Abstract: A multiple semiconductor chip (multi-chip) module for use in power applications includes at least a power semiconductor chip and a control semiconductor chip mounted on an electrically conductive heat sink. The power semiconductor chip may be a Silicon-On-Insulator (SOI) device and the control semiconductor chip may be a semiconductor device having a substrate connected to ground potential. The power semiconductor chip and the control semiconductor chip are directly mounted on the electrically conductive heat sink without the use of a separate electrical insulation layer in order to obtain a multi-chip module which is simple and economical to manufacture, and which offers superior performance characteristics.

Abstract: A high-voltage capacitive voltage divider circuit includes a high-voltage Silicon-On-Insulator (SOI) capacitor connected between a high-voltage terminal and a low-voltage terminal, and a low-voltage SOI capacitor connected between the low-voltage terminal and a common terminal. The voltage divider circuit also includes control circuitry for processing a signal generated at the low-voltage terminal in order to provide voltage-related control of a larger circuit employing the voltage divider circuit. The high-voltage SOI capacitor can include an oxide layer on a substrate, with a thinned drift region on the oxide layer, a thick oxide layer over the thinned drift region, and an electrode layer over the thick oxide layer, with the electrode layer and the thinned drift region forming capacitor plates insulated from each other by the thick oxide layer.

Abstract: A multiple semiconductor chip (multi-chip) module for use in high-power applications includes at least a power semiconductor chip and a control semiconductor chip mounted on an electrically conductive heat sink. The power semiconductor chip may be a Silicon-On-Insulator (SOI) device and the control semiconductor chip may be a semiconductor device having a substrate connected to ground potential. The power semiconductor chip and the control semiconductor chip are directly mounted on the electrically conductive heat sink without the use of a separate electrical insulation layer in order to obtain a multi-chip module which is simple and economical to manufacture, and which offers superior performance characteristics.

Abstract: A resonant mode power supply includes a soft-start circuit for, at start-up, for sweeping the frequency of the power supply from a maximum value to a minimum value. The soft-start circuit performs this frequency sweep using the functionF(x)=1-e.sup.-tUsing this function, change in the frequency, and correspondingly the increase of the output voltage decreases over time, thereby allowing a feedback circuit of the resonant mode power supply to respond to the level of the output voltage and to begin regulation when the output voltage achieves the desired regulation level. As such, overshoot of the output voltage with respect to the regulation level is lessened, if not eliminated.

Abstract: A resonant mode power supply includes a d.c. voltage source and switching elements for alternatively connecting an oscillating circuit, including the primary winding of a transformer, to the d.c. voltage source and to ground. In order to detect faults in the load on a secondary side of the transformer which would cause the resonant mode power supply to attempt to supply and inordinate amount of power, the power on the primary side is detected and if this primary power exceeds a predetermined threshold value, the frequency of oscillation is increased to reduce the power. If the fault condition persists, the switching of the switching elements is discontinued.

Abstract: A resonant mode power supply includes a D.C. voltage source and switching elements for alternatively connecting an oscillating circuit, including a primary winding of a transformer, to the D.C. voltage source and to ground. A first secondary winding supplies the main output voltage of the power supply and a second secondary winding provides a control output voltage. An opto-coupler is included and has a light emitter connected to the second secondary winding, and a light sensor connected to a controller for controlling the switching of the switching elements, wherein the higher the frequency of the switching, the lower the power being supplied by the power supply. Burst mode stand-by is started by the first secondary winding being shunted to the second secondary winding causing the light emitter to emit a maximum amount of light. The controller increases the switching frequency until it exceeds a predetermined maximum frequency.

Abstract: A switched-mode power supply includes a transformer (TR) provided with a primary winding (P) having a first primary terminal (1), coupled to receive a voltage (U) with respect to a ground terminal (GND), and a second primary terminal (2); a controllable switch (SM) coupled between the second primary terminal (2) and the ground terminal (GND); and a start-up circuit (ST) for starting up the switched-mode power supply. The start-up circuit (ST) includes a field effect transistor (T) of the normally-on type having a drain coupled to the second primary terminal (2), a source, and a gate. The start-up circuit (ST) further includes a voltage stabilizer (VS) for supplying an internal supply voltage to an internal supply terminal (VINT), the voltage stabilizer (VS) being coupled to the source.

Abstract: A switched-mode power supply circuit having an operating mode and a stand-by mode, includes a functional ON/OFF switch. The switched-mode power supply circuit includes a transformer and a controllable switch connected to a primary winding of the transformer for switchably connecting the primary winding to a source of d.c. voltage. In the stand-by mode, based on a detected voltage level at an input of a controller IC, the switched-mode power supply circuit is arranged to switchable connect the primary winding to the d.c. voltage source in bursts which occur at a low frequency. By switchably connecting this input to a power source for the switched-mode power supply circuit, the controller IC detects the absence of this power source, and turns off the switched-mode power supply circuit allowing a minimum current consumption by the switched-mode power supply circuit.

