Yep, this is mostly usefull for single high Vf LEDs, for example the Yinding round LED can’t be driven to it’s full potential with a direct drive or linear driver since its Vf is so high, but even an SFT-40 with a Vf of 3.5V at 9A will start to drop relatively quickly as the cell discharges. It’s also useful for UV and Laser diodes, although I’m not particularly interested in those.
That’s right, here are schematics of the relevant topologies :
The buck-boost converter is buck and boost switches joined together with the inductor in the middle. When bucking the TOP-BST FET is always ON (BOT-BST OFF) and when boosting the TOP-BCK FET is always ON (BOT-BCK OFF)
With the cascaded boost-buck converter it’s two separate converters that are always switching.
Bench PSU, much more convenient for testing different Vin, plus if I want a constant Vin for efficiency measurements I need to adjust the PSU voltage depending on the output current due to the voltage drop, which is quite significant because I use precision current shunts for current measurements.
Yes, I designed this one relatively quickly and made it single sided for ease of fabrication, at the end there was some space for a single AUX pad so I added it.
It has a 21mm diameter clearance, I ordered it in 26mm for Convoy M21D or M3C, it could also work in a KR1 with an added switch ring on the back, or K1/DM11 with a larger diameter.
It’s another driver I never ended up testing, for two reasons : I have very few TPS62867 buck ICs left and I prefer to keep them for other projects. Anduril tint ramping code would require some big modifications to work with HDR (could have tested without the HDR function though).