How to Use SparkFun Coulomb Counter Breakout - LTC4150: Examples, Pinouts, and Specs

The SparkFun Coulomb Counter Breakout - LTC4150 is an essential tool for battery monitoring and energy management in portable devices. This electronic component provides precise measurements of the charge entering or leaving a battery. It's commonly used in applications such as battery monitoring for handheld devices, energy monitoring in embedded systems, and power consumption analysis for battery-powered prototypes.

• Operating Voltage: 2.7V to 8.5V
• Operating Temperature: -40°C to 85°C
• Battery Voltage Monitoring Range: 0V to 8.5V
• Sensitivity: 1mAh per pulse output
• Quiescent Current: 120μA

1. Power Supply: Connect the VIN pin to a power source within the specified range (2.7V to 8.5V) and GND to the common ground.
2. Battery Connection: Attach the battery's positive terminal to SENSE+ and the negative terminal to SENSE-.
3. Output Monitoring: Connect the INT pin to a digital input on a microcontroller to monitor charge pulses.
4. Polarity Detection: Use the POL pin to determine the direction of current flow (charging or discharging).
5. Counter Reset: Optionally, connect the CLR pin to a digital output on a microcontroller to reset the counter when needed.

• Ensure that all connections are secure and that there is no risk of short circuits.
• Use a decoupling capacitor close to the VIN pin to stabilize the power supply.
• Avoid exposing the component to temperatures outside the specified operating range.
• When integrating with a microcontroller, use appropriate pull-up or pull-down resistors on the INT and POL pins if required by your design.

// Example code for interfacing the LTC4150 with an Arduino UNO

const int interruptPin = 2; // INT pin connected to digital pin 2
const int polarityPin = 3;  // POL pin connected to digital pin 3
volatile long int pulseCount = 0;

void setup() {
  pinMode(interruptPin, INPUT_PULLUP);
  pinMode(polarityPin, INPUT);
  attachInterrupt(digitalPinToInterrupt(interruptPin), countPulse, FALLING);
  Serial.begin(9600);
}

void loop() {
  // Main loop does nothing; pulse counting is handled by interrupt
}

void countPulse() {
  // Increment pulse count on each interrupt signal
  if (digitalRead(polarityPin) == HIGH) {
    // Battery is charging
    pulseCount++;
  } else {
    // Battery is discharging
    pulseCount--;
  }
  // Print the pulse count for monitoring (optional)
  Serial.println(pulseCount);
}

• No Pulse Output: Ensure that the battery is properly connected and that the LTC4150 is powered.
• Inaccurate Readings: Check for loose connections or potential sources of electrical noise.
• Intermittent Signals: Verify that the interrupt service routine is not being blocked by other lengthy processes in your code.

Q: Can the LTC4150 be used with any battery type? A: The LTC4150 is versatile and can be used with most rechargeable battery chemistries, provided the voltage is within the specified range.

Q: How do I reset the charge counter? A: To reset the counter, set the CLR pin high for at least one clock cycle. This can be done using a digital output from a microcontroller.

Q: What is the purpose of the POL pin? A: The POL pin indicates the direction of current flow. When high, the battery is charging; when low, the battery is discharging.

For further assistance, please refer to the SparkFun Coulomb Counter Breakout - LTC4150 datasheet or contact technical support.