Digital squib driver circuit
AssigneeFreescale Semiconductor, Inc.
InventorsErwan Hemon, Philippe Lance
Life of this patent
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Abstract
A driving circuit for generating a required firing current for a safety device comprising an arrangement of a first transistor (M2) connected in series with a second transistor (M3); and a power control transistor (M1) connected in series with the first transistor; characterised in that the first and second transistors operate in fully switched on mode (Rds(on)) and the required firing current (I(squib)) is generated by means of varying the voltage (Vc) across the gate source of power control transistor and the first and second transistors in a predetermined manner.
Claims20
A driving circuit for generating a required firing current for a safety device comprising:
- an arrangement of a first transistor connected in series with a second transistor;
- and a power control transistor connected in series with the first transistor;
- wherein, when in operation the first and second transistors operate in fully switched on mode and the required firing current is generated by means of varying the voltage across the gate source of power control transistor and the first and second transistors in a predetermined manner.
A method of activating a safety device by generating a required firing current using a driving circuit for comprising an arrangement of a first transistor connected in series with a second transistor;
- and a power control transistor connected in series with the first transistor;
- the method comprises:
- operating the first and second transistors in fully switched on mode and varying the voltage across the power control transistor and the first and second transistors in a pre-determined manner in order to generate the required firing current.
Dependencies are inferred from the claim text.