Serial port level conversion method and circuit

A conversion method and conversion circuit technology, applied in the direction of logic circuit connection/interface layout, etc., can solve the problems of criticality, negative pressure uncertainty, poor stability, etc., to achieve stable negative pressure generation, saving board space, and high flexibility Effect

Active Publication Date: 2013-06-05
FUJIAN LANDI COMML EQUIP CO LTD
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  • Abstract
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  • Claims
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AI Technical Summary

Problems solved by technology

However, using discrete devices to realize the serial port level conversion function needs to consider providing negative pressure for the receiving part of the RS232 interface of the PC, and there are many ways to realize the negative pressure. pressure, but the negative pressure provided by this method has the disadvantages of uncertainty, criticality, and poor stability

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  • Serial port level conversion method and circuit

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Embodiment Construction

[0024] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0025] This embodiment provides a serial port level conversion method, which is characterized in that: provide a negative voltage, cooperate with a transistor to control a positive voltage, when the transistor is turned on, it is positive and when it is turned off, it is negative, so as to realize the conversion of the serial port level output; The switch of the transistor is used to realize the conversion of the serial port level input and the state inversion; the negative voltage is generated by oscillation.

[0026] In an embodiment of the present invention, the above-mentioned oscillation generates a square wave, and by adjusting the frequency of the square wave, the stability of the negative voltage output can be adjusted. After the square wave is amplified, the capacitor has the characteristic of temporarily keeping the voltage constant to realize...

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Abstract

The invention relates to a serial port level conversion method. The serial port level conversion method is characterized in that a negative voltage is provided to control a positive voltage through the cooperation of a transistor. When the transistor is on voltage is positive and when the transistor is off voltage is negative, and serial port level output conversion is achieved. The serial port level input conversion and state reversion are achieved through on-off of the transistor. The negative voltage is generated by oscillation. The realization of the scheme of the level conversion is changed from a traditional chip to discrete devices. The used discrete devices are an audion, a resistor and the like. The discrete devices are low in price, and few discrete devices are needed. The level conversion function is realized and cost is lower than the cost when the chips are used.

Description

technical field [0001] The invention relates to the technical field of RS232 interface communication, in particular to a serial port level conversion method and circuit. Background technique [0002] The computer serial port uses RS232 level, when +3~+15V, it is ON state, logic level is 0; when PC interface level is -15~-3V, it is OFF state, logic level is 1. The serial port of the communication device uses TTL level. Since the logic level of the serial port of the computer is inconsistent with the logic level of the serial port of the communication device, level conversion is required when the computer and the communication device use the serial port for communication. Generally, this kind of level conversion is realized by a chip, but the cost of using a chip is relatively high. This function can be achieved using fewer discrete components and at a lower cost. However, using discrete devices to realize the serial port level conversion function needs to consider providin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03K19/0175
Inventor 冯玲李欢
Owner FUJIAN LANDI COMML EQUIP CO LTD
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