ELECTRONIC SYSTEM FOR CONVERTING DC VOLTAGE INTO AC VOLTAGE

• US 20120075753A1
• Filed: 09/08/2011
• Published: 03/29/2012
• Est. Priority Date: 09/24/2010
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Maebara, Tsuneo, Hamanaka, Yoshiyuki, Fukuta, Junichi, WATANABE, Kazunori, Tanimura, Yasunari, Takagi, Noriyuki
• Granted Patent: US 8,687,327 B2
• Time in Patent Office: Days
• US Class Current: 361/18
• CPC Class Codes: B60L 15/007 Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility

Abstract

An electronic system has IGBT, on driving FET and off driving FET connected with the gate of the IGBT, and a control circuit. The on driving FET in an on state supplies electric charge to the IGBT gate. The off driving FET in an on state releases the charge from the GET gate. The control circuit controls each of the on FETs according to a driving signal to be set in the on and off states every switching period of time and to control the voltage at the IGBT gate. When on-failure occurs in the on driving FET set in the on state so as to keep the on driving FET in the on state in spite of control of the control circuit, the control circuit controls a controlled element other than the off driving FET to set the IGBT in the off state.

Claims

1. An electronic system, comprising:

a first switching element, having a control terminal, which is driven by changing a voltage of the control terminal in response to electric charge supplied or released to/from the control terminal;

an on driving switching element, connected with the control terminal of the first switching element, which is set in an on state to supply electric charge to the control terminal of the first switching element;

an off driving switching element, connected with the control terminal of the first switching element, which is set in an on state to release the electric charge, supplied by the on driving switching element, from the control terminal of the first switching element; and

a control circuit which controls each of the on driving switching element and the off driving switching element according to a driving signal to set the switching element in the on or off state and to control the voltage of the control terminal of the first switching element and which controls the driving of the first switching element,

wherein the control circuit controls a controlled element other than the off driving switching element to set the first switching element in an off state when anon-failure occurs in the on driving switching element set in the on state so as to keep the on driving switching element in the on state in spite of the control of the control circuit.

2. The electronic system according to claim 1, wherein the on driving switching element has a control terminal, an input terminal and an output terminal and is driven by controlling a voltage at the control terminal of the on driving switching element, and the control circuit judges based on a voltage difference between the input and output terminals of the on driving switching element that the on-failure has occurred in the on driving switching element when the voltage difference indicates that the on driving switching element is in the on state while the voltage at the control terminal of the on driving switching element indicates that the on driving switching element is in the off state.

3. The electronic system according to claim 1, wherein the on driving switching element has a control terminal, an input terminal and an output terminal and is driven by controlling a voltage at the control terminal of the on driving switching element, the control circuit sets the first switching element in each of the on and off states every switching period of time according to the driving signal, and the control circuit judges that the on-failure has occurred in the on driving switching element when a voltage difference between the input and output terminals of the on driving switching element indicates that the on driving switching element is in the on state during a period of time longer than the switching period of time.

4. The electronic system according to claim 1, wherein the on driving switching element has a control terminal, an input terminal and an output terminal and is driven by controlling a voltage at the control terminal of the on driving switching element, and the control circuit judges based on a voltage difference between the input and output terminals of the on driving switching element that the on-failure has occurred in the on driving switching element when the voltage difference indicates that the on driving switching element is in the on state while the driving signal instructs the first switching element to be set in the off state.

5. The electronic system according to claim 1, wherein the on driving switching element has a control terminal and is driven by controlling a voltage at the control terminal of the on driving switching element, and the control circuit judges that the on-failure has occurred in the on driving switching element when an electric current flows through the on driving switching element while the voltage at the control terminal of the on driving switching element indicates that the on driving switching element is in the off state.

6. The electronic system according to claim 5, wherein the on driving switching element is connected with the control terminal of the first switching element through an on driving resistor, and the control circuit judges based on a voltage difference between ends of the on driving resistor that the electric current flows through the on driving switching element.

7. The electronic system according to claim 1, wherein the controlled element is a driving power source circuit that supplies a driving voltage required to drive the first switching element, and the control circuit stops the supply of the driving voltage from the driving power source circuit, when the control circuit judges that the on-failure has occurred in the on driving switching element, to set the first switching element in the off state.

9. The electronic system according to claim 1, further comprising an off holding switching element, connected with the control terminal of the first switching element, which is set in an on state to release the electric charge from the control terminal of the first switching element,

wherein the control circuit controls the off driving switching element to release the electric charge from the control terminal of the first switching element and to decrease the voltage at the control terminal of the first switching element to a value lower than an on-off threshold value,

the control circuit controls the off holding switching element to hold the off state of the first switching element when the voltage at the control terminal of the first switching element becomes equal to or lower than an off holding threshold value which is lower than the on-off threshold value,

the controlled element is a voltage clamp circuit that clamps the voltage at the control terminal of the first switching element at a value equal to or lower than the off holding threshold value, and

the control circuit controls the controlled element, when the control circuit judges that the on-failure has occurred in the on driving switching element, to clamp the voltage at the control terminal of the first switching element at a value equal to or lower than the off holding threshold value.

10. The electronic system according to claim 1, further comprising a second switching element, serially connected with the first switching element and having a control terminal, which is driven by con_trolling a voltage at the control terminal of the second switching element,

where in the control led element is a driving circuit that drives the second switching element according to another driving signal by controlling a voltage at the control terminal of the second switching element and sets the second switching element in an off state when an abnormal electric current flows through the second switching element, and

the control circuit sets the first switching element in an on state when the control circuit judges that the on-failure has occurred in the on driving switching element.

11. The electronic system according to claim 1, wherein the controlled element is a gate cutoff switching element which cuts off a connection between the control terminal of the first switching element and a pair of the on driving switching element and the off driving switching element, and

the control circuit controls the gate cutoff switching element, when the control circuit judges that the on-failure has occurred in the on driving switching element, to cut off the connection.

12. The electronic system according to claim 1, wherein the control circuit externally outputs an abnormal signal when the control circuit judges that the on-failure has occurred in the on driving switching element.

8. The electronic system according to claims, wherein the controlled element is an off holding switching element, connected with the control terminal of the first switching element, which is set in an on state to release the electric charge from the control terminal of the first switching element, the control circuit controls the off driving switching element to release the electric charge from the control terminal of the first switching element and to decrease the voltage at the control terminal of the first switching element to a value lower than an on-off threshold value, the control circuit controls the off holding switching element to hold the off state of the first switching element when the voltage at the control terminal of the first switching element becomes equal to or lower than an off holding threshold value which is lower than the on-off threshold value, and the control circuit controls the off holding switching element, when the control circuit judges that the on-failure has occurred in the on driving switching element, to set the first switching element in the off state.