Patent ID: 7362061
Filing Date: 2008-04-22
Classification: H03K

Abstract:
1. A gate driver for forcing a power transistor having a gate electrode insulated with oxide film and also having an input capacitance between the gate electrode and the source electrode, into a conductive state or a shut-off state, the gate driver comprising: a first current source configured to receive a first control signal and to output a first current value to charge said input capacitance and raise an electric potential of the gate electrode in a time corresponding to a charging time of said input capacitance, when changing the power transistor from the shut-off state to the conductive state, the first current value depending on a level of the first control signal; and a second current source configured to receive a second control signal and to output a second current value to discharge said input capacitance and lower the electric potential of the gate electrode in a time corresponding to the charging time of said input capacitance, when changing said power transistor from the conductive state to the shut-off state, the second current value depending on a further level of the second control signal; wherein the respective levels of the first control signal and the second control signal are independently controllable, and wherein the time of change from the shut-off state to the conductive state of the power transistor is controlled by controlling the rise time of the electric potential of said gate electrode with the first current value set with the first control signal, while the time of change from the conductive state to the shut-off state of the power transistor is controlled by controlling the fall time of the electric potential of said gate electrode with said second current value set with the second control signal.