How to Use Adafruit TPS61169: Examples, Pinouts, and Specs

The Adafruit TPS61169 is a high-efficiency boost converter designed to step up low input voltages to higher output voltages. This component is ideal for applications requiring a compact and efficient power supply solution, such as powering LEDs, OLED displays, or other devices from batteries or low-voltage sources. It features adjustable output voltage, high output current capability, and built-in protection features, making it versatile and reliable for a wide range of projects.

• Driving high-power LEDs or LED arrays
• Powering OLED displays or LCD backlights
• Boosting battery voltage for portable devices
• General-purpose DC-DC boost conversion

The Adafruit TPS61169 is based on the Texas Instruments TPS61169 IC and comes with the following key specifications:

The Adafruit TPS61169 module has six pins, as described in the table below:

1. Power Supply: Connect the input voltage (2.7V to 18V) to the VIN pin. Ensure the input voltage is within the specified range.
2. Inductor Selection: Choose an appropriate inductor value (typically 4.7 µH to 22 µH) based on your desired output voltage and current.
3. Output Voltage Adjustment: Use a resistor divider network connected to the FB pin to set the desired output voltage. The formula for the output voltage is: [ V_{OUT} = V_{FB} \times \left(1 + \frac{R1}{R2}\right) ] where ( V_{FB} ) is the feedback voltage (200 mV), and ( R1 ) and ( R2 ) are the resistors in the divider.
4. Enable Pin: Drive the EN pin high (logic level) to enable the boost converter. Pull it low to disable the device.
5. Output Capacitor: Connect a low-ESR capacitor (e.g., 10 µF or higher) to the VOUT pin to stabilize the output voltage.
6. Diode Selection: Use a fast-recovery Schottky diode (e.g., 1N5819) between the SW pin and VOUT to handle the switching current.

Below is a basic circuit diagram for using the Adafruit TPS61169 to drive an LED:

VIN (Battery) -----> [TPS61169 VIN]
                     [TPS61169 GND] -----> System Ground
                     [TPS61169 SW] -----> Inductor -----> Diode -----> LED -----> VOUT
                     [TPS61169 FB] -----> Resistor Divider -----> System Ground
                     [TPS61169 EN] -----> Logic High (Enable)

The Adafruit TPS61169 can be used with an Arduino to control the enable pin. Below is an example code snippet:

// Define the enable pin for the TPS61169
const int enablePin = 7;

void setup() {
  // Set the enable pin as an output
  pinMode(enablePin, OUTPUT);

  // Enable the TPS61169 by setting the pin HIGH
  digitalWrite(enablePin, HIGH);

  // Optional: Add a delay to allow the boost converter to stabilize
  delay(100);
}

void loop() {
  // Example: Toggle the enable pin to turn the boost converter on and off
  digitalWrite(enablePin, HIGH);  // Enable the TPS61169
  delay(5000);                   // Keep it on for 5 seconds
  digitalWrite(enablePin, LOW);  // Disable the TPS61169
  delay(5000);                   // Keep it off for 5 seconds
}

• Use low-ESR capacitors for both input and output to minimize voltage ripple.
• Ensure proper thermal management, as the device can heat up under high load conditions.
• Keep the feedback resistor divider close to the FB pin to reduce noise.
• Use short and wide traces for the power connections to minimize resistance and inductance.

1. No Output Voltage:

   • Ensure the EN pin is driven high to enable the device.
   • Verify that the input voltage is within the specified range (2.7V to 18V).
   • Check the connections for the inductor, diode, and output capacitor.

2. Output Voltage is Incorrect:

   • Double-check the resistor values in the feedback divider network.
   • Ensure the feedback pin (FB) is properly connected to the resistor divider.

3. Device Overheating:

   • Verify that the inductor and diode are rated for the required current.
   • Check for excessive input or output current beyond the device's specifications.

4. High Output Ripple:

   • Use low-ESR capacitors for the output.
   • Ensure proper grounding and minimize the length of high-current traces.

Q: Can the TPS61169 drive multiple LEDs in series?
A: Yes, the TPS61169 can drive multiple LEDs in series, provided the total forward voltage of the LEDs does not exceed the maximum output voltage (38V).

Q: What type of inductor should I use?
A: Use a shielded inductor with a current rating higher than the peak current of your application. Typical values range from 4.7 µH to 22 µH.

Q: How do I calculate the output voltage?
A: Use the formula ( V_{OUT} = V_{FB} \times (1 + R1/R2) ), where ( V_{FB} ) is 200 mV.

Q: Can I use the TPS61169 with a 3.3V microcontroller?
A: Yes, the EN pin can be controlled by a 3.3V logic signal to enable or disable the device.

By following this documentation, you can effectively integrate the Adafruit TPS61169 into your projects and troubleshoot common issues.