Patent ID: 7209819

Claim:
A drive circuit for a firing cap, triggerable by an electric direct current firing pulse, of a vehicle restraint system, the drive circuit comprising: a firing circuit connected between a supply voltage of a first potential, and a reference voltage of a second potential, said firing circuit containing: a high side switch having a control electrode and a controlled path connected to the firing cap; a low side switch having a control electrode and a controlled path connected to the firing cap, said high side switch, the firing cap and the low side switch being connected in series, said firing circuit being activated by a drive signal fed simultaneously to said control electrode of said high side switch and of said low side switch for feeding a firing current to the firing cap during the firing pulse; a power switching element having a controlled path connected in series with said controlled path of said high side switch and of said low side switch to draw lost power from said firing circuit during the firing pulse; and a capacitor for storing energy and connected in parallel with said firing circuit.