1. Background overview.
Nowadays, the performance requirements of the whole circuit system are getting higher and higher, the power consumption requirements are getting lower and lower, and its design is becoming more and more complex.
For example, when the voltage level of the communication interface of the master SoC is 3At 3V, the communication interface voltage level of the other peripheral is required to be 1At 8V, a voltage mismatch between components within the circuit system occurs (as shown in Figure 1).
In order to allow various devices in the entire circuit system to communicate normally, it is necessary to use the corresponding voltage level translation chip at this time.
2. The working principle of bidirectional level translation.
In practical applications, there are situations where the transmitter and receiver will be interchanged, such as IIC, MDIO, SPI, etc., where two-way communication is required, it is necessary to use a two-way level translation chip. Here's how it works:
If the output is left. When the left input level H (the input voltage is VCCA), the MOSFET is up to due to the VGS threshold, and the output voltage on the right side is VCCB), as shown in Figure 2-A. When the left D0 input is low l(0V), due to VGS vcca=""> threshold, so the MOSFET is on, and the output voltage on the right side is low at 0V, as shown in Figure 2-B.
When the right input is high H, since the left side is initially high VCCA, VGS = 0 "threshold, MOSFET cut-off, as shown in Figure 3-A; When the right input L is used, VS=VG=VCCA, VGs=0, and the MOSFET is closed, but since the FET has a parasitic diode, it pulls down the left output to the on-voltage of a diode, which is at 03v to 07V, so here we can consider the left output to be low. In this case, if the VCCA is 33v, then vgs (3..)3v-0.7v=2.6V) is greater than the gate threshold voltage of the MOSFET and the MOSFET is turned on, and the right input and left output are at the same voltage close to 0V, as shown in Figure 3-b.
3. The working principle of Gutai Micro two-way level conversion chip.
Gutai's bidirectional automatic direction detection voltage converter can be combined with open-drain and push-pull drive, with a maximum rate of 24Mbps (push-pull, open-drain 2Mbps maximum rate). It works similarly to the one described in Part 2 above, using the N-channel MOSFET to turn on and close the connection between ports A and B. When the driver connected to the A or B port is low, the corresponding terminal is pulled low by MOSFET N2 (as shown in Figure 4).
4. Introduction of Gutai micro bidirectional level converter.
Gutai micro-level converter series, support 1 8 channels, mainly used for UART, I2C, SMBUS, GPIO and other communication interfaces, automatic identification of direction, compatible with push-pull output architecture and open-drain output architecture, its main features are as follows:
No data direction control required;
The push-pull architecture supports a data rate of 24 Mbps and the open-drain architecture supports a data rate of 2 Mbps.
Side A supports 165v~3.6V, 2 on the B side3v~5.5v;
The power supplies on side A and B are isolated from each other;
No power-on sequencing requirement;
Supports -40°C +85°C.
It should be noted that the power supply voltage of VCCA cannot be greater than VCCB, that is, the A side is connected to the low-voltage system, and the B side is connected to the high-voltage system;
5. Gutai micro-level converter product list.