UNTETHERED STYLUS EMPLOYING LOW CURRENT POWER CONVERTER
First Claim
1. An untethered stylus configured to cooperate with a location sensor, the location sensor configured to generate a varying magnetic field and communicatively couple to the stylus, the stylus comprising:
- a housing configured for hand-held manipulation;
a coil resonant circuit provided in the housing and configured to develop an arbitrary AC voltage in response to the magnetic field, the coil resonant circuit comprising a first capacitor and an inductive coil; and
a power converter coupled to the coil resonant circuit and comprising a switch circuit having an output coupled to a second capacitor, an input coupled to the coil resonant circuit, and a threshold voltage, the switch circuit configured to facilitate charging of the second capacitor in response to the arbitrary AC voltage and discontinuance of second capacitor charging in response to a voltage across the first capacitor reaching the threshold voltage so as to prevent diversion of a discharging current when the arbitrary AC voltage exceeds the threshold voltage, wherein a stable DC voltage is provided at the output of the switch circuit.
1 Assignment
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Accused Products
Abstract
An untethered stylus, configured to cooperate with a location sensor, includes a coil resonant circuit configured to develop an arbitrary AC voltage in response to a varying magnetic field produced by the location sensor. The coil resonant circuit includes a first capacitor and an inductive coil. A power converter includes a switch circuit having an output coupled to a second capacitor, an input coupled to the coil resonant circuit, and a threshold voltage. The switch circuit facilitates charging of the second capacitor in response to the arbitrary AC voltage and discontinuance of second capacitor charging in response to a voltage across the first capacitor reaching the threshold voltage so as to prevent diversion of a discharging current when the arbitrary AC voltage exceeds the threshold voltage. A stable DC voltage is provided at the output of the switch circuit. The power converter is preferably devoid of a Zener diode.
130 Citations
20 Claims
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1. An untethered stylus configured to cooperate with a location sensor, the location sensor configured to generate a varying magnetic field and communicatively couple to the stylus, the stylus comprising:
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a housing configured for hand-held manipulation; a coil resonant circuit provided in the housing and configured to develop an arbitrary AC voltage in response to the magnetic field, the coil resonant circuit comprising a first capacitor and an inductive coil; and a power converter coupled to the coil resonant circuit and comprising a switch circuit having an output coupled to a second capacitor, an input coupled to the coil resonant circuit, and a threshold voltage, the switch circuit configured to facilitate charging of the second capacitor in response to the arbitrary AC voltage and discontinuance of second capacitor charging in response to a voltage across the first capacitor reaching the threshold voltage so as to prevent diversion of a discharging current when the arbitrary AC voltage exceeds the threshold voltage, wherein a stable DC voltage is provided at the output of the switch circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of communicatively coupling a stylus and a location sensor, comprising:
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receiving, at the stylus, a varying magnetic field generated by the location sensor; developing an arbitrary AC voltage in a coil resonant circuit of the stylus in response to the magnetic field, the coil resonant circuit comprising a first capacitor and an inductive coil; charging the second capacitor in response to the arbitrary AC voltage; discontinuing second capacitor charging using a switch circuit coupled to the coil resonant circuit in response to a voltage across the first capacitor reaching a threshold voltage so as to prevent diversion of a discharging current when the arbitrary AC voltage exceeds the threshold voltage; and producing a stable DC voltage at an output of the switch circuit. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification