Abstract: In a power semiconductor device and a method of forming a power semiconductor device, a thin layer of semiconductor substrate is left below the drift region of a semiconductor device. A power semiconductor device has an active region that includes the drift region and has top and bottom surfaces formed in a layer provided on a semiconductor substrate. A portion of the semiconductor substrate below the active region is removed to leave a thin layer of semiconductor substrate below the drift region. Electrical terminals are provided directly or indirectly to the top surface of the active region to allow a voltage to be applied laterally across the drift region.

Abstract: This invention relates to switch mode power supply (SMPS) controllers employing primary side sensing. We describe an (SMPS) controller which uses an area correlator to compare an area under a feedback signal waveform between a start point defined by said first timing signal and an end point defined by said second timing signal with a reference area. An output of the area correlator provides an error signal for regulating the SMPS output.

Abstract: This invention is generally concerned with semiconductor-on-insulator devices, particularly for high voltage applications. A lateral semiconductor-on-insulator device is described, comprising: a semiconductor substrate; an insulating layer on said semiconductor substrate; and a lateral semiconductor device on said insulator; said lateral semiconductor device having: a first region of a first conductivity type; a second region of a second conductivity type laterally spaced apart from said first region; and a drift region extending in a lateral direction between said first region and said second region; and wherein said drift region comprises at least one first zone and at least one second zone adjacent a said first zone, a said first zone having said second conductivity type, a said second zone being an insulating zone, a said first zone being tapered to narrow towards said first region.

Abstract: A half bridge circuit has a first switch having at least one control gate and a second switch having at least two control gates. A first driver has an output connected to a control gate of the first switch. A second driver has an output connected to a first control gate of the second switch. The output of the first driver is connected to a second control gate of the second switch by a circuit arrangement such that when the first driver is operated to apply a high, positive voltage to the control gate of the first switch, a positive voltage is applied to the second control gate of the second switch, and such that when the first driver is operated to apply a low, zero or small voltage to the control gate of the first switch, a negative voltage is applied to said second control gate of the second switch.

Abstract: Methods and apparatus for sensing the output current in a switch mode power supply (SMPS) using primary side sensing are described. A system includes a primary current sense input, a charge input to sense a charging time of an SMPS transformer; a discharge input to sense a discharging time of the transformer; at least one averager; and a calculator. The primary current is averaged by the averager over at least a switching cycle of the SMPS and the calculator estimates the output current of the SMPS using the averaged primary current, the charge signal and the discharge signal.

Abstract: We describe a switch mode power supply (SMPS) controller employing a combination of pulse frequency and pulse width modulation. The controller employs a “gear box” control scheme using two complementary control loops, one for real-time control of the SMPS using PFM and a second using a PWM control scheme which monitors the switching frequency and, at defined operating points, adjusts the pulse width up or down through a set of pre-determined values. This can be considered analogous to the gearbox of a motor vehicle with the SMPS pulse width, switching frequency and output power roughly corresponding to the vehicle's gear ratio, engine speed and road speed respectively.

Abstract: A high voltage/power semiconductor device has a semiconductor layer having a high voltage terminal end and a low voltage terminal end. A drift region extends between the high and low voltage terminal ends. A dielectric layer is provided above the drift region. An electrical conductor extends across at least a part of the dielectric layer above the drift region, the electrical conductor being connected or connectable to the high voltage terminal end. The drift region has plural trenches positioned below the electrical conductor. The trenches extend laterally across at least a part of the drift region in the direction transverse the direction between the high and low voltage terminal ends of the semiconductor layer, each trench containing a dielectric material. The trenches improve the distribution of electric field in the device in the presence of the electrical conductor.

Abstract: A half bridge circuit has a first switch having at least one control gate and a second switch having at least two control gates. A first driver has an output connected to a control gate of the first switch. A second driver has an output connected to a first control gate of the second switch. The output of the first driver is connected to a second control gate of the second switch by a circuit arrangement such that when the first driver is operated to apply a high, positive voltage to the control gate of the first switch, a positive voltage is applied to the second control gate of the second switch, and such that when the first driver is operated to apply a low, zero or small voltage to the control gate of the first switch, a negative voltage is applied to said second control gate of the second switch.

Abstract: This invention generally relates to discontinuous conduction mode switch mode power supply (SMPS) controllers employing primary side sensing. We describe an SMPS controller which integrates a feedback signal from a point determined by a target operating voltage to a peak or trough of an oscillatory or resonant portion of the feedback signal when substantially no energy is being transferred to the SMPS output. When regulation is achieved this value should be zero; the difference from zero can be used to regulate the output voltage of the SMPS.

Abstract: We describe a switching power converter comprising a bipolar switching device (BJT or IGBT) switching an inductive load, and including a closed-loop control system. The control system comprises a voltage sensing system to sense a voltage on a collector terminal of the switching device and provide a voltage sense signal; a controller; and a drive modulation system coupled to an output of the controller for modulating a drive to the control terminal of said bipolar switching device responsive to a controller control signal; wherein said controller is configured to monitor changes in the sensed voltage during a period when said switching device is switched on and to control said drive modulation system to control the degree of saturation of said bipolar switching device when the device is switched on and hence improve turn-off times.

