Hi;
I'd like to discuss the new chip and circuit by National Semiconductor. It claims to dim LEDs very smoothly with any basic Triac, using line voltage. This appears to be done with the addition of their circuit, which uses the LM3445 chip.
I will probably buy a sample of the board soon, to find out how many LEDs I can power with the circuit. As well, I will probably need some help in altering the resistors and capacitors on their board to get the maximum number of LEDs connected as possible. They claim it's good up to an amp of output, and around 70 volts, or more. However, both figures are a bit uncertain, as several different websites show several different values for the outputs. So it's a bit nebulus to say the least.
Please have a look at the attachments and see what you think. The theory is well beyond me. I just want to make it work.
So, to narrow it down to a question or two, what changes would be needed to drive, let's say, 6+ LEd bulbs. The bulbs would be custom made with something like 2 parallel sets of 20 LEDs in series. Each LED would be a 5 mm, 3.4 volt, 30mA, warm white, as an early guess. This concept needs lots of fine tuning, no doubt.
They do have a couple video clips on their website, including a demo of the board.
And, does the method seem sound? Any obvious concerns or weaknesses about their approach to LED dimming?
Thanks, Tom.
I'd like to discuss the new chip and circuit by National Semiconductor. It claims to dim LEDs very smoothly with any basic Triac, using line voltage. This appears to be done with the addition of their circuit, which uses the LM3445 chip.
I will probably buy a sample of the board soon, to find out how many LEDs I can power with the circuit. As well, I will probably need some help in altering the resistors and capacitors on their board to get the maximum number of LEDs connected as possible. They claim it's good up to an amp of output, and around 70 volts, or more. However, both figures are a bit uncertain, as several different websites show several different values for the outputs. So it's a bit nebulus to say the least.
Please have a look at the attachments and see what you think. The theory is well beyond me. I just want to make it work.
So, to narrow it down to a question or two, what changes would be needed to drive, let's say, 6+ LEd bulbs. The bulbs would be custom made with something like 2 parallel sets of 20 LEDs in series. Each LED would be a 5 mm, 3.4 volt, 30mA, warm white, as an early guess. This concept needs lots of fine tuning, no doubt.
They do have a couple video clips on their website, including a demo of the board.
And, does the method seem sound? Any obvious concerns or weaknesses about their approach to LED dimming?
Thanks, Tom.
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