CN203883467U - Electrical level self-adapted communication interface adaptive circuit - Google Patents
Electrical level self-adapted communication interface adaptive circuit Download PDFInfo
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- CN203883467U CN203883467U CN201420305022.4U CN201420305022U CN203883467U CN 203883467 U CN203883467 U CN 203883467U CN 201420305022 U CN201420305022 U CN 201420305022U CN 203883467 U CN203883467 U CN 203883467U
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- effect transistor
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Abstract
The utility model relates to a communication interface adaptive circuit which is composed of an N-channel enhanced MOS field effect transistor Q1, an N-channel enhanced MOS field effect transistor Q2, a pull-up resistor R1, a pull-up resistor R2, a working power supply VCC1 and a working power supply VCC2, wherein the pull-up resistor R1 is respectively connected to the VCC1 and a source electrode of the Q1, the pull-up resistor R2 is respectively connected to the VCC2 and the source electrode of the Q2, a grid electrode of the Q1 is connected to the VCC1, a drain electrode of the Q1 is connected to the drain electrode of the Q2, the grid electrode of the Q2 is connected to the VCC2, and the drain electrode of the Q1 is connected to the drain electrode of the Q2. By means of the circuit, not only is self-adapted adaption of an interface electrical level achieved without determination of a working voltage but also a power-off separation effect is achieved so that the circuit is more flexible to use.
Description
Technical field
The utility model relates to a kind of communication interface adapter circuit, relates to specifically a kind of communication interface adapter circuit of self-adaptive level.
Background technology
Conventional communication interface can be divided into two kinds, voltage-type and current mode.Voltage-type has UART, iic bus, 1wire, LIN bus, SPI etc.; Current mode has: RS-485, CAN bus etc.Current mode communication equipment can be independently-powered, do not require unified reference voltage; And the reference voltage that voltage-type communication equipment not only will be sought unification, and the size of voltage is also had to strict requirement, otherwise will affect the reliability of communication.For this problem, application number 200910047872.2 discloses a kind of " bidirectional transmission interface circuits between two non-communicated power supply systems ", utilizes lower cost, and high level can effectively be transmitted.Use this circuit need to meet following 2 points: (1) VCC1 voltage should be less than VCC2, otherwise M2 can be dragged down port one level with M1 conducting, causes communication failure; (2) if VCC2 power-off has electric current and flows to port 2 from port one, on the one hand cause port one level step-down, affected communicating by letter of port one and other port, allow on the other hand the equipment of receiving port 2 exist to fill with electric current cause the not dead problem in pass.Although this patent has solved the transmitted in both directions between two non-communicated power supply systems, high level can effectively be transmitted, but for different application scenarios, the size of operating voltage VCC1 and VCC2 first to make accurate judgment, and there is filling electric current, this has affected the flexibility that circuit is used.
Summary of the invention
The utility model object is to provide a kind of communication interface adapter circuit of self-adaptive level, has overcome the use of existing communication interface circuit dumb, causes the deficiency that communication reliability reduces.
For achieving the above object, the technical solution of the utility model and measure are:
The communication interface adapter circuit of self-adaptive level is comprised of N channel enhancement metal-oxide-semiconductor field effect transistor Q1, N channel enhancement metal-oxide-semiconductor field effect transistor Q2, pull-up resistor R1, pull-up resistor R2, working power VCC1, working power VCC2.
Described pull-up resistor R1 one end is connected with working power VCC1, and the pull-up resistor R1 other end is connected with the source electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1.
Described pull-up resistor R2 one end is connected with working power VCC2.
The grid of described N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is connected with working power VCC1.
The drain electrode of described N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is connected with the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q2.
The grid of described N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is connected with working power VCC2.
The source electrode of described N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is connected with pull-up resistor R2 one end.
N channel enhancement metal-oxide-semiconductor field effect transistor is meeting conducting in following two kinds of situations: (1) gate source voltage is greater than cut-in voltage; (2) drain voltage is less than source voltage.High level transmitting procedure: the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is zero, and port 2 is under pull-up resistor R2 effect, the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is also zero, now, the drain electrode of two field effect transistor is vacant state, and port one and port 2, respectively by moving operating voltage separately on pull-up resistor R1, pull-up resistor R2, need not judge operating voltage size, realized the adaptation function of interface level, used convenient.Low level transmitting procedure: if when port one is low level, the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is greater than cut-in voltage, enter conducting state, the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 becomes low level, now the drain voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is less than source voltage, cause also conducting of N channel enhancement metal-oxide-semiconductor field effect transistor Q2, the source electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 becomes low level, and port 2 also becomes low level.When if port 2 is low level, the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is greater than cut-in voltage, enter conducting state, the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 becomes low level, now the drain voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is less than source voltage, cause also conducting of N channel enhancement metal-oxide-semiconductor field effect transistor Q1, the source electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 becomes low level, and port one also becomes low level.If working power VCC1 or working power VCC2 close, the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 or N channel enhancement metal-oxide-semiconductor field effect transistor Q2 and current potential are zero, N channel enhancement metal-oxide-semiconductor field effect transistor Q1 or N channel enhancement metal-oxide-semiconductor field effect transistor Q2 are all the time in cut-off state, therefore do not have direct current and flow to port 2 or port 2 flows to port one from port one, realized the power-off buffer action of interface.
