A device for converting logic signals into low-voltage differential signals

Abstract

The invention discloses a device for converting a common dual-level logic signal into an LVDS. The device comprises a logic output unit and a trapezoidal resistor network unit. The single-end logic signal is input into the logic output unit and converted into a positive-negative logic signal in the logic output unit, then partial pressure and level conversion of the positive-negative logic signal are achieved through the trapezoidal resistor network unit, and under the condition that the load of an output port is 100 ohms, the voltage signal meeting the low voltage differential signal electrical standard is output. The working conditions of the device are free of limitation of the voltage of the logic signal. The device for converting the common dual-level logic signal into the LVDS is applicable to the transmission occasions of interface conversion between the common dual-level logic signal and the LVDS, and particularly applicable to converting a common positive-negative logic signal in an FPGA into the LVDS.

Description

technical field [0001] The invention relates to the technical field of high-speed communication circuits and integrated circuit design, in particular to a device for converting logic signals into low-voltage differential signals. The device is not limited by the level voltage of logic signals and has the characteristics of universal adaptability. Background technique [0002] In high-speed serial transmission, it is very common to use the low-voltage differential signal (LVDS) electrical standard for physical layer data transmission. The LVDS standard is an I / O electrical standard, which has the characteristics of high speed, low power consumption and strong noise immunity. The LVDS electrical standard has clear regulations on the common-mode voltage and differential-mode voltage range of the differential output signal. figure 1 It is an illustration of the LVDS electrical standard. Under the condition of a 100-ohm load, the LVDS output common-mode voltage is about 1.25V, ...

AI Technical Summary

Problems solved by technology

In general, the level voltage difference of ordinary logic signals is its IO (input output) voltage. Therefore, the common mode level of the differential output of the LVDS terminal depends on the IO (input output) voltage, which is half of the IO (input output) voltage. , since the LVDS electrical specification requires the output common-mode level to be 1.25V, the high-level voltage of ordinary logic signals that can be converted is limited to about 2.5V, thus limiting the scope of application of this method

At present, the input and output (I / O) ports adopt a wide variety of voltage standards (1.8V, 2.5V, 3.3V, 5V, etc.), and the application occasions are also relatively complicated. In view of this, the present invention proposes a novel circuit device, It is not limited by the input and output (I / O) voltage standards, and can convert logic signals under different voltage standards into differential signals that comply with the LVDS electrical standard

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