Design and Simulation of LED Color Control Conversion Circuit Based on Multisim 10

0 Introduction

At present, the design of digital integrated circuits is modular. EDA technology refers to the automatic design of electronic products based on the computer as the working platform and integrating the latest achievements of applied electronic technology, computer technology, information processing and intelligent technology. Using EDA tools, electronic designers can design electronic systems from concepts, algorithms and protocols. A lot of work can be completed by computers, and the whole process of electronic products from circuit design, performance analysis to IC layout or PCB layout can be completed automatically on computers.

Multisim 10 is an electronic circuit design and simulation tool. In scientific research, circuit simulation tools are mainly used for circuit design and simulation. Compared with other EDA software, it has a more intuitive human-computer interaction interface, especially the instruments in its instrument library are no different from the actual instruments in the real experiment.

LED electronic display screen is composed of semiconductor light-emitting diode pixels evenly arranged. LED pixels with different colors can be manufactured by using different materials. LED display screen has bright colors and strong three-dimensional sense. It is as static as oil painting and as dynamic as film. It is widely used in stations, docks, airports, shopping malls, hotels, securities markets, industrial enterprise management and other public places.

For example, in billboards or entertainment places, the LED display screen is often designed to change continuously according to a certain law, so as to obtain good viewing.

The following describes the design of an 8-bit digital signal generator based on Multisim 10, using bidirectional general mobile register 74ls194, led and character signal generator × 8 LED dot matrix controller to realize the cyclic display of multiple groups of light-emitting diodes according to a certain law.

Design and Simulation of color control conversion circuit

The color control conversion circuit is mainly composed of three parts: the setting of character signal generator, the setting of bidirectional general shift register group and 8 × 8 dot matrix LED tube setting.

1.1 setting of character signal generator

Word generator is an instrument that can generate 32-channel (bit) synchronous logic signals, also known as digital logic signal source, which can be used to test digital logic circuits. The character signal generator can send digital or binary digital signals into the circuit to drive or test the circuit.

In this circuit, pins 0 7 of the character signal generator correspond to a, B, C, D, SL, Sr, S0 and S1 of the first 74ls194 respectively; Pins 8 15 correspond to a, B, C, D, SL, Sr, S0 and S1 of the second 74ls194 respectively; Pins 16 23 correspond to a, B, C, D, SL, Sr, S0 and S1 of the third 74ls194 respectively; Pins 24 31 correspond to a, B, C, D, SL, Sr, S0 and S1 of the fourth 74ls194 respectively. Therefore, the transformation of character signal is the transformation of the four 74ls194 inputs. As shown in Figure 1.

1.2 main control circuit and simulation design results

eight × The 8-dot matrix LED color lamp conversion control circuit is a circuit composed of character signal generator, bidirectional moving register and LED dot matrix. Its design is shown in Figure 2.

1.2.1 logic function and circuit design process of 74ls194

74ls194 has three functions: merge and exit, move left and move right. Where a d are parallel input terminals, QA QD are parallel output terminals, S1 and S0 are mode control terminals. When CLR is 1 and the rising edge of the clock arrives, if s1s0 = 11, it will be incorporated and output, QD QA = D A; If s1s0 = 10, move left, QD QA = QC qasl; If s1s0 = 00, shift right, QD QA = srqc qa.sr shift right serial input, SL is shift left serial input, CLR is direct unconditional zero clearing end, CLR is clock pulse input, VCC is power supply and GND is grounding.

In this circuit, the output terminals QA, QB, QC and QD of the first 74ls194 correspond to the first row, the second row, the third row and the fourth row of the LED matrix respectively; The output terminals QA, QB, QC and QD of the second 74ls194 correspond to rows 5, 6, 7 and 8 of the LED matrix respectively; The output terminals QA, QB, QC and QD of the third 74ls194 correspond to column 1, column 2, column 3 and column 4 of the LED matrix respectively; The output terminals QA, QB, QC and QD of the fourth 74ls194 correspond to columns 5, 6, 7 and 8 of the LED matrix respectively. Therefore, the QA, QB, QC and QD values of 74ls194 determine the state of LED.

1.2.2 8 × 8 design and working principle of LED dot matrix

eight × The 8-dot matrix LED display consists of 64 light-emitting diodes, and each light-emitting diode is placed at the intersection of row line and column line.

When a corresponding row is set to high level and a column is set to low level, the LED at the intersection of row line and column line is lit; If the LEDs of a row are to be lit, the corresponding row is set to high level and all columns are set to low level; If the LEDs of a column are to be lit, all rows are set to high level and the corresponding column is set to low level.

1.2.3 simulation results

The color lamp transformation mainly realizes the rolling display by processing the parameter values of the character signal generator and controlling the on or off of the LED. The results and the parameter values of the character signal generator are described below.

(1) Scroll line by line (scroll from top to bottom and then from bottom to top):

â‘  Use the merge and exit function to realize the line by line scrolling function. The parameter values of character signal are shown in Table 1, which are represented in cycles from top to bottom and from left to right.

â‘¡ Use the merge and export, move right and move left functions. The parameter values of character signal are shown in Table 2, which are represented in cycles from top to bottom and from left to right.

(2) Use the merge and exit, move left and move right functions to realize the column by column scrolling function (the scrolling order is left to right, and then right to left). The parameter values of character signal are shown in Table 3, which are represented in cycles from top to bottom and from left to right.

(3) Use the merge and export function to realize point by point scrolling display (the scrolling order is row 1, column 1, row 1, column 2... Row 8, column 8).

The parameter values of character signal are shown in Table 4, which are represented in cycles from top to bottom and from left to right.

2 Conclusion

Multisim 10 is used to design and simulate each unit circuit and the overall circuit of the color lamp conversion control circuit, which can easily and quickly build the circuit, and quickly find and modify the circuit. After the circuit design simulation is completed, the actual circuit is built, which reduces the cost and improves the design efficiency.