Claims
- 1. A control device for a vehicle occupant protection device with a firing cap for activating the vehicle occupant protection device, comprising:
an energy source for providing a supply voltage for the firing cap; a switching transistor for connecting the firing cap to said energy source, said switching transistor having a control terminal and a controlled path connected in series with said energy source and the firing cap; and a control circuit connected to said control terminal of said switching transistor and configured to control said switching transistor to:
maintain a resistance of said controlled path constant in a switched-on state of said transistor, evaluate a signal present at said control terminal at that time, determine an energy being converted in said switching transistor from the signal at said control terminal and, when a predefined energy limiting value is reached within a specific time, switch off said switching transistor.
- 2. The controller according to claim 1, which comprises a capacitor connected in parallel with said energy source.
- 3. The controller according to claim 1, wherein said control circuit is connected to a sensor and said control circuit switches through said switching transistor upon receiving specific signals from said sensor.
- 4. The controller according to claim 3, wherein said control circuit is configured to switch through said switching transistor in clocked fashion.
- 5. The controller according to claim 1, wherein said control circuit includes a comparator transistor having a controlled path supplied by a power source, and wherein, for determining the resistance on said controlled path of said switching transistor, a resistance on said controlled path of said comparator transistor is determined by determining a voltage across said controlled path of said comparator transistor.
- 6. The controller according to claim 1, wherein said control circuit includes a comparator transistor having a controlled path, and wherein:
a resistance on said controlled path of said comparator transistor is determined when said switching transistor is switched off; a respective current resistance value is stored when said switching transistor is switched on; said control terminal of said switching transistor is coupled to a control terminal of said comparator transistor when said switching transistor is switched on; and a voltage value at said coupled control terminals of said switching transistor and said comparator transistor is subsequently regulated with respect to a stored voltage value of said comparator transistor when said switching transistor is switched on.
Priority Claims (2)
Number |
Date |
Country |
Kind |
199 47 096.0 |
Sep 1999 |
DE |
|
100 02 375.4 |
Jan 2000 |
DE |
|
CROSS-REFERENCE TO RELATED APPLICATION:
[0001] This application is a continuation of copending International Application No. PCT/DE00/03350, filed Sep. 26, 2000, which designated the United States.
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/DE00/03350 |
Sep 2000 |
US |
Child |
10113161 |
Apr 2002 |
US |