Abstract: A high voltage/power semiconductor device has a substrate, an insulating layer on the substrate, and a semiconductor layer on the insulating layer. Low and high voltage terminals are connected to the semiconductor layer. The device has a control terminal. The semiconductor layer includes a drift region and a relatively highly doped injector region between the drift region and the high voltage terminal. The device has a relatively highly doped region in electrical contact with the highly doped injector region and the high voltage terminal and forming a semiconductor junction with the substrate. The combination of the insulating layer and the relatively highly doped region of the first conductivity type effectively isolate the highly doped injector region from the substrate.

Abstract: This invention relates to SMPS controllers employing primary side sensing to detect a point of zero magnetic flux, at which the output voltage of the SMPS may be sampled accurately on the primary side. We describe a switch mode power supply (SMPS) controller for regulating the output voltage of an SMPS is response to a feedback signal from an auxilliary winding of a magnetic energy storage device forming part of an output circuit of the SMPS, the SMPS controller comprising: a reference level input to receive an output reference level signal; an input to receive said feedback signal, said feedback signal being responsive to a voltage on said auxilliary winding of said magnetic energy storage device; an integrator to integrate a difference between said feedback signal and a first fixed reference level signal; a first comparator to compare an output of said integrator with a second fixed reference level signal and to provide an output responsive to said comparison for regulating said SMPS output voltage.

Abstract: A power semiconductor device has an active region that includes a drift region. At least a portion of the drift region is provided in a membrane which has opposed top and bottom surfaces. In one embodiment, the top surface of the membrane has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region. In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface and at least one electrical terminal is connected directly or indirectly to the bottom surface to allow a voltage to be applied vertically across the drift region. In each of these embodiments, the bottom surface of the membrane does not have a semiconductor substrate positioned adjacent thereto.

Abstract: A bipolar high voltage/power semiconductor device has a low voltage terminal and a high voltage terminal. The device has a drift region of a first conductivity type and having first and second ends. In one example, a region of the second conductivity type is provided at the second end of the drift region connected directly to the high voltage terminal. In another example, a buffer region of the first conductivity type is provided at the second end of the drift region and a region of a second conductivity type is provided on the other side of the buffer region and connected to the high voltage terminal. Plural electrically floating island regions are provided within the drift region at or towards the second end of the drift region, the plural electrically floating island regions being of the first conductivity type and being more highly doped than the drift region.

Abstract: This invention is generally concerned with power semiconductors such as power MOS transistors, insulated gate by bipolar transistors (IGBTs), high voltage diodes and the like, and method for their fabrication. A power semiconductor, the semiconductor comprising a power device, said power device having first and second electrical contact regions and a drift region extending therebetween; and a semiconductor substrate mounting said device; and wherein said power semiconductor includes an electrically insulating layer between said semiconductor substrate and said power device, said electrically insulating layer having a thickness of at least 5 ?m.

Abstract: A bipolar high voltage/power semiconductor device has a low voltage terminal and a high voltage terminal. The device has a drift region of a first conductivity type and having first and second ends. In one. example, a region of the second conductivity type is provided at the second end of the drift region connected directly to the high voltage terminal. In another example, a buffer region of the first conductivity type is provided at the second end of the drift region and a region of a second conductivity type is provided on the other side of the buffer region and connected to the high voltage terminal. Plural electrically floating island regions are provided within the drift region at or towards the second end of the drift region, the plural electrically floating island regions being of the first conductivity type and being more highly doped than the drift region.

Abstract: Methods and apparatus for sensing the output current in a switch mode power supply (SMPS) using primary side sensing are described. A module senses a current in a primary winding of a transformer and a voltage on a primary or auxiliary winding of the transformer, and which includes a multiplier coupled to an output of a signal averager averaging a primary winding current and to an output of a timing signal generator using the sensed voltage to signal when a secondary winding is powering an output of the SMPS, to multiply an averaged current sense signal by a fraction of a total cycle period of said SMPS during which the secondary winding is providing power to provide a signal estimating an output current of the SMPS.

Abstract: A bipolar high voltage/power semiconductor device has a drift region having adjacent its ends regions of different conductivity types respectively. High and low voltage terminals are provided. A first insulated gate terminal and a second insulated gate terminal are also provided. One or more drive circuits provide appropriate voltages to the first and second insulated gate terminals so as to allow current conduction in a first direction or in a second direction that is opposite the first direction.

Abstract: A bipolar high voltage/power semiconductor device has a low voltage terminal and a high voltage terminal. The device has a drift region of a first conductivity type and having first and second ends. In one example, a region of the second conductivity type is provided at the second end of the drift region connected directly to the high voltage terminal. In another example, a buffer region of the first conductivity type is provided at the second end of the drift region and a region of a second conductivity type is provided on the other side of the buffer region and connected to the high voltage terminal. Plural electrically floating island regions are provided within the drift region at or towards the second end of the drift region, the plural electrically floating island regions being of the first conductivity type and being more highly doped than the drift region.

Abstract: This invention generally relates to discontinuous conduction mode switch mode power supply (SMPS) controllers employing primary side sensing. We describe an SMPS controller which integrates a feedback signal from a point determined by a target operating voltage to a peak or trough of an oscillatory or resonant portion of the feedback signal when substantially no energy is being transferred to the SMPS output. When regulation is achieved this value should be zero; the difference from zero can be used to regulate the output voltage of the SMPS.