A while back I remember seeing an SP70 on their Aliexpress store that was labeled as “BLF” but it was just the standard SP70 with the Sofirn 6 mode/ramping UI. I don’t see it on there anymore though.
Ok, my pictures of the driver are better than Sofirn's:
This is a classic FET design. Using the top pic as a reference, the large part on the left is a FET, one we are familiar with in fact. The bottom right pin of the FET is the FET gate, and you can see connected to that the 2 standard resistors our designs use for the FET gate - one is a low value inline, the other is a high resistor value going to ground.
The 5 leg part on the right is an LDO, to bring down the voltage to ~4V to run the MCU. The 3 leg part on the bottom appears to be another FET for lower power, but it appears to be not used, not connected to the MCU - I'm not sure, would have to trace the circuit myself.
I've seen these kind of dual FET, one hi power - one low power, driver designs before. In fact the Haikelite HK04 is very similar:
This uses 2 high power FET's instead of 1, and the part labeled Q7 near the FET's is the low power FET channel.