| 摘要 |
A system 500 and method 900 is disclosed for a driver circuit used for high speed data transmission in LVDS transceiver device applications (e.g., LVDS repeaters and PECL/ECL to LVDS converters). The transceivers are intended to receive a low voltage differential input signal and drive an TIA/EIA-644 compliant LVDS signal. The driver circuit operates at speeds up to 1.36 Gbps, making it compatible with the OC-24 signaling rate for optical transmission. To accomplish this, the driver uses a mixed combination of voltage and current mode drive sections in the output circuit. MOS transistors and a current source are used in the current mode switch portion to switch the drive with a constant current at the high speeds, and NPN transistors in the voltage mode output portion provide variable impedance for the output circuit. A common mode compensation circuit using a feedback voltage from the load, generates a compensation signal for variable impedance control of the NPN transistors to yield a regulated voltage for the common mode dc voltage.
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