High speed tracking dual direction current sense system

Patent metadata

Field	Value
Publication number	US-9664713-B2
Application number	US-201414528772-A
Country	US
Kind code	B2
Filing date	Oct 30, 2014
Priority date	Oct 30, 2014
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A tracking current sense system is described that includes a first current tracking system, a second current tracking system, and a pre-biasing device. The first current tracking system is configured to replicate a first current flowing through a first switch and the second current tracking system is configured to replicate a second current flowing through a second switch. The pre-biasing device is configured to pre-bias the second current tracking system based on first information detected at the first current tracking system that is indicative of the first current and also, pre-bias the first current tracking system based on second information detected at the second current tracking system that is indicative of the second current.

First claim

What is claimed is:

1. A tracking current sense system comprising:
a first current tracking system configured to replicate a first current flowing through a first switch;
a second current tracking system configured to replicate a second current flowing through a second switch; and
a pre-biasing device including an auxiliary comparator, a first current mirror, and a second current mirror, wherein the pre-biasing device is configured to:
drive, using the auxiliary comparator, the second current mirror to pre-bias the second current tracking system based on first information detected at the first current tracking system that is indicative of the first current; and
drive, using the auxiliary comparator, the first current mirror to pre-bias the first current tracking system based on second information detected at the second current tracking system that is indicative of the second current.

2. The tracking current sense system of claim 1 , wherein the second information is indicative of at least one of a respective level of the second current and a respective polarity of the second current and the first information is indicative of at least one of a respective level of the first current and a respective polarity of the first current.

3. The tracking current sense system of claim 1 , wherein the pre-biasing device is further configured to:
receive the first information from the first current tracking system while the first current tracking system is replicating the first current; and
receive the second information from the second current tracking system while the second current tracking system is replicating the second current.

4. The tracking current sense system of claim 1 , wherein the pre-biasing device is further configured to:
pre-bias the second current tracking system at a first current level that corresponds to a respective level of the first current; and
pre-bias the first current tracking system at a second current level that corresponds to a respective level of the second current.

5. The tracking current sense system of claim 1 , wherein the first switch is a high side switch of a half bridge and the second switch is a low side switch of the half-bridge.

6. A method comprising:
receiving, at a pre-biasing device, information detected by a first tracking current sense system that is indicative of a first current flowing through a first switch; and
pre-biasing, by the pre-biasing device, based on the information, a second tracking current sense system configured to replicate a second current flowing through a second switch by at least driving, by an auxiliary comparator of the pre-biasing device, a current mirror of the pre-biasing device to pre-bias the second current tracking system based on the first information.

7. The method of claim 6 , wherein the information is indicative of at least one of a respective level of the first current and a respective polarity of the first current.

8. The method of claim 6 , wherein the information is first information, the method further comprising:
receiving, at the pre-biasing device, second information detected by the second tracking current sense system that is indicative of the second current flowing through the second switch; and
pre-biasing, by the pre-biasing device, based on the second information, the first tracking current sense system.

9. The method of claim 6 , wherein pre-biasing the second tracking current sense system comprises pre-biasing the second tracking current sense system at a current level that corresponds to a level of the first current.

10. The method of claim 6 , wherein pre-biasing the second tracking current sense system comprises pre-biasing the second tracking current sense system in response to the first current flowing in either direction.

11. A tracking current sense system comprising:
means for replicating a first current flowing through a first switch;
means for replicating a second current flowing through a second switch; and
means for pre-biasing a second current tracking system based on first information received from a first current tracking system that is indicative of the first current, wherein the means for pre-biasing the second current tracking system includes means for driving a second current mirror to pre-bias the second current tracking system based on first information detected at the first current tracking system that is indicative of the first current; and
means for pre-biasing the first current tracking system based on second information received from the second current tracking system that is indicative of the second current, wherein the means for pre-biasing the first current tracking system includes means for driving a second current mirror to pre-bias the first current tracking system based on second information detected at the second current tracking system that is indicative of the second current,
wherein the means for driving the second current mirror and the means for driving the first current mirror comprise means for comparing two voltages.

12. The tracking current sense system of claim 1 , wherein:
the first current mirror is coupled to the first switch; and
the second current mirror is coupled to the second switch.

13. The tracking current sense system of claim 12 , wherein:
the auxiliary comparator is configured to drive the first current mirror by at least driving the first current mirror while the second switch is active; and
the auxiliary comparator is configured to drive the second current mirror by at least driving the second current mirror while the first switch is active.

14. The tracking current sense system of claim 12 , wherein the pre-biasing device further comprises:
a first comparator configured to drive the first current mirror while the first switch is active; and
a second comparator configured to drive the second current mirror while the second switch is active.

15. The tracking current sense system of claim 1 , wherein:
the pre-biasing device further comprises a third current mirror for positive currents and a fourth current mirror for negative currents, wherein:
the third current mirror for positive currents or the fourth current mirror for negative currents is an active current mirror configured to pre-bias, via the first current mirror, the first current tracking system or pre-bias, via the second current mirror, the second current tracking system, and
the third current mirror for positive currents or the fourth current mirror for negative currents that is not the active current mirror is an inactive current mirror; and

the auxiliary comparator comprises a zero-current crossing comparator configured to:
detect a zero crossing of a current at a node between the third current mirror for positive currents and the fourth current mirror for negative currents,
switch, in response to detecting the zero crossing of the current, the active current mirror to be inactive, and
switch, in response to detecting the zero crossing of the current, the inactive current mirror to be active.

16. The method of claim 6 , wherein:
the current mirror is a second current mirror and is coupled to the second switch;
the pre-biasing device further comprises a first current mirror coupled to the first switch; and
the method further comprises controlling, by the auxiliary comparator, the first current mirror.

17. The method of claim 16 , wherein:
controlling the first current mirror comprises driving, by the auxiliary comparator, the first current mirror while the second switch is active; and
driving the second current mirror c

Assignees

• Infineon Technologies Austria Ag

Inventors

• Sambucco Adriano
• Norling Karl

Classifications

• G01R19/0092 Primary

  Measuring current only · CPC title

• H02M1/0009

  Devices or circuits for detecting current in a converter · CPC title