CN102832923B - Bidirectional transmission circuit - Google Patents
Bidirectional transmission circuit Download PDFInfo
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- CN102832923B CN102832923B CN201210328439.8A CN201210328439A CN102832923B CN 102832923 B CN102832923 B CN 102832923B CN 201210328439 A CN201210328439 A CN 201210328439A CN 102832923 B CN102832923 B CN 102832923B
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- 230000005540 biological transmission Effects 0.000 title claims abstract description 22
- 230000002457 bidirectional effect Effects 0.000 title claims abstract description 21
- 230000001681 protective effect Effects 0.000 claims abstract description 8
- 238000004891 communication Methods 0.000 abstract description 15
- 230000009466 transformation Effects 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000012946 outsourcing Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
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Abstract
The invention discloses a bidirectional transmission circuit which is connected between a first I/O (input/output) port (A) of a first microcontroller and a second I/O port (B) of a second microcontroller, wherein the first microcontroller is a low-voltage microcontroller and is powered by a first power voltage (Vcca); and the second microcontroller is a high-voltage microcontroller and is powered by a second power voltage (Vccb). The bidirectional transmission circuit is characterized by also comprising a pull-up circuit, a voltage clamp protective circuit, a first unidirectional conduction circuit, a second unidirectional conduction circuit and a bleeder circuit, wherein the bleeder circuit is provided with voltage division points. The bidirectional transmission circuit is suitable for voltage transformation between a high-voltage communication interface and a low voltage communication interface.
Description
Technical field
The present invention relates to a kind of bidirectional transmission circuit, particularly a kind of bidirectional transmission circuit being applied to high pressure communication interface and forcing down voltage transformation between communication interface.
Background technology
At present, communication between the single-chip microcomputer of different electric pressure, and the communication between the digital signal processor of different electric pressure, generally realize voltage transformation with special control chip, this kind of control chip needs extra enable signal to carry out the transmission direction of control signal, and the cost of this kind of control chip is higher, when reality uses, not only application flexibility is restricted, but also occupies the communication interface of single-chip microcomputer or digital signal processor.In addition, this kind of control chip does not arrange voltage protection function, easily damages single-chip microcomputer or the digital signal processor of low pressure.
Summary of the invention
Technical problem to be solved by this invention is, overcomes above deficiency, provides a kind of bidirectional transmission circuit being applicable to voltage transformation between high pressure communication interface and low voltage communication interface with voltage protection function.
In order to solve the problems of the technologies described above, technical scheme of the present invention is: a kind of bidirectional transmission circuit, be connected between one of them I/O port of the first microcontroller and one of them the 2nd I/O port of second microcontroller, described first microcontroller is low voltage microcontroller, is powered by the first supply voltage; Described second microcontroller is high pressure microcontroller; by second source power voltage supply; it is characterized in that, also comprise the first pull-up circuit, voltage clamp protective circuit, the first one-way conduction circuit, the second one-way conduction circuit, bleeder circuit, described bleeder circuit is provided with dividing point.
Further, described first pull-up circuit, comprises the first resistance for being connected in parallel between an I/O port and the first supply voltage.
Further; described voltage clamp protective circuit; comprise reference voltage, the first Schottky diode, the second resistance; one end of described second resistance is connected with a described I/O port, the other end is connected with the anode of the first Schottky diode; the negative electrode of described first Schottky diode is connected with described reference voltage, described reference voltage ﹤ first supply voltage ﹤ second source voltage.
Further, described second one-way conduction circuit, comprises the second Schottky diode, and the negative electrode of described second Schottky diode is connected with described 2nd I/O port, anode is connected with a described I/O port.
Further, the conduction voltage drop of described second Schottky diode is 0.3 volt.
Further, described bleeder circuit, comprise the series arm be made up of the 3rd resistance and the 4th resistance, one end of described series arm is connected with described second source voltage, the other end is connected with described 2nd I/O port, the common point of described 3rd resistance and the 4th resistance is dividing point.
Further, described first one-way conduction circuit, comprises the first diode, and the negative electrode of described first diode is connected with a described I/O port, anode is connected with the dividing point of described bleeder circuit.
Further, the conduction voltage drop of described first diode is 0.6 volt.
Further, described first microcontroller and the second microcontroller are single-chip microcomputer.
Further, described first microcontroller and the second microcontroller are digital signal processor.
Compared with prior art, the invention has the beneficial effects as follows: bidirectional transmission circuit of the present invention, for realizing the single-chip microcomputer of different electric pressure and the voltage transformation between single-chip microcomputer and between the digital signal processor of different electric pressure, to realize the transmitted in both directions of data.
