How to Use tp4056: Examples, Pinouts, and Specs

The TP4056 is a lithium-ion battery charger IC that provides a constant current/constant voltage (CC/CV) charging profile. It is specifically designed for charging single-cell lithium-ion batteries. The IC integrates several safety features, including over-voltage protection, under-voltage lockout, and thermal regulation, making it a reliable and efficient solution for battery charging applications.

• Charging single-cell lithium-ion or lithium-polymer batteries
• Power banks and portable battery packs
• USB-powered charging circuits
• Wearable devices and IoT gadgets
• DIY electronics projects

The TP4056 is typically available in an 8-pin SOP package. Below is the pin configuration:

1. Power Supply: Connect a regulated DC power supply (4.0V to 8.0V) to the VCC pin. A USB port (5V) is commonly used as the power source.
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 charging current. The charging current can be calculated using the formula: [ I_{CHG} = \frac{1200}{R_{PROG}} ] For example, a 1.2kΩ resistor sets the charging current to 1A.
4. Status Indicators: Connect LEDs to the CHRG and STDBY pins (with appropriate current-limiting resistors) to monitor the charging status:
   • CHRG pin: Low when charging, high impedance when not charging.
   • STDBY pin: Low when charging is complete, high impedance otherwise.
5. Thermal Considerations: Ensure proper heat dissipation by placing the IC on a PCB with adequate copper area around the GND pin.

• Battery Protection: Use a battery with built-in protection circuitry to prevent overcharging or deep discharge.
• Thermistor Connection: For temperature monitoring, connect an NTC thermistor to the TEMP pin. If not used, connect the TEMP pin to ground.
• Input Voltage: Avoid exceeding the maximum input voltage of 8.0V to prevent damage to the IC.
• Capacitors: Place a 1µF ceramic capacitor close to the VCC pin and a 10µF capacitor near the BAT pin for stable operation.

The TP4056 can be used with an Arduino UNO to monitor the charging status. Below is an example code snippet:

// TP4056 Status Monitoring with Arduino UNO
// Connect CHRG pin to Arduino pin 2 and STDBY pin to Arduino pin 3

#define CHRG_PIN 2  // Pin connected to CHRG pin of TP4056
#define STDBY_PIN 3 // Pin connected to STDBY pin of TP4056

void setup() {
  pinMode(CHRG_PIN, INPUT);  // Set CHRG pin as input
  pinMode(STDBY_PIN, INPUT); // Set STDBY pin as input
  Serial.begin(9600);        // Initialize serial communication
}

void loop() {
  int chrgStatus = digitalRead(CHRG_PIN);   // Read CHRG pin status
  int stdbyStatus = digitalRead(STDBY_PIN); // Read STDBY pin status

  if (chrgStatus == LOW) {
    Serial.println("Battery is charging...");
  } else if (stdbyStatus == LOW) {
    Serial.println("Charging complete.");
  } else {
    Serial.println("No battery connected or idle state.");
  }

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

1. Problem: The battery is not charging.

   • Solution: Check the input voltage at the VCC pin. Ensure it is within the 4.0V to 8.0V range.
   • Solution: Verify the connection between the battery and the BAT pin.
   • Solution: Ensure the CE pin is pulled low to enable the IC.

2. Problem: The IC overheats during operation.

   • Solution: Reduce the charging current by increasing the value of the resistor on the PROG pin.
   • Solution: Improve heat dissipation by increasing the copper area around the GND pin.

3. Problem: Status LEDs are not functioning.

   • Solution: Check the connections and current-limiting resistors for the LEDs.
   • Solution: Verify the CHRG and STDBY pin voltages during operation.

• Q: Can I use the TP4056 to charge multiple batteries in series?
  A: No, the TP4056 is designed for single-cell lithium-ion batteries only. Charging multiple cells in series requires a specialized multi-cell charger.

• Q: What happens if the input voltage exceeds 8.0V?
  A: Exceeding the maximum input voltage can damage the IC. Always use a regulated power supply within the specified range.

• Q: Can I disable the temperature monitoring feature?
  A: Yes, connect the TEMP pin directly to ground if temperature monitoring is not required.

• Q: How do I adjust the charging current?
  A: Use the formula ( I_{CHG} = \frac{1200}{R_{PROG}} ) to calculate the required resistor value for the desired charging current.

This concludes the TP4056 documentation.