Abstract: An on-state low current detector uses a transistor with main (32) and sense (34) cells. Feedback circuit (36) acts to keep the voltage across main cells (32) at a substantially constant target value when the load current falls below a level that generates the target voltage value in the main cells. The target voltage value is sufficiently high to ensure that the voltages of low current detection comparator (18) are readily measurable.

Abstract: A vertical insulated gate field effect power transistor (3) has a plurality of parallel transistor cells (TC3) with a peripheral gate structure (G31, G2) at the boundary between each two transistor cells (TC3). The gate structure (G31, G32) comprises first (G31) and second (G32) gates isolated from each other so as to be independently operable. The first gate (G31) is a trench-gate (21, 22), and the second gate (G32) has at least an insulated planar gate portion (13, 14). Simultaneous operation of the first (G31) and second (G32) gates forms a conduction channel (23c, 23b) between source (16) and drain (12) regions of the device (3). The device (3) has on-state resistance approaching that of a trench-gate device, better switching performance than a DMOS device, and a better safe operating area than a trench-gate device. The device (3) may be a high side power transistor is series with a low side power transistor (6) in a circuit arrangement (50) (FIG. 14) for supplying a regulated output voltage.

Abstract: A driver for an inductive load such as a solenoid coil 92 includes three FETs 4,6,8. Two of the FETs are reversely connected between battery and output terminals 16, 18, and one of the FETs is connected between output and ground terminals 16, 14. A driver circuit 10 having high and low side control circuitry 58,56 is formed in a common substrate with two of the FETs 4,6. In use, a coil 92 is connected to the output terminal 16, and driven in an energize mode in which current in the coil 92 is built up as indicated by arrow 100, a freewheel mode in which current circulates freely as indicated by arrow 102, and then may be switched off. The reversely connected FETs allow both short circuits to be prevented in the energize mode and allow the coil to be rapidly switched off. In spite of the control circuitry being formed in a common substrate with some of the FETs, the arrangement allows the FETs to be properly driven.

Abstract: A power device circuit comprises a power semiconductor device (MPWR) in series with a load (LD) between a power supply line (1) and a return line (2), and a short-circuit detector (R1, R2, . . . R1', R2', . . . CP) for determining whether the load (LD) is short-circuit. The short-circuit detector examines the distribution of the supply-to-return voltage (Vbg) between the device (MPWR) and the load (LD) by comprising a comparator (CP) which has a first input (+) coupled to a series node (11) between the device and load and a second input (+) from circuit means (R1, R2, . . . , R1', R2', . . . ) coupled between the supply and return lines (1 and 2) to provide the second input (-) with a voltage supply signal (Vbg') which is a predetermined function of the supply-to-return voltage (Vbg).

Abstract: A temperature sensor circuit of a power semiconductor component comprises temperature-sensitive elements, some (Q1, and R1 to R3) of which are located in the vicinity of an active area of the component where heat is generated by the power semiconductor device (MPWR), whereas others (such as R4, R') are located more remote from the heat-generating active area and so are in a cool location. Hot-location elements (Q1, and R1 to R3) with different temperature coefficients are present in a first comparator circuit for indicating device temperature (Tabs) in the vicinity of the heat-generating active area. Both hot-location and cool-location elements (R2 and R4) are present in a second comparator circuit for indicating when a temperature gradient (Tdiff) threshold occurs.

Abstract: A protected switch has a power semiconductor device (P) having first and second main electrodes (D and S) for coupling a load (L) between first (2) and second (3) voltage supply lines, a control electrode (G) coupled to a control voltage supply line (4) and a sense electrode (S1) for providing in operation of the power semiconductor device a sense current that flows between the first (d) and sense electrodes (S1) and is indicative of the current that flows between the first (D) and second (S) main electrodes. A control arrangement (S) has a sense resistance (R4) coupled to the sense electrode (S1) and across which a sense voltage is developed by the sense current (I.sub.3). A control semiconductor device (M3) has its main electrodes coupled between the control electrode (G) and the second (S) main electrode of the power semiconductor device (P).

Abstract: A protected switch has a power first semiconductor device having a first main electrode for coupling to a first voltage supply line, a second main electrode coupled to a first terminal for connection via a load to a second voltage supply line and an insulated gate electrode coupled to a control terminal for supplying a gate control signal to enable conduction of the power semiconductor device. A control arrangement has a normally off second semiconductor device having first and second main electrodes coupling the normally off semiconductor device between the gate electrode of the power semiconductor device and one of the first and second main electrodes of the power first semiconductor device and a control electrode coupled via a resistance to the gate electrode of the power semiconductor device thereby causing the normally off semiconductor device to be rendered conducting when a gate control signal is supplied to the gate electyrode to enable conduction of the power semiconductor device.

Abstract: A respective power semiconductor switch (M1, M2, M3) is provided for each ignition coil (20) of an internal combustion engine. Each such switch (M1, M2, M3) has a first main electrode (C) for coupling the primary winding (20a) of the associated ignition coil (20) to a first voltage supply line (1), and a control electrode (G) coupled to an respective ignition control line (Ign1, Ign2, Ign3) for rendering these switches (M1, M2, M3) conducting in a given sequence. A further semiconductor device (M4) has first and second main electrodes (d and s) coupled between second main electrodes (E) of the power semiconductor switches (M1, M2, M3) and a second voltage supply line (2), and a control electrode (g) for a drive signal controlling the current flow through the device (M4). A current sensing arrangement (Rs) senses the current flowing through this further device (M4).

Abstract: A power semiconductor device circuit has an insulated gate field effect power semiconductor device with first and second main electrodes and a gate electrode. A gate control circuit provides a conductive path between the gate electrode and a gate voltage supply terminal. The gate control circuit has a resistance coupled between the gate electrode and the gate voltage supply terminal. A switching device has first and second main electrodes coupled to the gate voltage supply terminal and the gate electrode, respectively, so that the main current path between the first and second main electrodes is coupled in parallel with the resistance, the switching device having a first non-conducting state and a second conducting state for providing, in the second conducting state, an additional resistance in parallel with the resistance.

Abstract: A semiconductor body (10) has a first region (13) of one formed a semiconductor device (Rx) having a resistance which varies with temperature. The semiconductor device (Rx) is formed by a second region (14) of the opposite conductivity type formed within the first region (13) and a third region (15) of the one conductivity type formed within the second region (14), with first and second electrodes (16) and (17) being spaced apart on the third region (15) so that a resistive path is provided by the third region (15) between the first and second electrodes (16 and 17) and a reference electrode (18) connecting the second region (14) to a reference potential.

Abstract: An overvoltage protected switch (1) includes a power semiconductor device (10) formed by a plurality of second regions (11) within a first region (3) of a semiconductor body (2), and an insulated gate 12 overlying a conduction channel region (13) between each second region (11) and the first region (3) with the first and second regions (3 and 11) providing a conductive path to first and second main electrodes (4 and 5), respectively, of the switch (1). An auxiliary semiconductor device (100) is formed by a number of further second regions (11), less than the plurality of second regions (11), and a further insulated gate (120) overlying a further conduction channel region (13) between each further second region (11) and the first region (3).

Abstract: A temperature sensing circuit has a first insulated gate field effect device which is operated deep into its subthreshold region where the voltage across the device varies with temperature and has a second insulated gate field effect device which is operated in an area of its square law region where the voltage across the second insulated gate field effect device is substantially independent of temperature. A comparator compares the voltages across the first and second field effect devices and provides a signal OT indicating the temperature sensed by the first insulated gate field effect device.