It is intended to provide a control circuit of power supply, a power supply and a control method thereof capable of achieving power saving in an integrated circuit and reducing a delay time of the integrated circuit. The control circuit 50 of a power supply 10 which outputs plural DC voltages VCC, VBGP, VBGN each having a different voltage value includes a voltage changing portion SW1 which detects an output current I1 relating to a first DC voltage VCC which is one of the plural DC voltages and sets at least one DC voltage except the first DC voltage VCC based on the detected output current I1, and the like.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit structure diagram of a power supply according to a first embodiment of the present invention; and
FIG. 2 is a circuit structure diagram of a power supply according to a second embodiment.
Claims
1. A control circuit of power supply for outputting plural DC voltages each having a different voltage value, comprising:
a voltage changing portion that detects an output current relating to a first DC voltage that is one of the plural DC voltages and sets up at least one DC voltage except the first DC voltage based on the detected output current.
2. The control circuit of power supply according to claim 1, wherein the voltage changing portion comprises:
a detecting portion for detecting the output current;a comparing portion for outputting a result of comparison between a detection value of the detecting portion and a reference voltage value; anda selecting portion for selecting a setting voltage for use in setting at least one DC voltage from the preliminarily set plural setting voltages based on the comparison result.
3. The control circuit of power supply according to claim 2, wherein the detecting portion includes a buffer in which the value of the output current converted to a voltage is inputted to output the detection value.
4. The control circuit of power supply according to claim 2, wherein the preliminarily set plural setting voltages include: a first selection voltage set to the first DC voltage and a second selection voltage set to a larger value than the voltage value of the first selection voltage; a first power supply for supplying the first selection voltage and a second power supply for supplying the second selection voltage are provided; the selecting portion includes a first changing portion that is connected to any one of the first power supply and the second power supply; and when it is determined that the detection value is larger than the reference voltage value based on the comparison result, the selecting portion selects the first selection voltage by connecting the first changing portion to the first power supply and when it is determined that the detection value is smaller than the reference voltage value based on the comparison result, selects the second selection voltage by connecting the first changing portion to the second power supply.
5. The control circuit of power supply according to claim 4, wherein the first DC voltage is a power supply voltage to be outputted to the power supply terminal of a P type semiconductor device and the DC voltage having a voltage value set by the first selection voltage and the second selection voltage is a back gate voltage outputted to the back gate of the P type semiconductor device.
6. The control circuit of power supply according to claim 2, wherein the preliminarily set plural setting voltages include: a third selection voltage set to a smaller value than the voltage value of the first DC voltage and a fourth selection voltage set to a larger value than the voltage value of the third selection voltage; a third power supply for supplying the third selection voltage and a fourth power supply for supplying the fourth selection voltage are provided; the selecting portion includes a second changing portion that is connected to any one of the third power supply and the fourth power supply; and when it is determined that the detection value is larger than the reference voltage value based on the comparison result, the selecting portion selects the third selection voltage by connecting the second changing portion to the third power supply and when it is determined that the detection value is smaller than the reference voltage value based on the comparison result, selects the fourth selection voltage by connecting the second changing portion to the fourth power supply.
7. The control circuit of power supply according to claim 6, wherein the first DC voltage is a power supply voltage to be outputted to the power supply terminal of a N type semiconductor device and the DC voltage having a voltage value set by the third selection voltage and the fourth selection voltage is a back gate voltage outputted to the back gate of the N type semiconductor device.
8. A power supply for outputting plural DC voltages each having a different voltage value, comprising:
a voltage changing portion that detects an output current relating to a first DC voltage that is one of the plural DC voltages and sets up at least one DC voltage except the first DC voltage based on the detected output current.
9. The power supply according to claim 8, wherein the voltage changing portion comprises: a detecting portion for detecting the output current; a comparing portion for outputting a result of comparison between a detection value of the detecting portion and a reference voltage value; and a selecting portion for selecting a setting voltage for use in setting at least one DC voltage from the preliminarily set plural setting voltages based on the comparison result.
10. The power supply according to claim 9, wherein the detecting portion includes: a resistor device for conducting the output current to convert to a voltage; and a buffer in which the value of the output current converted to a voltage by the resistor device is inputted to output the detection value.
11. The power supply according to claim 9, wherein the preliminarily set plural setting voltages include: a first selection voltage set to the first DC voltage and a second selection voltage set to a larger value than the voltage value of the first selection voltage; a first power supply for supplying the first selection voltage and a second power supply for supplying the second selection voltage are provided; the selecting portion includes a first changing portion that is connected to any one of the first power supply and the second power supply; and when it is determined that the detection value is larger than the reference voltage value based on the comparison result, the selecting portion selects the first selection voltage by connecting the first changing portion to the first power supply and when it is determined that the detection value is smaller than the reference voltage value based on the comparison result, selects the second selection voltage by connecting the first changing portion to the second power supply.
12. The power supply according to claim 11, wherein the first DC voltage is a power supply voltage to be outputted to the power supply terminal of a P type semiconductor device and the DC voltage having a voltage value set by the first selection voltage and the second selection voltage is a back gate voltage outputted to the back gate of the P type semiconductor device.
13. The power supply according to claim 9, wherein the preliminarily set plural setting voltages include a third selection voltage set to a smaller value than the voltage value of the first DC voltage and a fourth selection voltage set to a larger value than the voltage value of the third selection voltage; a third power supply for supplying the third selection voltage and a fourth power supply for supplying the fourth selection voltage are provided; the selecting portion includes a second changing portion that is connected to any one of the third power supply and the fourth power supply; and when it is determined that the detection value is larger than the reference voltage value based on the comparison result, the selecting portion selects the third selection voltage by connecting the second changing portion to the third power supply and when it is determined that the detection value is smaller than the reference voltage value based on the comparison result, selects the fourth selection voltage by connecting the second changing portion to the fourth power supply.
14. The power supply according to claim 13, wherein the first DC voltage is a power supply voltage to be outputted to the power supply terminal of a N type semiconductor device and the DC voltage having a voltage value set by the third selection voltage and the fourth selection voltage is a back gate voltage outputted to the back gate of the N type semiconductor device.
15. A control method of power supply for outputting plural DC voltages each having a different voltage value, comprising the steps of:
detecting an output current relating to a first DC voltage that is one of the plural DC voltages; andsetting up at least one DC voltage except the first DC voltage based on the detected output current.
16. The control method of power supply according to claim 15, wherein the output current is detected; a result of comparison between the detection value originating from the output current and the reference voltage value is outputted; and a setting voltage for use in setting at least one DC voltage is selected from the preliminarily set plural setting voltages based on the result of comparison.
17. The control method of power supply according to claim 16, wherein the preliminarily set plural setting voltages include a first selection voltage set to the first DC voltage and a second selection voltage set to a larger value than the voltage value of the first selection voltage and when it is determined that the detection value is larger than the reference voltage value based on the comparison result, the first selection voltage is selected and when it is determined that the detection value is smaller than the reference voltage value based on the comparison result, the second selection voltage is selected.
18. The control method of power supply according to claim 17 further comprising outputting the first DC voltage to the power supply terminal of a P type semiconductor device and outputting the DC voltage having a voltage value set by the first selection voltage and the second selection voltage to the back gate of the P type semiconductor device.
19. The control method of power supply according to claim 16, wherein the preliminarily set plural setting voltages include a third selection voltage set to a smaller value than the voltage value of the first DC voltage and a fourth selection voltage set to a larger value than the voltage value of the third selection voltage and when it is determined that the detection value is larger than the reference voltage value based on the comparison result, the third selection voltage is selected and when it is determined that the detection value is smaller than the reference voltage value based on the comparison result, the fourth selection voltage is selected.
20. The control method of power supply according to claim 19, wherein the first DC voltage is outputted to the power supply terminal of the N type semiconductor device and the DC voltage having a voltage value set by the third selection voltage and the fourth selection voltage is outputted to the back gate of the N type semiconductor device.
Patent Application
20070217108
