Electronic Circuit with an Electronic Switch and a Monitoring Circuit

• US 20140091643A1
• Filed: 09/29/2012
• Published: 04/03/2014
• Est. Priority Date: 09/29/2012
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Norling, Karl
• Granted Patent: US 9,112,501 B2
• Time in Patent Office: Days
• US Class Current: 307/130
• CPC Class Codes: H01H 11/00 Apparatus or processes specially adapted for the manufacture of electric switches processes specially adapted for manufacture of rectilinearly movable switches having a plurality of operating members associated with different sets of contacts, e.g. keyboards, H01H13/88
• CPC Class Codes: H02H 3/00 Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems H02H7/00; systems for change-over to standby supply H02J9/00 ; integrated protection for motors H02H7/0822
• CPC Class Codes: H03K 17/0822 in field-effect transistor switches
• CPC Class Codes: H03K 17/18 Modifications for indicating state of switch
• CPC Class Codes: H03K 2217/0027 Measuring means of, e.g. currents through or voltages across the switch
• CPC Class Codes: Y10T 29/49107 Fuse making

Abstract

An electronic circuit includes an electronic switch having a control terminal and a load path. A monitoring circuit includes a switched-capacitor circuit with a capacitive storage element. The switched-capacitor circuit is coupled to the load path of the electronic switch. The monitoring circuit is operable to evaluate a load voltage of the electronic switch and to generate a failure signal dependent on the evaluation. A drive circuit is operable to provide a drive signal at the control terminal of the electronic switch dependent on the failure signal.

Claims

1. An electronic circuit, comprising:

an electronic switch having a control terminal and a load path;

a monitoring circuit comprising a switched-capacitor circuit with at least one capacitive storage element, the switched-capacitor circuit coupled to the load path of the electronic switch, the monitoring circuit operable to evaluate a load voltage of the electronic switch and to generate a failure signal dependent on the evaluation; and

a drive circuit operable to provide a drive signal at the control terminal of the electronic switch dependent on the failure signal.

2. The electronic circuit of claim 1, wherein the monitoring circuit further comprises a measure and compare unit operable to receive a voltage across the at least one capacitive storage element, to evaluate the voltage, and to generate the failure signal dependent on the evaluation.

3. The electronic circuit of claim 2, wherein the monitoring circuit further comprises:

a first capacitive storage element;

a charging voltage source;

a first switch network operable to couple the first capacitive storage element to the charging voltage source;

a second capacitive storage element coupled to the load path of the electronic switch; and

a second switch network operable to couple the first capacitive storage element to the second capacitive storage element.

4. The electronic circuit of claim 3, wherein the monitoring circuit further comprises a plurality of first capacitive storage elements, each capacitive storage element having associated therewith a first switch network operable to couple the respective first capacitive storage element to the charging voltage source, and a second switch network operable to couple the respective first capacitive storage element to the second capacitive storage element.

5. The electronic circuit of claim 3, further comprising a rectifier element coupling the second capacitive storage element to the load path.

6. The electronic circuit of claim 3, wherein the measure and compare unit receives the voltage across the second capacitive storage element.

7. The electronic circuit of claim 3, further comprising:

a drive voltage source operable to provide a drive voltage provided to the drive circuit, the drive voltage source connected in series with the second capacitive storage element;

wherein the measure and compare unit receives a voltage across the series circuit with the second capacitive storage element and the drive voltage source.

8. The electronic circuit of claim 3, wherein the measure and compare unit is operable to generate a failure level of the failure signal when the voltage across the capacitive storage element reaches a reference voltage.

9. The electronic circuit of claim 2, wherein the monitoring circuit further comprises:

a first capacitive storage element;

a charging voltage source;

a first switch network operable to couple the first capacitive storage element to the charging voltage source; and

a second switch network operable to couple the first capacitive storage element to the load path of the electronic switch.

10. The electronic circuit of claim 9, wherein the monitoring circuit further comprises a second capacitive storage element coupled to the load path of the electronic switch.

11. The electronic circuit of claim 9, wherein the monitoring circuit further comprises:

a plurality of first capacitive storage elements, each capacitive storage element having associated therewith a first switch network operable to couple the respective first capacitive storage element to the charging voltage source, and a second switch network operable to couple the respective first capacitive storage element to the second capacitive storage element.

12. The electronic circuit of claim 9, further comprising a rectifier element coupling the second switch network to the load path.

13. The electronic circuit of claim 9, wherein the monitoring circuit is configured to evaluate a voltage across the first capacitive storage element.

14. The electronic circuit of claim 13, wherein the monitoring circuit is configured to evaluate the voltage across the first capacitive storage element only during predefined time instances.

15. The electronic circuit of claim 9, further comprising a third switch network operable to couple the first capacitive storage element to the measure and compare unit.

16. The electronic circuit of claim 1, wherein the electronic switch comprises a normally-on transistor.

17. The electronic circuit of claim 1, wherein the electronic switch comprises a normally-off transistor.