Voltage protecting circuit for electronic device
AssigneeHon Hai Precision Industry Co., Ltd.
InventorHeng-Chen Kuo
Life of this patent
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Abstract
A voltage protecting circuit includes a switch unit, an upper limited voltage detecting unit, a lower limited voltage detecting unit, and a logic control unit. When a voltage output from a voltage input interface is less than the lower limited voltage or greater than the upper limited voltage, the logic control unit outputs a control signal to turn the switch unit off. The output voltage outputted from the voltage input interface is not provided to a working circuit. When the output voltage outputted from the voltage input interface is greater than the lower limited voltage and less than the upper limited voltage, the logic control unit outputs a control signal to turn the switch unit on. The output voltage output from the voltage input interface is provided to the working circuit.
Claims7
A voltage protecting circuit connected between a voltage input interface and a working circuit, the voltage protecting circuit comprising:
- an upper limit voltage detecting unit connected to the voltage input interface, to detect an output voltage of the voltage input interface and outputs a first detecting signal;
- a lower limit voltage detecting unit connected to the voltage input interface, to detect the output voltage of the voltage input interface and outputs a second detecting signal;
- a switch unit connected between the voltage input interface and the working circuit;
- a logic control unit connected to the upper limit voltage detecting unit, the lower limit voltage detecting unit, and the switch unit, wherein the logic control unit receives the first and the second detecting signals from the upper limit voltage detecting unit and the lower limit voltage detecting unit, and controls the switch unit to be closed or opened, when the output voltage of the voltage input interface is less than a lower limit voltage or is greater than an upper limit voltage, the logic control unit controls the switch unit to be opened, the output voltage of the voltage input interface is not provided to the working circuit;
- when the output voltage of the voltage input interface is greater than the lower limit voltage and is less than the upper limit voltage, the logic control unit controls the switch unit to close, the output voltage of the voltage input interface is provided to the working circuit.
Dependencies are inferred from the claim text.