Tristate Logic - Increasing current drive

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SUMMARY

The discussion focuses on the challenge of driving eight KINGBRIGHT ELECTRONIC SC15-11SRWA 7-segment displays using charlieplexing with a PIC16F84A microcontroller. Each display segment requires approximately 30 mA, while the microcontroller can only supply 25 mA per pin. To resolve the current limitation, the recommended solution is to use 245 type drivers to boost the current output from the microcontroller, enabling proper operation of all displays.

PREREQUISITES
  • Understanding of charlieplexing techniques
  • Familiarity with the PIC16F84A microcontroller specifications
  • Knowledge of current requirements for 7-segment displays
  • Experience with using 245 type drivers for current amplification
NEXT STEPS
  • Research the implementation of charlieplexing with multiple 7-segment displays
  • Learn about the specifications and usage of 245 type drivers
  • Explore alternative microcontrollers with higher current output capabilities
  • Investigate current-limiting resistors for 7-segment displays
USEFUL FOR

This discussion is beneficial for electronics hobbyists, embedded systems developers, and anyone involved in designing circuits that require driving multiple 7-segment displays efficiently.

Mike Charlie
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I am currently looking at charlieplexing that can in theory cause me to be able to control eight 7 segment displays using 8 microcontroller pins, however in practice there is not enough current to drive all the displays. What I need is to increase the current drive from the microcontroller,

The information that I can give you is that I plan on using "KINGBRIGHT ELECTRONIC SC15-11SRWA" 7 segment displays. From what I understand is that it requires around 30 mA per segment on the display. The microcontroller I am currently using (will probably upgrade to one with more I/O pins) is a PIC16f84a, which I believe drives 25mA per pin.

I appreciate any help anybody can give me. Thanks.
 
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Mike Charlie said:
I am currently looking at charlieplexing that can in theory cause me to be able to control eight 7 segment displays using 8 microcontroller pins, however in practice there is not enough current to drive all the displays. What I need is to increase the current drive from the microcontroller,

The information that I can give you is that I plan on using "KINGBRIGHT ELECTRONIC SC15-11SRWA" 7 segment displays. From what I understand is that it requires around 30 mA per segment on the display. The microcontroller I am currently using (will probably upgrade to one with more I/O pins) is a PIC16f84a, which I believe drives 25mA per pin.

I appreciate any help anybody can give me. Thanks.

Just use '245 type drivers to boost the current.
 

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