| 摘要 |
<p>A method for determining the charging capacitance of a capacitor in an air-bag system using a bus system. The charging capacitance of a capacitor required to normally operate an air-bag system is determined by the formula (I) below. C = 2E/V2 (I) [where C is the charging capacitance of the capacitor, V is the charging voltage, and E is the minimum ignition energy needed to heat the heating part of an igniter and thereby to ignite the igniter powder and given by the formula (II) below. E = Imin2×(Rmax + r1 + r2) × T + w × 10 (II) [Imin: the minimum ignition current value (A), Rmax: the maximum resistance value (Ω) of the heating part, r1: ON-resistance value (Ω) of the switching circuit (the maximum ON-resistance value at 150°C), r2: the resistance value (Ω) of another element, T: the time (μsec) when current flows through the heating part, w: the power consumed by the whole integrated circuit when the switching circuit is OFF.</p> |
