Tunable voltage regulator circuit
A voltage regulator has an output driver current mirror circuit and one or more control circuits. The output driver current mirror circuit includes an output driver transistor, a tunable resistance circuit, and a diode-connected transistor. The output driver transistor has one current electrode coupled to a supply voltage and another current electrode coupled to an output terminal for providing the output voltage of the voltage regulator. The tunable resistance circuit has one terminal coupled to a control electrode of the output driver transistor, and another terminal coupled to a current electrode of the diode-connected transistor. The one or more control circuits includes a comparator for controlling a current provided to the output driver current mirror in response to a feedback signal from the output terminal.
1. A voltage regulator comprising:
an output terminal;
an output driver current mirror circuit comprising:
an output driver transistor having a first current electrode coupled to a first power supply voltage terminal, a control electrode, and a second current electrode coupled to the output terminal;
a tunable resistance circuit having a first terminal, a control terminal, and a second terminal coupled to the control electrode of the output driver transistor; and
a first transistor having a first current electrode coupled to the first power supply voltage terminal, a control electrode and a second current electrode both coupled to the first terminal of the tunable resistance circuit;
a high power control circuit coupled to the first terminal of the tunable resistance circuit for providing a first current to the output driver current mirror circuit in a first operating mode; and
a low power control circuit coupled to the first terminal of the tunable resistance circuit for providing a second current to the output driver current mirror circuit in a second operating mode, the second current being smaller than the first current.
2. The voltage regulator of claim 1 , wherein the high power control circuit comprises:
a second transistor having a first current electrode coupled to the first terminal of the tunable resistance circuit, a control electrode, and a second current electrode;
a first comparator having a first input for receiving a first reference voltage, a second input for receiving a first feedback signal from the output driver current mirror circuit, and an output coupled to the control electrode of the second transistor;
a tunable current source having a first terminal coupled to the second current electrode of the second transistor, a control terminal, and a second terminal coupled to a second power supply voltage terminal.
3. The voltage regulator of claim 2 , wherein the high power control circuit further comprises:
a first current source having a first terminal coupled to the first power supply voltage terminal, and a second terminal;
a third transistor having a first current electrode coupled to the second terminal of the first current source, a control electrode, and a second current electrode;
a second comparator having a first input for receiving the first reference voltage, a second input for receiving a second feedback signal, and an output coupled to the control electrode of the third transistor; and
a fourth transistor having a first current electrode and a control electrode both coupled to the second current electrode of the third transistor and to the control terminal of the tunable current source, and a second current electrode coupled the second power supply voltage terminal.
4. The voltage regulator of claim 1 , wherein the low power control circuit comprises:
a third transistor having a first current electrode coupled to the first terminal of the tunable resistance circuit, a control electrode, and a second current electrode;
a third comparator having a first input for receiving a reference voltage, a second input for receiving a feedback signal from the output driver current mirror circuit, and an output coupled to the control electrode of the third transistor; and
a current source having a first terminal coupled to the second current electrode of the third transistor, and a second terminal coupled to a second power supply voltage terminal.
5. The voltage regulator of claim 1 , wherein the output driver transistor and the first transistor are characterized as being P-channel metal-oxide semiconductor transistors.
6. The voltage regulator of claim 1 , wherein the voltage regulator is implemented on a single integrated circuit and the output terminal is for providing an output voltage of the voltage regulator to a circuit external to the integrated circuit.
7. The voltage regulator of claim 1 , wherein the tunable resistance circuit provides a variable resistance in response to a resistance control signal, wherein the tunable resistance circuit provides di/dt control of an output voltage at the output terminal.
