CIRCUIT AND METHOD FOR OPERATING A HALF-BRIDGE

• US 20150188532A1
• Filed: 12/30/2013
• Published: 07/02/2015
• Est. Priority Date: 12/30/2013
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Lenz, Michael
• Granted Patent: US 9,379,695 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H03K 17/04123 in field-effect transistor switches
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 17/165 by feedback from the output circuit to the control circuit
• CPC Class Codes: H03K 5/023 using field effect transistors

Abstract

A circuit for operating a half-bridge is provided. The circuit may include a first multiplier circuit. The first multiplier circuit may be configured to multiply a first signal by a first factor to provide a turn-on signal. The turn-on signal may be configured to turn a first switch of the half-bridge on. The first multiplier circuit may be further configured to multiply the first signal by a second factor to provide a turn-off signal. The turn-off signal may be configured to turn a second switch of the half-bridge off. The first factor and the second factor may be chosen so that the second switch is turned off before the first switch is turned on.

Claims

1. A circuit for operating a half-bridge, comprising:

a first multiplier circuit configured;

to multiply a first signal by a first factor to provide a turn-on signal configured to turn on a first switch of the half-bridge; and

to multiply the first signal by a second factor to provide a turn-off signal configured to turn off a second switch of the half-bridge;

wherein the first factor and the second factor are chosen so that the second switch is turned off before the first switch is turned on.

2. The circuit of claim 1, wherein

the first multiplier circuit comprises:

a first current controlled current source comprising a control branch and a controlled branch, wherein

a first end of the control branch is configured to receive the first signal;

a second end of the control branch is coupled to a second end of the controlled branch and to the first switch; and

a first end of the controlled branch is coupled to the second switch.

3. The circuit of claim 2, wherein

the first current controlled current source is floating.

4. The circuit of claim 2, wherein

the first multiplier circuit further comprises:

a second current controlled current source comprising a control branch and a controlled branch, wherein

a first end of the control branch is coupled to a first end of the controlled branch of the first current controlled current source;

a second end of the control branch is coupled to a second end of the controlled branch; and

a first end of the controlled branch is coupled to the second switch.

5. The circuit of claim 1, comprising

a first generating unit configured to provide the first signal, wherein the first generating unit comprises a fifth current controlled current source controlled by a control current.

6. The circuit of claim 1, further comprising:

a second multiplier circuit configured;

to multiply a second signal by a third factor to provide a turn-on signal configured to turn-on the second switch; and

to multiply the second signal by a fourth factor to provide a turn-off signal configured to turn-off the first switch;

wherein the third factor and the fourth factor are chosen so that the first switch is turned off before the second switch is turned on.

7. The circuit of claim 5, further comprising

a second generating unit configured to provide the second signal, wherein the second generating unit comprises a sixth current controlled current source controlled by the same control current that the fifth current controlled current source is controlled by.

8. The circuit of claim 7, further comprising:

a control circuit configured to activate only one of the first generating unit and the second generating unit at a time.

9. An integrated circuit, comprising:

a half-bridge circuit, wherein the half-bridge circuit comprises a first switch and a second switch coupled in series to each other, wherein the first switch and the second switch have majority carriers of opposite polarity;

a half-bridge driver circuit, wherein the half-bridge driver circuit is configured;

to multiply a first current by a first factor to provide a first turn-on current, wherein the first turn-on current is configured to turn-on the first switch;

to multiply the first current by a second factor to provide a first turn-off current, wherein the first turn-off current is configured to turn-off the second switch;

to multiply a second current by a third factor to provide a second turn-on current, wherein the second turn-on current is configured to turn-on the second switch; and

to multiply the second current by a fourth factor to provide a second turn-off current, wherein the second turn-off signal is configured to turn-off the first switch;

wherein

the first current and the second current are provided alternately;

the first factor and the second factor are chosen so that the second switch is turned off before the first switch is turned on; and

the third factor and the fourth factor are chosen so that the first switch is turned off before the second switch is turned on.

10. A method for operating a half-bridge, comprising:

providing a first signal;

scaling the first signal to provide a first turn-on signal, wherein the first turn-on signal is configured to turn on a first switch of the half-bridge;

applying the first turn-on signal to the first switch;

scaling the first signal to provide a first turn-off signal, wherein the first turn-off signal is configured to turn off a second switch of the half-bridge; and

applying the first turn-off signal to the second switch;

wherein the first turn-on signal and the first turn-off signal are scaled so that the first turn-off signal turns the second switch off before the first turn-on signal turns the first switch on.

11. The method of claim 10, wherein

the first turn-on signal and the first turn-off signal are applied at the same time to the first switch and the second switch, respectively.

12. The method of claim 10, wherein

the first signal is scaled to provide the first turn-on signal by means of a first current mirror, wherein the first current mirror is floating.

13. The method of claim 12, wherein

the first turn-on signal is the sum of a current in a control branch of the first current mirror and a current in a controlled branch of the first current mirror.

14. The method of claim 12, wherein

the first signal is scaled to provide the first turn-off signal by means of the first current mirror and a third current mirror.

15. The method of claim 14, wherein

the first turn-off signal is a current in a controlled branch of the third current mirror, wherein a control branch of the third current mirror is coupled to a controlled branch of the first current mirror.

16. The method of claim 10, further comprising:

providing a second signal;

scaling the second signal to provide a second turn-on signal, wherein the second turn-on signal is configured to turn on the second switch of the half-bridge;

applying the second turn-on signal to the second switch;

scaling the second signal to provide a second turn-off signal, wherein the second turn-off signal is configured to turn off the first switch;

applying the second turn-off signal to the first switch of the half-bridge;

wherein the second turn-on signal and the second turn-off signal are scaled so that the second turn-off signal turns the first switch off before the second turn-on signal turns the second switch on; and

wherein the first signal and the second signal are provided alternately.

17. The method of claim 16, further comprising:

deriving the first signal and the second signal from a same control current.

18. The method of claim 17, wherein

the same control current is mirrored to provide the first signal and the second signal.

19. The method of claim 17, further comprising:

setting a switching speed of the first switch and a switching speed of the second switch via the same control current.

20. The method of claim 10, further comprising:

minimizing a time period during which both the first switch and the second switch are non-conducting by adjusting at least one of;

the magnitude of the same control current;

the scaling of the first signal; and

the scaling of the second signal.