How to Use TP4056: Examples, Pinouts, and Specs

The TP4056 is a lithium-ion battery charger IC designed to provide a constant current/constant voltage (CC/CV) charging profile. It is specifically tailored for charging single-cell lithium-ion batteries with high efficiency and safety. The IC integrates features such as over-voltage protection, under-voltage lockout, and thermal regulation, making it a reliable choice 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 a compact and efficient IC with the following key specifications:

The TP4056 comes in an 8-pin SOP package. Below is the pinout and description:

1. Power Supply: Connect a 5V DC power source (e.g., USB) to the VCC pin. Ensure the input voltage is within the 4.0V–8.0V 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 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 LEDs: Connect LEDs to the CHRG and STDBY pins (with appropriate current-limiting resistors) to indicate charging status:
   • CHRG pin low: Charging in progress.
   • STDBY pin low: Charging complete.
5. Temperature Monitoring: Optionally, connect an NTC thermistor to the TEMP pin for battery temperature monitoring. If unused, connect TEMP to GND.

• Thermal Management: Ensure proper heat dissipation, as the IC may heat up during high-current charging. Use a heat sink or adequate PCB copper area for thermal regulation.
• Battery Protection: Use a protection circuit module (PCM) with the battery to prevent over-discharge and over-current conditions.
• Input Voltage: Avoid exceeding the maximum input voltage of 8.0V to prevent damage to the IC.
• Current Limiting: Do not exceed the maximum charging current of 1A to ensure safe operation.

The TP4056 can be used in conjunction with an Arduino UNO to monitor the charging status of a battery. 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  // CHRG pin of TP4056 connected to Arduino digital pin 2
#define STDBY_PIN 3 // STDBY pin of TP4056 connected to Arduino digital pin 3

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("Battery is fully charged.");
  } else {
    Serial.println("No battery connected or charging stopped.");
  }

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

1. IC Overheating

   • Cause: High charging current or insufficient heat dissipation.
   • Solution: Reduce the charging current by increasing the RPROG resistor value. Ensure proper PCB design for heat dissipation.

2. Battery Not Charging

   • Cause: Incorrect wiring or insufficient input voltage.
   • Solution: Verify all connections and ensure the input voltage is within the 4.0V–8.0V range.

3. Status LEDs Not Working

   • Cause: Incorrect LED connections or missing current-limiting resistors.
   • Solution: Check the LED polarity and ensure resistors are properly connected.

4. Charging Stops Prematurely

   • Cause: Battery protection circuit triggered or thermal regulation activated.
   • Solution: Check the battery's protection circuit and ensure proper thermal management.

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

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

• Can I use the TP4056 without a thermistor? Yes, if temperature monitoring is not required, connect the TEMP pin to GND.

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