Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
  • H02H9/005—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection avoiding undesired transient conditions

Definitions

• the invention relates to a device for interference suppression of current interfaces, in particular between the sensor and control unit or control unit and trigger circuit of a motor vehicle airbag system, according to the features of claim 1.
• AC signals or pulses useful signals
• DC components DC components
• a noise limiter circuit is known from DE-AS 1 416 389, in which a parallel connection of two diodes with opposite polarity is provided on the input side of a receiver, with which a capacitor is connected in series.
• DE 29 15 105 AI discloses an interference limiter circuit in a radio receiver, which in series connection has a differential, one consisting of two diodes polarized in opposite directions. 2 henden amplitude limiter and an integrator (low pass).
• the transmitter interface is suppressed by a nonlinear, first limiter circuit
• the receiver interface is likewise suppressed by a nonlinear, second limiter circuit and a linear low-pass filter.
• FIG. 1 interfaces for useful signals with higher voltage levels.
• Figure 1 shows a dash-dotted framed signal transmitter 1 for small useful signal voltage levels ( ⁇ 0.5V) with or without a DC voltage component, for example an acceleration sensor of an airbag control for a motor vehicle, and a dash-dotted signal receiver 2, for example an acceleration sensor assigned central airbag control unit.
• Transmitter 1 and receiver 2 are connected to one another by means of lines a and b. Transmitter output signals are transmitted to the receiver in the direction of the arrow. The longer the lines a and b between transmitter and 3 are receivers, the more likely that impulsive interference signals can penetrate through them into the transmitter and receiver and impair their function or even destroy circuit parts.
• the current interface at the input of the receiver 2 consists of a non-linear, second limiter circuit which has a series connection of two diodes 3 'and 4' which conduct current in parallel to one another but in opposite directions and a capacitor 5 ', followed by a linear filter 6, for example an RC or LC low pass.
• a similar, non-linear, first limiter circuit comprising a series connection of two diodes 3 and 4 which conduct current in parallel but in opposite directions and a capacitor 5 is arranged to keep interference signals away from the transmitter.
• the interference signals are limited to the forward voltage of the diodes 3, 4, 3 ', 4' without influencing the useful signal.
• the capacitance of the capacitors 5, 5 ' is to be dimensioned as a function of the amplitude of possible interference signals.
• downstream linear low-pass filter 6 for example an RC or LC element
• useful and limited interference signals are filtered and the useful / interference signal distance is thus improved.
• FIG. 2 shows a circuit essentially corresponding to FIG. 1, but for useful signal voltage levels which are greater than ⁇ 0.5 V, with or without a DC voltage component.
• diodes 3, 4, 3 'and 4' each have a Zener 4 diode 7, 8, 7 'and 8' connected in series, which limits the signal voltage in the flow direction of the respective diode to the sum of the diode voltage and Zener voltage, the Zener voltage being dimensioned slightly larger than the largest useful voltage amplitude.

Landscapes

• Tone Control, Compression And Expansion, Limiting Amplitude (AREA)
• Emergency Protection Circuit Devices (AREA)
• Noise Elimination (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=7856752

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Family Cites Families (5)

• 1998
  • 1998-02-05 DE DE19804589A patent/DE19804589C1/de not_active Expired - Fee Related
• 1999
  • 1999-02-01 KR KR1020007008548A patent/KR20010040673A/ko not_active Application Discontinuation
  • 1999-02-01 WO PCT/DE1999/000266 patent/WO1999040666A1/de not_active Application Discontinuation
  • 1999-02-01 JP JP2000530972A patent/JP2002503076A/ja not_active Withdrawn
  • 1999-02-01 EP EP99942570A patent/EP1099287A1/de not_active Withdrawn

Non-Patent Citations (1)

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