Importance

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Abstract

A low voltage differential signal ('LVDS') line driver circuit includes a driver cell and a mimicking circuit. The driver cell includes a current sourcing transistor which provides a drive current to a current steering circuit. In response to first and second input signals, the current steering circuit provides a differential output signal. Each transistor of the driver cell and the resistive load driven by the LDVS line driver is replicated by the mimicking circuit to maintain a high output voltage reference signal and a low output voltage reference signal. A first operational amplifier couples to the current sourcing transistor and compares the high output voltage reference signal with a high output voltage signal of the differential output signal. When the high output voltage signal either exceeds or falls below the high output voltage reference signal, the first operational amplifier controls the sourcing transistor to supply enough current to the current steering circuit to maintain a desired offset voltage. A second operational amplifier couples to the current sinking transistor and compares the low output voltage reference signal with the low output voltage signal of the differential output signal. When the low output voltage signal either exceeds or falls below the low output voltage reference signal, the second operational amplifier controls the current sinking transistor to sink current from the current steering circuit to maintain the desired offset voltage. The mimicking circuit also includes an operational amplifier to maintain the desired offset voltage.

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First Claim