| 摘要 |
The level converter for converting a TTL level of input signal to a CMOS level comprises a NOR gate circuit (1), including a first voltage pull-up PMOS transistor (PI2), to which the TTL signal is inputted, an inverter (INV) connected to the NOR gate circuit, and a speed control circuit (2). The NOR gate circuit has a PMOS (PI1) and an NMOS (NI1) controlled by a control signal (CS), as well as a CMOS transistor (PI2, NI2) fed by the TTL signal. The speed control circuit includes a second voltage pull-up PMOS transistor (PI4). The two transistors (PI2,PI4) are connected in parallel between VCC and the input to the inverter. A fast conversion speed is obtained by turning on both PMOS (PI2,PI4) when the TTL signal goes from the high level to the low level.
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