Power source circuit for an occupant protecting device of motor vehicles

• US 5,506,775 A
• Filed: 05/20/1993
• Issued: 04/09/1996
• Est. Priority Date: 05/20/1993
• Status: Expired due to Term

• Current Assignee: Kansei Company
• Original Assignee: Kansei Company
• Inventors: Saito, Yasuo, Kaneko, Kunihiro, Ohneda, Katsushi, Matsumori, Satoru, Tsurushima, Shin-ichiro, Kon, Kazuyasu
• Primary Examiner(s): Trans, Vincent N.
• Assistant Examiner(s): Walker, Tyrone V.
• Application Number:
  US08/063,752
• Time in Patent Office: 1,055 Days
• Field of Search: 364/424.05, 280/735, 307/10.1, 340/436, 340/438, 180/274, 180/65.1, 180/65.2, 180/65.3, 180/65.8, 363/37, 320/48
• US Class Current: 701/45
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• CPC Class Codes: B60R 21/0133 by integrating the amplitude of the input signal
• CPC Class Codes: B60R 21/017 including arrangements for providing electric power to safety arrangements or their actuating means, e.g. to pyrotechnic fuses or electro-mechanic valves
• CPC Class Codes: B60R 21/0173 Diagnostic or recording means therefor

Abstract

An occupant protecting device for a motor vehicle, which inflates an air-bag system reliably to protect occupants in the event of a collision with high reliability. The occupant protecting device includes an acceleration sensor for sensing an acceleration signal of a vehicle in the event of collision with another vehicle or the like, a signal processor for detecting a collision waveform from an acceleration signal output from the acceleration sensor, a comparator for determining whether or not the output signal of the signal processor exceeds a preset level to produce a trigger signal when it exceeds the preset level, a latch circuit for latching the trigger signal from the comparator, and a firing circuit for operating an occupant protecting unit in response to a drive signal from the latch circuit.

Claims

1. A power source circuit for an occupant protecting device of motor vehicles comprising:

a DC converter means for boosting a battery voltage subsequently delivered to charge an output capacitor, the charge accumulated in said output capacitor being supplied to a drive circuit for an occupant protecting device;

a diagnostic voltage source for converting the battery voltage into a predetermined voltage to be supplied to a signal processing circuit for determining a condition of said occupant protecting device;

a switch regulator means for delivering the charge accumulated in said output capacitor to said diagnostic voltage source immediately after the battery voltage is reduced less than a predetermined level, wherein said switch regulator means comprises a control means for monitoring said battery voltage and for determining when said battery voltage is reduced less than said predetermined level, and wherein said switch regulator means remains in a non-operative condition as long as the battery voltage is applied to said control means, but operates to deliver said charge accumulated in said output capacitor to diagnostic voltage source when said battery voltage is reduced less than said predetermined level; and

a reverse-current preventing diode electrically connected between said switch regulator means and said diagnostic voltage source to prevent current flow in a direction from said diagnostic voltage source toward said switch regulator means.

2. The power source circuit as defined in claim 1 further comprising a feedback circuit for feeding the output voltage of said voltage source back to the input of said DC power source.

3. The power source circuit as defined in claim 1 wherein said DC power source comprises a voltage multiplying rectifier circuit including a transistor bridge, capacitors and diodes, and wherein the pulse width of a signal for driving the occupant protecting device is varied according to the output voltage value of said output capacitor.

4. The power source circuit as defined in claim 1, wherein said switch regulator means converts said charge accumulated in said output capacitor into a DC power, which in turn is supplied to said diagnosis voltage source.

5. The power source circuit as defined in claim 1, further comprising a backup capacitor for supplying a backup voltage to an input of said diagnosis voltage source.

6. A power source circuit for an occupant protecting device of motor vehicles comprising:

A battery voltage means for supplying a battery voltage;

a DC converter means for receiving and boosting said battery voltage to charge an output capacitor, the charge accumulated in said output capacitor being supplied to a drive circuit for an occupant protecting device;

a diagnostic voltage source for receiving said battery voltage and for converting said battery voltage into a predetermined voltage to be supplied to a signal processing circuit for determining a condition of said occupant protecting device;

a switch regulator means for providing an electrical connection between said output capacitor and said diagnosis voltage source and comprising a control terminal means for monitoring said battery voltage, wherein said switch regulator means supplies at least a portion of the charge accumulated in said output capacitor to said diagnosis voltage source when said control terminal means determines that the battery voltage is below a predetermined level; and

a reverse-current preventing diode electrically connected between said switch regulator means and said diagnostic voltage source to prevent current flow in a direction from said diagnostic voltage source toward said switch regulator means.

7. A power source circuit for an occupant protecting device of motor vehicles comprising:

a DC converter means for boosting a battery voltage subsequently delivered to charge an output capacitor, the charge accumulated in said output capacitor being supplied to a drive circuit for an occupant protecting device;

a diagnostic voltage source for converting the battery voltage into a predetermined voltage to be supplied to a signal processing circuit for determining a condition of said occupant protecting device;

a back-up capacitor electrically connected to said diagnostic voltage source for supplying electrical energy to said diagnostic voltage source; and

a switch regulator means for delivering the charge accumulated in said output capacitor to said diagnostic voltage source immediately after the battery voltage is reduced less than a predetermined level, wherein said switch regulator means comprises a control means for monitoring said battery voltage and for determining when said battery voltage is reduced less than said predetermined level, and wherein said switch regulator means remains in a non-operative condition as long as the battery voltage is applied to said control means, but operates to deliver said charge accumulated in said output capacitor to diagnostic voltage source when said battery voltage is reduced less than said predetermined level.

8. The power source circuit according the claim 7, further comprising a reverse-current preventing diode electrically connected between said switch regulator means and said diagnostic voltage source to prevent current flow in a direction from said diagnostic voltage source toward said switch regulator means.