Take the 2-minute tour ×
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free, no registration required.

I want to control 32x32 (or even 64x64) pieces of electroluminescent or electrochromic film with a microcontroller. Film itself will be driven by supertex hv816. Planned refresh frequency 2-4Hz.

There are two variants:

  • simple, where piece has only two states, turned off and turned on
  • more complex where there are some intermediate states

For the first variant I think I can use shift registers, and digitally controlled pots for the second variant.

Is it possible to control this drivers using matrix approach? I hope there is way better then one output-one piece of film implementation.

share|improve this question
    
You do not want to use digitally controlled potentiometers for the second variant. They cost a ton. Unless of course you might have had something simpler in mind, like a few resistors and mosfets. –  Jonny B Good May 15 '13 at 19:43
    
That would depend on if the outputs could tolerate something simpler such as PWM. You can PWM certain types of shift register or I/O expander devices at low rates, at higher rates an FPGA might be an option (easily commanded via SPI). –  Chris Stratton May 15 '13 at 21:19
add comment

1 Answer 1

One approach is to use 32 or 64 channel LED driver ICs to drive the EN pins of the SuperTex HV816.

AMS seems to be the key source for drivers beyond 48 channels, running all the way up to 144 channels. For instance, consider the AS1118, a 64-channel LED driver. Use the output channels to drive the enable pins, and you can control the individual EL panels that way.

While these devices are designed for driving LEDs, the 1.5+ Volt enable logic level of the HV816 permits an unconventional use of these devices, if a simplistic solution is desired:

  • Simply configure the LED driver to its smallest current level, use that to drive any red LED (1.7 to 2.1 Volts typical), with the EN line of the HV816 wired across this LED.
  • Each LED lighting up will not only enable the corresponding EL driver, but will give a visual indication of operation, as well.

This is assuming that the design has separate HV816 drivers for each EL panel. If not, please share the schematic for how you have the matrix configured, for further suggestions.

share|improve this answer
    
Yes, separate driver for each panel. –  ETK May 16 '13 at 9:09
    
@ETK Then this is your solution. Simple, elegant, and low part-count. –  Anindo Ghosh May 16 '13 at 10:58
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.