Protected idle mode bypassing power stage

Patent metadata

Field	Value
Publication number	US-10992123-B2
Application number	US-201816007316-A
Country	US
Kind code	B2
Filing date	Jun 13, 2018
Priority date	Jun 13, 2018
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

Circuits, systems and methods are provided wherein a bypass circuit provides an auxiliary current path to supply current from a power supply line to an electrical load. The bypass circuit is used during a low-power mode, and consumes less quiescent power than a main current path that provides current from the power supply line to the electrical load during normal operation. The bypass circuit includes a current limiter and a comparator, and generates a high-current detection signal responsive to the comparator detecting that a current through the current limiter exceeds a maximum allowed or expected current.

First claim

What is claimed is:

1. A bypass circuit, comprising:
a current limiter configured to provide an auxiliary current path between a power supply line and an electrical load if a main current path between the electrical load and the power supply line is disabled during a low-power mode, the auxiliary current path being configured to support a lower current than the main current path; and
a comparator configured to compare a voltage drop across the current limiter to a reference voltage, and output a detection signal if the voltage drop exceeds the reference voltage.

2. The bypass circuit of claim 1 , further comprising:
an enable input coupled to the current limiter and configured to receive an enable signal for enabling the current limiter when the main current path is disabled.

3. The bypass circuit of claim 2 , wherein the enable input is further coupled to the comparator and the comparator is configured to be enabled by the enable signal.

4. The bypass circuit of claim 1 , wherein the current limiter is a current source configured to provide a substantially constant voltage across the current limiter for a current magnitude of the current source below a predetermined current value, and wherein the voltage drop across the current limiter increases when the current magnitude of the current source exceeds the predetermined current value.

5. The bypass circuit of claim 1 , further comprising:
a reference voltage source configured to provide the reference voltage, wherein the reference voltage has a predetermined voltage value.

6. The bypass circuit of claim 1 , further comprising:
a programmable voltage source configured to provide the reference voltage, wherein the reference voltage has a programmable voltage value corresponding to a maximum supported current of the auxiliary current path.

7. The bypass circuit of claim 1 , wherein the reference voltage has a value selected to indicate a short fault in the electrical load.

8. The bypass circuit of claim 1 , wherein the reference voltage has a value selected to indicate an external excitation condition for the electrical load.

9. The bypass circuit of claim 1 , wherein the current limiter comprises a transistor coupled in series with a resistor, and wherein the voltage drop across the resistor increases linearly as a current drawn by the electrical load increases.

10. The bypass circuit of claim 1 , wherein the main current path has an associated maximum main current, the reference voltage corresponds to a maximum bypass current in the current limiter, and the maximum main current exceeds the maximum bypass current by a factor of 10 or more.

11. An electronic system, comprising:
an electrical load;
a main current path coupled between the electrical load and a power supply line, the main current path configured to provide current to the electrical load and to be disabled during a low-power mode; and
a bypass circuit comprising:
a current limiter configured to provide an auxiliary current path between the power supply line and the electrical load if the main current path is disabled during the low-power mode, the auxiliary current path being configured to support a lower current than the main current path; and
a comparator configured to compare a voltage drop across the current limiter to a reference voltage, and output a detection signal if the voltage drop exceeds the reference voltage.

12. The electronic system of claim 11 , wherein the bypass circuit further comprises:
an enable input coupled to the current limiter and configured to receive an enable signal for enabling the current limiter when the main current path is disabled.

13. The electronic system of claim 11 , further comprising a controller configured to:
receive the detection signal;
send a query signal to the electrical load;

receive, in response to the sent query signal, status information regarding expected current consumption of the electrical load;
determine that the expected current consumption is consistent with the received detection signal; and
responsive to said determination, enable the main current path.

14. The electronic system of claim 13 , wherein the controller is further configured to disable the bypass circuit responsive to determining that the expected current consumption is not consistent with the received detection signal, thereby isolating the electrical load from the power supply line.

15. The electronic system of claim 11 , wherein the electrical load is a sub-system of an electric or hybrid-electric vehicle.

16. A method of powering an electrical load coupled to a power supply line through a main current path, the method comprising:
providing current from the power supply line to the electrical load through the main current path when the main current path is enabled and the electrical load demands power;
providing an auxiliary current path between the power supply line and the electrical load via a current limiter, the auxiliary current path being configured to support a lower current than the main current path;
comparing a voltage drop across the current limiter to a reference voltage; and
generating a detection signal if the voltage drop exceeds the reference voltage.

17. The method of claim 16 , further comprising enabling the current limiter when the main current path is disabled.

18. The method of claim 16 , further comprising, responsive to the detection signal, disabling the current limiter to isolate the electrical load from the power supply line.

19. The method of claim 16 , further comprising, responsive to the detection signal, re-enabling the main current path.

20. The method of claim 16 , further comprising sending the detection signal to a controller of an electronic system for further processing.

Assignees

• Infineon Technologies Ag

Inventors

• Mourrier Andre
• Thevenet Kevin

Classifications

• H02H3/08 Primary

  responsive to excess current (responsive to abnormal temperature caused by excess current H02H5/04) · CPC title

• H02H9/02

  responsive to excess current {(current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025)} · CPC title

• H02H3/025 Primary

  Disconnection after limiting, e.g. when limiting is not sufficient or for facilitating disconnection · CPC title

• Y02B70/30

  Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level · CPC title

• Y04S20/20

  End-user application control systems · CPC title