System and method for high voltage protection of powered devices
First Claim
1. A powered device comprising:
- a rectifier circuit having two inputs to receive an input voltage from a powered network and having two output terminals to provide a rectified power supply voltage in response to the input voltage;
a logic circuit coupled between the two output terminals and adapted to receive data from the powered network, the logic circuit comprising a regulator to provide a regulated power supply to a load circuit; and
a power protection element coupled between the two output terminals in parallel with the logic circuit, the power protection element to protect to the logic circuit from high power transients, the power protection element comprising a circuit including a zener diode having a breakdown voltage defining a threshold voltage level and including at least one switch coupled to the zener diode, wherein, in a first mode of operation, the power protection element presents a high impedance to the two output terminals, in a second mode of operation, the power protection element has a first power protection characteristic, and in a third mode of operation, the voltage protection element has a second power protection characteristic, wherein the power protection element is adapted to reduce the rectified power supply voltage at the logic circuit when an over-voltage condition is detected and to return to the first mode of operation when the over-voltage condition is finished.
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Accused Products
Abstract
A powered device includes a rectifier circuit, a logic circuit, and a power protection element. The rectifier circuit includes two inputs to receive an input voltage from a powered network and includes two output terminals to provide a rectified power supply voltage in response to the input voltage. The logic circuit is coupled between the two inputs and adapted to receive data from the powered network. The power protection element is coupled between the two output terminals to protect to the logic circuitry from high power transients. In a first mode of operation, the power protection element presents a high impedance to the two output terminals. In a second mode of operation, the power protection element has a first power protection characteristic. In a third mode of operation, the power protection element has a second power protection characteristic.
41 Citations
27 Claims
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1. A powered device comprising:
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a rectifier circuit having two inputs to receive an input voltage from a powered network and having two output terminals to provide a rectified power supply voltage in response to the input voltage; a logic circuit coupled between the two output terminals and adapted to receive data from the powered network, the logic circuit comprising a regulator to provide a regulated power supply to a load circuit; and a power protection element coupled between the two output terminals in parallel with the logic circuit, the power protection element to protect to the logic circuit from high power transients, the power protection element comprising a circuit including a zener diode having a breakdown voltage defining a threshold voltage level and including at least one switch coupled to the zener diode, wherein, in a first mode of operation, the power protection element presents a high impedance to the two output terminals, in a second mode of operation, the power protection element has a first power protection characteristic, and in a third mode of operation, the voltage protection element has a second power protection characteristic, wherein the power protection element is adapted to reduce the rectified power supply voltage at the logic circuit when an over-voltage condition is detected and to return to the first mode of operation when the over-voltage condition is finished. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method comprising:
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receiving an input voltage from a cable coupled to a powered network at a first input terminal and a second input terminal of an integrated circuit, the integrated circuit including a voltage protection element and a voltage regulator circuit, the voltage protection element and the voltage regulator circuit coupled in parallel to the first and second input terminals; rectifying the input voltage using a diode bridge; detecting, via the voltage protection element, an over-voltage condition when the rectified voltage exceeds a threshold voltage; reducing power to the voltage regulator circuit in response to detecting the over-voltage condition; and sending a fault protection signal to the voltage regulator circuit to shut off power to a load circuit coupled to the voltage regulator circuit. - View Dependent Claims (13, 14, 15, 16, 17)
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18. An integrated circuit of a powered device, the integrated circuit comprising:
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a rectifier circuit having two input terminals to receive an input supply voltage from a powered network and having two output terminals to provide a rectified power supply voltage; at least one circuit coupled between the two output terminals, the at least one circuit including a voltage regulator circuit to provide a regulated power supply to device circuitry; and a voltage protection element coupled between the two output terminals in parallel with the voltage regulator circuit, the voltage protection element comprising a first switch and a zener diode adapted to break down in response to an over-voltage condition to activate the switch, wherein, in a first mode of operation, the voltage protection element presents a high impedance to the two output terminals, in a second mode of operation, the voltage protection element has a first over-voltage characteristic, and in a third mode of operation, the voltage protection element has a second over-voltage protection characteristic, wherein in the third mode of operation, the voltage protection element is adapted to reduce the rectified power supply voltage at the at least one circuit and to send a fault protection signal to the at least one circuit to turn off the regulated power supply to the device circuitry. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification