HYBRID PARALLEL REGULATOR AND POWER SUPPLY COMBINATION FOR IMPROVED EFFICIENCY AND DROOP RESPONSE WITH DIRECT CURRENT DRIVEN OUTPUT STAGE ATTACHED DIRECTLY TO THE LOAD

• US 20160179181A1
• Filed: 12/22/2014
• Published: 06/23/2016
• Est. Priority Date: 12/22/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Doyle, James Thomas, Fu, Zhengming, Mahmoudi, Farsheed, Shayan Arani, Amirali, Darbanian, Nazanin
• Granted Patent: US 9,785,222 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G05F 1/575 characterised by the feedback circuit
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system
• CPC Class Codes: G06F 1/3296 by lowering the supply or operating voltage
• CPC Class Codes: H02M 1/0045 Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode
• CPC Class Codes: H02M 3/1566 with means for compensating against rapid load changes, e.g. with auxiliary current source, with dual mode control or with inductance variation

Abstract

Operational mode changes in a system-on-a-chip (SoC) integrated circuit in a complex device such as a mobile phone cause spikes in current demand which can cause voltage droops that disrupt operation of the SoC. A hybrid parallel power supply connects a switching-mode power supply and a low-dropout voltage regulator in parallel to provide high efficiency and fast response times. Integration of the voltage regulator on the SoC reduces parasitic impedance be between the voltage regulator and the load to aid in reducing voltage droops. The switching-mode power supply and the low-dropout voltage regulator can regulate their outputs to slightly difference voltage levels. This can allow the switching-mode power supply to supply most of the SoC'"'"'s current demands.

Claims

1. A hybrid parallel power supply, comprising:

a first power supply connected to a power rail and configured to supply current to a load device via the power rail, the first power supply being further configured to regulate the power rail to a first target voltage level; and

a voltage regulator connected to the power rail and configured to supply current to the load device via the power rail, the voltage regulator being further configured to regulate the power rail to a second target voltage level.

2. The hybrid parallel power supply of claim 1, wherein the first power supply is a switching mode power supply.

3. The hybrid parallel power supply of claim 1, wherein the voltage regulator is a low dropout voltage regulator.

4. The hybrid parallel power supply of claim 1, wherein the first target voltage level is greater than the second target voltage level.

5. The hybrid parallel power supply of claim 1, wherein the voltage regulator comprises:

a current mirror having an output connected to the power rail; and

a first operational amplifier having a first input connected to the power rail, a second input arranged to receive a reference voltage at the second target voltage level, and an output connected to an input of the current mirror.

6. The hybrid parallel power supply of claim 5, wherein the operational amplifier is an operational transconductance amplifier.

7. The hybrid parallel power supply of claim 5, wherein the voltage regulator further comprises:

a bandgap source configured to produce a reference output voltage; and

a first reference converter configured to supply the reference voltage to the first operational amplifier based on a first digital input and the reference output voltage from the bandgap source.

8. The hybrid parallel power supply of claim 7,

wherein the first power supply is further configured to supply current to the load device based on a feedback signal, and

wherein the hybrid parallel power supply further comprises:

a second operational amplifier having a first input connected to the power rail, a second input arranged to receive a second reference voltage at the first target voltage level, and an output configured to provide the feedback signal to the first power supply; and

a second reference converter configured to supply the second reference voltage to the second operational amplifier based on a second digital input and the reference output voltage from the bandgap source.

9. The hybrid parallel power supply of claim 1, further comprising

a second power supply configured to supply power at a third target voltage level to an input of the voltage regulator.

10. The hybrid parallel power supply of claim 1, further the voltage regulator is disposed on a first die with the load device and the first power supply is disposed on a second die.

11. The hybrid parallel power supply of claim 10, further comprising a capacitor disposed on the first die and connected to an input of the voltage regulator.

12. A method of supplying power to a load device, the method comprising:

supplying current from a power supply to the load device via a power rail at a first target voltage level; and

supplying current from a voltage regulator to the load device via the power rail at a second target voltage level.

13. The method of claim 12, wherein the power supply is a switching mode power supply.

14. The method of claim 12, wherein the voltage regulator is a low dropout voltage regulator.

15. The method of claim 12, wherein the first target voltage level is greater than the second target voltage level.

16. The method of claim 12, wherein supplying current from the voltage regulator comprises:

amplifying a difference between a voltage of the power rail and the second target voltage level; and

supplying the current from the voltage regulator based on the amplified difference.

17. The method of claim 16, further comprising:

generating a reference output voltage based on a bandgap source; and

generating the second target voltage level based on a first digital input and the reference output voltage.

18. The method of claim 17, further comprising generating the first target voltage level based on a second digital input and the reference output voltage.

19. A hybrid parallel power supply, comprising:

a first means for supplying power connected to a power rail and configured to supply current at a first target voltage level to a load device via the power rail; and

a means for regulating voltage connected to the power rail and configured to supply current at a second target voltage level to the load device via the power rail.

20. The hybrid parallel power supply of claim 19, wherein the first means for supplying power is a switching mode power supply.

21. The hybrid parallel power supply of claim 19, wherein the means for regulating voltage is a low dropout voltage regulator.

22. The hybrid parallel power supply of claim 19, wherein the first target voltage level is greater than the second target voltage level.

23. The hybrid parallel power supply of claim 19, wherein the means for regulating voltage comprises:

a current mirror having an output connected to the power rail; and

a first operational amplifier having a first input connected to the power rail, a second input arranged to receive a reference voltage at the second target voltage level, and an output connected to an input of the current mirror.

24. The hybrid parallel power supply of claim 23, wherein the operational amplifier is an operational transconductance amplifier.

25. The hybrid parallel power supply of claim 23, wherein the means for regulating voltage further comprises:

a bandgap source configured to produce a reference output voltage; and

a first reference converter configured to supply the reference voltage to the first operational amplifier based on a first digital input and the reference output voltage from the bandgap source.

26. The hybrid parallel power supply of claim 25,

wherein the first means for supplying power is further configured to supply current to the load device based on a feedback signal, and

wherein the hybrid parallel power supply further comprises:

a second operational amplifier having a first input connected to the power rail, a second input arranged to receive a second reference voltage at the first target voltage level, and an output configured to provide the feedback signal to the first means for supplying power; and

a second reference converter configured to supply the second reference voltage to the second operational amplifier based on a second digital input and the reference output voltage from the bandgap source.

27. The hybrid parallel power supply of claim 19, further comprising

a second means for supplying power configured to supply power at a third target voltage level to an input of the means for regulating voltage.

28. The hybrid parallel power supply of claim 19, wherein the means for regulating voltage is disposed on a first die with the load device and the first means for supplying power is disposed on a second die.

29. The hybrid parallel power supply of claim 28, further comprising a capacitor disposed on the first die and connected to an input of the means for regulating voltage.