The beneficial effects of the utility model are: utilize the work characteristics of metal-oxide-semiconductor field effect transistor, not only have that to exempt to judge that operating voltage size is carried out the self adaptation of interface level adaptive, but also have power-off buffer action, use more flexible.
Accompanying drawing explanation
Fig. 1 is prior art structural representation.
Fig. 2 is the embodiment of circuit described in the utility model.
Fig. 3 is a kind of application circuit embodiment of circuit described in the utility model.
Embodiment
Below in conjunction with accompanying drawing 1, describe specific embodiment of the utility model in detail.
In Fig. 1, reality " bidirectional transmission interface circuits between two non-communicated power supply systems " be the disclosed a kind of bidirectional transmission interface circuit of application number 200910047872.2.
In Fig. 2, Q1, Q2 are N channel enhancement metal-oxide-semiconductor field effect transistor, and R1, R2 are pull-up resistor, and VCC1, VCC2 are working power.Pull-up resistor R1 one end is connected with working power VCC1, and the pull-up resistor R1 other end is connected with the source electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1.Pull-up resistor R2 one end is connected with working power VCC2.The grid of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is connected with working power VCC1, and the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is connected with the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q2.The grid of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is connected with working power VCC2.The source electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is connected with pull-up resistor R2 one end.
High level transmitting procedure: the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is zero, and port 2 is under pull-up resistor R2 effect, the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is also zero, now, the drain electrode of two field effect transistor is vacant state, and port one and port 2, respectively by moving operating voltage separately on pull-up resistor R1, pull-up resistor R2, need not judge operating voltage size, realized the adaptation function of interface level, used convenient.Low level transmitting procedure: if when port one is low level, the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is greater than cut-in voltage, enter conducting state, the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 becomes low level, now the drain voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is less than source voltage, cause also conducting of N channel enhancement metal-oxide-semiconductor field effect transistor Q2, the source electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 becomes low level, and port 2 also becomes low level.When if port 2 is low level, the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is greater than cut-in voltage, enter conducting state, the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 becomes low level, now the drain voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is less than source voltage, cause also conducting of N channel enhancement metal-oxide-semiconductor field effect transistor Q1, the source electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 becomes low level, and port one also becomes low level.If working power VCC1 or working power VCC2 close, the gate source voltage of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 or N channel enhancement metal-oxide-semiconductor field effect transistor Q2 and current potential are zero, N channel enhancement metal-oxide-semiconductor field effect transistor Q1 or N channel enhancement metal-oxide-semiconductor field effect transistor Q2 are all the time in cut-off state, therefore do not have direct current and flow to port 2 or port 2 flows to port one from port one, realized the power-off buffer action of interface.
Application example when Fig. 3 has provided a kind of the utility model enforcement, if there is the different equipment of a plurality of working power voltages to communicate at an order wire, the utility model can be realized the adaptation of carrying out to these a plurality of device communication interface.High level transmitting procedure: if while having the port of an equipment to be high level, the port of miscellaneous equipment by the operating voltage of moving on pull-up resistor separately, has been realized high level transmission respectively.Low level transmitting procedure: if while having the port of an equipment to be low level, field effect transistor all in figure all can enter conducting state, the port of other three equipment also becomes low level, has realized low level transmission.If having one or several equipment working power closes, field effect transistor on this device port will be all the time in cut-off state, can on port, not form direct current loop and affect the high level on miscellaneous equipment port, can not cause equipment to close not dead problem because electric current pours in down a chimney simultaneously, realize the effect of interface power-off isolation.
Claims (1)
1. the communication interface adapter circuit of a self-adaptive level, it is characterized in that: communication interface adapter circuit is comprised of N channel enhancement metal-oxide-semiconductor field effect transistor Q1, N channel enhancement metal-oxide-semiconductor field effect transistor Q2, pull-up resistor R1, pull-up resistor R2, working power VCC1, working power VCC2, wherein pull-up resistor R1 one end is connected with working power VCC1, and the pull-up resistor R1 other end is connected with the source electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1; Pull-up resistor R2 one end is connected with working power VCC2; The grid of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is connected with working power VCC1, and the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is connected with the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q2; The grid of N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is connected with working power VCC2; The drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q1 is connected with the drain electrode of N channel enhancement metal-oxide-semiconductor field effect transistor Q2; The source electrode of described N channel enhancement metal-oxide-semiconductor field effect transistor Q2 is connected with pull-up resistor R2 one end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420305022.4U CN203883467U (en) | 2014-06-10 | 2014-06-10 | Electrical level self-adapted communication interface adaptive circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420305022.4U CN203883467U (en) | 2014-06-10 | 2014-06-10 | Electrical level self-adapted communication interface adaptive circuit |
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| CN203883467U true CN203883467U (en) | 2014-10-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201420305022.4U Withdrawn - After Issue CN203883467U (en) | 2014-06-10 | 2014-06-10 | Electrical level self-adapted communication interface adaptive circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104009462A (en) * | 2014-06-10 | 2014-08-27 | 福建师范大学 | Communication interface adaptive circuit of self-adaptation level |
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2014
- 2014-06-10 CN CN201420305022.4U patent/CN203883467U/en not_active Withdrawn - After Issue
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104009462A (en) * | 2014-06-10 | 2014-08-27 | 福建师范大学 | Communication interface adaptive circuit of self-adaptation level |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20141015 Effective date of abandoning: 20160831 |
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| C25 | Abandonment of patent right or utility model to avoid double patenting |