Device and method for monitoring at least one energy reserve capacitor in a restraint system
First Claim
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1. A device for monitoring at least one energy reserve capacitor in a restraint system, comprising:
- a microcontroller configured to monitor a capacitance of the at least one energy reserve capacitor;
a voltage converter configured to convert an input voltage to a higher output voltage and charge the at least one energy reserve capacitor using the higher output voltage; and
a rectifier and a voltage divider configured to determine a charging current and a difference between at least one observed peak voltage value and at least one subsequently observed static voltage value, the at least one peak voltage value being a result of an active phase of the voltage converter and the at least one static voltage value being a result of an inactive phase of the voltage converter following the active phase of the voltage converter, a waiting period following the at least one observed peak voltage value,wherein the microcontroller generates a signal to selectively shut the voltage converter off to provide defined starting conditions, andwherein the voltage converter, the rectifier, and the voltage divider are configured to monitor an ohmic internal resistance of the at least one energy reserve capacitor.
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Abstract
A method and a device are provided for monitoring an energy reserve capacitor, in which monitoring of the internal resistance is provided in addition to monitoring of the capacitance. This is achieved by a time sequence of charging operations and an interruption of those charging operations.
16 Citations
14 Claims
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1. A device for monitoring at least one energy reserve capacitor in a restraint system, comprising:
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a microcontroller configured to monitor a capacitance of the at least one energy reserve capacitor; a voltage converter configured to convert an input voltage to a higher output voltage and charge the at least one energy reserve capacitor using the higher output voltage; and a rectifier and a voltage divider configured to determine a charging current and a difference between at least one observed peak voltage value and at least one subsequently observed static voltage value, the at least one peak voltage value being a result of an active phase of the voltage converter and the at least one static voltage value being a result of an inactive phase of the voltage converter following the active phase of the voltage converter, a waiting period following the at least one observed peak voltage value, wherein the microcontroller generates a signal to selectively shut the voltage converter off to provide defined starting conditions, and wherein the voltage converter, the rectifier, and the voltage divider are configured to monitor an ohmic internal resistance of the at least one energy reserve capacitor. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for monitoring at least one energy reserve capacitor in a restraint system, comprising:
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selectively turning off a voltage converter by a signal generated by a microcontroller to provide defined starting conditions, wherein the voltage converter is configured to convert an input voltage to a higher output voltage and charge the at least one energy reserve capacitor using the higher output voltage; monitoring a capacitance of the at least one energy reserve capacitor; determining a charging current on the at least one energy reserve capacitor; and monitoring an internal resistance of the at least one energy reserve capacitor by determining a difference between at least one observed peak voltage value and at least one static voltage value observed after a waiting period following the at least one observed peak voltage value, wherein the at least one peak voltage value is a result of a charging phase of the energy reserve capacitor and the at least one static voltage value is a result of a discharging phase of the energy reserve capacitor following the charging phase of the energy reserve capacitor. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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Specification