How to Use TPS22917 Load Driver/Power Switch: Examples, Pinouts, and Specs

The TPS22917 is a load driver and power switch designed to provide controlled power delivery to a load. Manufactured under part ID TPS22917, this component features low on-resistance, fast switching times, and built-in protection mechanisms such as overcurrent protection and thermal shutdown. These features make it highly reliable and efficient for power management applications.

• Power distribution in portable devices
• Battery-powered systems
• Consumer electronics
• Industrial and automotive power management
• Load switching in microcontroller-based systems

1. Power Supply Connection: Connect the input voltage (VIN) to a regulated power source within the range of 1 V to 5.5 V. Ensure the power source can supply sufficient current for the load.
2. Enable Pin (EN): Drive the EN pin high (above 0.85 V) to turn on the switch. Pull the EN pin low to disable the switch and disconnect the load.
3. Output Connection: Connect the load to the VOUT pin. Ensure the load does not exceed the maximum continuous current rating of 2 A.
4. Fault Indicator (FLT): