Method and system for producing a supply voltage during a first and second operating mode

• US 6,762,945 B2
• Filed: 10/04/2002
• Issued: 07/13/2004
• Est. Priority Date: 10/05/2001
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Morgen, Johann Egon
• Primary Examiner(s): Vu, Bao Q.
• Application Number:
  US10/265,032
• Publication Number:
  US 20030067287A1
• Time in Patent Office: 648 Days
• Field of Search: 363/15, 363/16, 363/17, 363/97, 363/98
• US Class Current: 363/17
• 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: G05F 1/465 Internal voltage generators for integrated circuits, e.g. step down generators
• CPC Class Codes: H02J 1/08 Three-wire systems; Systems having more than three wires
• CPC Class Codes: H02J 1/082 Plural DC voltage, e.g. DC supply voltage with at least two different DC voltage levels
• CPC Class Codes: H02J 2310/46 for ICE-powered road vehicles
• CPC Class Codes: H02M 1/0045 Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826

Abstract

The invention relates to a method for producing a supply voltage, in particular for digital circuits, in a motor vehicle from a relatively high input voltage of more than 12 volts, in particular from a vehicle power supply system voltage of 42 volts, in which an intermediate voltage at a level between the vehicle power supply system voltage and the supply voltage is produced from the vehicle power supply system voltage in a normal mode by means of a DC/DC converter (5), and the supply voltage is produced from the intermediate voltage by means of at least one linear regulator (9, 9′, 9″), in which the DC/DC converter (5) is switched off and is bridged by means of a bypass circuit (11) in a parking mode, so that the supply voltage is produced directly by the at least one linear regulator (9, 9′, 9″), and to a voltage supply circuit for this purpose.

Claims

1. A method for producing a supply voltage, in particular for digital circuits, in a motor vehicle from a relatively high input voltage of more than 12 volts, in particular from a vehicle power supply system voltage of 42 volts,

a) in which an intermediate voltage at a level between the vehicle power supply system voltage and the supply voltage is produced from the vehicle power supply system voltage in a normal mode by means of a DC/DC converter, and

b) the supply voltage is produced from the intermediate voltage by means of at least one linear regulator, wherein

c) the DC/DC converter is switched off and is bridged by means of a bypass circuit in a parking mode, so that the supply voltage is produced directly by the at least one linear regulator.

2. The method as claimed in claim 1, wherein a control device is used for switching between the normal mode and the parking mode, as a function of the load current flowing on the supply voltage side.

3. The method as claimed in one of claims 1, wherein different supply voltages are produced by using a number of linear regulators.

4. A voltage supply circuit having at least one linear regulator and having a DC/DC converter which is connected upstream of the at least one linear regulator, in order to produce a relatively low supply voltage, in particular for digital circuits, via an intermediate voltage from a voltage of more than 12 volts, in particular from a vehicle power supply system voltage of 42 volts, characterized in that the voltage supply circuit has a bypass circuit in order to bridge the converter in a parking mode.

5. The voltage supply circuit as claimed in claim 4, wherein the DC/DC converter is designed to be controllable, in order to be switched on when the bypass circuit is switched off, and to be switched off when the bypass circuit is switched on.

6. The voltage supply circuit as claimed in claim 5, wherein the voltage supply circuit has a control device in order to control the bypass circuit and, preferably, also the DC/DC converter as a function of the load current flowing on the supply voltage side.

7. The voltage supply circuit as claimed in claim 6, wherein the control device is in the form of a current threshold value switch.

8. The voltage supply circuit as claimed in claim 6, wherein the control device is in the form of a microcontroller.

9. The voltage supply circuit as claimed in claim 6, wherein the control device is in the form of a wake-up ASIC.

10. The voltage supply circuit as claimed in claim 4, wherein the at least one linear regulator has a reset output, which emits a reset signal when a voltage threshold value is undershot.

11. A method for producing a supply voltage during a first and second operation mode from a relatively high input voltage comprising the steps of:

a) during the first operation mode;

generating an intermediate voltage at a level between the high input voltage and the supply voltage from the high input voltage in a normal mode by means of a first converter, and

generating the supply voltage from the intermediate voltage by means of at least a second converter,

b) during the second operation mode;

switching off the first converter and bridging the first converter by means of a bypass circuit, so that the supply voltage is produced directly by the at least one second converter.

12. The method as claimed in claim 11, wherein the first converter is a DC/DC converter and the second converter is a linear regulator.

13. The method as claimed in claim 11, wherein the method is used within a vehicle and the first operation mode is a normal mode and the second operation mode is a parking mode.

14. The method as claimed in claim 11, wherein a control device is used for switching between the first operation mode and the second operation mode, as a function of the load current flowing on the supply voltage side.

15. The method as claimed in claim 11, wherein the high input voltage is approximately 42 volts and the intermediate voltage is approximately 12 volts.

16. The method as claimed in one of claims 11, wherein different supply voltages are produced by using a plurality of second converters.

17. A voltage supply circuit having two operation modes comprising:

a first converter receiving a high supply voltage generating an intermediate voltage;

a second converter receiving said intermediate voltage for generating a supply voltage;

a control circuit for either turning on said first converter or for turning off said converter and feeding said high supply voltage directly to said second converter.

18. Circuit as in claim 17, wherein the control circuit comprises a bypass circuit for bridging said first converter.

19. Circuit as in claim 17, wherein the control circuit further comprises a current sensor for sensing the output current of said first converter to switch from said first to said second operation mode.

20. Circuit as in claim 18, wherein the first converter is a DC/DC converter and the second converter is a linear regulator.

21. Circuit as claimed in claim 20, wherein the DC/DC converter is designed to be controllable, in order to be switched on when the bypass circuit is switched off, and to be switched off when the bypass circuit is switched on.

22. Circuit as claimed in claim 21, wherein the voltage supply circuit has a control device in order to control the bypass circuit and, preferably, also the DC/DC converter as a function of the load current flowing on the supply voltage side.

23. Circuit as claimed in claim 22, wherein the control device is in the form of a current threshold value switch.

24. Circuit as claimed in claim 22, wherein the control device is in the form of a microcontroller.

25. Circuit as claimed in claim 22, wherein the control device is in the form of a wake-up ASIC.

26. Circuit as claimed in claim 20, wherein the at least one linear regulator has a reset output, which emits a reset signal when a voltage threshold value is undershot.