8. A method of regulating a voltage by a voltage regulator comprising:
an output terminal;
an output driver current mirror circuit comprising an output driver transistor and a diode-connected transistor with a tunable resistance circuit coupled therebetween; and a first control circuit being a low power control circuit and comprising a first comparator,
the method comprising:
providing, by the output driver transistor, an output voltage to the output terminal;
controlling, by the first comparator, a first current to the output driver current mirror circuit in response to a first feedback signal from the output terminal;
controlling, by a second comparator comprised in a second control circuit being a high power control circuit, a second current to the output driver current mirror circuit in response to a second feedback signal from the output terminal; and
providing by the tunable resistance circuit, a variable resistance to control an electrode of the output driver transistor in response to a control signal, thereby providing di/dt control for the output voltage.
9. The method of claim 8 , further comprising, in response to a third feedback signal indicating that the output voltage at the output terminal is below a predetermined voltage level, increasing the second current to the output driver current mirror circuit, by means of a third comparator comprised in the second control circuit.
10. A voltage regulator comprising:
an output terminal;
an output driver current mirror circuit comprising an output driver transistor and a diode-connected transistor with a tunable resistance circuit coupled therebetween, the output driver transistor coupled to provide an output voltage to the output terminal; and
a first control circuit comprising a first comparator, the first comparator for controlling a first current to the output driver current mirror circuit in response to a first feedback signal from the output terminal.
11. The voltage regulator of claim 10 , further comprising:
a second control circuit comprising a second comparator, the second comparator for controlling a second current to the output driver current mirror circuit in response to a second feedback signal from the output terminal.
12. The voltage regulator of claim 11 , wherein the second control circuit comprising a third comparator coupled to increase the second current to the output driver current mirror circuit in response to a third feedback signal indicating that the output voltage at the output terminal is below a predetermined voltage level.
13. The voltage regulator of claim 10 , wherein the tunable resistance circuit provides a variable resistance to a control electrode of the output driver transistor in response to a control signal, and wherein the variable resistance provides di/dt control for the output voltage.
14. The voltage regulator of claim 10 , wherein the voltage regulator is formed on an integrated circuit.
15. A voltage regulator comprising:
an output driver transistor having a first current electrode coupled to a first power supply voltage terminal, a control electrode, and a second current electrode coupled to an output terminal;
a tunable resistance having a first terminal coupled to the control terminal of the output driver transistor, a second terminal, and a control terminal for receiving a control signal;
a first transistor having a first current electrode coupled to the first power supply voltage terminal, a control electrode, and a second current electrode coupled to the second terminal of the tunable resistance;
a second transistor having a first current electrode coupled to the second current electrode of the first transistor, a control electrode, and a second current electrode; and
a first comparator having a first input for receiving a first reference voltage, a second input coupled to the output terminal for receiving a first feedback signal, and an output coupled to the control electrode of the second transistor.
16. The voltage regulator of claim 15 , further comprising a tunable current source having a first terminal coupled to the second current electrode of the second transistor, a control terminal, and a second terminal coupled to a second power supply voltage terminal.
17. The voltage regulator of claim 16 , further comprising:
a second comparator having a first input for receiving the first reference voltage, a second input coupled to the output terminal for receiving a second feedback signal, and an output;
a first current source having a first terminal coupled to the first power supply voltage terminal, and a second terminal;
a third transistor having a first current electrode coupled to the second terminal of the first current source, a control terminal coupled to the output of the second comparator, and a second current electrode; and
a fourth transistor having a first current electrode coupled to the second current electrode of the third transistor, a control electrode coupled to the control terminal of the tunable current source, and a second current electrode coupled to the second power supply voltage terminal.
18. The voltage regulator of claim 15 , further comprising:
a fifth transistor having a first current electrode coupled to the second terminal of the tunable resistance circuit, a control electrode, and a second current electrode;
a third comparator having a first input for receiving a second reference voltage, a second input coupled to the output terminal for receiving a third feedback signal, and an output; and
a second current source having a first terminal coupled to the second current electrode of the fifth transistor, and a second terminal coupled to a second power supply voltage terminal.
19. The voltage regulator of claim 18 , wherein the second current source is switchable between a high impedance state and a low impedance state.
20. The voltage regulator of claim 15 , wherein the voltage regulator is implemented on a single integrated circuit.