Direct connect modem deriving power from telephone line
First Claim
1. An apparatus to generate negative and positive voltages from either negative voltages, positive voltages or a combination of positive and negative voltages using a CMOS voltage inverter which comprises:
- a first bi-directional switch;
a second bi-directional switch;
a third bi-directional switch;
a fourth bi-directional switch;
a switch controller for switching said first switch and said second switch in synchronism and for switching said third switch and said fourth switch in synchronism and in non-overlapping closed states with said first switch and said second switch;
said first switch having a first node in common with said third switch, said second switch having a second node in common with said third switch, and said fourth switch having a third node in common with said second switch, said first switch having a fifth node and said fourth switch having a seventh node, the apparatus comprising;
a first capacitor;
a second capacitor;
a third capacitor;
a first diode;
a second diode; and
wherein said second node is coupled to a first terminal of said first capacitor and to a first terminal of said second capacitor at a common ground reference;
wherein said third capacitor is coupled between said first node and said third node;
wherein said first diode is coupled from a first voltage source to a second terminal of said first capacitor and to said fifth node and which is disposed to pass current when forward biased by said first voltage source; and
wherein said second diode is coupled from said first voltage source to a second terminal of said second capacitor and to said seventh node and which is disposed to block current when the said first diode is forward biased by said first voltage source and to pass current when said first diode is reverse biased in order to charge said first capacitor and said second capacitor from positive voltage, from negative voltage or from both positive and negative voltage upon alternate switching by said switch control means to cause current to flow in either direction through said switches.
1 Assignment
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Accused Products
Abstract
A telephone modem which is at least partially powered by electrical power from a telephone line to which it is connected and which is further powered by a local power source, such as power extracted from digital serial data lines to which it is coupled or from a battery source or a combination thereof. Telephone line power is used to operate all analog signal processing, and local power is used to operate the remainder of the modem, including digital signal transmission, reception and manipulation, as well as modem control functions. In a preferred embodiment, optical isolation means provide isolation between differently-powered segments of the modem circuitry. The analog signal processing segment is coupled to the telephone line in a manner which maintains line current requirements and constant a.c. impedance, and regulated power is derived from the intermittent telephone line power source. In a further specific embodiment, charge pump circuitry is employed to extract both positive and negative inverted power from the digital serial data signal line for use as local power.
93 Citations
2 Claims
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1. An apparatus to generate negative and positive voltages from either negative voltages, positive voltages or a combination of positive and negative voltages using a CMOS voltage inverter which comprises:
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a first bi-directional switch; a second bi-directional switch; a third bi-directional switch; a fourth bi-directional switch; a switch controller for switching said first switch and said second switch in synchronism and for switching said third switch and said fourth switch in synchronism and in non-overlapping closed states with said first switch and said second switch; said first switch having a first node in common with said third switch, said second switch having a second node in common with said third switch, and said fourth switch having a third node in common with said second switch, said first switch having a fifth node and said fourth switch having a seventh node, the apparatus comprising; a first capacitor; a second capacitor; a third capacitor; a first diode; a second diode; and wherein said second node is coupled to a first terminal of said first capacitor and to a first terminal of said second capacitor at a common ground reference; wherein said third capacitor is coupled between said first node and said third node; wherein said first diode is coupled from a first voltage source to a second terminal of said first capacitor and to said fifth node and which is disposed to pass current when forward biased by said first voltage source; and wherein said second diode is coupled from said first voltage source to a second terminal of said second capacitor and to said seventh node and which is disposed to block current when the said first diode is forward biased by said first voltage source and to pass current when said first diode is reverse biased in order to charge said first capacitor and said second capacitor from positive voltage, from negative voltage or from both positive and negative voltage upon alternate switching by said switch control means to cause current to flow in either direction through said switches. - View Dependent Claims (2)
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Specification
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- Resources
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Current AssigneeVOCAL Technologies Ltd.
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Original AssigneeVOCAL Technologies Ltd.
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InventorsHirzel, Frederic J.
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Primary Examiner(s)Dwyer, James L.
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Assistant Examiner(s)MATAR, AHMAD
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Application NumberUS07/438,553Time in Patent Office809 DaysField of Search379/98, 379/99, 379/100, 323/313, 307/296.6, 375/36, 375/8, 375/7, 340/310 A, 363/60, 363/61US Class Current379/93.36CPC Class CodesH04M 11/06 Simultaneous speech and dat...H04M 19/08 with current supply sources...
