Communication bus power supply circuit

Abstract

The invention provides a power supply circuit of a communication bus. The circuit comprises a switch module, a reference module and a current limiting module, wherein the switch module provides a direct current for the communication bus; the current limiting module controls the switch module to output a current value; and the reference module controls branch voltages at two ends of the current limiting module, so that the current limiting module can accurately control the output current value of the switch module. Compared with an existing sampling pull-up resistor power supply circuit scheme,the power supply circuit of the communication bus has the advantages that a resistor power supply form is cancelled, so that when a communication signal is transmitted on the communication bus, a load capacitor on a communication port does not have the problem of reduced charging speed due to slow power voltage increment in resistor charging during high level output; the power supply circuit of the communication bus quickly increases the charging speed; and the communication speed of the whole communication bus is increased.

Description

technical field [0001] The invention relates to the field of communication bus control, in particular to a communication bus power supply circuit. Background technique [0002] In the existing I2C (Inter-Integrated Circuit) communication bus, several communication devices such as communication chips are connected in parallel on the communication bus, such as figure 1 As mentioned above, the two communication lines SCL (clock line) and SDA (data line) that constitute the communication bus are respectively connected to a pull-up resistor Rp2 and Rp1, and low-voltage direct current such as 3.3V provides working current for the communication line through these two pull-up resistors , because during the fast data communication process of the communication device through the communication bus, when the communication port of the communication device is performing high-speed high-low level switching, there is a distributed capacitance at the port. For example, when the SDA port of t...

AI Technical Summary

Problems solved by technology

[0003] The main purpose of the present invention is to provide a communication bus power supply circuit, the purpose is to solve the problem that the existing communication bus cannot increase the communication speed due to the use of a pull-up resistor power supply structure

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