Abstract: A transistor (1) has a FET (2) and a temperature sensing diode (4) integrated within it. Gate drive circuit (12) is arranged to switch off FET (2) and in this case biasing circuit (14) drives a constant current through the diode (4). The voltage across the diode (4) is measured by voltage sensor (15) which provides a measure of the temperature of the FET.

Abstract: A circuit (1) is described for determining the current (Iload) in a load (6), the circuit having a main transistor (2) and a sense transistor (3), each transistor having a main current path (4, 5) and a control terminal (9, 10), the main current paths each operably connected in parallel between the load and a ground terminal (7) and the control terminals being connected together. Means is provided for setting the voltage across the main current path (5) of the sense transistor (3) to a voltage level substantially equal to a predetermined portion of the voltage across the main current path (4) of the main transistor (3).

Abstract: A transistor (1) has a FET (2) and a temperature sensing diode (4) integrated within it. Gate drive circuit (12) is arranged to switch off FET (2) and in this case biasing circuit (14) drives a constant current through the diode (4). The voltage across the diode (4) is measured by voltage sensor (15) which provides a measure of the temperature of the FET.

Abstract: A circuit (1) is described for determining the current (Iload) in a load (6), the circuit having a main transistor (2) and a sense transistor (3), each transistor having a main current path (4, 5) and a control terminal (9, 10), the main current paths each operably connected in parallel between the load and a ground terminal (7) and the control terminals being connected together. Means is provided for setting the voltage across the main current path (5) of the sense transistor (3) to a voltage level substantially equal to a predetermined portion of the voltage across the main current path (4) of the main transistor (3).

Abstract: The present invention provides for a MOSFET device (10) having a body diode structure (22) and provided with biasing means arranged to provide a bias voltage selectively applied to the gate of the MOSFET (12) during reverse recovery of the body diode structure (22) so as to reduce reverse recovery transient signals associated with the body diode structure (22), the biasing means comprising a diode device (16) located in the gate path of the device (10).

Abstract: A drive circuit for an electromagnetic device includes an inductor which can be connected across a pair of supply lines by way of a first switch. Energy is stored in the core of the inductor which can be released into the device to cause rapid operation thereof by opening the first switch and closing a second switch. When the energy in the inductor has been dissipated a low level of current is allowed to flow into the device by way of the inductor from the supply lines and this flow of current can be maintained by means of a diode when the first switch is closed to re-energize the inductor.

Abstract: A control circuit for a vehicle transmission system having a multi-ratio gearbox the individual ratios of which are obtained by energizing one of a plurality of solenoids by means of a selector switch. The control circuit is connected to a source of supply by means of a master switch and circuit means is provided to prevent energization of the solenoids in the event that the selector switch is left in a selection position prior to closure of the master switch.