thefreeman’s HDR Anduril 2 high efficiency drivers - update : FWAA buck driver

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icpart
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thefreeman wrote:

LM34936/LM5176 controller, there is another one from Analog, but while both can convert single cell input voltage they require a >8V bias, I haven’t found a BB controller or powerfull converter that can be powered with single li-ion. 8V is not cool because that’s out of reach of small doubler charge pumps, need to use a boost converter to power the BB controller lol, though there are small micropower ones.

The reason I was thinking about it is because somebody I know was working on a high CRI high current 3V LED, but the project was abandoned due to the very high cost of high CRI phosphors, so I lost a bit of interest on this BB driver.

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I thinking as you. Time ago I had same idea as you for powerful Buck-boost but with LM25118 or LM5175. That’s are previous BB controllers before new one LM5176. LM25118 is asynchronous converter. You right they will need additional boost converter for bias voltage. These days I owned Q8 from friend. I really like it but the driver is sucks without any sort of stabilization. This type of big multi emitter flashlight can benefit from powerful BB. For small one it’s pointless anyway.
I think to design PCB for it maybe with linear driver based on code of Emisar D4 with 1634. I don’t need HR like in your design. Maybe simpler one channel is also good choice. Also I like to use Attiny 1616 and DAC. That’s is big step ahead compared to pwm DAC. Also with integrated DAC we can choose different internal reference voltages. I need to see if gchart is used that in him code. With that it is also possible to achieve good resolution of current control.
thefreeman
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Yes he did, he used the dynamic PWM code TK recently implemented to switch the VREF between 2.5V and 0.55V giving a dimming range of 1:1159 with the 8bits DAC.

icpart
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thefreeman wrote:
Yes he did, he used the dynamic PWM code TK recently implemented to switch the VREF between 2.5V and 0.55V giving a dimming range of 1:1159 with the 8bits DAC.

That’s are great news. So I think it is time to place my order on mouser for 1616 when they received new one.
thefreeman
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Farnell has an earlier availability estimate, Feb 2022.

icpart
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thefreeman wrote:
Farnell has a sooner availability estimate, Feb 2022.

Thanks for the info. I can order from them via their distributor in my country. About replacement for opamp do you know that NCS333A. It seem to be direct replacement of OPA333 and are cheaper. Specs are almost as OPA333. But they are also out of stock for now.
thefreeman
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Yeah the specs look good, there is also the MCP6V66.
Note that I don’t use the OPA333, but its low cost identical equivalent the TLV333, in stock at Mouser and Farnell right now.

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