How to Use TP4057: Examples, Pinouts, and Specs

The TP4057, manufactured by RUNCCI-YUN, is a lithium-ion battery charger IC designed for single-cell lithium-ion or lithium-polymer batteries. It provides a constant current/constant voltage (CC/CV) charging profile, ensuring efficient and safe charging. The IC integrates features such as over-voltage protection, under-voltage lockout, and thermal regulation, making it a reliable choice for battery-powered applications.

• Portable electronic devices (e.g., smartphones, tablets, and wearables)
• Power banks and battery packs
• IoT devices and sensors
• Rechargeable toys and gadgets
• Embedded systems requiring lithium-ion battery management

The TP4057 is a compact and efficient charging IC with the following key specifications:

The TP4057 is available in a 6-pin SOT-23 package. The pinout and descriptions are as follows:

1. Power Supply: Connect a DC power supply (4.0V to 8.0V) to the VCC pin. Ensure the supply voltage is stable and within the specified range.
2. Battery Connection: Connect the positive terminal of the lithium-ion battery to the BAT pin and the negative terminal to GND.
3. Programming Charging Current: Use a resistor (RPROG) between the PROG pin and GND to set the desired charging current. The charging current (ICHG) can be calculated using the formula: [ I_{CHG} = \frac{1000}{R_{PROG}} ] where ( R_{PROG} ) is in kΩ and ( I_{CHG} ) is in mA.
4. Status Indicator: Connect an LED with a pull-up resistor to the STAT pin to monitor the charging status:
   • LED ON: Charging in progress
   • LED OFF: Charging complete or no battery connected
5. Thermal Considerations: Ensure proper heat dissipation by placing the IC on a PCB with adequate thermal management.

Below is a basic circuit diagram for using the TP4057 to charge a single-cell lithium-ion battery:

VCC (4.0V-8.0V) ----> VCC
                     |
                     RPROG
                     |
                     PROG
                     |
                     GND
BATTERY + ----------> BAT
BATTERY - ----------> GND

The TP4057 can be used with an Arduino UNO to monitor the charging status. Connect the STAT pin to a digital input pin on the Arduino. Below is an example code snippet:

// TP4057 Charging Status Monitoring with Arduino UNO
const int statPin = 2; // STAT pin connected to digital pin 2
const int ledPin = 13; // Onboard LED for status indication

void setup() {
  pinMode(statPin, INPUT); // Set STAT pin as input
  pinMode(ledPin, OUTPUT); // Set onboard LED as output
  Serial.begin(9600);      // Initialize serial communication
}

void loop() {
  int chargingStatus = digitalRead(statPin); // Read STAT pin status

  if (chargingStatus == LOW) {
    // Charging in progress
    digitalWrite(ledPin, HIGH); // Turn on LED
    Serial.println("Charging in progress...");
  } else {
    // Charging complete or no battery connected
    digitalWrite(ledPin, LOW); // Turn off LED
    Serial.println("Charging complete or no battery connected.");
  }

  delay(1000); // Wait for 1 second before checking again
}

• Use a high-quality resistor for RPROG to ensure accurate charging current.
• Avoid exceeding the maximum input voltage (8.0V) to prevent damage to the IC.
• Ensure proper grounding to minimize noise and improve stability.
• Use a decoupling capacitor (e.g., 1µF) between VCC and GND for input voltage stability.

1. The battery is not charging.

   • Verify that the input voltage is within the specified range (4.0V to 8.0V).
   • Check the connections to the BAT and GND pins.
   • Ensure the RPROG resistor is correctly calculated and connected.

2. The IC is overheating.

   • Ensure proper thermal management on the PCB.
   • Reduce the charging current by increasing the RPROG resistor value.

3. The STAT pin does not indicate charging status.

   • Check the pull-up resistor and LED connections.
   • Verify that the battery is properly connected to the BAT pin.

4. The charging current is incorrect.

   • Recalculate the RPROG value using the formula ( I_{CHG} = \frac{1000}{R_{PROG}} ).
   • Use a precision resistor for accurate current programming.

Q: Can the TP4057 charge batteries with capacities greater than 500mAh?
A: Yes, the TP4057 can charge larger capacity batteries, but the charging current should not exceed 500mA. Adjust the RPROG resistor accordingly.

Q: Is the TP4057 suitable for multi-cell battery packs?
A: No, the TP4057 is designed for single-cell lithium-ion or lithium-polymer batteries only.

Q: Can I use the TP4057 with a solar panel as the input source?
A: Yes, as long as the solar panel provides a stable voltage within the 4.0V to 8.0V range. Use a capacitor to stabilize the input voltage.

Q: What happens if the input voltage drops below 4.0V?
A: The TP4057 features under-voltage lockout and will stop charging the battery to prevent damage.

By following this documentation, users can safely and effectively integrate the TP4057 into their projects for reliable lithium-ion battery charging.