Abstract: A power insulated gate field effect transistor has main cells (2) controlled by a main cell insulated gate and sense cells (4) controlled by a sense cell insulated gate. A sample and hold circuit (10, 50) is arranged to operate in a plurality of states including at least one sample state and a hold state to sense the current flowing through the sense cells (4) when in the at least one sample state but not in the hold state. The sample states may be used in a feedback loop to control a drive amplifier (20) driving the gates of the main and sense cells (2,4) and/or to mirror the current in the sense cells (4) on a measurement output terminal (58).

Abstract: A power insulated gate field effect transistor has main cells (2) controlled by a main cell insulated gate and sense cells (4) controlled by a sense cell insulated gate. A sample and hold circuit (10, 50) is arranged to operate in a plurality of states including at least one sample state and a hold state to sense the current flowing through the sense cells (4) when in the at least one sample state but not in the hold state. The sample states may be used in a feedback loop to control a drive amplifier (20) driving the gates of the main and sense cells (2,4) and/or to mirror the current in the sense cells (4) on a measurement output terminal (58).

Abstract: A power insulated gate field effect transistor has main cells (2) controlled by a main cell insulated gate and sense cells (4) controlled by a sense cell insulated gate. A sample and hold circuit (10,50) is arranged to operate in a plurality of states including at least one sample state and a hold state to sense the current flowing through the sense cells (4) when in the at least one sample state but not in the hold state. The sample states may be used in a feedback loop to control a drive amplifier (20) driving the gates of the main and sense cells (2,4) and/or to mirror the current in the sense cells (4) on a measurement output terminal (58).

Abstract: A power MOSFET has a main current carrying section and a sense current carrying section, with separate source electrodes. The source electrode of the main section is connected to the device source terminal. The source electrode of the sense section is connected through a current sensing resistance to the same terminal. Both sections have separate gate electrodes. By comparing a reference voltage with the sense voltage across the sensing resistance, a first control signal is provided for the gate electrode of the sense section. A control circuit includes an adjustment circuit coupled to the first control signal and to the sense voltage and provides a second control signal to the gate electrode of the main section. This second control signal maintains the gate-source voltage of the main section equal to the gate source voltage of the sense section.

Abstract: A power MOSFET (1) has a main current carrying section (MCT) and a sense current carrying section (SCT), with separate source electrodes (s1, s2). The source electrode (s1) of the main section (MCT) is connected to the device source terminal (S1, S2). The source electrode (s2) of the sense section (SCT) is connected through a current sensing resistance (R1) to the same terminal (S1, S2). Both sections (MCT; SCT) have separate gate electrodes (g1, g2). By comparing a reference voltage (Vr) with the sense voltage Vs) across the sensing resistance (R1), a first control signal (CS1) is provided for the gate electrode (g2) of the sense section (SCT). Further control means (RG, MDD) comprises an adjustment circuit (RG) coupled to the first control signal (CS1) and to the sense voltage (Vs) and provides a second control signal (CS2) to the gate electrode (g1) of the main section (MCT).

Abstract: A power transistor device, for example a MOSFET or an IGBT, comprises a semiconductor body (10) which accommodates an array (11) of parallel device cells (1a) in which heat is generated in operation of the device. A hot-location temperature sensor (Mh) is located inside the array (11), and a cool-location temperature sensor (Mc) is located outside the array (11). These sensors each comprises at least one sensor cell (1b; 1c) which is of the same transistor type as the device cells (1a). The sensor cells (1b; 1c) have a cellular region structure (12,13,14,15) similar to that of the device cells (1a), but each sensor (Mh; Mc) has a respective output electrode (31; 32) separate from electrodes (22,23,25) of the device cells (1a).

Abstract: A temperature sensing circuit suitable for integration with a power semiconductor device (MOSFET/IGBT) includes temperature-sensing p-n diode means (D1, D2, etc . . . ) integrated together with first and second IGFETs (M1 and M2). A current path through the temperature-sensing p-n diode means (D1, D2, etc . . . ) provides a voltage drop (Vf) having a negative temperature coefficient. The IGFETs (M1 and M2) are coupled in separate current paths from each other so as to have separate gate-to-source voltage signals (Vgs1 and Vgs2) between their source and gate electrodes (s and g). The gate-to-source voltage (Vgs1) of the first IGFET (M1) has a negative temperature coefficient of greater magnitude than the temperature coefficient (if any) of the gate-to-source voltage (Vgs2) of the second IGFET (M2). One of the source and gate electrodes (s or g) of the first IGFET (M1) is coupled to the p-n diode means (D1, D2, etc . . .

Abstract: A stable voltage regulator circuit of simple circuit configuration 174,222 includes a differential amplifier (M2, M3) which is powered from a supply line (1) at a nominal voltage level (Vin), by being coupled between the supply line and a return line (2). A reference device (M1) is coupled to a first input (4) of the differential amplifier (M2, M3) for defining a desired output voltage (Vca) on an output line (3) coupled to an output (6) of the differential amplifier (M2, M3). The differential amplifier (M2, M3) is coupled to the return line (2) by a varying current source (M4) which feeds a varying bias current to the differential amplifier (M2, M3) and which is controlled from the supply line (1) in accordance with variations in the nominal voltage level (Vin) on the supply line (1). The varying bias current to the differential amplifier (M2, M3) provides a first-order compensation of the output voltage (Vca) for these voltage variations on the supply line (1).

Abstract: In a multi-processor environment, a plurality of nodes interconnected by a number of networks each run a number of users processes and messages transferred by the processes are transmitted sequentially from a transmitting node to a receiving node using a different network for each datagram to be transferred.

Abstract: An automated top head cover and stem guide assembly adapted for covering a top opening in vertical vessels such as coking drums, and a method for remotely operating the assembly. The top head assembly includes a flanged connector unit attached pressure-tightly to a top flange opening of a coking drum and a top cover device including a cover unit pivotally attached to the flanged connector unit, so that the cover unit can be pivotally lifted and moved aside. A stem guide device is also pivotally attached to the top flange unit, so that a stem guide unit can be pivotally moved downwardly into place over the top flange unit opening, after a stem member is inserted into the vessel. Following coke removal from the drum, the stem member is withdrawn, the stem guide unit is pivotally moved upwardly, and the head cover unit is moved downwardly to cover the coking drum flanged unit. The invention also discloses method steps for operating the head cover and stem guide devices of the assembly.

Abstract: An automated top head cover and stem guide assembly adapted for covering a top opening in vertical vessels such as coking drums, and a method for remotely operating the assembly. The top head assembly includes a flanged connector unit attached pressure-tightly to a top flange opening of a coking drum, and a top cover device including a cover unit pivotally attached to the flanged connector unit, so that the top cover unit can be pivotally lifted and moved aside. A stem guide device is also pivotally attached to the flanged connector unit, so that a stem guide unit can be pivotally moved downwardly into place over the top flange unit opening, after a stem member is inserted into the vessel. Following coke removal from the drum, the stem member is withdrawn, the stem guide unit is pivotally moved upwardly, and the head cover unit is moved downwardly to cover the coking drum flanged connector unit. The invention also discloses method steps for operating the head cover and stem guide devices of the assembly.