ELECTRONIC DEVICE WITH SWITCHING ELEMENT DRIVEN BY CONTROL VOLTAGE

• US 20120086496A1
• Filed: 10/07/2011
• Published: 04/12/2012
• Est. Priority Date: 10/07/2010
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: ITOU, Akito, Maebara, Tsuneo
• Granted Patent: US 8,610,487 B2
• Time in Patent Office: Days
• US Class Current: 327/398
• CPC Class Codes: H03K 17/06 Modifications for ensuring a fully conducting state
• CPC Class Codes: H03K 17/0828 in composite 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
• CPC Class Codes: H03K 17/6877 the control circuit comprising active elements different from those used in the output circuit
• CPC Class Codes: H03K 2017/066 Maximizing the OFF-resistance instead of minimizing the ON-resistance

Abstract

In an electronic device with a switching element, a control circuit controls the voltage at the control terminal of the switching element and drives the switching element, by controlling an ON-drive switching element and an OFF-drive switching element based on an inputted drive signal to the control circuit. The control circuit is configured to turn OFF a switching element using a switching circuit other than the OFF-drive switching element after an elapse of a predetermined period of time from a timing at which the drive signal switches from an ON instruction thereof to an OFF instruction thereof, the ON instruction giving an instruction to turn ON the switching element, the OFF instruction giving an instruction to turn OFF the switching element.

Claims

1. An electronic device comprising:

a switching element having a control terminal and being driven by a voltage at the control terminal;

an ON-drive switching element electrically connected to the control terminal of the switching element and configured to charge the control terminal of the switching element with electrical charge by the ON-drive switching element being turned ON;

an OFF-drive switching element electrically connected to the control terminal of the switching element and configured to discharge electrical charge from the control terminal of the switching element by the ON-drive switching element being turned ON; and

a control circuit that controls the voltage at the control terminal of the switching element and drives the switching element, by controlling the ON-drive switching element and the OFF-drive switching element based on an inputted drive signal to the control circuit,

wherein the control circuit is configured to turn OFF a switching element using a time drive circuit other than the OFF-drive switching element after an elapse of a predetermined period of time from a timing at which the drive signal switches from an ON instruction thereof to an OFF instruction thereof, the ON instruction giving an instruction to turn ON the switching element, the OFF instruction giving an instruction to turn OFF the switching element.

2. The electronic device according to claim 1, wherein the control circuit is configured to turn OFF the switching element using the time drive circuit other than the OFF-drive switching element when the predetermined period of time has passed from a designated timing at which the drive signal switches from the ON instruction thereof to the OFF instruction thereof, the designated timing being after a timing at which the OFF-drive switching element is turned ON in a state where the drive signal presents the OFF instruction thereof.

3. The electronic device according to claim 1, wherein the control circuit is configured to turn OFF the switching element using the time drive circuit other than the OFF-drive switching element when the predetermined period of time has passed from a designated timing at which the drive signal switches from the ON instruction thereof to the OFF instruction thereof, the designated timing being after a timing at which the ON-drive switching element is turned OFF in a state where the drive signal presents the OFF instruction thereof.

4. The electronic device according to claim 1, wherein the control circuit is configured to stop the switching element from being turned OFF when the drive signal is switched from the OFF instruction thereof to the ON instruction thereof before the predetermined period of time has passed.

5. The electronic device according to claim 2, comprising

an ON-drive capacitor electrically connected between the control terminal of the switching element and an output terminal thereof, and

an OFF-drive resistor electrically connected between the OFF-drive switching element and the control terminal of the switching element,

wherein the control circuit is configured to turn OFF the switching element using the time drive circuit other than the OFF-drive switching element after a predetermined period of time equal to or longer than a time constant has passed after the timing at which the OFF-drive switching element is turned ON, the time constant being defined by a product of a total amount of capacitance between the control terminal and the output terminal of the switching element and a resistance value of the OFF-drive resistor, the total amount of capacitance including a capacitance of the ON-drive capacitor.

6. The electronic device according to claim 1, wherein the predetermined period of time is set in accordance with a voltage between an input terminal of the switching element and the output terminal thereof.

7. The electronic device according to claim 6, wherein the predetermined period of time is set to be shorter as the voltage between the input and output terminals of the switching element becomes lower.

8. The electronic device according to claim 1, wherein the predetermined period of time is set in accordance with temperature of the switching element.

9. The electronic device according to claim 8, wherein the predetermined period of time is set to be shorter as the temperature becomes lower.

10. The electronic device according to claim 1, comprising an OFF-holding switching element electrically connected to the control terminal of the switching element and configured to discharge electric charge from the control terminal of the switching element by being turned ON,

wherein the control circuit is configured to control the OFF-holding switching element to hold an OFF state of the switching element when a voltage at the control terminal becomes equal to or lower than a first threshold voltage lower than a second threshold voltage for turning ON and OFF the switching element.

11. The electronic device according to claim 10, wherein the control circuit is configured to control the OFF-holding switching element to turn OFF the switching element at a timing when the predetermined period of time has passed after the drive signal was switched from the ON instruction thereof to the OFF instruction thereof.

12. The electronic device according to claim 11, wherein the control circuit is configured to control the OFF-holding switching element to turn OFF the switching element when the predetermined period of time has passed from a designated timing at which the drive signal switches from the ON instruction thereof to the OFF instruction thereof, the designated timing being after a timing at which the OFF-drive switching element is turned ON in a state where the drive signal presents the OFF instruction thereof.

13. The electronic device according to claim 1, comprising a disconnecting switching element electrically connected to the control terminal of the switching element and configured to discharge electric charge from the control terminal of the switching element by being turned ON,

wherein the control circuit is configured to control the disconnecting switching element to turn OFF the switching element when an abnormal current passes through the switching element.

14. The electronic device according to claim 13, wherein the control circuit is configured to control the disconnecting switching element to turn OFF the switching element at a timing when the predetermined period of time passes after the drive signal switches from the ON instruction thereof to the OFF instruction thereof.

15. The electronic device according to claim 2, wherein the control circuit is configured to turn OFF the switching element using the time drive circuit other than the OFF-drive switching element when the predetermined period of time has passed from a designated timing at which the drive signal switches from the ON instruction thereof to the OFF instruction thereof, the designated timing being after a timing at which the ON-drive switching element is turned OFF in a state where the drive signal presents the OFF instruction thereof.

16. The electronic device according to claim 15, wherein the control circuit is configured to stop the switching element from being turned OFF when the drive signal is switched from the OFF instruction thereof to the ON instruction thereof before the predetermined period of time has passed.

17. The electronic device according to claim 16, wherein the predetermined period of time is set in accordance with a voltage between an input terminal of the switching element and the output terminal thereof.

18. The electronic device according to claim 17, wherein the predetermined period of time is set to be shorter as the voltage between the input and output terminals of the switching element becomes lower.

19. The electronic device according to claim 16, wherein the predetermined period of time is set in accordance with temperature of the switching element.

20. The electronic device according to claim 19, wherein the predetermined period of time is set to be shorter as the temperature becomes lower.