RS485 driver of low bit error rate, low working power supply voltage and high ESD

Abstract

The invention discloses an RS485 driver of a low bit error rate, a low working power supply voltage and high ESD, and relates to integrated-circuit technology. The driver includes two power tube circuits. Each power tube circuit includes a front-stage driving unit, a power tube unit and a feedback detection unit. The driver is characterized in that power tube substrates in the power tube unit are floating, and the front-stage driving unit adopts constant-current source front-stage driving. The driver has the advantages that the working power supply voltage is low, costs are low, the bit error rate is low, ESD performance is high, the bit error rate of RS485 transmission can be effectively decreased, and ESD capability of power tubes can be improved.

Description

technical field [0001] The present invention relates to integrated circuit technology. Background technique [0002] At present, in long-distance communication, RS485 has become the first choice for people, because the RS485 bus has the advantages of simple structure, easy control, and easy price. The structure of the RS485 transmitter on the market is usually a dual-tube structure, the working voltage is at least 5V, and the bit error rate is relatively high. [0003] The ESD performance of the double-tube stack structure is relatively high, but the working voltage usually needs to be above 5V, and the chip area is relatively large to ensure that the output swing of the transmitter is greater than the requirement of 1.5V. [0004] The operating power supply voltage of the single-tube structure is relatively low, and the requirement of a differential swing greater than 1.5V can be achieved at a relatively low voltage, but the ESD performance is poor. [0005] For RS485 tra...

AI Technical Summary

Problems solved by technology

[0004] The operating power supply voltage of the single-tube structure is low, and the requirement of a differential swing greater than 1.5V can be achieved at a low voltage, but the ESD performance is poor

[0005] For RS485 transmitters on the market, the pre-driver usually uses a switch circuit, the charging and discharging current is unstable, and the noise is large, resulting in a high bit error rate and a short transmission distance for RS485 transmission data.

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