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
- 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
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.
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:
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.