Power supply circuit, power supply method and power supply system
View Patent ↗A power supply circuit supplies power to a load from a main power source or an auxiliary power source. The power supply circuit includes a hybrid selection unit that selects one of the main power source and the auxiliary power source and supplies power to the load from the selected one, a voltage comparing unit that compares a voltage of the main power source and a voltage of the auxiliary power source, and a power source control unit that controls the auxiliary power source in accordance with a comparison result of the voltage comparing unit, and supplies a voltage higher than the voltage of the main power source by a predetermined voltage to the load from the auxiliary power source through the hybrid selection unit.
1. A power supply circuit which supplies power to a load from a main power source or an auxiliary power source, the power supply circuit comprising:
an energy storage unit that stores power that is supplied from the auxiliary power source;
a hybrid selection unit that elects one of the main power source and the auxiliary power source and supplies power to the load from the selected one;
a first voltage comparing unit that compares a voltage of the main power source and a voltage of the auxiliary power source;
a power source control unit that controls the auxiliary power source in accordance with a comparison result of the voltage comparing unit, and supplies a voltage higher than the voltage of the main power source by a predetermined voltage to the load from the auxiliary power source through the hybrid selection unit;
a reference voltage unit that holds a minimum voltage that is necessary for the load; and
another voltage comparing unit that compares a power source voltage selected by the hybrid selection unit with the voltage of the reference voltage unit, wherein:
the power source control unit suspends supply of power from the auxiliary power source during a period when the first voltage comparing unit determines that the voltage of the auxiliary power source is higher than the voltage of the main power source by a predetermined voltage or more and the another voltage comparing unit determines that the selected power source voltage is higher than the voltage of the reference voltage unit.
2. The power supply circuit according to claim 1 , wherein
the main power source is a battery.
3. The power supply circuit according to claim 1 , wherein
The first voltage comparing unit compares the voltage of the main power source and the voltage of the energy storage unit successively.
4. The power supply circuit according to claim 1 , wherein
the hybrid selection unit selects one, having a higher voltage, of the main power source and the energy storage unit, and supplies power to the load from the selected one.
5. The power supply circuit according to claim 1 , wherein
the power source control unit suspends supply of power from the auxiliary power source to the energy storage unit during a period when the voltage comparing unit determines that the voltage of the energy storage unit is higher than the voltage of the main power source by a predetermined voltage or more.
6. The power supply circuit according to claim 1 , wherein
a second energy storage unit is provided in a wiring line which connects the auxiliary power source and the power source control unit, the second energy storage unit being provided for storing power to be supplied from the auxiliary power source to the energy storage unit.
7. The power supply circuit according to claim 1 , wherein
a resistor unit is provided in a wiring line which connects the first voltage comparing unit and the energy storage unit, the resistor unit having a predetermined resistance for securing a voltage difference between the voltage of the main power source and the voltage of the energy storage unit which are compared by the first voltage comparing unit.
8. The power supply circuit according to claim 1 , wherein
the hybrid selection unit supplies power to the load from the auxiliary power source when the power source control unit can supply the voltage higher than the voltage of the main power source by the predetermined voltage.
9. The power supply circuit according to claim 8 , further comprising
an energy storage unit for storing power that is supplied from the auxiliary power source and outputting the stored power to the hybrid selection unit, wherein
the power source control unit controls power supply from the auxiliary power source to the energy storage unit in accordance with the comparison result of the first voltage comparing unit.
10. A power supply method for supplying power to a load from a main power source or an auxiliary power source, the power supply method comprising:
a selection step of selecting one of the main power source and the auxiliary power source and supplying power to the load from the selected one;
a voltage comparing step of comparing a voltage of the main power source and a voltage of the auxiliary power source;
a power source control step of controlling the auxiliary power source in accordance with a comparison result of the voltage comparing step and supplying a voltage higher than the voltage of the main power source by a predetermined voltage to the load from the auxiliary power source;
a reference voltage step of holding a reference voltage that is a minimum voltage that is necessary for the load; and
another voltage comparing step of comparing the power supplied by the selected one of the main power source and the auxiliary power source with the reference voltage, wherein:
the power source control step includes suspending supply of power from the auxiliary power source during a period when the first voltage comparing step determines that the voltage of the auxiliary power source is higher than the voltage of the main power source by a predetermined voltage or more and the another voltage comparing step determines that the selected power source voltage is higher than the reference voltage.
11. The power supply method according to claim 10 , wherein
the selection step supplies power to the load from the auxiliary power source when the power source control step can supply the voltage higher than the voltage of the main power source by the predetermined voltage.
12. The power supply method according to claim 11 , further comprising:
a charge storage step of storing power that is supplied from the auxiliary power source and outputting the stored power in the hybrid selection unit, wherein
the power source control step controls power supply from the auxiliary power source in the charge storage step in accordance with the comparison result of the first voltage comparing step.