EL Driver Shield

The EL Driver Shield will drive 8 channels of EL wire, generating required voltages on the shield itself. Each channel will support dimming individually.

Project Status

• 2011-11-17: Removed base transistor between opto and NPNs, now the right hand low side of the H-bridge works too. In testing earlier a probe slipped and shorted the resistor on the opto's first channel, destroying it. New optos on order, will arrive tomorrow.
• 2011-11-16: Replaced all transistors with ones rated to +160V to rule out problems with exceeding specs. Much troubleshooting, no real progress.
• 2011-11-15: Pulled the low side transistors and found that the high side is switching between +42V and +55V. Changed base resistor values to 1k and resolved this issue.
• 2011-11-10: Reworked the H-bridge to eliminate NPNs being used to pull signals high, it is now switching the DC but only getting ~40V p-p out of it for some reason. More investigation is required.
• 2011-11-08: Assembled low voltage end, able to program the micro and flash the LEDs associated with the channels. Lost two of the LEDs assembling it, doh! Now I remember why I don't normally use 0603 LEDs...
• 2011-11-03: First assembly started, HVDC generator works fine, HVAC converter is arcing in the H-bridge section somewhere when switched, need to investigate further.
• 2011-10-26: Boards arrived.
• 2011-10-07: Added LEDs for each channel to assist in troubleshooting, and test points for each side of the HVAC. Completed adding silkscreen and ran checklist, CAM files now sent to Laen for manufacturing. Parts still need to be ordered.
• 2011-10-06: Completed board routing, still need to do silkscreen and checklist.
• 2011-10-05: Completed revision 1 schematic, passes checklist. Started board layout, got about 50% complete.
• 2011-10-04: Almost finished HV AC switching/control.
• 2011-10-03: Finished BOM/schematic for HV AC converter/inverter.
• 2011-10-02: Finished designing/simulating HV DC generator in LTSpice, put BOM and schematic for this section together.
• 2011-10-01: Many hours spent in LTSpice putting together a design for the HV DC generation.
• 2011-09-30: Started putting basic design ideas together.

Ideas / Brainstorming

• One single high voltage converter with separate switches for each channel
• Dimming using PWM via optoTRIAC on each channel, synced with the HV AC converter
• Shield will likely need a microcontroller on it
  • Inputs: 2x I2C address setting
  • Outputs: 1x HV DC converter sync pulse, 1x HV AC converter polarity signal, 8x optoTRIAC gate outputs
  • Bus: I2C, RS232

Revision 1 Issues

• C3 missing from BOM
• R17 is on BOM as "R18"