Damping modulation circuit for a full-duplex transponder
First Claim
1. A damping modulation circuit within a transponder, wherein the transponder comprises a circuit having a fieldstrength voltage in dependence upon the transponder'"'"'s proximity to an interrogator wherein the damping modulation circuit comprises:
- a high fieldstrength circuit comprising a plurality of voltage limiters, each of said voltage limiters comprising a modulation input for controlling the limiter voltage by conducting a large portion of transponder current to an electrical ground in response to said transponder circuit having a high fieldstrength voltage;
a low fieldstrength circuit comprising a first plurality of transistors for conducting a small portion of transponder current to ground while leaving the remaining portion of transponder current for providing power for operating said transponder in response to said transponder circuit having a low fieldstrength voltage; and
a medium fieldstrength circuit comprising a second plurality of transistors, said second plurality of transistors activated to establish a sufficient amount of current flow for a desired degree of modulation of energy within said transponder and in response to said transponder circuit having a medium fieldstrength voltage.
1 Assignment
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Accused Products
Abstract
An improved damping modulation circuit (140) for a transponder (14) receives energy transmitted from a transmitter/receiver antenna (16) to produce a unique recognition signal in the transponder. The improved damping modulation circuit (140) includes a high fieldstrength circuit (152, 160, 174) that protects full-duplex transponder (14) from over-voltage through the use of voltage limiters (132), while still providing power to transponder (14). Low fieldstrength circuit (152) activates only minimal circuitry to provide the highest possible amount of power to full-duplex transponder (14). Medium fieldstrength circuit (152, 160) increases the fieldstrength in full-duplex transponder (14) for establishing a sufficient amount of current flow for proper modulation using only a medium amount of transponder (14) circuit elements.
116 Citations
20 Claims
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1. A damping modulation circuit within a transponder, wherein the transponder comprises a circuit having a fieldstrength voltage in dependence upon the transponder'"'"'s proximity to an interrogator wherein the damping modulation circuit comprises:
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a high fieldstrength circuit comprising a plurality of voltage limiters, each of said voltage limiters comprising a modulation input for controlling the limiter voltage by conducting a large portion of transponder current to an electrical ground in response to said transponder circuit having a high fieldstrength voltage; a low fieldstrength circuit comprising a first plurality of transistors for conducting a small portion of transponder current to ground while leaving the remaining portion of transponder current for providing power for operating said transponder in response to said transponder circuit having a low fieldstrength voltage; and a medium fieldstrength circuit comprising a second plurality of transistors, said second plurality of transistors activated to establish a sufficient amount of current flow for a desired degree of modulation of energy within said transponder and in response to said transponder circuit having a medium fieldstrength voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of forming a damping modulation circuit for a transponder, wherein the transponder comprises a circuit having a fieldstrength voltage in dependence upon the transponder'"'"'s proximity to an interrogator comprising:
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forming a high fieldstrength circuit comprising a plurality of voltage limiters, each of said voltage limiters comprising a modulation input for controlling the limiter voltage by conducting current to an electrical ground in response to said transponder circuit having a high fieldstrength voltage; forming a low fieldstrength circuit comprising a first plurality of transistors for conducting a small portion of transponder current to ground while leaving the remaining portion of transponder current for providing power for operating said transponder in response to said transponder circuit having a low fieldstrength voltage; forming a medium fieldstrength circuit comprising a second plurality of transistors for establishing a sufficient amount of current flow for a desired degree of modulation of energy within said transponder and in response to said transponder circuit having a medium fieldstrength voltage. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification