CN205883194U - Level switching circuit - Google Patents
Level switching circuit Download PDFInfo
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- CN205883194U CN205883194U CN201620620020.3U CN201620620020U CN205883194U CN 205883194 U CN205883194 U CN 205883194U CN 201620620020 U CN201620620020 U CN 201620620020U CN 205883194 U CN205883194 U CN 205883194U
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- down resistor
- electric capacity
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Abstract
The utility model discloses a level switching circuit, this level switching circuit includes: pull -up resistance, pull down resistor, first conversion resistance, second conversion resistance, first electric capacity and second electric capacity, the voltage source is connected to pull -up resistance one end, and pull down resistor one end is connected to the other end, the earthing terminal is connected to the pull down resistor other end, first electric capacity and second electric capacity and drop -down resistor parallel with, the one end of first conversion resistance and second conversion resistance is connected to one of them strip of a pair of differential signal line, the common junction of connecting at pull -up resistance and pull down resistor of the other end respectively, wherein, first conversion resistance is the same with second conversion resistance. In the technical scheme provide by the utility model, conversion resistance can be voltage signal with difference current signal conversion, and pull -up resistance and pull down resistor form the DC bias circuit, guarantees that the signal line magnitude of voltage fluctuates on DC bias's basis, and realization current mode differential signal has fine compatibility to the conversion of voltage type differential signal.
Description
Technical field
This utility model relates to technical field of circuit design, particularly to a kind of level shifting circuit.
Background technology
At present in the design of FPGA, can use two-way signaling under a lot of occasions, now signal pin must use BLVDS
Level standard, but for using the back-end chip of voltage-type differential signal, the most do not support this level standard, therefore need
Level conversion to be done, current way is differential signal line all without plus pull down resistor, but current mode this for BLVDS
For differential level, do so can largely effect on signal quality, thus causes the erroneous judgement of some signal, and uses level conversion core
Sheet one is to affect sequential, and two is to increase hardware cost.
Utility model content
In designing in view of prior art circuits, signal output pin level and the unmatched problem of back-end chip level, propose
A kind of level shifting circuit of the present utility model, in order to overcome the problems referred to above or solve the problems referred to above at least in part.
According to an aspect of the present utility model, it is provided that a kind of level shifting circuit, this level shifting circuit includes: on
Pull-up resistor, pull down resistor, the first transfer resistance, the second transfer resistance, the first electric capacity and the second electric capacity；
Described pull-up resistor one end connects voltage source, and the other end connects pull down resistor one end；The described pull down resistor other end
Connect earth terminal；
Described first electric capacity and the second electric capacity are in parallel with pull down resistor；
One end of described first transfer resistance and the second transfer resistance is respectively connecting to wherein the one of a pair differential signal line
Bar, the other end is commonly connected to the junction of described pull-up resistor and pull down resistor；
Wherein, described first transfer resistance and the second transfer resistance resistance are identical.
Alternatively, described level shifting circuit is for being converted to voltage-type differential signal by current mode differential signal.
Alternatively, the magnitude of voltage of described voltage source, the resistance of described pull-up resistor and described pull down resistor and described the
The resistance of one transfer resistance and described second transfer resistance is changed according to the difference of level standard.
Alternatively, described pull-up resistor is 2.49k Ω, and described pull down resistor is 1.5k Ω, and described first electric capacity is 10 μ F,
Described second electric capacity is 0.01 μ F, and described first transfer resistance and the second transfer resistance size are identical, are 49.9 Ω, described voltage
Source is 3.3V.
In sum, in the technical solution of the utility model, differential current signal can be converted to voltage by transfer resistance
Signal, pull-up resistor and pull down resistor form DC bias circuit, can be attached in predetermined value by the voltage clamp of differential signal line
Closely, it is ensured that line voltage signal value fluctuates on the basis of direct current biasing, it is achieved current mode differential signal is to voltage-type
The conversion of differential signal, uses pure hardware logic line cost low, does not affect sequential, and signal quality is high, will not judge by accident, tool
There is the most compatible performance.
Accompanying drawing explanation
A kind of level shifting circuit principle schematic that Fig. 1 provides for one embodiment of this utility model.
Detailed description of the invention
For making the purpose of this utility model, technical scheme and advantage clearer, new to this practicality below in conjunction with accompanying drawing
Type embodiment is described in further detail.
A kind of level shifting circuit principle schematic that Fig. 1 provides for one embodiment of this utility model, as it is shown in figure 1,
This level shifting circuit includes: pull-up resistor R1, pull down resistor R2, the first transfer resistance R3, the second transfer resistance R4, the first electricity
Hold C1 and the second electric capacity C2；Pull-up resistor R1 one end connects voltage source VCC, and the other end connects pull down resistor R2 one end；Drop-down electricity
The resistance R2 other end connects earth terminal；First electric capacity C1 and the second electric capacity C2 is in parallel with pull down resistor R2；First transfer resistance R3 and
One end of second transfer resistance R4 is respectively connecting to wherein of a pair differential signal line, and the other end is commonly connected to pull-up electricity
Resistance R1 and the junction of pull down resistor R2；Wherein, the first transfer resistance R3 and the second transfer resistance R4 resistance are identical.
Preferably, this level shifting circuit is for being converted to voltage-type differential signal by current mode differential signal.
Preferably, the magnitude of voltage of this voltage source VCC, the resistance of pull-up resistor R1 and pull down resistor R2 and the first conversion
The resistance of resistance R3 and the second transfer resistance R4 is changed according to the difference of level standard.
Preferably, in level shifting circuit shown in Fig. 1, pull-up resistor R1 is 2.49k Ω, and pull down resistor R2 is 1.5k Ω,
First electric capacity C1 is 10 μ F, and the second electric capacity C2 is 0.01 μ F, and the first transfer resistance R3 and the second transfer resistance R4 size are identical, for
49.9 Ω, voltage source is 3.3V.
