Monitoring device for at least one ignition circuit for a personal protection means for a vehicle, and method for operating a monitoring device

Patent metadata

Field	Value
Publication number	US-10369950-B2
Application number	US-201515526094-A
Country	US
Kind code	B2
Filing date	Oct 27, 2015
Priority date	Dec 16, 2014
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

A monitoring device for an ignition circuit for a personal protection device for a vehicle. The ignition circuit activates the personal protection device when an ignition voltage is present that exceeds a voltage threshold value and/or an ignition current is present that exceeds a current threshold value. The monitoring device has a control device and a voltage source connected via a voltage source terminal of the control device. The control device is connected via a high-side ignition circuit terminal to a first supply terminal of the ignition circuit and via a low-side ignition circuit terminal to a second supply terminal of the ignition circuit. The monitoring device is fashioned such that a no-load voltage of a high-side current source of the control device situated between the voltage source terminal and the high-side ignition circuit terminal corresponds at least to the voltage threshold value.

First claim

What is claimed is:

1. A monitoring device for at least one ignition circuit for a personal protection device for a vehicle, the at least one ignition circuit designed to activate the personal protection device when at least one of: i) an ignition voltage is present that exceeds a voltage threshold value, and ii) an ignition current is present that exceeds a current threshold value, the monitoring device comprising:
a control device; and
a voltage source connected via a voltage source terminal of the control device, the control device being connected via a high-side ignition circuit terminal to a first supply terminal of the ignition circuit and via a low-side ignition circuit terminal to a second supply terminal of the ignition circuit;
wherein the monitoring device designed such that a no-load voltage of a high-side current source of the control device situated between the voltage source terminal and the high-side ignition circuit terminal corresponds at least to the voltage threshold value, the no-load voltage corresponding at least to a maximum ignition voltage of the ignition circuit.

2. The monitoring device as recited in claim 1 , wherein the no-load voltage of the high-side current source is at least 26 V.

3. The monitoring device as recited in claim 1 , wherein the no-load voltage of the high-side current source is at least 30 V.

4. The monitoring device as recited in claim 1 , wherein the no-load voltage of the high-side current source is at least 42 V.

5. The monitoring device as recited in claim 1 , further comprising:
a current source control device designed to control a temporal course of a current rise of the high-side current source in the transition from a first current level to a second current level corresponding to a predefined transition shape, the current source control device being designed to control the temporal course of the current rise corresponding to a transition shape with a raised cosine curve.

6. The monitoring device as recited in claim 1 , further comprising:
a filter device for filtering at least a measurement voltage, the filter device in including at least one low-pass filter.

7. The monitoring device as recited in claim 1 , further comprising:
an analog-digital converter connected via an ADC multiplexer to an instrument amplifier for measuring a voltage via a low-pass filter between the high-side ignition circuit terminal and the low-side ignition circuit terminal for the at least one ignition circuit and between an ignition circuit amplifier terminal and an analog ground terminal, or between an offset terminal and the analog ground terminal.

8. The monitoring device as recited in claim 1 , further comprising:
at least one of; i) a current limiting resistor between the voltage source and the voltage source terminal, and ii) a current limiting resistor between the ground terminal and a voltage sink terminal.

9. The monitoring device as recited in claim 1 , further comprising:
at least one of: i) a switchable high-side terminating resistor, and ii) a switchable low-side terminating resistor.

10. The monitoring device as recited in claim 1 , further comprising: at least one of: i) a switchable high-side terminating resistor situated between an output of a high-side multiplexer connected to the high-side current source and a voltage sink terminal, and ii) a switchable low-side terminating resistor situated between an output of a low-side multiplexer connected to the low-side ignition circuit terminal and the voltage sink terminal.

11. The monitoring device as recited in claim 1 , further comprising:
at least one of: i) a switchable high-side voltage divider, and ii) a switchable low-side voltage divider.

12. The monitoring device as recited in claim 1 , further comprising:
at least one of: i) a switchable high-side voltage divider situated between an output of a high-side multiplexer connected to the high-side current source and an ADC-multiplexer connected to an analog-digital converter, and ii) a switchable low-side voltage divider situated between an output of a low-side multiplexer connected to the low-side ignition circuit terminal and the ADC multiplexer.

13. The monitoring device as recited in claim 1 , further comprising:
a polarity reversal protection diode between and an output capacitor of the voltage source in series to the current limiting resistor.

14. A method for operating a monitoring device for at least one ignition circuit for a personal protection device for a vehicle, the at least one ignition circuit designed to activate the personal protection device when at least one of: i) an ignition voltage is present that exceeds a voltage threshold value, and ii) an ignition current is present that exceeds a current threshold value, the monitoring device including a control device, and a voltage source connected via a voltage source terminal of the control device, the control device being connected via a high-side ignition circuit terminal to a first supply terminal of the ignition circuit and via a low-side ignition circuit terminal to a second supply terminal of the ignition circuit, wherein the monitoring device designed such that a no-load voltage of a high-side current source of the control device situated between the voltage source terminal and the high-side ignition circuit terminal corresponds at least to the voltage threshold value, the no-load voltage corresponding at least to a maximum ignition voltage of the ignition circuit, the method comprising:
connecting the high-side ignition circuit terminal to the high-side current source, a and connecting the low-side ignition circuit terminal to a voltage sink terminal;
activating the high-side current source;
determining a difference voltage signal between the high-side ignition circuit terminal and the low-side ignition circuit terminal; and
ascertaining an ignition circuit resistance using the difference voltage signal.

15. A control device for operating a monitoring device for at least one ignition circuit for a personal protection device for a vehicle, the at least one ignition circuit designed to activate the personal protection device when at least one of: i) an ignition voltage is present that exceeds a voltage threshold value, and ii) an ignition current is present that exceeds a current threshold value, the monitoring device including a control device, and a voltage source connected via a voltage source terminal of the control device, the control device being connected via a high-side ignition circuit terminal to a first supply terminal of the ignition circuit and via a low-side ignition circuit terminal to a second supply terminal of the ignition circuit, wherein the monitoring device designed such that a no-load voltage of a high-side current source of the control device situated between the voltage source terminal and the high-side ignition circuit terminal corresponds at least to the voltage threshold value, the no-load voltage corresponding at least to a maximum ignition voltage of the ignition circuit, the control device configured to:
connect the high-side ignition circuit terminal to the high-side current source, a and connect the low-side ignition circuit terminal to a voltage sink terminal;
activate the high-side current source;
determine a difference voltage signal between the high-side ignition circuit terminal and the low-side ignition circuit terminal; and
ascertain an ignition circuit resistance using the difference voltage signal.

16. A non-transitory computer readable storage medium on which is stored a computer program for operating a monitoring device

Assignees

• Bosch Gmbh Robert

Inventors

• Schumacher Hartmut
• Karner Ruediger

Classifications

• B60R21/0173 Primary

  Diagnostic or recording means therefor · CPC title

• B60R2021/01184

  Fault detection or diagnostic circuits · CPC title

• B60R21/01 Primary

  Electrical circuits for triggering {passive} safety arrangements, {e.g. airbags, safety belt tighteners,} in case of vehicle accidents or impending vehicle accidents {(electrical circuits for transmission of signals between steering wheel and the vehicle itself B60R16/027; for electrically actuating belt retractor locking means B60R22/343)} · CPC title

• B60R21/017 Primary

  including arrangements for providing electric power to safety arrangements {or their actuating means, e.g. to pyrotechnic fuses or electro-mechanic valves} · CPC title

• B60R2021/01286

  Electronic control units · CPC title