Low voltage power supply system for an electric blanket or the like
First Claim
1. An electrically powered device, comprising:
- a pliable heating member having a resistive heating element; and
a power supply for supplying power to the resistive heating element of the pliable heating member, comprising;
a power input arrangement adapted to receive input power having a high voltage exceeding a predetermined low voltage threshold;
an isolation-type power conversion device including an input and an isolated output, wherein the input is interconnected with the power input arrangement;
a switching arrangement interconnected with the power conversion device, wherein the switching arrangement is configured and arranged to provide continuous intermittent operation of the power conversion device; and
a low voltage power output arrangement interconnected with the isolated output of the power conversion device, wherein the low voltage power output arrangement is interconnected with the resistive heating element of the pliable heating member;
wherein the intermittent operation of the power conversion device by the switching arrangement is operable to supply continuous low voltage output power having a voltage below the low voltage threshold to the resistive heating element of the pliable heating member through the isolated output of the power conversion device and the low voltage power output arrangement.
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Accused Products
Abstract
A power supply system for outputting low voltage electrical power from a high voltage power source includes an isolation-type power conversion device, such as a transformer having a primary high voltage side and an isolated secondary low voltage side. The low voltage side is interconnected with a power output arrangement, which is adapted to supply low voltage power to a load, which may be in the form of an electric blanket or the like. A switching arrangement is interconnected with the high voltage primary side of the power conversion device, for providing intermittent operation of the power conversion device. The period of intermittent operation of the power conversion device is controlled via a control arrangement, to vary the power output from the low voltage secondary side of the transformer and thereby to the electrical load. The control arrangement is preferably in the form of a pulse width modulation (PWM) control, which receives inputs from a controller that is powered from the isolated secondary low power output of the power conversion device via isolated primary and secondary circuits, to vary the duty cycle of the switching power conversion device. The power supply includes a burst logic circuit that provides high frequency intermittent operation of the power conversion device through the switching arrangement when the controller is off, to supply low voltage power to the controller which enables initial operation of the controller and thereby operation of the power conversion device. The low voltage output is interconnected with a load detection arrangement which disables the controller in the event the load is disconnected from the low voltage output. An over-voltage switch is also interconnected with the low voltage output, to shutdown the power supply in the event the voltage of power supplied to the low voltage output exceeds a predetermined low voltage threshold.
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Citations
28 Claims
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1. An electrically powered device, comprising:
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a pliable heating member having a resistive heating element; and
a power supply for supplying power to the resistive heating element of the pliable heating member, comprising;
a power input arrangement adapted to receive input power having a high voltage exceeding a predetermined low voltage threshold;
an isolation-type power conversion device including an input and an isolated output, wherein the input is interconnected with the power input arrangement;
a switching arrangement interconnected with the power conversion device, wherein the switching arrangement is configured and arranged to provide continuous intermittent operation of the power conversion device; and
a low voltage power output arrangement interconnected with the isolated output of the power conversion device, wherein the low voltage power output arrangement is interconnected with the resistive heating element of the pliable heating member;
wherein the intermittent operation of the power conversion device by the switching arrangement is operable to supply continuous low voltage output power having a voltage below the low voltage threshold to the resistive heating element of the pliable heating member through the isolated output of the power conversion device and the low voltage power output arrangement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An electrically operated heating arrangement, comprising:
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a pliable heating member having a resistive load in the form of a resistive heating element;
a power supply to which the resistive heating element is connected, wherein the power supply includes a high voltage power input adapted to be supplied with power exceeding a predetermined low voltage threshold, a power conversion arrangement, and a low voltage power output that is supplied with power below the low voltage threshold from the power conversion arrangement, wherein the resistive heating element is connected to the low voltage power output and wherein the supply of low voltage power to the resistive heating element is operable to generate heat from the resistive heating element; and
a controller interconnected with the power supply to vary the low voltage power output and to thereby control the heat generated by the resistive heating element, wherein the controller is configured and arranged to control operation of the switching arrangement without interruption in the supply of low voltage power to the resistive heating element from the low voltage power output. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of supplying low voltage output power to a resistive heating element of a pliable member from a high voltage power source, comprising the steps of:
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supplying high voltage power from the high voltage power source to a high voltage power input associated with a power conversion device having a low voltage power output electrically isolated from the high voltage power input;
providing intermittent operation of the power conversion device to supply power to the low voltage output of the power conversion device;
supplying low voltage power from the low voltage power output of the power conversion device to the resistive heating element of the pliable member; and
controlling the intermittent operation of the power conversion device to vary the power supplied by the power conversion device to the low voltage output of the power conversion device, wherein the step of controlling intermittent operation of the power conversion device is carried out without disrupting the supply of low voltage power from the low voltage power output of the power conversion device. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification