Texas Instruments Incorporated
Systems with power transistors, transistors coupled to the gates of the power transistors, and capacitive dividers coupled to the power transistors

Abstract:

A system to regulate power from a first power supply to a load coupled to the first power supply, wherein a power transistor is coupled between the load and ground. The system includes: a transistor having a control terminal, a first current terminal adapted to be coupled to an external second power supply and a second current terminal adapted to be coupled to a control terminal of the power transistor; a first resistor having a first node coupled to the control terminal of the transistor and a second node adapted to be coupled to a first terminal of a second external capacitor, the first node of the first resistor is adapted to be coupled to a first terminal of a first external capacitor; a second resistor having a first node coupled to the control terminal of the transistor and a second node adapted to be coupled to ground, the first node of the second resistor is adapted to be coupled to a first terminal of an first external resistor; and wherein a second terminal of the first external capacitor is coupled to a node between the load and a first current terminal of the power transistor and a second terminal of the second external capacitor is coupled to form a capacitive divider with the first external capacitor and the first resistor, and a second node of the first external resistor is coupled to the node between the load and the first current terminal of the power transistor to form a resistive divider with the second resistor.