Seven segment display
Seven-Segment LED Displays
Nicholas Neumann
11/19/2010
Abstract
Seven-segment displays are electronic display devices used as an easy way to display decimal numerals and an alterative to the more complex dot-matrix displays. The LDS-C303RI, a common seven-segment display, will be examined. Common anode vs. common cathode will be outlined.
LED drivers such as the CD74HC4511E will also be discussed. Design applications such as digital clocks and electronic meters will be covered briefly.
Keywords: Seven-Segment, LED Display, Common Anode/Cathode, Drivers, LDS-C303RI,
CD74HC4511E
Introduction
Seven-segment displays first became widely used as a popular way of displaying numbers. Today they are used as displays in home appliances, cars, and various digital devices. The LDS-C303RI is commonly used in many designs, it includes seven LED bars aligned in a figure eight pattern as seen in Figure 1. It is capable of displaying the numbers 0-9 and the letters A-F by lighting the appropriate segments. This is typically controlled by a driver like the CD74HC4511E.
Figure 1: Seven-Segment Layout
Objective
The following will detail the necessary requirements to implement a display into a circuit. This application note will also provide the basic functionality of a seven-segment display. In terms of hardware, the implementation of the display into a counter using a CD74HC4511E driver will be discussed. Schematics are included in order to explicitly show the correct implementation of the display into a simple binary counter.
Methods
Seven-Segment Display
When dealing with seven-segment displays, there are two types. Common anode and common cathode; in common anode all the anodes on the display are tied to a common pin, typically the power source, and the LED are controlled via the cathodes with ground being on and power being off. In common cathode all the cathodes are tied to a common pin, in this case generally ground, and the LED are
Nicholas Neumann
11/19/2010
Abstract
Seven-segment displays are electronic display devices used as an easy way to display decimal numerals and an alterative to the more complex dot-matrix displays. The LDS-C303RI, a common seven-segment display, will be examined. Common anode vs. common cathode will be outlined.
LED drivers such as the CD74HC4511E will also be discussed. Design applications such as digital clocks and electronic meters will be covered briefly.
Keywords: Seven-Segment, LED Display, Common Anode/Cathode, Drivers, LDS-C303RI,
CD74HC4511E
Introduction
Seven-segment displays first became widely used as a popular way of displaying numbers. Today they are used as displays in home appliances, cars, and various digital devices. The LDS-C303RI is commonly used in many designs, it includes seven LED bars aligned in a figure eight pattern as seen in Figure 1. It is capable of displaying the numbers 0-9 and the letters A-F by lighting the appropriate segments. This is typically controlled by a driver like the CD74HC4511E.
Figure 1: Seven-Segment Layout
Objective
The following will detail the necessary requirements to implement a display into a circuit. This application note will also provide the basic functionality of a seven-segment display. In terms of hardware, the implementation of the display into a counter using a CD74HC4511E driver will be discussed. Schematics are included in order to explicitly show the correct implementation of the display into a simple binary counter.
Methods
Seven-Segment Display
When dealing with seven-segment displays, there are two types. Common anode and common cathode; in common anode all the anodes on the display are tied to a common pin, typically the power source, and the LED are controlled via the cathodes with ground being on and power being off. In common cathode all the cathodes are tied to a common pin, in this case generally ground, and the LED are
References: 1. LDS-C303RI Data Sheet. Lumex Incorporated. May 1997. 2. CD74HC4511E BCD-To-7 Segment Latch/Decoder/Drivers Datasheet. Texas Insturments. October 2003. 3. “Fundamentals of Seven Segment Displays.” Electronic Project Design. Web. 19 Nov. 2010. . 4. Wood, Vincent. “Numitron Readout: Simplified Seven-Segment Display in One Tube.” Decode Systems. Web. 19 Nov. 2010. . 5. “BCD Decoder.” Diagram. Web. 19 Nov. 2010. . Appendix