Abstract: A switched-mode power supply includes a transformer having a primary winding, a secondary winding and an auxiliary winding. A switching device is included in series with the primary winding for alternately interrupting the flow of current through the primary winding. The switched-mode power supply further includes a controller circuit connected to the auxiliary winding for receiving information related to an output voltage across the secondary winding and for controlling the switching of the switching device so as to maintain the information at a desired level. The controller circuit including a sample-and-hold circuit which is controlled to sample the information related to the output voltage only when there is current flowing in the secondary winding.

Abstract: A sample-and-hold circuit is provided for a switched-mode power supply of the type having a transformer with a primary winding, an auxiliary winding and a secondary winding, with a switching transistor coupled in series with the primary winding and a sample-and-hold capacitor for storing a voltage proportional to an output voltage of the auxiliary winding and coupled to a controlled terminal of the switching transistor in a feedback loop which normally operates in a closed-loop mode for switchably regulating the power supply. To prevent the feedback loop from being driven to an open-loop or "stuck" mode of operation, a discharge capacitor is provided which is switchably coupled in parallel with the sample-and-hold capacitor to discharge excess voltage from the sample-and-hold capacitor and thereby restore the feedback loop to its normal closed-loop operating mode.

Abstract: A switched-mode power supply circuit includes a first controller for controlling power to a main power output through a first transformer, and a second controller for controlling power to a control output through a second transformer. In order to effect a very low power stand-by mode, the second controller turns off the first controller, the second controller only operating. When a load is selectively coupled across the control output, the second controller detects this load and turns on the first controller thereby effecting the operating mode.

Abstract: A switched-mode power supply circuit having an operating mode and a stand-by mode. The switched-mode power supply circuit includes a transformer and a controllable switch connected to a primary winding of the transformer for switchably connecting the primary winding to a source of d.c. voltage. In the stand-by mode, the switched-mode power supply circuit is arranged to switchable connect the primary winding to the d.c. voltage source in bursts which occur at a low frequency. Between each of the bursts, an auxiliary capacitor, which is ordinarily charged by an auxiliary winding during switching of the controllable switch, is now charged by a start-up current source contained in a controller for controlling the controllable switch.

Abstract: An overvoltage protection circuit is provided for a switched-mode power supply of the type having a transformer with a primary winding, an auxiliary winding, and a secondary winding, with a switching transistor coupled in series with the primary winding. The overvoltage protection circuit includes a sensing resistor having a first terminal directly connected to the auxiliary winding for generating a current proportional to the voltage across the auxiliary winding, with a second terminal of this resistor being coupled to an input of a current mirror. The reflected current output of the current mirror is compared to an overvoltage reference current generated by an overvoltage reference current source by means of a current comparator, and a circuit is provided to generate a signal to turn off the switching transistor when the reflected current exceeds the overvoltage reference current.

Abstract: A controller for supplying a switching drive voltage signal to a semiconductor power switch includes a wave-shaper circuit that generates a piece wise linear (PWL) waveform that slows the rate of change of the drive voltage supplied to the control electrode of the semiconductor power switch. As a result, the radiated electromagnetic interference generated by the apparatus can be appreciably reduced.

Abstract: A power integrated circuit pre-regulator AC/DC converter circuit which employs a slow turn-off lateral insulated gate bipolar transistor (LIGBT) device as the switching transistor so as to reduce the decay time of a current generated by the parasitic inductance in the circuit upon turn-off of the LIGBT device, thereby to substantially reduce the level of a ringing voltage produced at the drain of the LIGBT device.

Abstract: A high-voltage differential sensor includes an attenuator formed of two matched monolithic capacitance divider networks. Each divider network is formed of a series connection of monolithically integrated capacitors, which together generate an attenuated differential signal from a high-voltage differential input signal. The attenuated differential signal from the capacitance divider networks is then amplified and fed to a comparator, which generates a first output level when the high-voltage differential input signal is above a selected level, and generates a second output level when the high-voltage differential input signal is below the selected level. By using monolithically integrated capacitors in the divider networks of the attenuator, a simple, compact, low power, high performance high-voltage differential sensor is obtained.

Abstract: A power supply system employs a control circuit to regulate the voltage across a load capacitor by monitoring the capacitor voltage by means of a differential voltage sensor and by monitoring the drain-source voltage of a switching power FET connected in series with the load capacitor across input terminals that supply a full wave rectified voltage derived from a commercial AC supply voltage. The control circuit controls the switching action of the power FET in a manner such that the load capacitor is charged at least once during each cycle of the rectified voltage (unfiltered). This method of voltage regulation by monitoring the load capacitor voltage and the FET voltage (V.sub.ds) provides significant advantages over other forms of voltage regulation.