A buffer circuit includes a first transistor, a second transistor, a feed-forward circuit and a resistive bias circuit. The first transistor has a first terminal, a second terminal and a third terminal, wherein the first terminal of the first transistor is served as an input terminal of the buffer circuit. The second transistor has a first terminal and a second terminal, wherein the second terminal of the second transistor is coupled to the third terminal of the first transistor and served as an output terminal of the buffer circuit. The feed-forward circuit has a first terminal and a second terminal respectively coupled to the first terminal of the second transistor and the second terminal of the first transistor. The resistive bias circuit has a first terminal and a second terminal respectively coupled to the second terminal of the first transistor and the first terminal of the feed-forward circuit.

A buffer circuit includes a first transistor, a second transistor, a feed-forward circuit and a resistive bias circuit. The first transistor has a first terminal, a second terminal and a third terminal, wherein the first terminal of the first transistor is served as an input terminal of the buffer circuit. The second transistor has a first terminal and a second terminal, wherein the second terminal of the second transistor is coupled to the third terminal of the first transistor and served as an output terminal of the buffer circuit. The feed-forward circuit has a first terminal and a second terminal respectively coupled to the first terminal of the second transistor and the second terminal of the first transistor. The resistive bias circuit has a first terminal and a second terminal respectively coupled to the second terminal of the first transistor and the first terminal of the feed-forward circuit.

A current source circuit includes a first variable resistor circuit. The first variable resistor circuit includes a resistive material and a first plurality of tap inputs configured to set a resistance of the first variable resistor circuit. The current source circuit includes an output configured to provide a current. The current is adjustable by varying the resistance of the first variable resistor circuit. The current source circuit includes a second variable resistor circuit. The second variable resistor circuit includes a resistive material of a same resistive material type as the resistive material of the first variable resistor circuit. The second variable resistor circuit includes a second plurality of tap inputs configured to set a resistance of the second variable resistor circuit. Each tap resistance of the second variable resistor circuit is proportional to a corresponding tap resistance of the first variable resistor circuit. A first terminal of the second variable resistor circuit is coupled to a first test port and a second terminal of the second variable resistor circuit is coupled to a second test port to allow for a resistance measurement of the second variable resistor circuit during a test mode. The current source circuit includes a non-volatile storage circuit configured to store a tap value generated during the test mode corresponding to a set of select signal values for the second plurality of tap inputs which provides a desired resistance of the second variable resistor circuit as determined during the test mode and to provide a set of select signal values for the first plurality of tap inputs based on the tap value stored in the non-volatile storage circuit.

A current source circuit includes a first variable resistor circuit. The first variable resistor circuit includes a resistive material and a first plurality of tap inputs configured to set a resistance of the first variable resistor circuit. The current source circuit includes an output configured to provide a current. The current is adjustable by varying the resistance of the first variable resistor circuit. The current source circuit includes a second variable resistor circuit. The second variable resistor circuit includes a resistive material of a same resistive material type as the resistive material of the first variable resistor circuit. The second variable resistor circuit includes a second plurality of tap inputs configured to set a resistance of the second variable resistor circuit. Each tap resistance of the second variable resistor circuit is proportional to a corresponding tap resistance of the first variable resistor circuit. A first terminal of the second variable resistor circuit is coupled to a first test port and a second terminal of the second variable resistor circuit is coupled to a second test port to allow for a resistance measurement of the second variable resistor circuit during a test mode. The current source circuit includes a non-volatile storage circuit configured to store a tap value generated during the test mode corresponding to a set of select signal values for the second plurality of tap inputs which provides a desired resistance of the second variable resistor circuit as determined during the test mode and to provide a set of select signal values for the first plurality of tap inputs based on the tap value stored in the non-volatile storage circuit.

An integrated circuit voltage regulator includes a transconductor first stage; and a negative impedance cancellation stage, where the negative impedance cancellation stage comprises cross-coupled transistors at outputs of said transconductor first stage, and resistors in the transconductor first stage and the negative impedance cancellation stage introduce zeros in a transfer function, compensating for parasitic poles. The resistors may compensate for parasitic capacitance inherent in transistors. Load transistors may be coupled to outputs of the transconductance first stage. The voltage regulator may be implemented in a Complementary Metal-Oxide-Semiconductor (CMOS) structure, which may be a system-on-chip integrated circuit. The voltage regulator may provide immunity to power supply noise. The negative impedance cancellation stage may include differential input transistors coupled to the cross-coupled transistors.

An integrated circuit voltage regulator includes a transconductor first stage; and a negative impedance cancellation stage, where the negative impedance cancellation stage comprises cross-coupled transistors at outputs of said transconductor first stage, and resistors in the transconductor first stage and the negative impedance cancellation stage introduce zeros in a transfer function, compensating for parasitic poles. The resistors may compensate for parasitic capacitance inherent in transistors. Load transistors may be coupled to outputs of the transconductance first stage. The voltage regulator may be implemented in a Complementary Metal-Oxide-Semiconductor (CMOS) structure, which may be a system-on-chip integrated circuit. The voltage regulator may provide immunity to power supply noise. The negative impedance cancellation stage may include differential input transistors coupled to the cross-coupled transistors.

An integrated circuit voltage regulator includes a transconductor first stage; and a negative impedance cancellation stage, where the negative impedance cancellation stage comprises cross-coupled transistors at outputs of said transconductor first stage, and resistors in the transconductor first stage and the negative impedance cancellation stage introduce zeros in a transfer function, compensating for parasitic poles. The resistors may compensate for parasitic capacitance inherent in transistors. Load transistors may be coupled to outputs of the transconductance first stage. The voltage regulator may be implemented in a Complementary Metal-Oxide-Semiconductor (CMOS) structure, which may be a system-on-chip integrated circuit. The voltage regulator may provide immunity to power supply noise. The negative impedance cancellation stage may include differential input transistors coupled to the cross-coupled transistors.

An integrated circuit voltage regulator includes a transconductor first stage; and a negative impedance cancellation stage, where the negative impedance cancellation stage comprises cross-coupled transistors at outputs of said transconductor first stage, and resistors in the transconductor first stage and the negative impedance cancellation stage introduce zeros in a transfer function, compensating for parasitic poles. The resistors may compensate for parasitic capacitance inherent in transistors. Load transistors may be coupled to outputs of the transconductance first stage. The voltage regulator may be implemented in a Complementary Metal-Oxide-Semiconductor (CMOS) structure, which may be a system-on-chip integrated circuit. The voltage regulator may provide immunity to power supply noise. The negative impedance cancellation stage may include differential input transistors coupled to the cross-coupled transistors.

An adaptive negative impedance system for improving power supply rejection (PSR) of a voltage regulator (VR) includes a variable negative impedance circuit with a control input; and a signal adjustment block (SAB), wherein a negative impedance value of the variable negative impedance circuit is dependent on a voltage regulator output current, and wherein the variable negative impedance circuit is a variable negative capacitance circuit and/or a variable negative resistance circuit, and the negative impedance value is a negative capacitance value and/or a negative resistance value.

An adaptive negative impedance system for improving power supply rejection (PSR) of a voltage regulator (VR) includes a variable negative impedance circuit with a control input; and a signal adjustment block (SAB), wherein a negative impedance value of the variable negative impedance circuit is dependent on a voltage regulator output current, and wherein the variable negative impedance circuit is a variable negative capacitance circuit and/or a variable negative resistance circuit, and the negative impedance value is a negative capacitance value and/or a negative resistance value.