Systems and methods for power reduction in systems having removable media devices
View Patent ↗In some embodiments, if a card in a card reader has not been accessed in a first specified amount of time, the card may be powered down. The card may be powered back up if an attempt is made to access the card. In some embodiments, if a memory card is in the memory card slot of the card reader, but has not been accessed in a second specified amount of time, the card reader may be electrically disconnected from the host controller if a sideband signal is available to signal the card reader when to electrically reconnect.
1. A system, comprising:
a processor;
a host controller coupled to the processor; and
a card reader coupled to the host controller;
wherein the card reader does not apply power to a memory card inserted into the card reader if the memory card has not been accessed in a first specified amount of time;
wherein the card reader is electrically disconnected from the host controller if the memory card has not been accessed for a second specified amount of time; and
wherein a sideband signal is used to signal the card reader to electrically reconnect to the host controller if there is an attempt to access the memory card.
2. The system of claim 1 , wherein the card reader is internal to a computer system housing the processor.
3. The system of claim 1 , wherein the card reader, is external to a computer system housing the processor.
4. The system of claim 1 , wherein the memory card is a flash memory card.
5. The system of claim 1 , wherein the first specified amount of time is approximately in a range of 0 to 10 seconds.
6. The system of claim 1 , wherein if the memory card is accessed, the system is operable to apply power to the memory card.
7. The system of claim 1 , wherein the host controller is a universal serial bus (USB) host controller and the card reader is a USB card reader.
8. The system of claim 1 , wherein the system is operable to power down the processor if the memory card has not been accessed for a third specified amount of time.
9. The system of claim 1 , wherein the host controller provides a peripheral bus interface for the card reader.
10. The system of claim 1 , wherein the second specified amount of time is approximately in a range of 0 to 10 minutes.
11. A system, comprising:
a processor;
a host controller coupled to the processor; and
a card reader coupled to the host controller;
wherein the card reader is operable to apply power to a memory card in the card reader;
wherein the card reader is operable to discontinue applying power to the memory card in the card reader, without the processor being powered down, if the memory card has not been accessed in a first specified amount of time;
wherein the system is operable to electrically disconnect the card reader from the host controller if the card has not been accessed for a second specified amount of time; and
wherein the system is operable to send a sideband signal to signal the card reader to electrically reconnect to the host controller if there is an attempt to access the card.
12. The system of claim 11 , wherein the memory card is a flash memory card.
13. The system of claim 11 , wherein the first specified amount of time is approximately in a range of 0 to 10 seconds.
14. The system of claim 11 , wherein if the memory card is accessed, the system is operable to apply power to the memory card.
15. The system of claim 11 , wherein the host controller is a universal serial bus (USB) host controller and the card reader is a USB card reader.
16. The system of claim 11 , wherein the second specified amount of time is approximately in a range of 0 to 10 minutes.
17. A method, comprising:
applying power to a memory card in a card reader coupled to a computer;
detecting whether the memory card has been accessed during a first specified amount of time;
if the memory card has not been accessed during the first specified amount of time, removing power from the memory card, without the computer being powered down;
if the memory card has been accessed during the first specified amount of time, continuing to power the memory card;
if the memory card has not been accessed during a second specified amount of time, electrically disconnecting the card reader from a host controller coupled to the card reader; and
if there is an attempt to access the card, a sideband signal is used to signal the card reader to electrically reconnect to the host controller.
18. The method of claim 17 , wherein the memory card is a flash memory card.
19. The method of claim 17 , wherein the first specified amount of time is approximately in a range of 0 to 10 seconds.
20. The method of claim 17 , wherein if the memory card is accessed, power is applied to the memory card.
21. The method of claim 17 , wherein the second specified amount of time is approximately in a range of 0 to 10 minutes.