Level shifting circuit as shown in Figure 1, is connected to for poor at BLVDS current mode differential signal equipment and voltage-type
Carry out on a pair differential signal line of signal transmission between sub-signal equipment (as used the chip of Transistor-Transistor Logic level), wherein, conversion electricity
Resistance R3 and R4 be respectively connecting to this in a signal line of differential signal line, differential current signal can be converted to voltage letter
Number, pull-up resistor R1 and pull down resistor R2 forms DC bias circuit, can be by the voltage clamp of differential signal line in predetermined value
Near, it is ensured that line voltage signal value fluctuates on the basis of direct current biasing, it is achieved BLVDS current mode differential signal arrives
The conversion of voltage-type differential signal, the first electric capacity C1 and the second electric capacity C2 can play filter action, eliminate noise, improve anti-dry
Disturbing ability, improve signal transmission quality, circuit conversion uses pure hardware logic electric circuit to be designed realizing, and implementation cost is low, phase
Should be fast, do not affect signal sequence.
In sum, in the technical solution of the utility model, differential current signal can be converted to voltage by transfer resistance
Signal, pull-up resistor and pull down resistor form DC bias circuit, can be attached in predetermined value by the voltage clamp of differential signal line
Closely, it is ensured that line voltage signal value fluctuates on the basis of direct current biasing, it is achieved current mode differential signal is to voltage-type
The conversion of differential signal, uses pure hardware logic line cost low, the soonest, does not affect sequential, and signal quality is high, will not occur
Erroneous judgement, has the most compatible performance.
The foregoing is only preferred embodiment of the present utility model, be not intended to limit protection model of the present utility model
Enclose.All any modification, equivalent substitution and improvement etc. made within spirit of the present utility model and principle, are all contained in this reality
With in novel protection domain.
Claims (4)
1. a level shifting circuit, it is characterised in that this level shifting circuit includes: pull-up resistor, pull down resistor, first turn
Change resistance, the second transfer resistance, the first electric capacity and the second electric capacity；
Described pull-up resistor one end connects voltage source, and the other end connects pull down resistor one end；The described pull down resistor other end connects
Earth terminal；
Described first electric capacity and the second electric capacity are in parallel with pull down resistor；
One end of described first transfer resistance and the second transfer resistance is respectively connecting to wherein of a pair differential signal line, separately
One end is commonly connected to the junction of described pull-up resistor and pull down resistor；
Wherein, described first transfer resistance and the second transfer resistance resistance are identical.
2. level shifting circuit as claimed in claim 1, it is characterised in that described level shifting circuit is for poor by current mode
Sub-signal is converted to voltage-type differential signal.
3. level shifting circuit as claimed in claim 1, it is characterised in that the magnitude of voltage of described voltage source, described pull-up electricity
The resistance of resistance and the resistance of described pull down resistor and described first transfer resistance and described second transfer resistance is according to level mark
Accurate difference is changed.
4. level shifting circuit as claimed in claim 1, it is characterised in that described pull-up resistor is 2.49k Ω, described drop-down
Resistance is 1.5k Ω, and described first electric capacity is 10 μ F, and described second electric capacity is 0.01 μ F, described first transfer resistance and second turn
Changing resistance sizes identical, be 49.9 Ω, described voltage source is 3.3V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620620020.3U CN205883194U (en) | 2016-06-21 | 2016-06-21 | Level switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620620020.3U CN205883194U (en) | 2016-06-21 | 2016-06-21 | Level switching circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205883194U true CN205883194U (en) | 2017-01-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620620020.3U Active CN205883194U (en) | 2016-06-21 | 2016-06-21 | Level switching circuit |
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| CN (1) | CN205883194U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110187732A (en) * | 2019-05-22 | 2019-08-30 | 清华大学 | A Hybrid Voltage Mode and Current Mode PAM-4 High Speed Driving Circuit |
| CN110260906A (en) * | 2019-06-26 | 2019-09-20 | 浙江阿尔法电气有限公司 | A kind of code device signal detection circuit of compatible with multiple encoder type |
| CN110401490A (en) * | 2019-08-02 | 2019-11-01 | 东莞铭普光磁股份有限公司 | Level conversion circuit and level conversion method supporting MDIO communication |
| CN111200236A (en) * | 2018-11-20 | 2020-05-26 | 余姚舜宇智能光学技术有限公司 | A high frequency narrow pulse semiconductor laser drive circuit |
| CN114089043A (en) * | 2021-11-22 | 2022-02-25 | 上海美控智慧建筑有限公司 | Method, device, equipment and medium for calculating bias resistor in 485 communication circuit |
-
2016
- 2016-06-21 CN CN201620620020.3U patent/CN205883194U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111200236A (en) * | 2018-11-20 | 2020-05-26 | 余姚舜宇智能光学技术有限公司 | A high frequency narrow pulse semiconductor laser drive circuit |
| CN110187732A (en) * | 2019-05-22 | 2019-08-30 | 清华大学 | A Hybrid Voltage Mode and Current Mode PAM-4 High Speed Driving Circuit |
| CN110260906A (en) * | 2019-06-26 | 2019-09-20 | 浙江阿尔法电气有限公司 | A kind of code device signal detection circuit of compatible with multiple encoder type |
| CN110401490A (en) * | 2019-08-02 | 2019-11-01 | 东莞铭普光磁股份有限公司 | Level conversion circuit and level conversion method supporting MDIO communication |
| CN114089043A (en) * | 2021-11-22 | 2022-02-25 | 上海美控智慧建筑有限公司 | Method, device, equipment and medium for calculating bias resistor in 485 communication circuit |
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