Miner signal level conversion circuit

1.

Send an article for your reference, the article is based on 3.3V and 5V mutual conversion to write, but also explains how other voltage mutual conversion, understand the principle of casually change the mutual conversion voltage

link here

please continue to ask

2.

Level conversion is very common in circuit design, because circuit design is often like building blocks. This circuit mole, together with that circuit mole, is an electronic proct. The voltage domain is often inconsistent between the circuit moles, so the level conversion circuit should be used in the communication between the moles

for example, when each mole communicates through I2C bus, there are devices using 3.3V voltage domain and devices using 5V voltage domain on the bus. Through the level conversion circuit, we can play and chat happily

the figure below shows the level conversion circuit that can be used in I2C bus

refer to the article "MOS transistor level conversion circuit"

3. It can be solved by a 1a400v bridge reactor
it is equivalent to four diodes. One n4007 will do
after rectifying the input voltage signal directly, it enters the optocoupler. That's it

4.

The 74 series buffer 74ls07 with open collector output can be used. Its output terminal can be connected with a maximum voltage of 30V. You can use a resistor to connect the 12V power supply and the output terminal of sn74ls07. As shown in the following figure -

5. Do you have a waveform

6. Tlp521

5-24 input - - "series resistance 10K - -" optocoupler diode positive - - "optocoupler negative grounding

optocoupler triode Collector - -" series 1K resistance - - "3.3V, and the collector is the signal output
optocoupler triode emitter grounding, base suspended

complete the level conversion

7. 1) the input signal is inverted by two-stage triode to make the output and input in phase
2 〉 the output high level is limited by the voltage on the collector resistance of the output stage, so it is easy to realize the high level conversion of the signal, and different signal levels can be obtained by taking different power supply voltages.

8. There are two solutions:
one is to increase the current limiting resistance, for example, to 4.7K ~ 10K, but the signal load capacity is very poor, it is not necessarily effective, you try
the second is to add two-stage 74ls00 inverter after the previous 5V output signal to improve the carrying capacity
it's not easy to answer the question. If you have any help, please take it. Thank you!!

9. This does not work, SDA is bidirectional, MMA7455 to SCM response signal is in the SDA line output low (SCM suspended, SDA connected to pull resistance), SCM detected low output data, you are such a one-way, SCM can not detect the process of MMA7455 pull low SDA, unable to communicate
the way of resistance voltage division is to connect 4K resistor between MCU and MMA7455, and connect 10K resistor to the ground near MMA7455 side of SDA, so that the level from MCU to MMA7455 is close to 3.3V, while that from MMA7455 to MCU is almost unaffected.