Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
50 words
A switching circuit comprising a solid state switch (9) and drive circuitry (10, 11, 12) for driving the switch characterised in that sensing circuitry (2, 3, 4) for sensing an operating characteristic of the switch (9) and for producing a control signal in dependence upon the characteristic sensed is provided.
Claim 2
Dependent Claim
50 words
A switching circuit comprising a solid state switch (9) and drive circuitry (10, 11, 12) for driving the switch characterised in that sensing circuitry (2, 3, 4) for sensing an operating characteristic of the switch (9) and for producing a control signal in dependence upon the characteristic sensed is provided.
Claim 3
Dependent Claim
21 words
A switching circuit as claimed in Claim 1, in which the solid state switch (9) is a PNP or NPN transistor.
Claim 4
Dependent Claim
27 words
A switching circuit as claimed in Claim 1, in which the solid state switch (9) is a p-channel or n-channel . vertical metal oxide semiconductor device (VMOS).
Claim 5
Dependent Claim
24 words
A switching circuit as claimed in Claim 2, in which the sensing circuitry (2, 3, 4) is connected to sense the saturation emitter-collector voltage.
Claim 6
Dependent Claim
25 words
A switching circuit as claimed in Claim 3, in which the sensing circuitry (2, 3, 4) is connected to sense the saturation source drain voltage.
Claim 7
Dependent Claim
59 words
A switching circuit as claimed in any preceding claim, in which the sensing circuitry comprises one or more individual circuits (2, 3, 4) the or each being respectively set to indicate whether the operating characteristic of the switch sensed is greater or less than a given threshold value for that circuit and to produce an output digital signal accordingly.
Claim 8
Dependent Claim
86 words
A switching circuit as claimed in Claim 6, in which digital logic circuit means (5, 6, 8) are provided operative to produce two digital output signals from one or more individual output.signals of the respective individual circuits (2, 3, 4) of the sensing circuitry, one of the two signals indicating whether a fault in the switch, or a load which in operation of the circuit is fed from the switch is present or not and the other signal indicating whether that fault is serious or not.
Claim 9
Dependent Claim
25 words
A switching circuit as claimed in any preceding claim, in which logic circuitry (7) is provided to disable the switch if a serious fault exists.
Claim 10
Dependent Claim
28 words
A switching circuit as claimed in Claim 8, in which means (33, 34) are provided in the logic circuitry (7) for delaying the application of a disabling signal.
Claim 11
Dependent Claim
18 words
A switching circuit as claimed in any preceding claim which is in the form of an integrated circuit.