Voltage regulator with a bandwidth variation reduction network

• US 8,351,886 B1
• Filed: 02/04/2010
• Issued: 01/08/2013
• Est. Priority Date: 02/04/2010
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: TriQuint Semiconductor Incorporated (Qorvo, Inc.)
• Inventors: Karnik, Kiran
• Primary Examiner(s): Trinh, Sonny
• Application Number:
  US12/700,663
• Time in Patent Office: 1,069 Days
• Field of Search: 455/127.2, 455/127.3, 455/194.2, 455/195.1, 455/169.1, 323/280, 323/316, 323/269, 323/351, 323/274, 323277-278
• US Class Current: 455/195.1
• CPC Class Codes: G05F 1/575 characterised by the feedback circuit

Abstract

Embodiments of circuits, apparatuses, and systems for a voltage regulator with a bandwidth variation reduction network are disclosed. Other embodiments may be described and claimed.

Claims

1. A voltage regulator comprising:

an operational amplifier having an output;

a pass transistor having a first gate coupled with the output of the operational amplifier and configured to provide a load current; and

a network including a replica transistor having a second gate coupled with the output of the operational amplifier, the network being configured to provide a current, which is based on the load current, to the operational amplifier,

wherein the current comprises a mirror current and the replica transistor is configured to provide a sense current that is proportional to the load current, and the mirror current is proportional to the sense current.

2. The voltage regulator of claim 1, wherein the network comprises:

a current mirror configured to generate the mirror current based on the sense current.

3. The voltage regulator of claim 1, wherein the pass transistor is a p-type metal oxide semiconductor field effect transistor.

4. The voltage regulator of claim 1, further comprising:

a resistor coupled with, and disposed between, the replica transistor and a supply rail.

5. The voltage regulator of claim 1, wherein the replica transistor is proportional to the pass transistor.

6. A voltage regulator comprising:

an operational amplifier having an output,

a pass transistor having a first gate coupled with the output of the operational amplifier and configured to provide a load current;

a network including a replica transistor having a second gate coupled with the output of the operational amplifier, the network being configured to provide a current, which is based on the load current, to the operational amplifier; and

a feedback network coupled with the pass transistor and the operational amplifier and configured to provide a feedback voltage to the operational amplifier that is proportional to an output voltage at a drain of the pass transistor.

7. The voltage regulator of claim 6, wherein the operational amplifier includes a first input coupled with the feedback network and a second input to receive a reference or ramp voltage.

8. A voltage regulator comprising:

an operational amplifier having an output;

a pass transistor having a first gate coupled with the output of the operational amplifier and configured to provide a load current; and

a network including a replica transistor having a second gate coupled with the output of the operational amplifier, the network being configured to provide a current, which is based on the load current, to a power supply of the operational amplifier to change a gain of the operational amplifier.

9. The voltage regulator of claim 8, wherein the operational amplifier includes a pair of input differential transistors, the current is a first current, and the network comprises:

a current mirror coupled with, and disposed between, a supply rail and the pair of input differential transistors and configured to mirror a second current to generate the first current and to provide the first current to the pair of input differential transistors at a positive power supply terminal of the operational amplifier.

10. A voltage regulator comprising:

an operational amplifier having an output;

a pass transistor having a first gate coupled with the output of the operational amplifier and configured to provide a load current; and

a network including a replica transistor having a second gate coupled with the output of the operational amplifier, the network being configured to provide a current, which is based on the load current, to the operational amplifier,

wherein the operational amplifier includes a pair of input differential transistors configured to receive the current at a negative power supply terminal of the operational amplifier.

11. A method of providing a regulated output voltage comprising:

driving a transistor with an amplified differential input voltage, generated by an operational amplifier, to provide the regulated output voltage and an output load current; and

dynamically changing a gain of the operational amplifier, based on the output load current, by dynamically changing a current provided to an input stage of the operational amplifier.

12. The method of claim 11, wherein the input stage comprises a pair of input differential transistors.

13. The method of claim 11, wherein the transistor is a first transistor and said dynamically changing the gain comprises:

driving a second transistor, which is proportional in size to the first transistor, with the amplified differential input voltage;

generating, with the second transistor, a sense current that is proportional to the output load current;

mirroring the sense current to provide a mirror current; and

providing a current based on the mirror current to the operational amplifier.

14. The method of claim 11, further comprising:

providing a first voltage to the operational amplifier;

providing a second voltage to the operational amplifier; and

generating, with the operational amplifier, the amplified differential input voltage based on the first and second voltages.

15. The method of claim 14, wherein said providing the first voltage comprises providing a feedback voltage and said providing the second voltage comprises providing a ramp voltage that varies with time during said providing of the regulated output voltage.

16. A system comprising:

a voltage regulator having an operational amplifier configured to output a voltage, a transistor coupled with the operational amplifier and configured to provide an output load current and a regulated output voltage based on the voltage, and a network to dynamically change a gain of the operational amplifier based on the output load current; and

a power amplifier including a power input supply terminal coupled with the voltage regulator to receive the regulated output voltage, the power amplifier configured to amplify a radio frequency (RF) signal to be transmitted over the air.

17. The system of claim 16, further comprising:

a transceiver coupled with the voltage regulator and the power amplifier and configured to provide a ramp voltage to the voltage regulator and the RF signal to the power amplifier.

18. The system of claim 16, wherein the transistor is a first transistor and the network comprises:

a second transistor, which is proportional to the first transistor, coupled with the operational amplifier and configured to generate a sense current that is proportional to the output load current; and

a current mirror configured to mirror the sense current to provide the current.

19. The system of claim 16, wherein the operational amplifier includes an input stage provided with a current based on the output load current.