TWO-STAGE LOW-DROPOUT LINEAR POWER SUPPLY SYSTEMS AND METHODS

• US 20140091775A1
• Filed: 10/02/2012
• Published: 04/03/2014
• Est. Priority Date: 10/02/2012
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Inventors: TAN, FANG DONG, ZEE, JEFF
• Granted Patent: US 9,753,473 B2
• Time in Patent Office: Days
• US Class Current: 323/280
• CPC Class Codes: G05F 1/563 including two stages of regulation at least one of which is output level responsive, e.g. coarse and fine regulation
• CPC Class Codes: G05F 1/575 characterised by the feedback circuit

Abstract

Aspects of the present invention include a low-dropout (LDO) linear power supply system. The system includes a pass-element configured to generate an output voltage at an output based on an input voltage. The system also includes a compensation amplifier stage coupled to the output and configured to provide frequency compensation and provide a desired frequency response of the output voltage. The system further includes a gain amplifier stage interconnecting the compensation amplifier stage and the pass-element and configured to provide DC gain scaling to generate the output voltage substantially proportional to the input voltage within a given range of the input voltage.

Claims

1. A low-dropout (LDO) linear power supply system comprising:

a pass-element configured to generate an output voltage at an output based on an input voltage;

a compensation amplifier stage coupled to the output and configured to provide frequency compensation and provide a desired frequency response of the output voltage; and

a gain amplifier stage interconnecting the compensation amplifier stage and the pass-element and configured to provide DC gain scaling to generate the output voltage substantially proportional to the input voltage within a given range of the input voltage.

2. The system of claim 1, wherein the compensation amplifier stage comprises a compensation operational amplifier (OP-AMP) configured to generate a stabilization voltage in response to a feedback voltage associated with the output voltage and a reference voltage.

3. The system of claim 2, wherein the compensation amplifier stage comprises a resistive-capacitive feed-forward network coupled between the output and a first input of the compensation OP-AMP and a resistive-capacitive feedback network coupled between the first input and an output of the compensation OP-AMP, the resistive-capacitive feed-forward and feedback networks cooperating to affect the frequency response of the output voltage and to provide substantially rapid transient response of the stabilization voltage.

4. The system of claim 3, wherein the first input of the compensation OP-AMP is an inverting input, such that the compensation OP-AMP is configured as an inverting OP-AMP.

5. The system of claim 2, wherein the gain stage comprises a gain OP-AMP configured to receive the stabilization voltage at a first input and to generate a control voltage at an output, the control voltage being provided to control the pass-element at a control input.

6. The system of claim 5, wherein the control voltage has a magnitude that is proportional to the stabilization voltage.

7. The system of claim 2, wherein the reference voltage and the output voltage are interconnected by a voltage divider configured to generate the feedback voltage.

8. The system of claim 1, wherein the pass-element is configured as one of a bipolar junction transistor (BJT), a metal-oxide semiconductor field-effect transistor (MOSFET), and a Darlington pair of transistors.

9. An integrated circuit (IC) chip comprising the LDO linear power supply system of claim 1.

10. The IC chip of claim 9, wherein the IC chip comprises terminals configured to receive a capacitor and an associated equivalent series resistor (ESR) coupled to the output external to the IC to provide output filtering of the output voltage.

11. A low-dropout (LDO) linear power supply system comprising:

a pass-element configured to generate an output voltage at an output based on an input voltage;

a compensation amplifier stage coupled to the output and configured to provide frequency compensation and provide a desired frequency response of the output voltage;

a gain amplifier stage interconnecting the compensation amplifier stage and the pass-element and configured to provide DC gain scaling to generate the output voltage substantially proportional to the input voltage; and

a capacitor and an associated equivalent series resistor (ESR) coupled to the output to provide output filtering of the output voltage.

12. The system of claim 11, wherein the compensation amplifier stage comprises a compensation operational amplifier (OP-AMP) configured to generate a stabilization voltage in response to a feedback voltage associated with the output voltage and a reference voltage.

13. The system of claim 12, wherein the compensation amplifier stage comprises a resistive-capacitive feed-forward network coupled between the output and a first input of the compensation OP-AMP and a resistive-capacitive feedback network coupled between the first input and an output of the compensation OP-AMP, the resistive-capacitive feed-forward and feedback networks cooperating to affect the frequency response of the output voltage and to provide substantially rapid transient response of the stabilization voltage.

14. The system of claim 12, wherein the gain stage comprises a gain OP-AMP configured to receive the stabilization voltage at a first input and to generate a control voltage at an output, the control voltage being provided to control the pass-element at a control input.

15. The system of claim 12, wherein the reference voltage and the output voltage are interconnected by a voltage divider configured to generate the feedback voltage.

16. An integrated circuit (IC) chip comprising the LDO linear power supply system of claim 11, wherein the IC chip is configured to receive the capacitor and the resistor as an external capacitor and an external resistor.

17. An integrated circuit (IC) chip comprising a low-dropout (LDO) linear power supply system, the LDO linear power supply system comprising:

a pass-element configured to generate an output voltage at an output based on an input voltage;

a compensation amplifier stage coupled to the output and comprising a compensation operational amplifier (OP-AMP) configured to generate a stabilization voltage in response to a feedback voltage associated with the output voltage and a reference voltage, the compensation amplifier stage being configured to provide frequency compensation and provide a desired frequency response of the output voltage;

a gain amplifier stage interconnecting the compensation amplifier stage and the pass-element and comprising a gain OP-AMP configured to receive the stabilization voltage at a first input and to generate a control voltage at an output, the control voltage being provided to control the pass-element at a control input, the gain amplifier stage being configured to provide DC gain scaling to generate the output voltage substantially proportional to the input voltage; and

terminals configured to receive a capacitor and an associated equivalent series resistor (ESR) coupled to the output external to the IC to provide output filtering associated with the output voltage.

18. The system of claim 17, wherein the compensation amplifier stage comprises a resistive-capacitive feed-forward network coupled between the output and a first input of the compensation OP-AMP and a resistive-capacitive feedback network coupled between the first input and an output of the compensation OP-AMP, the resistive-capacitive feed-forward and feedback networks cooperating to affect the frequency response of the output voltage and to provide substantially rapid transient response of the stabilization voltage.

19. The system of claim 17, wherein the reference voltage and the output voltage are interconnected by a voltage divider configured to generate the feedback voltage.

20. The system of claim 17, wherein the first input of the compensation OP-AMP is an inverting input, such that the compensation OP-AMP is configured as an inverting OP-AMP.