I was just wondering if anyone has experimented with the current regulation instead of the usual voltage regulation. (for the sake of doing so more than anything)
It would require careful planning on atty/current combos, but I think it could be done.... just as an example:
A boost regulator set to 1.5A running from a single (large format or IMR required) 3.7V li-ion cell driving a 4 ohm atty would result in ~6V (9W) at the atty. Comparable performance to running a 1.5Ohm atty direct drive on a large cell, but now it's regulated a bit better. In this case, getting higher wattage at the atty is achieved by going to higher resistance atty's instead of lower resistance. (because the regulator is always trying to achieve a particular current, higher resistance results in higher voltage necessary to hit that current). As you raise the resistance of the load (which requires more and more voltage boost to drive) the efficiency of the regulator drops lower and lower. ~80% efficiency is possible when operating at output voltages that are less than double the effective supply voltages. Going beyond that is very possible with some designs.
Buck style current regulators could be used with 2x3.7V cell configurations to achieve similar ends...
My thought process being that there are loads of LED regulators already out on the market. They are often times cheap and easy to implement, and are usually on round boards which would complement a typical round body quite well. The only major problem I see is that some designs will self destruct if presented with an open circuit (no load) condition when power is supplied to the input rail.
A buck style current regulator would have the inherent advantage of never causing cell damage or over-heating in the case of an atty shorting out. The current is clamped to whatever it is supposed to operate at whether it is presented with a normal load or a dead short. When the atty shorts out, the power drawn from the power source drops down very low by comparison.
Another consideration... Granted I am very new to all of this so I am just sort of throwing out ideas: I know that with a filament in a light bulb, inrush current plays a role in bulb life. I wonder if inrush current is a factor for atty's... I assume that like the filament of a bulb, an atty has a lower cold resistance than hot operating resistance. Current regulation provides a natural forced soft start feature that could theoretically improve atty life (maybe?)
I would love to hear some feedback on this line of thinking.
Eric
It would require careful planning on atty/current combos, but I think it could be done.... just as an example:
A boost regulator set to 1.5A running from a single (large format or IMR required) 3.7V li-ion cell driving a 4 ohm atty would result in ~6V (9W) at the atty. Comparable performance to running a 1.5Ohm atty direct drive on a large cell, but now it's regulated a bit better. In this case, getting higher wattage at the atty is achieved by going to higher resistance atty's instead of lower resistance. (because the regulator is always trying to achieve a particular current, higher resistance results in higher voltage necessary to hit that current). As you raise the resistance of the load (which requires more and more voltage boost to drive) the efficiency of the regulator drops lower and lower. ~80% efficiency is possible when operating at output voltages that are less than double the effective supply voltages. Going beyond that is very possible with some designs.
Buck style current regulators could be used with 2x3.7V cell configurations to achieve similar ends...
My thought process being that there are loads of LED regulators already out on the market. They are often times cheap and easy to implement, and are usually on round boards which would complement a typical round body quite well. The only major problem I see is that some designs will self destruct if presented with an open circuit (no load) condition when power is supplied to the input rail.
A buck style current regulator would have the inherent advantage of never causing cell damage or over-heating in the case of an atty shorting out. The current is clamped to whatever it is supposed to operate at whether it is presented with a normal load or a dead short. When the atty shorts out, the power drawn from the power source drops down very low by comparison.
Another consideration... Granted I am very new to all of this so I am just sort of throwing out ideas: I know that with a filament in a light bulb, inrush current plays a role in bulb life. I wonder if inrush current is a factor for atty's... I assume that like the filament of a bulb, an atty has a lower cold resistance than hot operating resistance. Current regulation provides a natural forced soft start feature that could theoretically improve atty life (maybe?)
I would love to hear some feedback on this line of thinking.
Eric
