Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
179 words
A control circuit for energizing an electric load comprising: input terminals for supplying a source of electric current to the load, a controlled semiconductor power device having a characteristic that defines a safe operation area (SOA) of the semiconductor power device, current sensing means, means for coupling at least a part of said semiconductor power device, said current sensing means and said load in series circuit across said input terminals, means coupled to said current sensing means for setting first and second current limits for the control circuit, each of which is set near to the boundary of the SOA of said semiconductor power device, means controlled by a voltage developed at said load for selecting said first and second current limits as a function of the level of the load voltage, and means coupled to a control electrode of the semiconductor power device and controlled by said setting means for controlling and limiting the current passed by said semiconductor power device to the load as a function of the current limit selected in response to the load voltage.
Claim 2
Dependent Claim
179 words
A control circuit for energizing an electric load comprising: input terminals for supplying a source of electric current to the load, a controlled semiconductor power device having a characteristic that defines a safe operation area (SOA) of the semiconductor power device, current sensing means, means for coupling at least a part of said semiconductor power device, said current sensing means and said load in series circuit across said input terminals, means coupled to said current sensing means for setting first and second current limits for the control circuit, each of which is set near to the boundary of the SOA of said semiconductor power device, means controlled by a voltage developed at said load for selecting said first and second current limits as a function of the level of the load voltage, and means coupled to a control electrode of the semiconductor power device and controlled by said setting means for controlling and limiting the current passed by said semiconductor power device to the load as a function of the current limit selected in response to the load voltage.
Claim 3
Dependent Claim
52 words
A control circuit as claimed in claim 1 wherein said selecting means comprises a comparison circuit having a first input coupled to a terminal of the load and a second input that receives a reference voltage that determines the voltage level at which switchover occurs between said first and second current limits.
Claim 4
Dependent Claim
48 words
A control circuit as claimed in claim 2 wherein said setting means comprises second and third comparison circuits controlled by a voltage developed across said current sensing means, output signals of said second and third comparison circuits being selected at mutually exclusive times by the first comparison circuit.
Claim 5
Dependent Claim
49 words
A control circuit as claimed in claim 3 wherein said controlling and limiting means comprise a feedback circuit coupled between outputs of the second and third comparison circuits and the control electrode of the semiconductor power device and including a logic circuit and a driver circuit connected in cascade.
Claim 6
Dependent Claim
16 words
A control circuit as claimed in claim 1 wherein said load includes an incandescent electric lamp.
Claim 7
Dependent Claim
22 words
A control circuit as claimed in claim 1 wherein said current sensing means comprises a resistor with a relatively low resistance value.
Claim 8
Dependent Claim
37 words
A control circuit as claimed in claim 1 wherein said current limit setting means sets said first and second current limits so that each of said current limits falls within the SOA of said semiconductor power device.