Switch Device and Method

• US 20180175855A1
• Filed: 12/13/2017
• Published: 06/21/2018
• Est. Priority Date: 12/16/2016
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Romano, Francesca, Mayer, Alexander, Petruzzi, Luca
• Granted Patent: US 10,454,469 B2
• Time in Patent Office: Days
• CPC Class Codes: H03K 17/08104 in field-effect transistor switches H03K17/0812, H03K17/0814 take precedence
• CPC Class Codes: H03K 17/08112 in bipolar transistor switches H03K17/0812, H03K17/0814 take precedence
• CPC Class Codes: H03K 17/166 Soft switching
• CPC Class Codes: H03K 17/18 Modifications for indicating state of switch
• CPC Class Codes: H03K 17/30 Modifications for providing a predetermined threshold before switching shaping pulses by thresholding H03K5/08
• CPC Class Codes: H03K 17/302 in field-effect transistor switches

Abstract

Devices and methods related to switches are discussed. An inverse current condition may be detected, and a voltage at a node associated with a switch driver may be driven to a predetermined voltage in case of detection of an inverse current condition.

Claims

1. A switch device, comprising:

a switch comprising a control terminal, a first load terminal and a second load terminal,

a switch driver coupled to the control terminal of the switch,

an inverse current detector configured to detect an inverse current condition at the first and second load terminals of the switch, and

a voltage driver configured to drive a node associated with the switch driver to a predetermined voltage in response to the inverse current detector detecting an inverse current condition.

2. The switch device of claim 1, wherein the switch driver is coupled between the node and the control terminal of the switch.

3. The switch device of claim 1, wherein the inverse current detector comprises a comparator.

4. The switch device of claim 3, wherein the first load terminal of the switch is configured to be coupled to a supply voltage terminal, wherein a first input terminal of the comparator is coupled to the second load terminal of the switch, and wherein a second input terminal of the comparator is coupled to the supply voltage terminal.

5. The switch device of claim 4, wherein the comparator has an offset.

6. The switch device of claim 4, further comprising a voltage offset element coupled between the second input terminal of the comparator and the supply voltage terminal.

7. The switch device of claim 1, wherein the voltage driver comprises a first switch configured to couple the node to the predetermined voltage in case the inverse current detector detects an inverse current condition.

8. The switch device of claim 7, wherein the voltage driver further comprises a second switch configured to decouple the node from the second load terminal of the switch in case the inverse current detector detects an inverse current condition.

9. The switch device of claim 8, further comprising a current source element coupled between a bulk terminal of the second switch and the node and a third switch coupled between the bulk terminal of the second switch and the second load terminal of the switch.

10. The switch device of claim 9, wherein at least one of the current source element and the third switch is configured to be controlled by the inverse current detector.

11. The switch device of claim 9, wherein the current source element comprises at least one of a depletion transistor, a current source and a resistor.

12. The switch device of claim 1, wherein the first load terminal of the switch is configured to be coupled to a supply voltage, and the second load terminal of the switch is configured to be coupled to a load.

13. The switch device of claim 12, wherein the predetermined voltage is the supply voltage.

14. The switch device of claim 1, wherein the switch driver comprises a semiconductor structure including a parasitic bipolar transistor, the voltage driver being configured to prevent the parasitic bipolar transistor from drawing the node to a potential preventing a closing of the switch during an inverse current condition.

15. A method, comprising:

detecting an inverse current condition at a switch, and

driving a node associated with a switch driver driving the switch to a predetermined voltage in response to the detection of an inverse current condition at the switch.

16. The method of claim 15, wherein driving the node comprises coupling the node to a supply voltage.

17. The method of claim 15, wherein driving the node further comprises decoupling the node from a second load terminal of the switch, the second load terminal being coupled to a load.

18. The method of claim 17, further comprising selectively coupling a bulk terminal of a switch for decoupling the node from the second load terminal of the switch to the node or to the second load terminal responsive to the detection of an inverse current condition.

19. The method of claim 17, wherein a first load terminal of the switch is coupled to a supply voltage, and wherein the predetermined voltage corresponds to the supply voltage.

20. The method of claim 19, wherein detecting the inverse current condition comprises comparing a voltage at the second load terminal of the switch to at least one of a supply voltage and a voltage at the first load terminal of the switch.

21. A switch control circuit, comprising:

a driver having an output terminal configured to be coupled to a control terminal of a switching transistor;

a first switch having a first terminal coupled to a reference terminal of the driver and a second terminal configured to be coupled to a first load terminal of the switching transistor;

a second switch coupled between a power supply terminal and the reference terminal of the driver; and

an inverse current detector having an output coupled to control terminals of the first switch and the second switch, and an input configured to be coupled to the switching transistor, wherein the inverse current detector is configured to detect an inverse current condition of the switching transistor, open the first switch and close the second switch when the inverse current condition is detected, and close the first switch and open the second switch when the inverse current condition is not detected.

22. The switch control circuit of claim 21, wherein the inverse current detector comprises a comparator having a first input configured to be coupled to the reference terminal of the driver and a second terminal configured to be coupled to a second load terminal of the switching transistor.

23. The switch control circuit of claim 22, further comprising a level shifter coupled between an output of the comparator and the control terminal of the first switch.