Apparatus and method for linearizing field effect transistors in the OHMIC region
First Claim
1. An apparatus comprising:
- a field effect transistor having a gate, a source, and a drain;
a first series circuit in parallel with the gate and the source of the field effect transistor, the first series circuit comprising;
a first capacitor; and
a first switch in series with the first capacitor, wherein the first switch is configured to be on when the field effect transistor is on, and to be off when the field effect transistor is off; and
a second series circuit in parallel with the gate and the drain of the field effect transistor, the second series circuit comprising;
a second capacitor; and
a second switch in series with the second capacitor, wherein the second switch is configured to be on when the field effect transistor is on, and to be off when the field effect transistor is off.
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Accused Products
Abstract
Apparatus and methods are disclosed related to using one or more field effect transistors as a resistor. One such apparatus includes a field effect transistor with a first series circuit in parallel with the gate and the source of the field effect transistor and a second series circuit in parallel with the gate and the drain of the field effect transistor. Each series circuit can include a capacitor and a switch in series with the capacitor. The switch can be configured to be on when the field effect transistor is on, and to be off when the field effect transistor is off. This can improve the linearity of the field effect transistor as a resistor. In some implementations, the apparatus can further include an isolation resistor having a first end and a second end, the first end electrically coupled to the gate of the field effect transistor.
12 Citations
20 Claims
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1. An apparatus comprising:
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a field effect transistor having a gate, a source, and a drain; a first series circuit in parallel with the gate and the source of the field effect transistor, the first series circuit comprising; a first capacitor; and a first switch in series with the first capacitor, wherein the first switch is configured to be on when the field effect transistor is on, and to be off when the field effect transistor is off; and a second series circuit in parallel with the gate and the drain of the field effect transistor, the second series circuit comprising; a second capacitor; and a second switch in series with the second capacitor, wherein the second switch is configured to be on when the field effect transistor is on, and to be off when the field effect transistor is off. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus comprising:
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a variable resistance circuit configured to generate an output based on an input and a plurality of control signals, the variable resistance circuit comprising a plurality of linear resistance circuits, wherein each linear resistance circuit comprises; a field effect transistor having a gate, a source, and a drain, the gate controlled by a control signal of the plurality of control signals, the drain configured to receive the input, and the source configured to drive the output when the field effect transistor is on; a first series circuit in parallel with the gate and the source of the field effect transistor, the first series circuit comprising; a first capacitor; and a first switch in series with the first capacitor, wherein the first switch is configured to be on when the field effect transistor is on, and to be off when the field effect transistor is off; and a second series circuit in parallel with the gate and the drain of the field effect transistor, the second series circuit comprising; a second capacitor; and a second switch in series with the second capacitor, wherein the second switch is configured to be on when the field effect transistor is on, and to be off when the field effect transistor is off; wherein each of the plurality of linear resistance circuits is configured to switch the field effect transistor based on one of the plurality of control signals. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method of using a field effect transistor, the method comprising:
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controlling activation of the field effect transistor based at least partly on one or more control signals, the field effect transistor having a gate, a source, and a drain; filtering an input signal with the field effect transistor when the field effect transistor operates in the ohmic region; and controlling filtering such that; a first switch electrically couples a first capacitor in parallel with the gate and the drain of the field effect transistor when the field effect transistor is on, and the first switch does not electrically couple the first capacitor in parallel with the gate and the drain of the field effect transistor when the field effect transistor is off; and a second switch electrically couples a second capacitor in parallel with the gate and the source of the field effect transistor when the field effect transistor is on, and the second switch does not electrically couple the second capacitor in parallel with the gate and the source of the field effect transistor when the field effect transistor is off. - View Dependent Claims (18, 19, 20)
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Specification