How to Use TP5100 4.2V-8.4V: Examples, Pinouts, and Specs

The TP5100 is a lithium battery charger IC designed for charging single-cell or dual-cell lithium-ion batteries with a voltage range of 4.2V to 8.4V. It is a highly efficient charging solution that integrates thermal regulation, overcurrent protection, and short-circuit protection to ensure safe and reliable operation. The TP5100 supports both constant current (CC) and constant voltage (CV) charging modes, making it suitable for a wide range of battery charging applications.

• Lithium-ion battery charging for portable devices
• Power banks and battery packs
• Solar-powered battery chargers
• Embedded systems requiring rechargeable power sources

1. Power Supply: Connect a DC power supply (5V to 18V) to the VIN pin. Ensure the supply voltage matches the battery's charging requirements.
2. Battery Connection: Connect the positive terminal of the lithium-ion battery to the BAT pin and the negative terminal to GND.
3. Set Charging Current: Use a resistor on the ISET pin to configure the desired charging current. The resistor value can be calculated using the formula: [ R_{\text{ISET}} = \frac{1000}{I_{\text{CHARGE}}} ] where ( I_{\text{CHARGE}} ) is the charging current in amperes.
4. Thermal Protection: Connect a thermistor to the TEMP pin for temperature monitoring. If not used, connect this pin to ground.
5. Status Indicators: Use the CHRG and STDBY pins to monitor the charging and standby status. These pins can be connected to LEDs for visual indication.

• Ensure the input voltage does not exceed 18V to avoid damaging the IC.
• Use appropriate decoupling capacitors (e.g., 10µF) on the VIN and VCC pins for stable operation.
• Place the IC and associated components on a well-designed PCB with proper thermal management to prevent overheating.
• If using the TP5100 with a dual-cell battery (8.4V), ensure the battery pack includes a balancing circuit for safety.

The TP5100 can be used with an Arduino UNO to monitor the charging status. Below is an example code snippet:

// Define pin connections for TP5100 status indicators
const int chrgPin = 2;  // CHRG pin connected to Arduino digital pin 2
const int stdbyPin = 3; // STDBY pin connected to Arduino digital pin 3

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

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

  if (chrgStatus == LOW) {
    Serial.println("Battery is charging...");
  } else if (stdbyStatus == HIGH) {
    Serial.println("Battery is fully charged or in standby mode.");
  } else {
    Serial.println("No battery detected or error.");
  }

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

1. No Charging Current Detected

   • Cause: Incorrect resistor value on the ISET pin.
   • Solution: Verify the resistor value using the formula ( R_{\text{ISET}} = \frac{1000}{I_{\text{CHARGE}}} ).

2. Overheating of the IC

   • Cause: Insufficient thermal dissipation or high ambient temperature.
   • Solution: Use a heat sink or improve PCB thermal design. Ensure proper ventilation.

3. Battery Not Charging

   • Cause: Incorrect battery connection or damaged battery.
   • Solution: Check the battery polarity and ensure the battery is functional.

4. Status LEDs Not Working

   • Cause: Incorrect connections to the CHRG or STDBY pins.
   • Solution: Verify the connections and ensure the LEDs are functional.

1. Can the TP5100 charge other types of batteries?

   • No, the TP5100 is specifically designed for lithium-ion batteries. Using it with other battery chemistries may result in damage or unsafe operation.

2. What happens if the input voltage exceeds 18V?

   • The IC may be permanently damaged. Always ensure the input voltage is within the specified range.

3. Is it necessary to use the TEMP pin?

   • While not mandatory, using the TEMP pin with a thermistor provides additional safety by monitoring the battery temperature during charging.

4. Can I use the TP5100 for parallel battery configurations?

   • Yes, but ensure the batteries are balanced and have the same capacity and charge state to avoid issues.