Adaptive MOS transistor gate driver and method therefor
First Claim
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1. An adaptive MOS gate driver circuit comprising:
- a gate control circuit configured to form a drive signal to drive a gate of an MOS transistor;
a variable frequency oscillator configured to form a clock signal and to adjust a frequency of the clock signal responsively to a difference between a Vgs of the MOS transistor and a first threshold value;
a charge pump circuit configured to provide an output voltage and an output current to the gate control circuit wherein a value of the output current varies proportionally to variations of the frequency of the clock signal; and
the gate control circuit configured to couple the output current from the charge pump circuit to the gate of the MOS transistor responsively to the Vgs of the MOS transistor having a value greater than a second threshold value and to provide a current from a selectively enabled current source of the gate control circuit responsively to the Vgs of the MOS transistor having a value no greater than the second threshold value.
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Abstract
In an embodiment, a gate driver circuit and/or method therefor may include configuring the gate driver circuit form a drive current to supply to a gate of an MOS transistor wherein the value of the drive current is a minimum value that can be supplied to the gate without increasing a charge stored on a gate-to-source capacitance of the MOS transistor; configuring the gate driver circuit to change the value of the drive current responsively to changes of a Vgs of the MOS transistor.
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Citations
20 Claims
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1. An adaptive MOS gate driver circuit comprising:
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a gate control circuit configured to form a drive signal to drive a gate of an MOS transistor; a variable frequency oscillator configured to form a clock signal and to adjust a frequency of the clock signal responsively to a difference between a Vgs of the MOS transistor and a first threshold value; a charge pump circuit configured to provide an output voltage and an output current to the gate control circuit wherein a value of the output current varies proportionally to variations of the frequency of the clock signal; and the gate control circuit configured to couple the output current from the charge pump circuit to the gate of the MOS transistor responsively to the Vgs of the MOS transistor having a value greater than a second threshold value and to provide a current from a selectively enabled current source of the gate control circuit responsively to the Vgs of the MOS transistor having a value no greater than the second threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of forming a gate driver circuit for an MOS transistor comprising:
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configuring the gate driver circuit to form a first drive current to supply to a gate of an MOS transistor; configuring the gate driver circuit to change the first drive current to a second drive current in response to a Vgs of the MOS transistor having a value that is no less than a second threshold value; and configuring the gate driver circuit to change a value of the second drive current responsively to changes of the Vgs for values of the Vgs that are no less than a first threshold value wherein the first threshold value is greater than the second threshold value. - View Dependent Claims (10, 11, 12, 13)
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14. A method of forming a gate driver circuit for an MOS transistor comprising:
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configuring the gate driver circuit to form a drive current to supply to a gate of an MOS transistor; configuring the gate driver circuit to change the drive current responsively to a Vgs of the MOS transistor having a value greater than a second threshold value and less than a first threshold value wherein the second threshold value is less than the first threshold value; and configuring the gate driver circuit to adjust the value of the drive current responsively to the value of the Vgs for Vgs values no less than the first threshold value. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification