Power supply circuit and method for stable system turn-off

• US 20060072268A1
• Filed: 09/30/2005
• Published: 04/06/2006
• Est. Priority Date: 10/06/2004
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kang, Bum-Suk
• Application Number:
  US11/241,476
• Publication Number:
  US 20060072268A1
• Time in Patent Office: Days
• US Class Current: 361/92
• CPC Class Codes: G06F 1/30 Means for acting in the event of power-supply failure or interruption, e.g. power-supply fluctuations for resetting only G06F1/24
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02J 9/005 using a power saving mode for copiers G03G15/5004
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: H04M 1/72403 with means for local support of applications that increase the functionality
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Disclosed are a power supply circuit and method for mobile communication terminals, such as PDAs and portable phones. When a main power source such as a battery is abruptly detached from a system, the abrupt detachment of the main power source is detected and the system is stably turned off only with a backup power source. The power supply circuit includes a first switch for providing a driving voltage from the main power source to the system, a second switch for providing a driving voltage from the backup power source to the system when the main power source is detached from the system, a controller for generating a control signal for opening the first switch and closing the second switch when the main power source is detached from the system, and a memory for storing user data.

Claims

1. A power supply circuit equipped with a main power source and a backup power source for stably turning off a system, the power supply circuit comprising:

a first switch for providing a driving voltage from the main power source to the system;

a second switch for providing a driving voltage from the backup power source to the system when the main power source is detached from the system;

a controller for generating a control signal for opening the first switch and closing the second switch when detachment of the main power source from the system is detected; and

a memory for storing user data.

2. The power supply circuit of claim 1, further comprising:

a capacitor for instantaneously providing driving voltage to the controller when the main power source is detached from the system.

3. The power supply circuit of claim 2, wherein, during normal operation, the capacitor is charged by the main power source.

4. The power supply circuit of claim 2, wherein the capacitor is connected in parallel to the main power source.

5. The power supply circuit of claim 1, wherein the memory is an SDRAM.

6. The power supply circuit of claim 1, wherein the memory receives power from the backup power source when the main power source is detached from the system.

7. The power supply circuit of claim 1, wherein the controller receives power from the backup power source when the main power source is detached from the system.

8. The power supply circuit of claim 1, further comprising:

a main power source detection switch for transmitting a detection signal to the controller when the main power source is detached from the system.

9. A mobile communication terminal equipped with a power supply circuit including a main power source and a backup power source for stably turning off the mobile communication terminal, the power supply circuit comprising:

a first switch for providing a driving voltage from the main power source to the mobile communication terminal;

a second switch for providing a driving voltage from the backup power source to the mobile communication terminal when the main power source is detached from the mobile communication terminal;

a controller for generating a control signal for opening the first switch and closing the second switch when detachment of the main power source from the mobile communication terminal is detected; and

a memory for storing user data.

10. The mobile communication terminal of claim 9, further comprising:

a capacitor for instantaneously providing driving voltage to the controller when the main power source is detached from the mobile communication terminal.

11. The mobile communication terminal of claim 10, wherein, during normal operation, the capacitor is charged by the main power source.

12. The mobile communication terminal of claim 10, wherein the capacitor is connected in parallel to the main power source.

13. The mobile communication terminal of claim 9, wherein the memory is an SDRAM.

14. The mobile communication terminal of claim 9, wherein the memory receives power from the backup power source when the main power source is detached from the mobile communication terminal.

15. The mobile communication terminal of claim 9, wherein the controller receives power from the backup power source when the main power source is detached from the mobile communication terminal.

16. The mobile communication terminal of claim 9, further comprising:

a main power source detection switch for transmitting a detection signal to the controller when the main power source is detached from the mobile communication terminal.

17. A power supply method for stably turning off a system, comprising the steps of:

providing driving voltage from a capacitor to a controller when a main power source is detached from the system;

providing driving voltage from a backup power source to the system when the main power source is detached from the system; and

performing, by the controller, a refresh command for a memory and then performing a system turn-off operation.

18. The method of claim 17, wherein driving voltage from the backup power source is provided to the system by opening a first switch for supplying main power and closing a second switch for supplying backup power.

19. The method of claim 17, wherein, during normal operation, the capacitor is charged by the main power source.

20. The method of claim 17, wherein the capacitor is connected in parallel to the main power source.

21. The method of claim 17, wherein the memory is an SDRAM.