Capacitor-Less Low Drop-Out (LDO) Regulator

• US 20180275706A1
• Filed: 05/25/2018
• Published: 09/27/2018
• Est. Priority Date: 11/04/2014
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Murukumpet, Raghuveer, Lawrence, Kent, Iqbal, Asif
• Granted Patent: US 10,761,552 B2
• Time in Patent Office: Days
• CPC Class Codes: G05F 1/569 for protection
• CPC Class Codes: G05F 1/575 characterised by the feedback circuit
• CPC Class Codes: G05F 1/59 including plural semiconductor devices as final control devices for a single load

Abstract

An integrated circuit including a low drop out (LDO) regulator configured to implement transient response and loop stability in a capacitor-less configuration, including an error amplifier configured to receive a bandgap reference input; first and second pass elements configured to receive outputs from the error amplifier; first and second resistor feedback networks, the first resistor network configured to provide a feedback output as an input to the error amplifier; an overshoot protection circuit; and an output connected to the pass transistors; wherein the capacitor-less low dropout (LDO) regulator is operable without an output capacitor.

Claims

1. A capacitor-less low drop out (LDO) regulator, comprising:

an error amplifier configured to receive a bandgap reference input;

first and second pass transistors configured to receive outputs from the error amplifier;

first and second resistor feedback networks, the first resistor network configured to provide a feedback output as an input to the error amplifier;

an overshoot protection circuit; and

an output connected to the pass transistors;

wherein the capacitor-less low dropout (LDO) regulator is operable without an output capacitor.

2. The capacitor-less low drop out (LDO regulator of claim 1, further including a driver coupled between the error amplifier and the output.

3. The capacitor-less low drop out (LDO) regulator of claim 1, wherein the second resistor feedback network is configured to provide a comparator feedback output as an input to the overshoot protection circuit.

4. The capacitor-less low drop out (LDO) regulator of claim 2, wherein the overshoot protection circuit includes a comparator configured to compare the comparator feedback output and the bandgap reference input.

5. The capacitor-less low drop out (LDO) regulator of claim 3, wherein the error amplifier comprises a folded cascode amplifier.

6. The capacitor-less low drop out (LDO) regulator of claim 4, wherein the first pass transistor implements a capacitor at the output of the error amplifier to compensate for slow response.

7. The capacitor-less low drop out (LDO) regulator of claim 5, wherein the second pass transistor implements a capacitor coupled to a differential pair input circuit of the folded cascode amplifier.

8. An integrated circuit including a low drop out (LDO) regulator configured to implement transient response and loop stability in a capacitor-less configuration, comprising:

an error amplifier configured to receive a bandgap reference input;

first and second pass elements configured to receive outputs from the error amplifier;

first and second resistor feedback networks, the first resistor network configured to provide a feedback output as an input to the error amplifier;

an overshoot protection circuit; and

an output connected to the first and second pass elements;

wherein the integrated circuit is operable to implement the low dropout regulator without an output capacitor.

9. The integrated circuit of claim 8, further including a driver coupled between the error amplifier and the output.

10. The integrated circuit of claim 8, wherein the second resistor feedback network is configured to provide a comparator feedback output as an input to the overshoot protection circuit.

11. The integrated circuit of claim 10, wherein the overshoot protection circuit includes a comparator configured to compare the comparator feedback output and the bandgap reference input.

12. The integrated circuit of claim 8, wherein the error amplifier comprises a folded cascode amplifier.

13. The integrated circuit of claim 12, wherein the first pass element implements a capacitor at the output of the error amplifier to compensate for slow response.

14. The integrated circuit of claim 13, wherein the second pass element implements a capacitor coupled to a differential pair input circuit of the folded cascode amplifier.

15. A method for providing a low drop out (LDO) regulator configured to implement transient response and loop stability in a capacitor-less configuration, comprising:

providing an error amplifier configured to receive a bandgap reference input;

providing first and second pass elements configured to receive outputs from the error amplifier;

providing first and second resistor feedback networks, the first resistor network configured to provide a feedback output as an input to the error amplifier;

providing an overshoot protection circuit; and

providing an output connected to the pass transistors;

wherein the capacitor-less low dropout (LDO) regulator is operable without an output capacitor.

16. The method of claim 15, further including providing a driver coupled between the error amplifier and the output.

17. The method of claim 15, wherein the second resistor feedback network is configured to provide a comparator feedback output as an input to the overshoot protection circuit.

18. The method of claim 17, wherein the overshoot protection circuit includes a comparator configured to compare the comparator feedback output and the bandgap reference input.

19. The method of claim 17, wherein the error amplifier comprises a folded cascode amplifier.

20. The method of claim 18, wherein the first pass element implements a capacitor at the output of the error amplifier to compensate for slow response.

21. The method of claim 19, wherein the second pass element implements a capacitor coupled to a differential pair input circuit of the folded cascode amplifier.