Circuit arrangement for momentarily maintaining an internal operating direct current voltage in the event of an interruption in the vehicle electrical system power supply voltage

• US 7,342,326 B2
• Filed: 11/13/2002
• Issued: 03/11/2008
• Est. Priority Date: 01/18/2002
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schou, Frank
• Primary Examiner(s): Sherry; Michael
• Assistant Examiner(s): KAPLAN, HAL IRA
• Application Number:
  US10/502,211
• Publication Number:
  US 20050111152A1
• Time in Patent Office: 1,945 Days
• Field of Search: 307/56, 307/58, 307/82, 307/23
• US Class Current: 307/23
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

A circuit arrangement, to which the vehicle electric system supply voltage is applied and which for briefly maintaining at least one internal normal d.c. voltage in the event of failure of the vehicle electric system supply voltage, includes a reserve energy accumulator, to which a charging voltage higher than the at least one internal normal d.c. voltage is applied in regular operation, and which, in the event of failure of the vehicle electric system supply voltage, delivers a reserve voltage with which operation of at least some electronic circuits may be maintained for a limited period of time, and it includes at least one step-down regulator which steps down the applied input direct voltage to the at least one internal normal d.c. voltage.

Claims

1. A circuit arrangement to which a motor vehicle electric system supply voltage from a high-voltage vehicle electric system is applied and for briefly maintaining at least one internal normal d.c. voltage for electronic circuits in the event of failure of the motor vehicle electric system supply voltage, comprising:

a reserve energy accumulator to which a charging voltage higher than the at least one internal normal d.c. voltage is applied by the high-voltage vehicle electric system during regular operation, and wherein the reserve energy accumulator, in the event of failure of the motor vehicle electric system supply voltage, delivers a reserve voltage with which operation of at least one of the electronic circuits can be maintained for a period of time; and

at least one step-down regulator that steps down an input direct voltage applied thereto to the at least one internal normal d.c. voltage, wherein the step-down regulator does not include an inductor, and wherein in regular operation the motor vehicle electric system supply voltage is applied directly by the high-voltage vehicle electric system via a diode as the charging voltage to the reserve energy accumulator and is also applied via a diode as an input direct voltage to the step-down regulator, and wherein the reserve voltage supplied by the reserve energy accumulator is applied directly as input direct voltage to the at least one step-down regulator in an emergency.

2. The circuit arrangement as recited in claim 1, further comprising:

an upstream step-down regulator to which is applied the reserve voltage, the upstream step-down regulator deriving from the reserve voltage the input direct voltage for the at least one step-down regulator.

3. The circuit arrangement as recited in claim 2, wherein:

the upstream step-down regulator includes a switching regulator, and

the at least one step-down regulator includes a linear regulator.

4. The circuit arrangement as recited in claim 1, wherein:

in order to maintain a plurality of internal normal d.c. voltages, the at least one step-down regulator includes a plurality of step-down regulators to which the motor vehicle electric system supply voltage is applied via a diode as an input direct voltage during regular operation, each step-down regulator stepping down the motor vehicle electric system supply voltage to one of the plurality of internal normal d.c. voltages for a group of electronic circuits.

5. The circuit arrangement as recited in claim 4, wherein the reserve voltage is applied directly as an input direct voltage to the plurality of step-down regulators in an emergency.

6. The circuit arrangement as recited in claim 4, further comprising:

an upstream step-down regulator, wherein the reserve voltage is applied to the upstream step-down regulator, the upstream step-down regulator deriving therefrom the input direct voltage for the plurality of step-down regulators.

7. The circuit arrangement as recited in claim 6, wherein:

the upstream step-down regulator includes a switching regulator, and

the plurality of step-down regulators are linear regulators.

8. The circuit arrangement as recited in claim 1, wherein the reserve energy accumulator includes a capacitor.