Parallel connected CCFLs
Conundrum, Sun Nov 26 2006, 02:17AMHi all.
For your information, I found out how to parallel CCFL units so the outputs add together, generating 2000+V at several hundred mA to an amp.
The trick is to connect 120 ohm resistor between the "low" (i.e. Gnd) side of the HV transformer to the main ground, then diode on HV output.
I had five working at once and so far they seem stable; without the resistors this does not work and the transistors fry.
Did the "hv sparkler" effect :)
-A
]1164507463_96_FT0_sparkler.avi[/file]
Re: Parallel connected CCFLs
Wilson, Sun Nov 26 2006, 05:18AM
Did u just arc it to a regular sparkler? -__-'
Wilson, Sun Nov 26 2006, 05:18AM
Did u just arc it to a regular sparkler? -__-'
Re: Parallel connected CCFLs
..., Sun Nov 26 2006, 05:41AM
Nope, bare copper does that when you give it enough power
..., Sun Nov 26 2006, 05:41AM
Nope, bare copper does that when you give it enough power
Re: Parallel connected CCFLs
ragnar, Sun Nov 26 2006, 08:27AM
Bare steel does it even better. =P
ragnar, Sun Nov 26 2006, 08:27AM
Bare steel does it even better. =P
Re: Parallel connected CCFLs
thedatastream, Sun Nov 26 2006, 09:47AM
Even if they are high power CCFL inverters, I would have thought that 10mA would have been a decent output current per inverter.
Better to use a series high voltage capacitor instead of a resistor because it is lossless. Select a value that gives you the reactance equivalent to the resistance you reqire using 1 / ( 2 * pi * f * C ). Ceramic cap for preference.
Not puting impedance in the inverter output will cause one inverter to try and supply more output current - too much and *pop* unless thre is some curent or power limit bult in to the control circuit.
Rgds,
James
thedatastream, Sun Nov 26 2006, 09:47AM
Conundrum wrote ...
For your information, I found out how to parallel CCFL units so the outputs add together, generating 2000+V at several hundred mA to an amp.
...
I had five working at once and so far they seem stable; without the resistors this does not work and the transistors fry.
2000V * 700mA = 1.4kW? Are you sure?For your information, I found out how to parallel CCFL units so the outputs add together, generating 2000+V at several hundred mA to an amp.
...
I had five working at once and so far they seem stable; without the resistors this does not work and the transistors fry.
Even if they are high power CCFL inverters, I would have thought that 10mA would have been a decent output current per inverter.
Better to use a series high voltage capacitor instead of a resistor because it is lossless. Select a value that gives you the reactance equivalent to the resistance you reqire using 1 / ( 2 * pi * f * C ). Ceramic cap for preference.
Not puting impedance in the inverter output will cause one inverter to try and supply more output current - too much and *pop* unless thre is some curent or power limit bult in to the control circuit.
Rgds,
James
Re: Parallel connected CCFLs
Marko, Sun Nov 26 2006, 10:21AM
You can try using traditional 'or gate' made of diodes and connect it to ccfl's outputs. (shouldn't be too hard with 2kV
While system is weakly loaded only the ccfl with highest voltage output will be drained; others are blockd by it.
As load increases output voltage of first ccfl drops and this makes others come into use (system would be self-balancing).
Marko, Sun Nov 26 2006, 10:21AM
You can try using traditional 'or gate' made of diodes and connect it to ccfl's outputs. (shouldn't be too hard with 2kV
While system is weakly loaded only the ccfl with highest voltage output will be drained; others are blockd by it.
As load increases output voltage of first ccfl drops and this makes others come into use (system would be self-balancing).
Re: Parallel connected CCFLs
Conundrum, Sun Nov 26 2006, 02:54PM
"The trick is to connect 120 ohm resistor between the "low" (i.e. Gnd) side of the HV transformer to the main ground, then diode on HV output."
:)
-A
Conundrum, Sun Nov 26 2006, 02:54PM
Firkragg wrote ...
You can try using traditional 'or gate' made of diodes and connect it to ccfl's outputs. (shouldn't be too hard with 2kV
While system is weakly loaded only the ccfl with highest voltage output will be drained; others are blockd by it.
As load increases output voltage of first ccfl drops and this makes others come into use (system would be self-balancing).
You can try using traditional 'or gate' made of diodes and connect it to ccfl's outputs. (shouldn't be too hard with 2kV
While system is weakly loaded only the ccfl with highest voltage output will be drained; others are blockd by it.
As load increases output voltage of first ccfl drops and this makes others come into use (system would be self-balancing).
"The trick is to connect 120 ohm resistor between the "low" (i.e. Gnd) side of the HV transformer to the main ground, then diode on HV output."
:)
-A
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