Patent ID: 7142407

Claim:
A circuit, realizing a driver device for secure and reliable firing of an igniter or squib, connecting said squib via a high-side electronic switch to a power source and via a low-side electronic switch to circuit ground, incorporating separate power supply parts for high voltage and low voltage domains and equipped with elaborate intrinsic diagnostics and online testing features for circuit protection and operation securing purposes, comprising: a means for control of said firing, said diagnostics, and said online testing having a safing sensor signal input pin, four pins for voltage sense input signals, four pins for two pairs of current control output signals, and a ground pin; a means for said high-side switching of said squib to said power source performing high-side switching transistor functions for said firing, for said diagnostics, and for said online testing; a means for said low-side switching of said squib to said circuit ground performing low-side switching transistor functions for said firing, for said diagnostics, and for said online testing; a means for providing said high voltage domain power supply; a means for providing said low voltage domain power supply; a means for secured supply of electrical energy to said means for said high-side switching derived from said high voltage domain; a means for steered supply of currents to said means for said low-side switching derived from said low voltage domain and controlled by one pair of said current control output signals; a means for steered supply of currents to a means for driving said high-side switching means derived from said low voltage domain and controlled by the other pair of said current control output signals; a means for driving said high-side switching means for said squib controlled by said means for control of firing, diagnostic and online testing and supplying drive current to said high-side switching means either for the case of said diagnostic and online testing operations or for the case of said firing operation; and a means for connecting said high-side switching means and said low-side switching means to said means for control of firing, diagnostic and online testing in order to execute said diagnostic measurement and online testing by said four voltage sense input signals whereby in said case of diagnostic and online testing operations a switchable and controllable current flow is initiated in conjunction with appropriate voltage measurements and resistance evaluations thereby strictly observing that no firing condition for said squib is allowed to occur and whereby in case of said firing operation a secure firing of said squib is always guaranteed.