Power supplying methods and apparatus that provide stable output voltage
First Claim
1. A power supply apparatus, comprising:
- a first power supply circuit that converts a source voltage from a direct current power source into a first voltage and providing the first voltage to an output voltage terminal; and
a second power supply circuit that converts the source voltage from the direct current power source into a second voltage and provides the second voltage to the output terminal, said second power supply circuit being controlled to be turned on and off,wherein the first power supply circuit is further operable to;
sense an output voltage at the output terminal,determine whether the second power supply circuit is inactivated based on the output voltage sensed at the output terminal, andprovide the first voltage to the output terminal when the second power supply circuit is inactivated, andwherein said first and second voltages are unequal.
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Accused Products
Abstract
A direct current power supply apparatus includes a first power supply circuit and a second power supply circuit. The first power supply circuit converts a source voltage from an externally supplied direct current power source into a first voltage and provides the first voltage to an output terminal. The second power supply circuit converts the source voltage from the externally supplied direct current power source into a second voltage and provides the second voltage to the output terminal. The second power supply circuit is controlled to be turned on and off. The first power supply circuit detects voltage at the output terminal and, when the second voltage is not being provided because the second power supply circuit is inactivated, provides the first voltage.
39 Citations
17 Claims
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1. A power supply apparatus, comprising:
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a first power supply circuit that converts a source voltage from a direct current power source into a first voltage and providing the first voltage to an output voltage terminal; and a second power supply circuit that converts the source voltage from the direct current power source into a second voltage and provides the second voltage to the output terminal, said second power supply circuit being controlled to be turned on and off, wherein the first power supply circuit is further operable to; sense an output voltage at the output terminal, determine whether the second power supply circuit is inactivated based on the output voltage sensed at the output terminal, and provide the first voltage to the output terminal when the second power supply circuit is inactivated, and wherein said first and second voltages are unequal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A power supplying method for supplying voltage at an output voltage terminal, comprising:
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supplying a source voltage; in response to sensing a voltage at an output voltage terminal, converting the source voltage into a first voltage and providing the first voltage to the output terminal; and in response to a control signal, converting the source voltage into a second voltage and providing the second voltage to the output terminal; sensing an output voltage at the output terminal; determining whether the second power supply circuit is inactivated based on the output voltage sensed at the output terminal; and providing the first voltage to the output terminal when the second power supply circuit is inactivated, wherein said first and second output voltages are unequal.
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17. A power supply apparatus, comprising:
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a first power supply circuit that converts a source voltage from a direct current power source into a first voltage and provides the first voltage to an output voltage terminal;
said first power supply comprising;a first reference voltage generator that generates a first reference voltage, a first voltage divider that divides a voltage at the output terminal and provides a first divided voltage, an output control transistor that controls output of a source current supplied by the direct current power source in accordance with a gate signal, and a first operational amplifier that provides the gate signal to the output control transistor such that the first divided voltage from the first voltage divider becomes equal to the first reference voltage; and a second power supply circuit that converts the source voltage from the direct current power source into a second voltage and provides the second voltage to the output terminal, said second power supply circuit being controlled to be turned on and off, wherein the first power supply circuit is further operable to; sense an output voltage at the output terminal, determine whether the second power supply circuit is inactivated based on the output voltage sensed at the output terminal, and provide the first voltage to the output terminal when the second power supply circuit is inactivated, and wherein the first power supply circuit adjusts an output current to the output terminal so that the voltage detected at the output terminal becomes equal to the first voltage, and the first voltage is smaller than the second voltage.
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Specification