| 摘要 |
<p>The present invention provides a control system for a heating unit in a cooktop that is capable of detecting the presence (or absence) of a cooking pan or utensil. The heating unit has a spirally wound ribbon heater element and may be mounted below a glass-ceramic cooking surface. The control system includes a pan detection unit electrically connected to the heater element. The pan detection unit generates a high frequency signal through the heater element to determine whether a pan is present on the cooktop. The pan detection unit may have an oscillation circuit to generate the high frequency signal through the heater element. In one embodiment, the control system further includes at least one switch device that is connected between element and the power source. The switch device is opened to remove the heater element from the power source when the pan detection unit generates the high frequency signal through the heater element. The present invention also includes a heating unit having dual heater units to determine the size of the pan placed on the cooktop. The present invention further includes methods of operating a heater unit and control system having the capability of detecting the presence of a pan.</p> |
