SAFE PLANAR ELECTRICAL HEATER
First Claim
1. An electrical heater comprisinga heating element andone or more conductive sense wires connected to the heating element in a predetermined position between points at which power is applied to the heating element, wherein the one or more sense wires is further connected to a voltage detector, to compare a voltage from the voltage detector with a predetermined range, and triggering a safety indicator or safety trip if the voltage is outside the predetermined range.
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Accused Products
Abstract
An electrical heater element containing one or more sense wires located at a point or points between the power terminals that provides a voltage signal that is compared with a predefined level or ratio, to trigger a power supply trip should the sense voltage fall outside those limits.
25 Citations
20 Claims
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1. An electrical heater comprising
a heating element and one or more conductive sense wires connected to the heating element in a predetermined position between points at which power is applied to the heating element, wherein the one or more sense wires is further connected to a voltage detector, to compare a voltage from the voltage detector with a predetermined range, and triggering a safety indicator or safety trip if the voltage is outside the predetermined range.
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6. An electrical heating system comprising:
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a heating element; and one or more conductive sense wires connected to the heating element in a predetermined position between points at which power is applied to the heating element, wherein the one or more conductive sense wires are connected to a voltage detector for comparing a voltage from the voltage detector with a predetermined value, and activating a power regulator that reduces the power to the heating element if the voltage is outside the predetermined range. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. An electronic circuit to drive and monitor an electrical heater, the heater having a high-side electrical bus bar, a low-side electrical bus bar, a first heater sensor responsive to the high-side electrical bus bar, and a second heater sensor responsive to the low-side electrical bus bar, the electronic circuit comprising:
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a first and a second power terminal, wherein a power voltage is supplied across the first and second power terminals; a first rail to electrically connect the first power terminal to the high-side electrical bus bar, the first rail comprising; a series connection of a first current sense circuit and a first switch; a second rail to electrically connect the second power terminal to the low-side electrical bus bar, the second rail comprising; a second current sense circuit; a first voltage comparator to compare an output of the first heater sensor to a first predetermined threshold; a second voltage comparator to compare an output of the second heater sensor to a second predetermined threshold; a control logic to receive outputs from the first and second voltage comparators and from the first and second current sensors, wherein the control logic drives the first switch in response to the received outputs; - View Dependent Claims (15, 16, 17, 18, 19)
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Specification