltage cables connecting the power supply to the X-ray tube discharge any capacitive voltage remaining on the cables between pulses, so as to eliminate any tail on the output waveform.
Abstract: A flyback transformer includes at least one primary coil and at least one secondary coil formed thereon. Each primary and secondary coil may be a metal plating coil with an insulating bobbin and a conductor formed thereon. Secondary coils may be formed of pairs of metal plating coils connected in series. One to three primary coils may have secondary coils sandwiched therebetween. The transformer may also have a resonance capacitor integrally formed therein, and may have respective rectifying diodes connected between the secondary coils.
Abstract: An inverter for converting DC power into AC power includes first and second controllable switches which are alternately operated to produce first and second AC waveforms which are combined to form a composite AC waveform that assumes at least three different levels during a cycle of the AC power.
Abstract: First and second P-regions are disposed in N-wells to form first and second PN junctions. The area of the second PN junction is greater than that of the first PN junction. The N-wells and the first and second P-regions are connected between the power supply level for and the ground level, thereby generating a potential difference between the first and second P-regions. This potential difference has a positive temperature coefficient, which is amplified to be supplied as a reference voltage.
Abstract: A ripple feedback circuit for use with a current-sourced rectifier system with a resonant load balancing filter. The ripple feedback circuit eliminates the oscillation of the rectifiers and improves the line-current waveform by sensing the low frequency AC components of the output current and by combining such AC components with the control voltage at the input to the multiplier of the pulse width modulator of the rectifier system. A sample of the rectified line voltage is multiplied by the control voltage less ripple feedback to form the input to the pulse-width modulator which produces the gating waveform for the converter of the rectifier system.
Abstract: An improved forward converter switching at zero-current incorporates a mechanism for selectively regulating the amount of forward energy which is delivered to a load during each converter operating cycle. Energy is transferred from a voltage source toward a load in discrete packets via a small effective inductance (specifically the small effective leakage inductance of a transformer) and a capacitor, the combination of which define a characteristic time scale for the rise and fall of current such that a switching device connected in series with the voltage source can be cycled on and off at zero-current. The capacitor is connected to the load via a second inductor.
Abstract: A high power-factor converter (50) for use with motor drives and power supplies. A first and "buck"-type converter section (62) is connected to an a.c. voltage source. This section provides an output voltage having preselected voltage characteristics. This section is operational during that portion of an input voltage cycle in which the input voltage level exceeds that of the output voltage level. A second and "boost"-type converter section (70) is also connected to the voltage source. This second section also provides the output voltage, and is operational during that portion of the input voltage cycle in which the output voltage level exceeds that of the input voltage level.
Abstract: An IC built-in connector for power source stabilization including a connector body having a plurality of contacts to be brought into contact with a cable terminal connector, and a wiring board built in the connector body and adapted to have thereon a variable direct voltage converter acting as a power source stabilizing IC. The wiring board has a plurality of output voltage control resistors for the power source stabilizing IC having coefficients of temperature which are generally equal, and the resistors are arranged right under or proximate to a surface of the wiring board where the power source stabilizing IC is mounted, so as to be heated equally thereby, so that a resistance ratio of each IC output voltage control resistor is equally compensated with respect to the temperature of the power source stabilizing IC.
Abstract: A current sense/limit circuit senses a current of a power switch and turns off the switch when a peak current of the power switch surpasses a preprogrammed value. To prevent the circuit from reacting to a leading edge current spike resulting from the reverse recovery of a clamp or diode which is a part of most power processing circuits, the current sense/limit circuit monitors the voltage on the power switch and disables the current sense circuitry as long as this voltage does not drop below a predetermined threshold value. The predetermined threshold value is higher than the worst case voltage on the power switch during its on-time under normal operating conditions, and much lower than the switch voltage during off-time. As a result, this method adaptively blocks the current sense mechanism during most of the reverse recovery current spike period.
Abstract: A high impedance current source includes a voltage to current transducer having positive and negative inputs with an output current passed through a monitor resistor. Matched resistances are connected from both sides of the monitor resistor back to the positive and negative inputs to the transducer. Matched resistances are also connected between the positive and negative inputs and a common base, and the control voltage is applied across the inputs through matched resistances. The circuit is preferably utilized to provide current to a circuit utilized in differential calorimetry.
Abstract: The synchronous switching power supply can be employed in power supply systems requiring multiple outputs and extremely high efficiency. No minimum load is necessary. A switching power supply with boost and/or flyback converters comprises a switching circuit for providing an AC signal. Two diodes rectify the AC signal and provide a pulsating DC signal to a node. An inductor is coupled thereto for attaining a current. A capacitor is coupled to the inductor for providing a first DC output signal which is also fed back to the switching circuit. The boost and flyback converters are coupled to the node for converting the pulsating DC signal into a second and third DC output signals.
Abstract: The magnetic core of the transformer is an E--E shaped core. The primary winding of the transformer is divided into three substantially identical planar coils, each coil being wound on one of the three separate core posts. The coils are wired in series such that a current in the primary winding will induce substantially identical magnetic fluxes in the two outer core posts, and an opposite flux in the center post. The secondary of the transformer is formed by a contact plate and a conductor frame which provide conducting paths through the window regions of the E--E core. The bottom of the core is mounted in a recess in the conductor frame. Positioned within in the conductor frame are four rectifiers which make electrical connections to the secondary contact plate. When the transformer delivers power, the voltage on the primary winding will be divided 1/4 on each of the outer coils and 1/2 on the center coil post. During this time only two of the rectifiers will be conducting current.
Type:
Grant
Filed:
January 8, 1992
Date of Patent:
July 6, 1993
Assignee:
International Business Machines Corporation
Abstract: A method and apparatus are provided for bidirectional current conduction between first and second nodes of an electronic circuit. A first substantially constant current is conducted through a first current mirror pair of transistors coupled between the first and second nodes, in a first direction away from the first node toward the second node, in response to the first node having a voltage higher than the second node. A second substantially constant current is conducted through a second current mirror pair of transistors coupled between the first and second nodes, in a second direction away from the second node toward the first node, in response to the first node having a voltage lower than the second node.
Abstract: A direct current flux compression transformer includes a magnetic envelope having poles defining a magnetic axis and characterized by a pattern of magnetic flux lines in polar symmetry about the axis. The magnetic flux lines are spatially displaced relative to the magnetic envelope using control elements which are mechanically stationary relative to the core. Further provided are inductive elements which are also mechanically stationary relative to the magnetic envelope. Spatial displacement of the flux relative to the inductive elements will cause flow of electrical current. Further provided are magnetic flux valves which provide for the varying of the magnetic reluctance to create a time domain pattern of respectively enhanced and decreased magnetic reluctance across such magnetic valves and, thereby, across the inductive elements. A flow of electric current is generated without mechanical motion of inductive elements relative to the magnetic envelope.
Type:
Grant
Filed:
October 4, 1991
Date of Patent:
June 22, 1993
Inventors:
Richard A. Sullivan, Melvin K. Silverman
Abstract: A method and circuit for detecting rapid increase in line voltages applied to variable speed drives utilizing a phase controlled converter. A three phase alternating current line voltage is applied to a full wave bridge rectifier to generate a direct current signal. A buffer amplifier having a high input impedance is coupled to the output of the rectifier and a diode is utilized to ensure that only positive voltage transients are detected. Positive voltage transients output through the buffer amplifier rapidly charge a capacitor through the low output impedance of the buffer amplifier and that charge is permitted to bleed off slowly through an associated resistor. The rate of change of the capacitor charge level is compared to a preset voltage level and increases beyond that preset level are utilized to trigger an inhibit signal which momentarily resets the delay angle of the switching devices within the phase controlled converter.
Abstract: An arrangement is provided for accurately sensing the source voltage of a high-impedance source while supplying a variable burden. A current-sensing element is connected in series with a load circuit across a high-impedance source. The load circuit includes a variable burden load. A shunt regulator is connected with the variable burden load and is arranged to operate so that the combination of the shunt regulator and the variable burden present a controlled, nearly constant burden to the high-impedance source. The source voltage of the high-impedance source is sensed via the voltage across the series current-sensing element. While the output voltage is directly proportional to the burden, the output current is essentially unaffected by small variations in the burden.