TK61 Driver - TK Seis-Um - BLF Edition

TK Seis-Um - BLF Edition

THIS POST IS A WORK IN PROGRESS!
I will continue filling it out as time permits. Please feel free to ask questions.

Special Thanks!

First off, I need to give special thanks to all of those who have helped along the way with this project, including but not limited to: Mattaus, wight, tterev3, and JonnyC.

What Is It?

A mostly drop-in replacement driver for the TK61, and with some additional modifications, the TK75 (see section below for TK75). I am releasing this BLF edition of the driver to give back to the community. I will also be selling complete drivers at some point in the future, but I hope that all of you that would like to assemble your own give it a shot!

Specifications:

  • Low drain while driver is off (low quiescent current)
  • Efficient
  • Configurable for up to 10A
    • 5.5A is recommended starting point for newer XM-L2 emitters
      • You have a 90%+ chance of blowing a newer XM-L2 with anything more than this. Even some of the newer XM-L2 cannot handle this much current.
    • Older XM-L2 emitters can usually handle 6.5A-6.6A
  • Single switch input (tie both switches together)
  • Temperature sensor
Components Needed (TK61, 8.4v Input):
If you know what you're doing, you can substitute these parts for many others. These are simply what I have used and know works.
  • VS1: Sense Resistor
    • 2512 2W or Higher
    • Formula: 0.2/R=I
    • ~5.7A = 0.035 Ohm (recommended starting point, for newer XM-L2s)
    • ~6A = 0.033 Ohm
    • ~6.5A = 0.030 Ohm
  • VS2: Sense Resistor - Optional
    • Can be used to tweak current, or to use lower value resistors in parallel
  • BULK C: Bulk Input Capacitor
    • On battery side
    • 470uF, 16V, Organic Polymer (very low ESR)
    • 8mm diameter or less
  • CIN1; CIN2: Input Capacitors
    • 1206, 22uF, 16V (or higher), X5R or better
  • C_LDO; C_TINY; CMAX1: Component Capacitors
    • 0805, 10uF, 16V (or higher), X7R
  • CMAX2: Buck IC Bypass Capacitor
    • 0603, 0.1uF, 16V (or higher), X7R
  • C_OUT: Output Capacitors (3)
    • Optional, can slightly lower ripple.
    • 0805, 10uF, 10V (or higher), X7R
  • LDO: Voltage Regulator
    • On Semiconductor MC78LC50NTRG
  • TSENSE: Temperature Sensor
    • Microchip Technology MCP9700AT-E/TT
  • C_TS: Temperature Sensor Bypass Capacitor
    • 0603, 1uF, 10V (or higher), X7R
  • TINY: MCU attiny13a-SSx
    • STAR Momentary Firmware
  • MAX: Buck IC
    • Maxim Integrated MAX16820
  • NFET: Buck IC Lockout MOSFET
    • Diodes Incorporated DMG3420U-7
  • Q1: Main Switch
    • LFPAK56 N-Channel
    • NXP PSMN2R4-30YLDX
  • D1: Flyback/Freewheel Diode
    • Diodes Inc. PDS1040L-13
  • L1: Inductor
    • SMD 1265 4.7uH or 6.8uH
  • RV1: 36K 0603/0805 1% (or better)
  • RV2: 4.7K 0603/0805 1% (or better)
  • RT1: 19.1K 0603/0805 1% (or better)
  • RT2: 36K 0603/0805 1% (or better)
  • RGATE: 100 ohm 0603/0805
  • PLDWN_N: 19.1K 0603/0805
  • RDIM: 100 ohm 0603/0805
  • PLDWN_D: 4.7K 0603/0805
TK75 Component Changes (16.8V Input)

This driver can be made to work with the TK75, but it is a much more involved conversion. To save build costs, the components specified for the TK61 build cannot handle a 16.8V input. Here is what needs to be changed:
  • Battery Carrier. This is the biggest and most difficult change. The battery carrier needs to be rewired from 2S to 4S. RaceR86 has already documented how to do this in his TK75 R86 edition thread. After you do this, you need to be 100% certain that you ALWAYS place cells in the carrier with the correct polarity. I would recommend using protected cells if you go this route.
  • LDO. The MC78LC50NTRG LDO is only rated for 12V input.
    • Recommended Part: [INSERT]
  • Bulk Capacitor. You really should have something that is rated for 25V or more. 330uF or more, with the lowest ESR possible while staying with the 8mm diameter limitation.
    • Recommended Part: [INSERT]
  • CIN1; CIN2; C_MAX1; C_MAX2; C_LDO. These all need to be rated for 25V or higher.
MCU HEX File:
Download link.
  • 4 Modes ~0.25A, 2.5A, 4.5A, 6A
  • Temperature Set at ~60C
  • Low voltage ramp begins at around 6.2V, shuts off at 6V

Oshpark PCB Link:

Oshpark Link.

TK61 Parts Shopping Cart Links:

Mouser (with some slight tweaks due to out of stock parts). $15.52 + shipping.

Mountain Electronics (coming soon). $13.99 + shipping.

Please don't make me buy a TK61.

Wow (insert naughty words here). I'm going to have some homework ahead of me to find out how the TK61 works with two switches to see how it would work in a custom light. Nice, no make that orsm effort guys.

:slight_smile:

I’m with ya.

Bravo! Finally a temp sensor! Nice work! Looks to be a straight press fit w/o the anti rotate tabs. :beer:

Sounds great. So would the same changes that will enable it to be put in a TK75 be used to run a MT-G2 in a TK-61?

Soo excited about this!

Nice…

Looks very familiar.

Subscribed…. I’ve got a TK75 that I wouldn’t mind giving a bit of love to.

Watching this one with anticipation, this would be a great excuse to get me a TK-61.I am really interested in a pre - built version of it since I have little free time anymore.Thanks Richard.

What's the purpose of the N-fet on pin4 (GND) of the MAX16820?

The MAX has a 5V reg built in, might be able to use it to power the Tiny13 - if it uses less than 10mA. Anyone know what they draw?

I put that FET and the LDO there just to complicate things and add parts to the design.

The MAX16820 has a high quiescent current drain, so that FET is to cut power to it when the light isn't on. For an extra $2 worth of parts you cut the quiescent drain down to around 20uA-30uA.

Yes, it can power the attiny if the tiny is only switching on the MAX's DIM pin.

I like the way you think!

But, I wonder if grounding the EP pad doesn't bypass the FET. The datasheet is vague as to whether they are connected internally.

But you've probably already checked that haven't you?

I look forward to your results!

Of course I've already checked that. They are electrically isolated.

Just to be clear, this is not a prototype or work in progress. This is a driver that has gone through several revisions where I've actually ordered boards, tested them, tweaked them, then revised them, and gone through the process again. I have tested every aspect of the board for proper function, both on the bench and in several lights, with different emitters and output currents.

I didn't want to release a board like this until all of the bugs were ironed out. I've been working on this since October, but didn't want to announce anything until it was finished and tested.

I figured you knew what you were doing, just needed to be clear.

Keep up the great work!

Am I gonna have to get another TK61 now? No way! But this will fit something else. Surely. :slight_smile:

I'm not sure about that, but this one does work correctly.

Congratulations! excellent work H) , waiting for news, I am interested :slight_smile:

These two questions are worth repeating …

I have a TK61 but dont really want to play about with that light. However, the driver might also be handy if ever the one in it failed…