When the first microcontroller is transmitter, when second microcontroller is receiver, 2nd I/O port B is high-impedance state, when an I/O port A output low level, the anode voltage of the first diode D1 of the first one-way conduction circuit is pulled to a certain numerical value by the 3rd resistance R3 by second source voltage vcc b, because a 2nd I/O port B and I/O port A is by the 4th resistance R4, first diode D1 conducting, therefore, the voltage of the 2nd I/O port B also numerical value for this reason, because this numerical value is the forward conduction voltage drop adding the first diode D1 in an I/O port A output low level, and be less than the low level input higher limit of second source voltage vcc b, therefore, 2nd I/O port B is low level, therefore, one I/O port A sends low level success, when an I/O port A exports high level, first diode D1 anode voltage is pulled to a certain numerical value by the 3rd resistance R3 by second source voltage vcc b, the voltage of the 2nd I/O port B also numerical value for this reason, because this numerical value exports at an I/O port A forward conduction voltage drop high level adding the first diode D1, and this numerical value is greater than the high level input lower limit of second source voltage vcc b, therefore, 2nd I/O port B is high level, therefore, an I/O port A sends high level success.
When the second microcontroller is transmitter, the first microcontroller is receiver, and an I/O port A is high-impedance state, when the 2nd I/O port B output low level, the anode voltage of the second Schottky diode SD2 of the second one-way conduction circuit is pulled to a certain numerical value by the first resistance R1 by the first power source voltage Vcc a, the voltage of the one I/O port A also numerical value for this reason, because this numerical value is the forward conduction voltage drop adding SD2 in the 2nd I/O port B output low level, because this numerical value is less than the low level input higher limit of the first power source voltage Vcc a, compared with the first power source voltage Vcc a, this numerical value is still lower, therefore, one I/O port A is low level, therefore, 2nd I/O port B sends low level success, when the 2nd I/O port B exports high level, this high level voltage is along the voltage clamp protective circuit of the 4th resistance R4, the first diode D1, the second resistance R2, the first Schottky diode SD1, reference voltage Vref composition, then the voltage of an I/O port A is clamped at the forward conduction voltage drop value being greater than reference voltage Vref and adding the second Schottky diode SD2, the magnitude of voltage of this I/O port A is greater than the high level input lower limit of the first power source voltage Vcc a, therefore, one I/O port A is high level, and the 2nd I/O port B sends high level success,
In addition; when 2nd I/O port B of the second microcontroller sends high level signal to an I/O port A of the first microcontroller; because an I/O port A is clamped at the forward conduction voltage drop value that reference voltage Vref adds the second Schottky diode SD2; and be less than the first power source voltage Vcc a; so an I/O port A of the first microcontroller can not be damaged by the 2nd I/O port B high level signal of the second microcontroller, therefore possesses voltage protection function.
In sum, bidirectional transmission circuit of the present invention achieves two-way communication between high pressure communication interface and low voltage communication interface.
Accompanying drawing explanation
Fig. 1 is the frame principle figure of one embodiment of the invention;
Fig. 2 is the circuit theory diagrams of one embodiment of the invention;
Fig. 3 is the frame principle figure that one embodiment of the invention is applied to OLED display circuit;
Fig. 4 is the circuit theory diagrams that one embodiment of the invention is applied to OLED display circuit.
Embodiment
Below in conjunction with accompanying drawing, the present invention is described in detail:
Please refer to Fig. 1 to 2, bidirectional transmission circuit of the present invention, between one of them the 2nd I/O port B being connected to one of them I/O port A and second microcontroller of the first microcontroller, described first microcontroller is low voltage microcontroller, is powered by the first power source voltage Vcc a; Described second microcontroller is high pressure microcontroller; powered by second source voltage vcc b; it is characterized in that, also comprise the first pull-up circuit, voltage clamp protective circuit, the first one-way conduction circuit, the second one-way conduction circuit, bleeder circuit, described bleeder circuit is provided with dividing point.
Wherein, described first pull-up circuit, comprises the first resistance R1 for being connected in parallel between an I/O port A and the first power source voltage Vcc a.
Wherein, described voltage clamp protective circuit; comprise reference voltage Vref, the first Schottky diode SD1, the second resistance R2; one end of described second resistance R2 is connected with a described I/O port A, the other end is connected with the anode of the first Schottky diode SD1; the negative electrode of described first Schottky diode SD1 is connected with described reference voltage Vref, described reference voltage Vref ﹤ first power source voltage Vcc a ﹤ second source voltage vcc b.
Wherein, described second one-way conduction circuit, comprises the second Schottky diode SD2, and the negative electrode of described second Schottky diode SD2 is connected with described 2nd I/O port B, anode is connected with a described I/O port A.The conduction voltage drop of described second Schottky diode SD2 is 0.3 volt.
Wherein, described bleeder circuit, comprise the series arm be made up of the 3rd resistance R3 and the 4th resistance R4, one end of described series arm is connected with described second source voltage vcc b, the other end is connected with described 2nd I/O port B, and the common point of described 3rd resistance R3 and the 4th resistance R4 is dividing point.
Wherein, described first one-way conduction circuit, comprises the first diode D1, and the negative electrode of described first diode D1 is connected with a described I/O port A, anode is connected with the dividing point of described bleeder circuit.The conduction voltage drop of described first diode D1 is 0.6 volt.
Wherein, described first microcontroller and the second microcontroller are single-chip microcomputer or digital signal processor (Digital Signal Processor, DSP).
Please refer to Fig. 3, Fig. 4, now the present invention is applied in OLED display circuit.OLED, English full name Organic Light-Emitting Diode is Organic Light Emitting Diode.
Second microcontroller is main frame, and its power source voltage Vcc b is+5V; First microcontroller is the inner single-chip microcomputer of OLED display screen or DSP, and for from machine, its power source voltage Vcc a is+3V, and reference voltage Vref is+2.5V.Because OLED display screen is outsourcing finished product, again cannot develop its inside single-chip microcomputer or DSP; And the hardware circuit of main frame and software are standard platform products, will spend more development time and human cost to amendment, and so be not too applicable to use specialized chip to realize transmitted in both directions function, and adopt the present invention can simple realization.In this invention example, transmitted in both directions way is 8 tunnels.Below for a wherein road bidirectional transmission circuit, its operation principle is described.
In 1st road bidirectional transmission circuit of example of the present invention, R1 resistance is 20K ohm, and R2 resistance is 100 ohm, R3 resistance is 20K ohm, and R4 resistance is 2K ohm, and D1 forward conduction voltage drop is about 0.6V, SD1, SD2 are Schottky diode, and forward conduction voltage drop is about 0.3V.The device parameters of other 7 road bidirectional transmission circuits is identical with the 1st tunnel.
If main frame is to from machine signal transmission, an I/O port A is high-impedance state; As the 2nd I/O port B output low level Vblow, one I/O port A voltage is by Vcca pull-up, its magnitude of voltage is the forward conduction voltage drop value that Vblow adds SD2, i.e. Vblow+0.3V, this numerical value is less than the low level input higher limit of Vcca, therefore an I/O port A is low level, and the 2nd I/O port B sends low level success; When the 2nd I/O port B exports high level Vbhigh, voltage lands along R4, D1, R2, SD1, Vref, one I/O port A voltage is clamped at the value being greater than Vref and adding the forward conduction voltage drop value of SD2, i.e. 2.5V+0.3V=2.8V, this numerical value is greater than the high level input lower limit of Vcca, therefore, an I/O port A is high level, and the 2nd I/O port B sends high level success.
In addition, when the 2nd I/O port B exports high level Vbhigh, the voltage of an I/O port A is clamped at Vref+0.3V, because Vref+0.3V is less than Vcca, so an I/O port A can not be damaged, has possessed voltage protection function.
If from machine to Host Transfer signal, the 2nd I/O port B is high-impedance state; As an I/O port A output low level Valow, D1 anode voltage is pulled to a certain numerical value by Vccb, 2nd I/O port B voltage also numerical value for this reason, this numerical value is in an I/O port A output low level, add D1 forward conduction voltage drop and Valow+0.6V, this numerical value is less than the low level input higher limit of VccbV, therefore the 2nd I/O port B is low level, sends low level success; When an I/O port A exports high level Vahigh, D1 anode voltage is pulled to a certain numerical value by Vccb, 2nd I/O port B voltage also numerical value for this reason, this numerical value exports at an I/O port A forward conduction voltage drop and the Vahigh+0.6V that high level add D1, this numerical value is greater than the Vccb i.e. high level input lower limit of+5V, therefore the 2nd I/O port B is high level, sends high level success.
Bidirectional transmission circuit of the present invention, is applicable to voltage transformation between high pressure communication interface and low voltage communication interface, is specially adapted to the single-chip microcomputer in different electric pressure, and the both-way communication between the digital signal processor of different electric pressure.
