IP Library › Granted Patent US 7,728,550
Granted Patent B2
US 7,728,550 · App. 11/780,539 · Granted Jun 1, 2010

Integrated CMOS DC-DC converter implementation in low-voltage CMOS technology using LDO regulator

View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 7,728,550
App. No.
11/780,539
Granted
Jun 1, 2010
Kind
B2
Abstract

An electrical circuit and method of power management of a cellular telephone includes a battery adapted to produce a battery voltage; a LDO regulator operatively connected to the battery and adapted to provide a constant supply voltage from the battery voltage; and a DC-DC converter operatively connected to the LDO regulator, wherein the DC-DC converter is adapted to step down the constant supply voltage to a lower voltage level, wherein the LDO regulator and the DC-DC converter are embedded on a single integrated circuit chip. The constant supply voltage equals 3.6V at an output of the LDO, and the constant supply voltage is applied to an input of the DC-DC converter. Moreover, the battery voltage equals at most 5.5V.

Claims (45)

1. An electrical circuit comprising:

a battery adapted to produce a battery voltage;

a low dropout (LDO) regulator operatively connected to said battery and adapted to provide a constant supply voltage from said battery voltage; and

a DC-DC converter operatively connected to said LDO regulator, wherein said DC-DC converter is adapted to step down said constant supply voltage to a lower voltage level,

wherein said LDO regulator and said DC-DC converter are embedded on a single integrated circuit, and

wherein said LDO is adapted to keep said constant supply voltage being input to said DC-DC converter at 3.6V.

2. The electrical circuit of claim 1 , wherein said constant supply voltage equals 3.6V at an output of said LDO, and wherein said constant supply voltage is applied to an input of said DC-DC converter.

3. The electrical circuit of claim 1 , wherein said battery voltage equals at most 5.5V when said battery is being charged by an AC power source.

4. The electrical circuit of claim 1 , further comprising an alternating current (AC) source that charges said battey.

5. The electrical circuit of claim 1 , wherein said LDO is adapted to drop said battery voltage from 5.5V to 3.6V.

6. The electrical circuit of claim 1 , wherein said DC-DC converter comprises:

a pair of complementary metal oxide semiconductor (CMOS) switches; and

a pulse width modulator (PWM) adapted to provide pulse signals to drive said CMOS switches.

7. A communications system comprising:

an alternating current (AC) source;

a battery charger; and

a cellular telephone comprising:

a battery adapted to produce a battery voltage; and

a single system on-chip (SoC) integrated circuit chip comprising:

a low dropout (LDO) regulator operatively connected to said battery and adapted to provide a constant supply voltage from said battery voltage; and

a DC-DC converter operatively connected to said LDO regulator, wherein said DC-DC converter is adapted to step down said constant supply voltage to a lower voltage level.

8. The communications system of claim 7 , wherein said constant supply voltage equals 3.6V at an output of said LDO, and wherein said constant supply voltage is applied to an input of said DC-DC converter.

9. The communications system of claim 7 , wherein said battery voltage equals at most 5.5V when said battery is being charged by said AC source.

10. The communications system of claim 7 , wherein said LDO is adapted to keep said constant supply voltage being input to said DC-DC converter at 3.6V.

11. The communications system of claim 7 , wherein said LDO is adapted to drop said battery voltage from 5.5V to 3.6V.

12. The communications system of claim 7 , wherein said DC-DC converter comprises:

a pair of complementary metal oxide semiconductor (CMOS) switches; and

a pulse width modulator (PWM) adapted to provide pulse signals to drive said CMOS switches.

13. The communications system of claim 7 , wherein said cellular telephone is adapted to be in a power-down mode while said battery charger is plugged to said AC source.

14. A method of performing power management of a cellular telephone, said method comprising:

using a battery to produce a battery voltage;

operatively connecting a low dropout (LDO) regulator to said battery;

using said LDO regulator to provide a constant supply voltage from said battery voltage;

operatively connecting a DC-DC converter to said LDO regulator; and

using said DC-DC converter to step down said constant supply voltage to a lower voltage level,

wherein said LDO regulator and said DC-DC converter are embedded on a single integrated circuit chip, and

wherein said LDO is adapted to keep said constant supply voltage being input to said DC-DC converter at 3.6V.

15. The method of claim 14 , wherein said constant supply voltage equals 3.6V at an output of said LDO, and wherein said constant supply voltage is applied to an input of said DC-DC converter.

16. The method of claim 14 , wherein said battery voltage equals at most 5.5V in said cellular telephone.

17. The method of claim 14 , further comprising providing an alternating current (AC) source and a battery charger.

18. The method of claim 14 , wherein said LDO is adapted to drop said battery voltage from 5.5V to 3.6V.

19. The method of claim 17 , wherein said cellular telephone is adapted to be in a power-down mode while said battery charger is plugged to said AC source.

20. The method of claim 14 , wherein said DC-DC converter comprises:

a pair of complementary metal oxide semiconductor (CMOS) switches; and

a pulse width modulator (PWM) adapted to provide pulse signals to drive said CMOS switches.