Circuit for providing a logical output signal in accordance with crossing points of differential signals

摘要

Disclosed is a circuit (Fig. 6a) for providing a logical output signal (OUTD) in accordance with crossing points of a differential signal, whereby the logical output signal (OUTD) has a first logical level (high) and a second logical level (low), the differential signal comprises a normal input signal (SIG) and a complementary input signal (NSIG) as the complementary signal to the normal input signal (SIG), and the crossing points occur when the normal input signal (SIG) and the complementary input signal (NSIG) have the same level. The circuit comprises a first amplifier (C1) for amplifying a first signal difference between the normal input signal (SIG) and a first threshold value (TH1), and for providing as a first output signal (SIGOUT) the amplified first signal difference, and a second amplifier (C2) for amplifying a second signal difference between the complementary input signal (NSIG) and a second threshold value (TH2), and for providing as a second output signal (NSIGOUT) the amplified second signal difference, whereby the first and the second threshold values are set to the same level (VTH=TH1=TH2). The circuit further comprises a first comparator (C3) for providing the first logical level (high) when a third signal difference between the first output signal (SIGOUT) and the second output signal (NSIGOUT) is greater than a third threshold value (VTH3), and for providing the second logical level (low) when the third signal difference is smaller than the third threshold value. <IMAGE>