| 摘要 |
An interface circuit includes a slew rate control unit 110, a pre buffer unit 120, and a main buffer unit 130. The slew rate control unit 110 is configured as a current source circuit of the pre buffer unit 120. The slew rate control unit 110 provides a constant current value by using a loop circuit which consists of a slew rate control macro 111, a decoder 112, a comparator 113, N transistor 114, an external terminal resistance (Rref) 115, and a reference voltage (Vref) 116. A size of the N transistor 114 is adjusted based on a code gradually changed in the loop circuit, and finally the current value is determined uniquely.
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