That is a really cool driver zeroflow!
No such skills to design my own driver here or else I would have made a new better boost driver for the Convoy T2 (higher freq. PWM, no memory, no strobe)
Instead I converted the T2 to li-ion, led=my very last 219C SM4070e, driver FET-converted AK-47 C1 (low-med-high no memory) 680 Ohm bleeder, lighted tail with 6x 0603 630nm leds, spring bypassed, orange tailcap.
High at 3 seconds 740 lumen, 30 seconds 580 lumen. Nice beam and very good tint, but not as rosy as some other SM4070e leds that I used, this one is only very slightly under the BBL. (CRI=91.7 R9=60, CCT=3976, duv=–0.0016)
Some pictures
A KD DTP board was sanded to 1mm thickness by soldering a handle on the wire-pads, grab it with pliers and using the disc sander to thin the board, then removed the handle. Then the board was sanded from 16mm diameter to 14mm.
The driver had all 3 7135 chips removed and a FET added (see comfychair-inspired quick+cheap+lazy single-sided 17DD FET-driver (poor man's nanjg92)).
A brass button was soldered and a 680 Ohm bleeder resistor soldered in a shallow 2.5mm hole.
I used the stock tailboard with switch and added a pd68 6-led ringboard, 6x 630nm leds 3x 8.4 kOhm resistors.
