The TP4056 chip is a lithium-Ion battery charger for a single cell battery, protecting the cell from over and undercharging. It has two status outputs indicating charging in progress and charging complete. It also has a programmable charge current of up to 1A.
You can use it to charge batteries directly from a USB port since the working input voltage range is 4V ~ 8V.
There are two types of common breakout boards for this chip:
- One with only the charger chip on board.
- One with three chips on board.
Note: You need to change the current programming resistor on the breakout board to match the lithium battery you are using – the default is 1.2k which is for a 1Ah (1000mAh) battery.
Note: Follow this link to learn how to use the DW01A correctly.
Lithium batteries can be dangerous if not charged properly and that’s why the TP4056 is useful as it stops over-voltage and current charging at specific conditions.
Warning
There are a lot of circuits out there that show the use of the TP4056 as both a charger and a load driver – Not Good. If a load is attached to the battery while charging, then the TP4056 can not detect when the charge current has fallen to C/10. So it carries on charging- this could be dangerous.
You should never use the TP4056 as a charger and as a load driver at the same time. When charging the battery, switch off the load, and when loading the battery, switch off the charger. Alternatively use a PMOSFET, a resistor, and a Schottky diode.
Lithium batteries can not absorb overcharge – the current must be cut off after charging. If not there could be a thermal runaway.
TP4056 Features
- Constant Current / Constant voltage charging method.
- C/10 Charge termination.
- 2.9V trickle charge threshold (for deeply discharged batteries).
- Upper charge stop voltage: 4.2V.
- Soft start inrush current limit.
- Automatic recharge (keeps batteries optimally charged when connected to a charger).
