【Jiaqin Comment】In the communication chip scheme of single-wire power supply communication invented by national technology, a solution for power supply and communication using a single bus was invented, which effectively improved the compatibility problem of single bus power supply and high-speed communication, and in the case of ensuring the power supply of the communication chip, it can further accelerate the communication rate and shorten the communication time.
Set micro-network messages, at present, single bus communication using a single signal line for communication, a single signal line can save input and output communication resources, not only simple structure and low cost, easy to bus expansion and maintenance, etc., so it is widely used in the industry.
The existing single-bus communication scheme mainly includes the Single Bus Scheme of The Maxim chip and the Single Bus Scheme of the Infineon Chip: the Single Bus Scheme of the Maxim Chip adopts single-bus power supply and communication, and the chip communication rate is slower due to the need to take into account the single-line communication and power supply; while the single-bus communication rate of the Infineon chip single-bus scheme can be matched, supporting fast communication, but requiring a separate power supply will affect the use in some mobile scenarios.
In view of the certain defects in the prior art, on January 19, 2020, National Technology applied for an invention patent entitled "A Communication Chip for Single-Wire Power Supply Communication" (application number: 202010058232.8), and the applicant was National Technology Co., Ltd.
According to the relevant information currently published in the patent, let's take a look at this technical solution.
As shown above, is a schematic structural diagram of the communication chip invented in the patent for single-wire power supply communication, the communication chip is connected by a power supply communication line with other communication chips, which mainly includes a transmission circuit 10. Wherein, the power supply communication line can transmit power supply signals and communication signals, the transmission circuit is connected to the power supply communication line to generate a transmission signal on the power supply communication line, that is, the transmission circuit can generate a transmission signal, and the transmission signal is sent to other communication chips through the power supply communication line.
The transmission circuit usually works in the first modulation mode or the second modulation mode, and in the first modulation mode of operation may produce a full modulation transmission signal (amplitude modulation signal), and the amplitude modulation index is 100%; in the second modulation mode of operation, a non-full modulation transmission signal can be generated, and its corresponding amplitude index is less than 100%, for example, 10% or 20%.
The reason why the two modulation modes are set is because the non-fully modulated transmission signal does not transmit the signal at the time corresponding to the low level, so the modulation speed of the non-fully modulated transmission signal is faster than the modulation speed of the fully modulated transmitted signal. When the transmission circuit works in the second modulation mode, it can improve the communication speed and reduce the signal transmission time while realizing single-wire power supply, and can be compatible with high-speed single-wire communication and ordinary single-wire communication, providing a variety of working modes for users to choose, so as to meet the needs of different application scenarios.
As shown above, for the above-described structural schematic diagram of the transmission circuit, the transmission control unit 11 may receive the data signal to be transmitted tx_data and modulation mode signal tx_mode, and according to the modulation mode signal to be transmitted data signal processing, thereby determining whether to generate a first control signal ctrl_a or a second control signal ctrl_b.
The first transmit processing unit 12 is used to receive the first control signal, after receiving the first control signal works in the first modulation working mode, to process the signal to generate a fully modulated transmission signal; the second transmission processing unit 13 is used to receive the second control signal, after receiving the second control signal to work in the second modulation working mode, and processing the second control signal to generate a non-fully modulated transmission signal.
Finally, as shown in the figure above, a schematic diagram of the structure of such a communication chip and other communication chips, in the figure, other communication chips as host chips, the communication chips proposed in the scheme as slave chips. The host chip includes MCU and power supply VCC, resistance R0, diode D0 and NPN type triode Q, MCU is provided with two GPIO interfaces, and through this interface control NPN type triode Q with diode D0, so as to achieve non-100% modulated communication during high-speed communication, to meet the power supply of the chip is not too affected at the same time, to achieve high-speed communication.
Slave chip in addition to including a transmission circuit 10, a single-wire interface 20, a control logic unit 30 and a receiving circuit 40, further comprising diode D1, capacitor C1 and power supply VDD, diode D1 and capacitor C1 can play a buffer and filtering role, the signal of the power supply VDD is derived from the power supply VCC in the host chip, through the design of the transmission circuit and the receive circuit can achieve high-speed communication and ordinary communication compatibility.
The above is the communication chip scheme of single-wire power supply communication invented by the national technology, which invents a solution for using a single bus for power supply and communication, which effectively improves the compatibility problem of single bus power supply and high-speed communication, and can further accelerate the communication rate and shorten the communication time in the case of ensuring the power supply of the communication chip.