Circuit for voltage stabilization in an onboard power supply

• US 9,240,704 B2
• Filed: 12/22/2008
• Issued: 01/19/2016
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: LISA Draxlmaier GmbH
• Original Assignee: LISA Draxlmaier GmbH
• Inventors: Wortberg, Michael, Uhl, Gunter, Grohmann, Dieter
• Primary Examiner(s): Amrany, Adi
• Application Number:
  US12/809,731
• Publication Number:
  US 20110012424A1
• Time in Patent Office: 2,584 Days
• Field of Search: 307/9.1, 307/10.1
• US Class Current: 1/1
• CPC Class Codes: B60R 16/03 for supply of electrical power to vehicle subsystems or for circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: H02J 1/08 Three-wire systems; Systems having more than three wires
• CPC Class Codes: H02J 2310/46 for ICE-powered road vehicles
• CPC Class Codes: H02J 7/1423 with multiple batteries

Abstract

A circuit (20, 50) for voltage stabilization in an onboard power supply (10), particularly for motor vehicles, which is electrically connected between the onboard power supply (10) to be stabilized and a first energy store (E1) is disclosed. The circuit (20, 50) includes a diode element (24) which contains a plurality of semiconductor switches (34) connected in parallel. The circuit (20, 50) also includes a pilot and control circuit (33). The control circuit (33) determines the level of a current flowing through the diode element (24) and controls the semiconductor switches (34) of the diode element (24) on the basis of the determined current level. The circuit (20, 50) includes a second energy store (E2) which is electrically connected to the diode element (24) and to the onboard power supply (10).

Claims

1. A circuit for voltage stabilization of an on-board motor vehicle electrical system, the circuit comprising:

a diode element comprising a plurality of first semi-conductor switches connected in parallel, wherein the diode element is configured and arranged to allow current flow only in a direction from an energy storage towards the on-board motor vehicle electrical system;

a pilot and control circuit configured to determine an intensity of a current flowing through the diode element and to control said plurality of first semi-conductor switches of the diode element based on the determined current intensity in such manner that said plurality of first semi-conductor switches allow a current flow from the energy storage to the on-board motor vehicle electrical system, but block a current flow from the on-board motor vehicle electrical system to the energy storage;

a battery electrically connected to the diode element and connectable to the on-board motor vehicle electrical system; and

a switching unit connecting the battery to the on-board motor vehicle electrical system, the switching unit including;

two inversely arranged second semi-conductor switches connected in series; and

a micro-controller for controlling the second semi-conductor switches, the micro-controller being configured to;

determine a voltage and a temporal voltage drop across the second semi-conductor switches, and

turn on the second semi-conductor switches such that the battery supplies power to the on-board electrical system if;

the voltage across the second semi-conductor switches is smaller than a normal operating voltage of the on-board electrical system, and

the temporal voltage drop across the second semi-conductor switches exceeds a predetermined rate,

wherein the circuit is electrically connected between the on-board motor vehicle electrical system and the energy storage and wherein the circuit is electrically connected between the onboard motor vehicle electrical system and a starter, the circuit being adapted to stabilize the onboard motor vehicle electrical system.

2. The circuit according to claim 1, wherein the diode element comprises a diode connected in parallel to said plurality of first semi-conductor switches.

3. The circuit according to claim 2, wherein the diode is a Schottky diode.

4. The circuit according to claim 1, wherein the micro-controller is further configured to monitor the temperature of the first semi-conductor switches of the diode element.

5. The circuit according to claim 1, further comprising:

a device configured to test the charge condition of the battery.

6. The circuit according to claim 5, wherein the device is adapted to measure an impedance of the battery.

7. The circuit according to claim 1, wherein the first semi-conductor switches of the diode element are field effect transistors.

8. The circuit according to claim 1, wherein the circuit is electrically connectable between the motor vehicle on-board electrical system to be stabilized and one or a plurality of high-current consumer loads connectable to the energy storage.

9. The circuit according to claim 8, wherein one of the high-current consumer loads is one of a start-stop function, electronic power steering system, and an electro-hydraulic brake.

10. The circuit according to claim 1, in combination with a motor vehicle.

11. The circuit according to claim 1, wherein each of the two second semi-conductor switches comprises a field effect transistor.

12. The circuit according to claim 1, wherein the pilot and control circuit is configured to stabilize an operating voltage of the on-board motor vehicle electrical system by controlling the plurality of first-semiconductor switches.