Hybrid parallel regulator and power supply combination for improved efficiency and droop response with direct current driven output stage attached directly to the load

Patent metadata

Field	Value
Publication number	US-9785222-B2
Application number	US-201414579899-A
Country	US
Kind code	B2
Filing date	Dec 22, 2014
Priority date	Dec 22, 2014
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

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.

First claim

What is claimed is:

1. A hybrid parallel power supply operating to regulate a voltage level of a power rail, comprising:
a first power supply connected to the 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;
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,
wherein the first power supply and the voltage regulator operate to regulate the voltage level of the power rail so that when the voltage level differs from a respective target voltage level which is either the first target voltage or the second target voltage, the first power supply and the voltage regulator drive the power rail so that the voltage level moves toward the respective target voltage level; and
a second power supply configured to supply power at a third target voltage level to an input of the voltage regulator,
wherein the voltage regulator is disposed on a first die with the load device and the first power supply and the second power supply are disposed on a second die.

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 capacitor disposed on the first die and connected to an input of the voltage regulator.

10. 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, wherein supplying current from the voltage regulator comprises:
amplifying a difference between a voltage of the power rail and the second target voltage level;
supplying the current from the voltage regulator based on the amplified difference;
generating a reference output voltage based on a bandgap source;
generating the second target voltage level based on a first digital input and the reference output voltage;

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

11. The method of claim 10 , wherein the power supply is a switching mode power supply.

12. The method of claim 10 , wherein the voltage regulator is a low dropout voltage regulator.

13. The method of claim 10 , wherein the first target voltage level is greater than the second target voltage level.

14. A hybrid parallel power supply operating to regulate a voltage level of a power rail, comprising:
a first means for supplying power connected to the power rail and configured to supply current at a first target voltage level to a load device via the power rail;
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,
wherein the first means for supplying power and the means for regulating voltage operate to regulate the voltage level of the power rail so that when the voltage level differs from a respective target voltage level which is either the first target voltage or the second target voltage, the first means for supplying power and the means for regulating voltage drive the power rail so that the voltage level moves toward the respective target voltage level; and
a second means for supplying power at a third target voltage level to an input of the means for regulating voltage,
wherein the means for regulating voltage is disposed on a first die with the load device and the first and second means for supplying power are disposed on a second die.

15. The hybrid parallel power supply of claim 14 , wherein the first means for supplying power is a switching mode power supply.

16. The hybrid parallel power supply of claim 14 , wherein the means for regulating voltage is a low dropout voltage regulator.

17. The hybrid parallel power supply of claim 14 , wherein the first target voltage level is greater than the second target voltage level.

18. The hybrid parallel power supply of claim 14 , 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.

19. The hybrid parallel power supply of claim 18 , wherein the operational amplifier is an operational transconductance amplifier.

20. The hybrid parallel power supply of claim 18 , 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.

21. The hybrid parallel power supply of claim 20 ,
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 pow

Assignees

• Qualcomm Inc

Inventors

• Doyle James Thomas
• Fu Zhengming
• Mahmoudi Farsheed
• Shayan Arani Amirali
• Darbanian Nazanin

Classifications

• G05F1/575 Primary

  characterised by the feedback circuit · CPC title

• G06F1/3287 Primary

  by switching off individual functional units in the computer system · CPC title

• H02M2003/1566

  Electricity · mapped topic

• H02M2001/0045

  Electricity · mapped topic

• G06F1/3296

  by lowering the supply or operating voltage · CPC title