How to Make Lipo Battery Charger Circuit

Introduction

In this project, we are going to make a simple lipo battery charger using TP4056 module with battery protection. The circuit that charges the battery by supplying the charge carrier (i.e-electrons) to it is battery charger circuit. Most of the rechargeable battery has common problem of over charging and over discharging. we need a smart charging solution that protects our battery from over charging and damage cause by over charging.

This lithium battery charger circuit automatically cut off the charging process when the full charge limit of battery is reached (i.e-4.2V) . This circuit also protect our battery from over discharging by automatically cutting the output power when the battery voltage falls below 2.4 volt.

Bill Of Materials

ValueReferenceQuantity
U1TP40561
IC1DW01A1
Q1FS8205A1
RV11K pot1
R1-R60.4, 220, 100, 1KOhmsfew
C1, C2100nF, 10uFfew
D1, D23 mm led2

TP4056 Chip

The TP4056 is a complete chip for designing a constant-current/constant-voltage linear charger for single cell lithium-ion batteries.

Features

Programmable Charge Current Up to 1000mA

Constant-Current/Constant-Voltage

Preset 4.2V Charge Voltage with 1.5% Accuracy

Automatic Recharge

Two Charge Status Output Pins

Pin Description

Pin Diagram of TP4056

Pin Description of TP4056

Pin description of TP4056

Circuit Diagram of Lipo charger using TP4056 with out protection unit

Circuit Diagram of Lipo charger using TP4056 with out protection unit
tp4056 pin diagram

Power Pin

Starting with the power pin, Pin 4 is Positive input supply voltage. We can provide voltage from 4V to 8V in this pin. In this project, we are providing 5V from any external source to this pin. For bypassing unwanted voltage spikes and noise, a capacitor is also connected from Vcc to ground. However the large value of capacitor (C1 -10uF) need to decouple with a series resistor(shown as resistor R3 in the circuit diagram) of 0.2 ohms to 0.5 ohms which reduces the ripple voltage. 

How to Make Lipo Battery Charger Circuit-Power part

Pin 3 of this pin is connected to ground which mean to sayo, this pin has been directly connected to the supply voltage to enable the IC. that negative terminal of battery is connected to this point as a common ground.

Pin 8 of TP4056 is chip enable pin. A high input to this pin enables the chip and low input disables this chip. In our case, we have directly connected this pin to input power supply. so, our chip is enabled.

Programming pin

Pin 2 is very important pin of TP4056 form where we can set the charging current. The charging current plays a important role in charging a battery and it must be programmed according to the battery used. The main advantage of using this TP4056 chip is we can program the charging current by selecting the proper resistor as per our requirements.

How to Make Lipo Battery Charger Circuit-Programming current

The Programming resistor with corresponding current value shown in the table below :

Programming resistor with corresponding current value in TP4056

The value of program Resistor can be calculated by using the below formula

RPROG  = (Vprog/ Ibat)* 1200   (Icharge =1A and VPROG = 1V)

Charge Indication Pins

The charge pin or pin 7 of TP4056 is use to indicate the charging process of the battery. This pin goes to the low state while the battery is charging otherwise it remains in high impedance. A Red LED is connected with a resistance (R2) in series to this pin for the visual indication of the charging process.

Circuit showing charging and full charged state of battery

The STDBY pin or pin 6 is used to indicate the full charge of the battery. This pin goes to the low state while the battery is fully charged otherwise it remains in high impedance.

The resistor R1 and R2 is used to limit the flow of current from the LED. 

The Led indication is shown in the figure below:

led indication of tp4056

Output Pin

The BAT pin or Pin 5 is connected to the positive terminal of battery. This BAT pin provides the regulated 4.2V and charging current to the battery. In this circuit, a capacitor is connected in parallel with the BAT pin which connects to the ground for bypassing unwanted voltage spikes and noise.

Working Principle and Working modes

This chip TP4056 operates is 4 different modes. We can observe these mode from the following graph.

Graph showing Charging Modes of TP-4056 IC

1) Trickle mode

When the battery voltage is less than 2.8V then the IC will enter in trickle charge mode to bring the voltage of the battery in safe mode. In this mode, the charging current (value of current by which battery will be charged) reduces to 13% (Typ 130mA) of the full-scale current. When the battery voltage reaches above trickle voltage (Vtrickle(2.9V) + Delta Vtrickle (0.08V)), the IC enters in constant current mode. 

2) Constant Current Mode

The current flowing out of the PROG pin will be constant. This current is used to charge the battery and is called charging current. In this experiment, this charging current is 1A (Icharge) (as set by the programmable resistor at pin 2) and the battery will be charged through this constant current of 1A until the terminal voltage of the battery will reach its maximum rated voltage (4.2 V).

3) Constant voltage mode

when the battery voltage has reached peak value of 4.2 V then the battery voltage tries to exceed the 4.2 V. Then, the IC will not allow more current to flow through the battery. The current in this mode will slowly start dropping down by maintaining a constant voltage of 4.2 V at the battery.

4) Standby mode

The IC automatically stops the charging when the charge current drops to 1/10Th of the programmed current/charging current after the maximum voltage (4.2 V) of the battery is reached.

In this mode, the IC will draw maximum 100uA current as per the datasheet.

5) Shut down mode

When the RPROG Pin is not connected and the input voltage is less than battery voltage then the IC will be in shutdown mode.

Circuit Diagram of Lipo charger using TP4056 with protection unit

Circuit Diagram of Lipo charger using TP4056 with protection unit

The Lipo Charger Circuit using TP4056 with protection unit contains the following things as a complete module:

TP4056 lipo battery charger

This module uses the TP4056 Li-ion charge controller IC and a separate DW01A Li-ion battery protection IC which provides the following features:

1) Over-discharge protection :

If the battery voltages drops below the healthy minimum voltage of the battery that is 2.4V. The module automatically cut output power from the battery until the battery voltage has been re-charged above 3.0V (the over-discharge release voltage). Although the module cuts output power from the battery during an over-discharge situation, it still allows charging of the battery to occur through the parasitic diode of the discharge control MOSFET (FS8205A Dual MOSFET).

2) Overcharge protection

This modules protects your battery by over charging by not allowing the charging current to flow across the battery when the maximum charging voltage(4.2V) is reached.

3) Overcurrent and short-circuit protection

The module will cut the output from the battery if the discharge rate exceeds 3A or if a short-circuit condition occurs.

Pcb of Current Adjustable Lipo Charger

Pcb of Current Adjustable Lipo Charger

3D of Current Adjustable Lipo Charger

3D of Current Adjustable Lipo Charger

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