The Tangent NiMH Charger (TANC) is a small circuit board for safely fast-charging NiMH batteries. It is designed to work transparently in concert with the circuit being powered: when wall power is available, that both charges the battery pack and runs the powered circuit, and when the wall power goes away, the battery takes over. It is particularly designed for the needs of the headphone amplifier designs covered elsewhere on this site, but it should work for any single-voltage system with flexible supply voltage requirements.
The "-F" designation is meant to indicate that this version of the board is made for fast-charging but, it is configurable for trickle-only charging. Plans for a dedicated trickle-charging variant ("-T"?) never came to fruition.
The TANC-F is essentially the old PPA battery board circuit plus a few small improvements, minus the on-board battery holders.
Features of the TANC-F:
Eurocard-width board size for use in Hammond 1455 and similar cases: 3.925 in × 1.6 in (100 mm × 41 mm)
On-board wire pads for up to 3 battery holders in series
Reverse power supply voltage protection
Low-voltage cut-off circuit to reduce the risk of overdischarge
Cut-off circuit can be removed, giving a charge-only board approx. 2.25 in wide (58 mm)
Uses the On Semiconductor MC3334x charge controller chip to ensure safe and effective fast charging
Fast-charges cells in as little as one hour, followed by a trickle charging step to top cells off and maintain charge
Full charge detected using the -ΔV method
Backup fast charge termination based on charge time or pack temperature
Indicator LED to distinguish between fast and trickle-charging modes
TANC-F Schematic
TANC-F PCB Layout
Part List
Checklist
Part Selection Guide
Configuration Calculator
Step-by-Step Assembly Guide
Theory of Operation
| Part List >> |
| Updated Fri Dec 16 2022 12:23 MST | Go back to Electronics | Go to my home page |
