HQB17C v1
The arrival of the Convoy T2 revived my interest and I shared 2 new drivers, the HQB17C and the HQB17D, that are made specifically with the T2 in mind. Both are 17mm boost drivers.
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This is the ‘classic’ version, with SOT23 mosfet and up to 4.3mm inductor. There’s enough space for a SOIC clamp to program the Attiny.
There a some design changes to prior versions.
The driver features vias for a programming key, to allow true ISP.
I added a gate resistor (R4) between Pin6 and gate, can’t hurt to have one.
All 3 resistors went onto the spring side, that allowed to make the connection between PAM pin5 and LED+ without vias. That way the complete boost circuit is on one side of the board. The BAT+ pad is still 8mm, that’s ample space.
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Parts
(more on parts and values see partlist overview in post#2)
U1: PAM2803, SOT-23-6
L1: max 4.3x4.3mm
D1: SOD323
C1: 0805
C2: 0805
C3: 0805
R1: 0805
R2: 0603
R3: 0603
R3: 0603
MCU: ATTiny13A-SSU, 8S1
OTC: 0603 (optional)
FET: N-Channel, SOT-23-3
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PCB
The brd-pictures do not show the ground plane on both sides of the PCB, the Oshpark pictures do.
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