Memory card device having low consumed power in the consumed power state
View Patent ↗A card device has a regulator ( 5 ), a first internal circuit ( 6 ) and a second internal circuit ( 7 ), and the regulator supplies, to the second internal circuit, an internal voltage generated by dropping an external voltage (VCC) when the external voltage is high, and exactly supplies the external voltage as the internal voltage to the second internal circuit when the external voltage is low, and the external voltage is supplied as an operating power source to the first internal circuit and a transition to a low consumed power state is carried out if a command is not input for a certain period. The card device stops the operation of the regulator and suppresses the supply of the internal voltage to the second internal circuit in the transition to the low consumed power state. In the low consumed power state, consequently, it is possible to suppress a power consumption in each of the regulator and the second internal circuit in the card device.
1. A card device having a normal operation state and a low consumed power state as an operation state and serving to carry out a transition from the normal operation state to the low consumed power state if a command is not input for a certain period, comprising a regulator, a first internal circuit and a second internal circuit,
wherein the regulator supplies, to the second internal circuit, an internal voltage generated by dropping an external voltage when the external voltage is high, and exactly supplies the external voltage as an internal voltage to the second internal circuit when the external voltage is low,
the external voltage is supplied as an operating power source to the first internal circuit and the supply of the external voltage to be the operating power source is continuously carried out also after the transition to the low consumed power state, and
when the operation state of the card device carries out the transition to the low consumed power state, an operation of the regulator is stopped and the supply of the internal voltage to be supplied to the second internal circuit by the regulator is suppressed.
2. The card device according to claim 1 , wherein when a return from the low consumed power state to the operation state is performed, the first internal circuit can restart the operation of the regulator to supply the internal voltage to the second internal circuit.
3. The card device according to claim 2 , wherein the regulator has a voltage detecting circuit for deciding whether an external voltage is high or not and a reference voltage generating circuit for generating a reference voltage to be utilized when dropping the external voltage, and
a stop of the operation of the regulator in the transmission to the low consumed power state is set to be that of operations of the voltage detecting circuit and the reference voltage generating circuit.
4. The card device according to claim 1 , wherein the second internal circuit has a microcomputer and the transition to the low consumed power state triggers a transition to a sleep state of the microcomputer.
5. The card device according to claim 4 , wherein the first internal circuit operates the regulator in response to a command input and restarts the supply of the internal voltage to the second internal circuit in a low consumed power state.
6. The card device according to claim 5 , wherein the microcomputer detects the supply of the operating power source in the sleep state, thereby carrying out a power-ON reset processing.
7. The card device according to claim 6 , wherein the first internal circuit has a storage region for saving and the microcomputer saves necessary internal information for a return of an internal state in the storage region for saving in the transition to the sleep state.
8. The card device according to claim 7 , wherein the microcomputer returns necessary internal information retained in the storage region for saving in the power-ON reset processing.
9. A card device having a normal operation state and a low consumed power state as an operation state and serving to carry out a transition from the normal operation state to the low consumed power state if a command is not input for a certain period of time,
wherein a regulator generates an internal voltage by dropping an external voltage supplied from an outside and supplies the internal voltage to an internal circuit when the external voltage is high, and exactly supplies the external voltage as the internal voltage to the internal circuit when the external voltage is low, and
an operation of the regulator is stopped, a supply of a power to a part of the internal circuit is stopped and the external voltage is exactly supplied as the internal voltage to the other portions of the internal circuit in a transition from the operation state to the low consumed power state.
10. The card device according to claim 9 , wherein the part of the internal circuit in which the supply of the power is stopped in the transition from the normal operation state to the low consumed power state includes a microcomputer to be brought into a sleep state.
11. The card device according to claim 10 , wherein the other portions of the internal circuit have a storage region for saving and the microcomputer saves necessary internal information for a return of an internal state in the storage region for saving in a transition to the sleep state.
12. The card device according to claim 11 , wherein the microcomputer carries out the return of the necessary internal information retained in the storage region for saving in a power-ON reset processing.