| 摘要 |
A voltage protection circuit for a terminal of an electronic device, for example the TIP and RING lines of a linecard, is provided. The voltage protection circuit comprises a protection element, a first terminal of which is coupled to the terminal of the electronic device, a second terminal of which is coupled to a ground potential and a control terminal of which is coupled to a reference voltage element, the protection element having a low resistance between its first and second terminals when the control terminal is in a first state and a higher resistance between its first and second terminals when the control terminal is in a second state, the reference voltage element being further coupled to a reference voltage and being adapted such that the state of the control terminal depends on an applied voltage at the first terminal and the reference voltage. Additionally, a voltage limiting element for limiting the voltage drop over the reference voltage element coupled to the reference voltage and the ground potential is provided, leading to less severe demands on the reference voltage element. Additionally or alternatively, a voltage limiting element between the protection element and the reference voltage element may be provided.
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