IP telephone with power source circuit
First Claim
1. An internet protocol (IP) telephone, comprising:
- an input connector for receiving from a network a signal containing a digital component and a current component;
a separator for separating said current component from said digital component;
telephone circuitry for providing audio input and output;
a central processing unit (CPU) for controlling operations of said telephone circuitry to cause said telephone circuitry to provide said audio input and output; and
a power source circuit for receiving said current component from said separator, said power source circuit comprising;
an input current limiting resistor for limiting said current component;
a direct-current to direct-current (DC/DC) converter that is connected to said input current limiting resistor;
an input capacitor that is charged by said current component; and
limit removing means for removing the limitation imposed by said input current limiting resistor when said limit removing means is turned on;
wherein said CPU is configured to determine an amount of power being consumed by said CPU; and
wherein said CPU is configured to turn said limit removing means on or off based on the determined amount of power being consumed by the CPU.
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Accused Products
Abstract
An IP telephone has a power source circuit. A direct current from a network is used to charge an input capacitor via an input current limiting resistor. A resultantly charged voltage is inputted to and is converted by a DC/DC converter to produce an output voltage. In parallel with the input current limiting resistor, a limit removing unit including a switching transistor is arranged. The output voltage is delayed by a delay circuit to activate a driving transistor, which drives the switching transistor. The input voltage to the converter is monitored by an input voltage sensor. Therefore, the telephone power source circuit copes with a plurality of hubs of different power supplying specifications in an internet (IP) telephone network in which telephones are connected to a local-area network of the IEEE802.3 standard and the like.
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Citations
16 Claims
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1. An internet protocol (IP) telephone, comprising:
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an input connector for receiving from a network a signal containing a digital component and a current component; a separator for separating said current component from said digital component; telephone circuitry for providing audio input and output; a central processing unit (CPU) for controlling operations of said telephone circuitry to cause said telephone circuitry to provide said audio input and output; and a power source circuit for receiving said current component from said separator, said power source circuit comprising; an input current limiting resistor for limiting said current component; a direct-current to direct-current (DC/DC) converter that is connected to said input current limiting resistor; an input capacitor that is charged by said current component; and limit removing means for removing the limitation imposed by said input current limiting resistor when said limit removing means is turned on; wherein said CPU is configured to determine an amount of power being consumed by said CPU; and wherein said CPU is configured to turn said limit removing means on or off based on the determined amount of power being consumed by the CPU. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification