Circuit Design of Parallel Power Supply System of Switching Power Supply Module of C8051F340

Probe domestic switch needle KG-300K needle head diameter is 3.0mm normally open switch needle

MOS power IC full range

L0504-Murata muRata common mode inductor 90Ω 150mA

Overview:
The system uses C8051F340 single-chip microcomputer as the control core. By sampling the output voltage and current, changing the PWM duty cycle output of the single-chip microcomputer and controlling the on-off of the MOS tube, the 8V DC/DC modules with two rated output powers of 16W are connected in parallel. powered by. After testing, the power supply system has a power supply efficiency of 70.57%; adjusting the load resistance, the sum of the output currents I1 and I2 of the two modules is 4 A, and I1 and I2 are automatically distributed in the 1:1 and 1:2 modes. The absolute value of the relative error is not more than 2%; it has the load short-circuit protection function and the protection threshold current is 4.5A.

In recent years, with the continuous improvement and rapid development of microelectronics technology and technology, magnetic materials science and sintering processing technology and other edge technology, switching regulator technology has also made breakthroughs. At present, multi-module parallel power supply has replaced the single centralized power supply and has become an important direction for the development of power systems. The parallel distributed power supply has the advantages of parallel expansion, high power density of the power module, small volume and weight, but also the problem that one or more modules operate in the current limit state due to the direct parallel connection of the power modules. . At present, current sharing control is a key technology for realizing high-power power and redundant power. In this paper, a photovoltaic grid-connected power generation simulation device is designed and fabricated, which realizes parallel power supply of dual-switch power supply modules, improves system power supply efficiency, and realizes automatic current distribution.

The design task designed and fabricated a parallel power supply system consisting of two 8 VDC/DC modules with rated output power of 16 W. The block diagram is shown in Figure 1. It is required to adjust the load resistance and keep the output voltage UO=8.0+0.4V, so that the sum of the output currents of the two modules is IO=1.0A and the current is automatically distributed in two modes: I1:I2=1:1 and I1:I2=1:2. The absolute value of the relative error of the output current of each module is not more than 5%; the sum of the output currents of the two modules is IO=4.0A and the current is automatically distributed according to the I1:I2=1:1 mode, and the output current of each module The absolute value of the relative error is not more than 2%; under the rated output power working state, the efficiency of the power supply system is not less than 60%; the system is required to have load short-circuit protection and automatic recovery function, and the protection threshold current is 4.5A.

Figure 1 Diagram of the associated power supply system

System overall design Parallel power supply system is mainly composed of controller module, DC/DC conversion voltage regulator module, current detection module and output voltage sampling module. The overall hardware block diagram of the system is shown in Figure 2. In the system, the DC/DC conversion voltage regulator module adopts a step-down chopper circuit that selects non-isolated mode; the current detection module derives the current value by sampling the voltage on the constantan wire; the C8051F340 single-chip output PWM wave adjusts the DC/DC module. Output, control output current.

Figure 2 system hardware block diagram

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