초록

A gate drive circuit creates a bipolar voltage to a gate of an IGB power transistor, and compensates for Miller currents of the IGB power transistor. The compensating is performed by a switching element connected in series with a capacitor between the gate (X4) and a supply voltage.

대표청구항 ▼

1. A gate drive circuit with an active gate voltage stabilizer, comprising: means for creating a bipolar voltage to a gate of an IGB power transistor; andmeans for compensating for Miller currents of the IGB power transistor, the means for compensating being formed by a switching element connected i

1. A gate drive circuit with an active gate voltage stabilizer, comprising: means for creating a bipolar voltage to a gate of an IGB power transistor; andmeans for compensating for Miller currents of the IGB power transistor, the means for compensating being formed by a switching element connected in series with a capacitor between the gate and a supply voltage input;wherein a switching voltage of the switching element is controlled by two resistances; andwherein one of the two resistances is connected between a source and gate of the switching element, and is an NTC-resistor. 2. The gate drive circuit according to claim 1, wherein the means for compensating comprises: a ceramic capacitor as the capacitor, and a power MOSFET as the switching element connected in series. 3. The gate drive circuit according to claim 1, wherein the means for compensating is connected between a positive supply voltage and the gate of the IGB transistor. 4. The gate drive circuit according to claim 1, wherein the switching element is a varistor or transient suppressor. 5. A method for controlling an IGB power transistor with a gate drive circuit, which method comprises: creating a bipolar voltage to a gate of the IGB power transistor;compensating for Miller currents of the IGB power transistor with a switching element connected in series with a capacitor between the gate and supply voltage input; andcontrolling a switching voltage of the switching element by two resistances;wherein one of the two resistances is a resistor connected between a source and gate of the switching element, and is an NTC-resistor. 6. The method according to claim 5, whereby the compensating is performed by a ceramic capacitor as the capacitor, and a power MOSFET as the switching element connected in series. 7. The method according to claim 6, wherein the switching element and capacitor are connected between a positive supply voltage of the supply voltage input and the gate of the IGB transistor. 8. The method according to claim 5, wherein the switching element is a varistor or transient suppressor. 9. The method according to claim 5, wherein the compensating is performed after an actual switching event, when a temperature load of a chip housing the IGB power transistor has started to decrease and the chip is recovering from the switching event. 10. The method according to claim 9, wherein a decreasing edge of a temperature load curve is adjusted such that a decreasing edge of at least a heated portion of the chip decreases faster than a corresponding edge of an unheated cold module. 11. The method according to claim 9, comprising: compensating thermal cycling by changing voltage losses in a conducting state of the IGBT power transistor even though control occurs during a state change of the IGBT power transistor. 12. The gate drive circuit according to claim 2, wherein the means for compensating is connected between a positive supply voltage and the gate of the IGB transistor. 13. The gate drive circuit according to claim 12, wherein the switching element is a varistor or transient suppressor. 14. The method according to claim 5, wherein the compensating is performed after an actual switching event, when a temperature load of a chip housing the IGB power transistor has started to decrease and the chip is recovering from the switching event. 15. The method according to claim 10, comprising: compensating thermal cycling by changing voltage losses in a conducting state of the IGBT power transistor even though control occurs during a state change of the IGBT power transistor. 16. The method according to claim 5, wherein the switching element and capacitor are connected between a positive supply voltage of the supply voltage input and the gate of the IGB transistor. 17. The method according to claim 6, wherein the switching element is a varistor or transient suppressor. 18. The method according to claim 6, wherein the compensating is performed after an actual switching event, when a temperature load of a chip housing the IGB power transistor has started to decrease and the chip is recovering from the switching event. 19. The method according to claim 18, wherein a decreasing edge of a temperature load curve is adjusted such that a decreasing edge of at least a heated portion of the chip decreases faster than a corresponding edge of an unheated cold module. 20. The method according to claim 19, comprising: compensating thermal cycling by changing voltage losses in a conducting state of the IGBT power transistor even though control occurs during a state change of the IGBT power transistor.