Driving circuit for a control terminal of a bipolar transistor in an emitter-switching configuration and corresponding method for reducing the VCESAT dynamic phenomenon

• US 7,053,678 B2
• Filed: 03/05/2004
• Issued: 05/30/2006
• Est. Priority Date: 03/05/2003
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Scollo, Rosario, Buonomo, Simone
• Primary Examiner(s): Wells, Kenneth B.
• Application Number:
  US10/794,788
• Publication Number:
  US 20040217801A1
• Time in Patent Office: 816 Days
• Field of Search: 327108-112, 327/478, 327/482, 326 64- 67, 326/82, 326/84, 326/85
• US Class Current: 327/108
• CPC Class Codes: H03K 17/04126 in bipolar transistor switches
• CPC Class Codes: H03K 17/567 Circuits characterised by the use of more than one type of semiconductor device, e.g. BIMOS, composite devices such as IGBT

Abstract

A driving circuit is provided for a control terminal of a bipolar transistor in an emitter-switching configuration. The emitter-switching configuration is between first and second voltage references. The driving circuit includes at least one first resistive element connected to the control terminal of the bipolar transistor and a first capacitor connected to the resistive element with respect to a first circuit node and to the second voltage reference. The driving circuit further includes a Zener diode connected between the first circuit node and a second circuit node, and a second capacitor between the second circuit node and the second voltage reference.

Claims

1. A driving circuit for a control terminal of a bipolar transistor in an emitter-switching configuration between first and second voltage references, the driving circuit comprising:

a first resistive element having a first terminal directly connected to the control terminal of the bipolar transistor, and a second terminal directly connected to a first circuit node;

a first capacitor having a first terminal directly connected to the first circuit node, and a second terminal directly connected to the second voltage reference;

a Zener diode having a first terminal directly connected to the first circuit node, and a second terminal directly connected to a second circuit node; and

a second capacitor connected between the second circuit node and the second reference voltage.

2. A driving circuit according to claim 1, wherein said first capacitor has a value lower than a value of said second capacitor.

3. A driving circuit according to claim 1, wherein the first terminal of said Zener diode is a cathode terminal and the second terminal is an anode terminal.

4. A driving circuit according to claim 1, wherein said second capacitor comprises an electrolytic capacitor.

5. A driving circuit according to claim 1, wherein said second capacitor has a positive plate connected to the second circuit node.

6. A driving circuit according to claim 1, wherein said first capacitor has a value within a range of about 680 and 180 nF for operating frequencies within a range of about 60 and 150 kHz.

7. A driving circuit according to claim 1, wherein said first resistive element has a value less than 0.5 ohms.

8. A driving circuit according to claim 1, wherein the emitter-switching configuration further comprises a MOS transistor cascode-connected between an emitter of the bipolar transistor and the second voltage reference.

9. A circuit comprising:

a MOS transistor and a bipolar transistor cascode-connected therewith, said MOS transistor and said bipolar transistor to be connected between first and second voltage references; and

a driving circuit for a control terminal of the bipolar transistor, and comprising

a firer resistive element connected between the control terminal of the bipolar transistor and a first circuit node,

a first capacitor connected between the first circuit node and the second voltage reference,

a Zener diode connected between the first circuit node and a second circuit node, and

a second capacitor connected between the second circuit node and the second reference voltage.

10. A circuit according to claim 9, wherein said first capacitor has a value lower than a value of said second capacitor.

11. A circuit according to claim 9, wherein said Zener diode has a cathode terminal connected to the first circuit node and an anode terminal connected to the second circuit node.

12. A circuit according to claim 9, wherein said second capacitor comprises an electrolytic capacitor.

13. A circuit according to claim 9, wherein said second capacitor has a positive plate connected to the second circuit node.

14. A circuit according to claim 9, wherein said first capacitor has a value within a range of about 680 and 180 nF for operating frequencies within a range of about 60 and 150 kHz.

15. A circuit according to claim 9, wherein said first resistive element has a value less than 0.5 ohms.

16. An apparatus comprising:

a load connected to a first voltage reference;

a MOS transistor and a bipolar transistor cascode-connected therewith, said bipolar transistor also connected to said load and said MOS transistor also connected to a second voltage reference; and

a driving circuit for a control terminal of the bipolar transistor, and comprising

a first resistive element connected between the control terminal of the bipolar transistor and a first circuit node,

a first capacitor connected between the first circuit node and the second voltage reference,

a Zener diode connected between the first circuit node and a second circuit node, and

a second capacitor connected between the second circuit node and the second reference voltage.

17. An apparatus according to claim 16, wherein said first capacitor has a value lower than a value of said second capacitor.

18. An apparatus according to claim 16, wherein said Zener diode has a cathode terminal connected to the first circuit node and an anode terminal connected to the second circuit node.

19. An apparatus according to claim 16, wherein said second capacitor comprises an electrolytic capacitor.

20. An apparatus according to claim 16, wherein said second capacitor has a positive plate connected to the second circuit node.

21. An apparatus according to claim 16, wherein said first capacitor has a value within a range of about 680 and 180 nF for operating frequencies within a range of about 60 and 150 kHz.

22. An apparatus according to claim 16, wherein said first resistive element has a value less than 0.5 ohms.

23. A method for driving a control terminal of a bipolar transistor in an emitter-switching configuration between first and second voltage references based upon a driving circuit comprising a first resistive element having a first terminal directly connected to the control terminal of the bipolar transistor and a second terminal directly connected to a first circuit node, a first capacitor having a first terminal directly connected to the first circuit node, and a second terminal directly connected to the second voltage reference, a Zener diode having a first terminal directly connected to the first circuit node, and a second terminal directly connected to a second circuit node, and a second capacitor connected between the second circuit node and the second reference voltage, the method comprising:

applying a first voltage to the control terminal of the bipolar transistor via the first capacitor; and

applying a second voltage to the control terminal of the bipolar transistor via the second capacitor, the second voltage being less than the first voltage.

24. A method according to claim 23, wherein the second voltage is kept constant by the second capacitor.

25. A method according to claim 23, wherein the first voltage varies based upon varying a value of the first capacitor and the Zener diode.

26. A method according to claim 23, wherein the first capacitor has a value lower than a value of the second capacitor.

27. A method according to claim 23, wherein the Zener diode has a cathode terminal connected to the first circuit node and an anode terminal connected to the second circuit node.

28. A method according to claim 23, wherein the second capacitor comprises an electrolytic capacitor.

29. A method according to claim 23, wherein the second capacitor has a positive plate connected to the second circuit node.

30. A method according to claim 23, wherein the first capacitor has a value wherein a range of about 680 and 180 nF for operating frequencies within a range of about 60 and 150 kHz.

31. A method according to claim 23, wherein the first resistive element has a value less than 0.5 ohms.