Patent ID: 7982524
Filing Date: 2011-07-19
Classification: H01L

Abstract:
1. A level shift circuit of a driving circuit for driving a gate of a power device, which has one main terminal connected to a high-potential side of a high-voltage power supply and another main terminal connected to a load, wherein a signal of a low-potential side low-voltage circuit region to which current is supplied from a low-voltage power supply, with a low-potential side of the high-voltage power supply as a reference, is converted into a signal of a high-potential side low-voltage circuit region to which current is supplied from the low-voltage power supply with the other main terminal of the power device as a reference, the level shift circuit comprising: a first circuit provided between the high-potential side of the low-voltage power supply, with the another main terminal of the power device as a reference, and the low-potential side of the high-voltage power supply, wherein the first circuit comprises: a current-limiting resistor; a MOSFET, with a source region and a channel region connected via a terminal, connected in series with the current-limiting resistor; a level shift resistor connected in series with the current-limiting resistor; and a protection diode connected in parallel with the level shift resistor, with the high-potential side of the low-voltage power supply as a cathode, wherein the current-limiting resistor limits current flowing in a body diode connected in parallel with, and integral with the MOSFET and is connected in series with a drain region of the MOSFET, with the current-limiting resistor between the MOSFET and the level shift resistor; and wherein the current-limiting resistor has a resistance value in the range of 1/10 to 1/100 of a resistance value of the level shift resistor.