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US 11,616,141 B2Granted
Current reference
AssigneeTexas Instruments Incorporated
InventorsSundeep Lakshmana Javvaji, Shalakha Singhal
Life of this patent
Estimating the term…
Abstract
In an example, an integrated circuit includes a junction-gate field effect transistor (JFET), a current generator, a dynamic filter, and an output transistor. The JFET has a JFET gate, a JFET source, and a JFET drain, the JFET drain adapted to be coupled to a power supply. The current generator has a current generator input and current generator outputs, the current generator input coupled to the JFET source and a first of the current generator outputs coupled to the JFET gate. The dynamic filter has a dynamic filter input and a dynamic filter output, the dynamic filter input coupled to a second of the current generator outputs. The output transistor has an output transistor gate coupled to the dynamic filter output.
Claims15
An integrated circuit, comprising:
- a junction-gate field effect transistor (JFET) having a JFET gate, a JFET source, and a JFET drain, the JFET drain coupled to a power supply terminal;
- a current generator having first and second current generator outputs and a current generator input, wherein the current generator input is coupled to the JFET source, and the first current generator output is coupled to the JFET gate;
- a dynamic filter having a dynamic filter input and a dynamic filter output, wherein the dynamic filter input is coupled to the second current generator output;
- a first transistor having a first gate, a first source and a first drain, wherein the first gate is coupled to the dynamic filter output;
- a second transistor having a second gate, a second source and a second drain, wherein the second gate is coupled to the JFET gate;
- first and second resistors, wherein the first resistor is coupled between the second source and the JFET gate;
- a third transistor having a third gate, a third source and a third drain, wherein the third gate is coupled to the third drain, and the third source is coupled to the JFET gate;
- a fourth transistor having a fourth gate, a fourth source and a fourth drain, wherein the fourth gate and fourth drain are coupled to the third drain, and the fourth source is coupled to a ground terminal;
- a fifth transistor having a fifth gate, a fifth source and a fifth drain, wherein the fifth gate is coupled to the fourth gate, and the fifth source is coupled to a ground terminal through the second resistor;
- a sixth transistor having a sixth gate, a sixth source and a sixth drain, wherein the sixth drain is coupled to the fifth drain, and the sixth source is coupled to the JFET source;
- and;
- and
- a seventh transistor having a seventh gate, a seventh source and a seventh drain, wherein the seventh gate is coupled to the sixth gate, and the seventh source is coupled to the JFET source.
10 more elements
An apparatus, comprising:
- a junction-gate field effect transistor (JFET) having a JFET gate, a JFET source, and a JFET drain, wherein the JFET drain is coupled to a power input, and the JFET is configured to provide a local power supply at the JFET source, the local power supply having a value approximately equal to a voltage at the JFET gate plus a pinch-off voltage of the JFET;
- a current generator having a current generator input and first and second current generator outputs, wherein the current generator input is coupled to the JFET source, the first current generator output is coupled to the JFET gate, and the current generator is configured to provide a reference current (IREF);
- a dynamic filter having a dynamic filter input and a dynamic filter output, wherein the dynamic filter input is coupled to the second current generator output and configured to receive a mirrored version of IREF, the dynamic filter configured to provide an output current (IOUT) at the dynamic filter output responsive to the mirrored version of IREF;
- and
- an output transistor having an output gate, an output source and an output drain, wherein the output gate is coupled to the dynamic filter output, and the output transistor is configured to provide IOUT at the output drain;
- wherein the dynamic filter includes a pass transistor configured to provide a second mirrored version of IREF to the output gate.
3 more elements
A system, comprising:
- an integrated circuit comprising a current reference having an input coupled to a battery and an output, the current reference comprising:
- a junction-gate field effect transistor (JFET) having a JFET gate, a JFET source, and a JFET drain, wherein the JFET drain is coupled to the battery, and the JFET is configured to provide a local power supply at the JFET source, the local power supply having a value approximately equal to a voltage at the JFET gate plus a pinch-off voltage of the JFET, the voltage being independent of a voltage of the battery;
- a current generator having a current generator input and first and second current generator outputs, wherein the current generator input is coupled to the JFET source, the first current generator output is coupled to the JFET source, and the current generator is configured to provide a reference current (IREF) that is responsive to the local power supply and a resistor having a resistance that is inversely proportional to IREF;
- a dynamic filter having a dynamic filter input and a dynamic filter output, wherein the dynamic filter input is coupled to the second current generator output and is configured to receive a mirrored version of IREF, the dynamic filter is configured to provide an output current (TOUT) responsive to the mirrored version of IREF, and the dynamic filter includes a pass transistor;
- and
- an output transistor having an output gate, an output source and an output drain, wherein the output gate is coupled to the dynamic filter output and the pass transistor, and the pass transistor provides a second mirrored version of IREF to the output gate;
- and
- a circuit having a circuit input coupled to the output drain.
5 more elements
Dependencies are inferred from the claim text.