A GATE DRIVE CIRCUIT AND A METHOD FOR SETTING UP A GATE DRIVE CIRCUIT

摘要

A gate drive circuit (10a) used to drive a power transistor (12a). The gate drive circuit includes a first switch (SW1) and a first capacitor (C1). A first terminal (T11) of the first capacitor (C1) is electrically coupled to the first switch (SW1). The first switch (SW1) is electrically coupled between the first terminal (T11) and a voltage supply (HV) of the power transistor (12a). A second terminal (T12) of the first capacitor (C1) is electrically coupled to the reference potential (GND). The gate drive circuit (10a) further includes a first voltage limiter (VL) in parallel with the first capacitor (C1). The first voltage limiter (VL) limits a voltage across the first capacitor (C1) to a first predetermined voltage. The gate drive circuit (10a) further includes a second capacitor (C2), a pre-charging circuit (PC) arranged between the first terminal (T11) of the first capacitor (C1) and a first terminal (T21) of the second capacitor (C2). The gate drive circuit (10a) further includes a third capacitor (C3) with a first terminal (T31) electrically coupled to a second terminal (T22) of the second capacitor (C2) and a second terminal (T32) electrically coupled to a gate terminal (G) of the power transistor (12a). Additionally the gate drive circuit (10a) includes a second switch (SW2) arranged between the first terminal (T11) of the first capacitor (C1) and the second terminal (T22) of the second capacitor (C2), a third switch (SW3) arranged between the first terminal (T31) of the third capacitor (C3) and the reference potential (GND) and a fourth switch (SW4) arranged between the second terminal (T32) of the third capacitor (C3) and the reference potential (GND). During a setup of the gate drive circuit (10a) after applying the voltage supply (HV), the gate drive circuit (10a) is configured to arrange the first switch (SW1) in an on state to electrically couple the supply voltage (HV) to the first terminal (T11). The first capacitor (C1) is in this way charged to obtain the first predetermined voltage across the first capacitor (C1). The gate drive circuit (10a) is further configured to configure the pre-charging circuit to pre-charge the second capacitor (C2) to obtain a second predetermined voltage across the second capacitor (C2). The gate drive circuit (10a) is also configured to pre-charge the third capacitor (C3) to obtain a third predetermined voltage across the third capacitor (C3). The gate drive circuit (10a) is configured to be powered by the voltage across the first capacitor (C1). By charging the first capacitor (C1) and by pre-charging the second and third capacitors (C2, C3), the gate drive circuit (10a) is setup, powered up and and ready to be used to drive the gate terminal (G) of the power transistor (12a).