U.S. Philips Corporation

Nxp B.v.

Brendan P Kelly

Royce Lowis

Steven Thomas Peake

Raymond J Grover

Paul T Moody

John R Cutter

An on-state low current detector uses a transistor with main () and sense () cells. Feedback circuit () acts to keep the voltage across main cells () 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 () are readily measurable.

Undercurrent sense arrangement and method

A vertical insulated gate field effect power transistor () has a plurality of parallel transistor cells (TC) with a peripheral gate structure (G, G) at the boundary between each two transistor cells (TC). The gate structure (G, G) comprises first (G) and second (G) gates isolated from each other so as to be independently operable. The first gate (G) is a trench-gate (), and the second gate (G) has at least an insulated planar gate portion (). Simultaneous operation of the first (G) and second (G) gates forms a conduction channel () between source () and drain () regions of the device (). The device () 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 () may be a high side power transistor is series with a low side power transistor () in a circuit arrangement () (FIG.) for supplying a regulated output voltage. The device () may also be a switch in a circuit arrangement () (FIG.) for supplying current to a load (L). These circuit arrangements () include a terminal (Vcc, V) for applying a supplied fixed potential to an electrode (G) for the first gates (G) and a gate driver circuit () for applying modulating potential to an electrode (G) for the second gates (G).

Power semiconductor devices

A driver for an inductive load such as a solenoid coilincludes three FETsTwo of the FETs are reversely connected between battery and output terminalsand one of the FETs is connected between output and ground terminalsA driver circuithaving high and low side control circuitryis formed in a common substrate with two of the FETsIn use, a coilis connected to the output terminaland driven in an energize mode in which current in the coilis built up as indicated by arrowa freewheel mode in which current circulates freely as indicated by arrowand 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.

Driver for inductive load

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). By so comparing the voltage (Vdl) at the series node (11) with the predetermined function of the supply-to-return voltage (Vbg), the detector (SC) provides an output signal (sc) indicating whether or not a short-circuit is present. Preferably pinch-resistors (R1,R2) or a voltage-clamp (ZD) are used with the circuit means (R1, R2, . . ., R1', R2', . . . ), so that the predetermined function of the supply-to-return voltage (Vbg) input to the comparator (CP) varies with the magnitude of the supply-to-return voltage (Vbg). By this means a lower percentage of the supply-to-return voltage (Vbg) can be input at a higher magnitude of the supply-to-return voltage (Vbg) than at a lower magnitude.

Power device with a short-circuit detector

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. A circuit connection (5, 7) between the first and second comparator circuits, preferably at the inputs of their respective comparators (CP1, CP2) couples together the hot-location temperature-sensitive elements (Q1, R1, R2, R3) of the first and second comparator circuits so that the temperature gradient threshold sensed by the second comparator circuit decreases as a function of the device temperature (Tabs).

Power semiconductor devices with a temperature sensor circuit

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). A semiconductor device (M2) has one (d) of its main electrodes coupled to the control electrode (g) of the control semiconductor device (M3) and the other (s) to the sense resistance (R4). A reference arrangement (50) provides a biasing voltage V.sub.b for the control electrode (g) of the semiconductor device (M2) to cause the semiconductor device (M2) to conduct sufficiently to cause the control semiconductor device (M3) to be non-conducting until the sense voltage reaches a reference voltage determined by the biasing voltage when the semiconductor device (M2) becomes less conducting, causing the control semiconductor device (M3) to start to conduct, so reducing the voltage at the control electrode (G) of the power semiconductor device (P) and thus reducing the current through the power semiconductor device (P).

Protected switch having a power semiconductor device

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. A disabling arrangement including a normally off third semiconductor device inhibits conduction of the normally off semiconductor device during normal operation of the power semiconductor device.

Protected switch

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). A control device (30) common to the switches (M1, M2, M3) of the coils (20) controls the drive signal to the control electrode (g) of the further device (M4) to limit the current through this further device (M4) to a predetermined value and then to turn off this further device (M4) so as to render a conducting one of the switches (M1, M2, M3) non-conducting to initiate sparking in the cylinder associated with that one switch. Sophisticated logic and control functions can be integrated with the common control device (30). The complex impedance of the ignition coil (20) can be isolated readily from the control loop of the further device (M4) and control device (30) by the switches (M1, M2, . . . ) operating in cascade with the further device (M4).

Ignition control circuit, and engine system

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. The switching device switches from one of the first and second states to the other when the voltage at the gate voltage supply terminal changes in order to turn the power semiconductor device on or off, or upon the detection of a fault condition within the power semiconductor device. In either case, the overall resistance of the conductive path between the gate electrode and the gate voltage supply terminal is altered.

IGFET power semiconductor circuit with GAE control and fault detection

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. The impurity concentrations within the second and third regions (14 and 15) are such that the semiconductor device (Rx) has a temperature coefficient of resistance which changes, generally increases or falls only slightly, with absolute temperature such that the relative temperature coefficient of resistance referred to the sensed temperature is substantially constant. Respective temperature sensing devices may be provided adjacent to and remote from an active semiconductor device to provide a differential temperature sensor.

Temperature sensing device and a temperature sensing circuit using such

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). A further conductive path connects the further second region (11) to the insulated gate (12) of the power semiconductor device (10) and a diode arrangement (30 ) connects the insulated gate (120) of the auxiliary semiconductor device (100) to the first main electrode (4) for causing the auxiliary semiconductor device (100) to conduct to supply a signal via the further inductive path to the insulated gate (12) of the power semiconductor device (10) to switch the power semiconductor device (10) on when the voltage on the first main electrode (4) exceeds the predetermined value. The auxiliary semiconductor device (100) thus has a large current-handling capability enabling rapid turn-on of the power device (10) in the event of an overvoltage.

Overvoltage protected semiconductor switch

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.

Growing community of inventors

Stockport, United Kingdom

Brendan P Kelly