| 摘要 |
A THERMAL PROTECTION ARRANGEMENT FOR AN INTEGRATED CIRCUIT SUBSCRIBER LINE INTERFACE A thermal protection arrangement for an integrated circuit subscriber line interface is disclosed. The thermal protection arrangement monitors the temperature of the integrated circuit and develops an output voltage signal that shuts-down the integrated circuit when a specific temperature is exceeded. The thermal protection arrangement includes first and second current networks arranged to each develop first and a second currents respectively, of substantially the same value. A matching network connected between the first current network, the second current network and a ground reference terminal provides for the perfect matching of the currents in each network. The second current develops a reference voltage which is applied to an output transistor. When the base-emitter junction voltage of the output transistor is less than or equal to the reference voltage, the transistor begins to operate. This increases the current flowing through the first current network which is replicated in the second current network. The increased current flowing in the second current network increases the reference voltage, thereby, fully operating the output transistor and developing the output voltage signal.
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