Claims (5)
1. a bidirectional transmission circuit, be connected between one of them I/O port (A) of the first microcontroller and one of them the 2nd I/O port (B) of the second microcontroller, described first microcontroller is low voltage microcontroller, is powered by the first supply voltage (Vcca); Described second microcontroller is high pressure microcontroller, powered by second source voltage (Vccb), it is characterized in that, also comprise the first pull-up circuit, voltage clamp protective circuit, the first one-way conduction circuit, the second one-way conduction circuit, bleeder circuit, described bleeder circuit is provided with dividing point; Described first pull-up circuit, comprises the first resistance (R1) for being connected in parallel between an I/O port (A) and the first supply voltage (Vcca); Described voltage clamp protective circuit, comprise reference voltage (Vref), the first Schottky diode (SD1), the second resistance (R2), one end of described second resistance (R2) is connected with a described I/O port (A), the other end is connected with the anode of the first Schottky diode (SD1), the negative electrode of described first Schottky diode (SD1) is connected with described reference voltage (Vref), described reference voltage (Vref) ﹤ first supply voltage (Vcca) ﹤ second source voltage (Vccb); Described bleeder circuit, comprise the series arm be made up of the 3rd resistance (R3) and the 4th resistance (R4), one end of described series arm is connected with described second source voltage (Vccb), the other end is connected with described 2nd I/O port (B), and the common point of described 3rd resistance (R3) and the 4th resistance (R4) is dividing point; Described first one-way conduction circuit, comprises the first diode (D1), and the negative electrode of described first diode (D1) is connected with a described I/O port (A), anode is connected with the dividing point of described bleeder circuit; Described second one-way conduction circuit, comprise the second Schottky diode (SD2), the negative electrode of described second Schottky diode (SD2) is connected with described 2nd I/O port (B), anode is connected with a described I/O port (A).
2. bidirectional transmission circuit according to claim 1, is characterized in that, the conduction voltage drop of described second Schottky diode (SD2) is 0.3 volt.
3. bidirectional transmission circuit according to claim 1, is characterized in that, the conduction voltage drop of described first diode (D1) is 0.6 volt.
4. bidirectional transmission circuit according to claim 1, is characterized in that, described first microcontroller and the second microcontroller are single-chip microcomputer.
5. bidirectional transmission circuit according to claim 1, is characterized in that, described first microcontroller and the second microcontroller are digital signal processor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210328439.8A CN102832923B (en) | 2012-09-06 | 2012-09-06 | Bidirectional transmission circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210328439.8A CN102832923B (en) | 2012-09-06 | 2012-09-06 | Bidirectional transmission circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102832923A CN102832923A (en) | 2012-12-19 |
| CN102832923B true CN102832923B (en) | 2014-12-31 |
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| CN201210328439.8A Expired - Fee Related CN102832923B (en) | 2012-09-06 | 2012-09-06 | Bidirectional transmission circuit |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003133937A (en) * | 2001-10-23 | 2003-05-09 | Funai Electric Co Ltd | Bidirectional level converter circuit |
| US20060006907A1 (en) * | 2004-07-08 | 2006-01-12 | Hon Hai Precision Industry Co., Ltd. | Circuit for translating voltage signal levels |
| CN1734940A (en) * | 2004-08-13 | 2006-02-15 | 鸿富锦精密工业（深圳）有限公司 | The signal potential change-over circuit |
| CN101461137A (en) * | 2006-06-02 | 2009-06-17 | 飞思卡尔半导体公司 | Slew-rate control apparatus and methods for a power transistor to reduce voltage transients during inductive flyback |
| CN202043034U (en) * | 2011-05-19 | 2011-11-16 | 台安科技(无锡)有限公司 | Level shift circuit realizing shifting from 5v signal to 3.3v signal for singlechip system |
-
2012
- 2012-09-06 CN CN201210328439.8A patent/CN102832923B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003133937A (en) * | 2001-10-23 | 2003-05-09 | Funai Electric Co Ltd | Bidirectional level converter circuit |
| US20060006907A1 (en) * | 2004-07-08 | 2006-01-12 | Hon Hai Precision Industry Co., Ltd. | Circuit for translating voltage signal levels |
| CN1734940A (en) * | 2004-08-13 | 2006-02-15 | 鸿富锦精密工业（深圳）有限公司 | The signal potential change-over circuit |
| CN101461137A (en) * | 2006-06-02 | 2009-06-17 | 飞思卡尔半导体公司 | Slew-rate control apparatus and methods for a power transistor to reduce voltage transients during inductive flyback |
| CN202043034U (en) * | 2011-05-19 | 2011-11-16 | 台安科技(无锡)有限公司 | Level shift circuit realizing shifting from 5v signal to 3.3v signal for singlechip system |
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| Publication number | Publication date |
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| CN102832923A (en) | 2012-12-19 |
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Granted publication date: 20141231 Termination date: 20180906 |