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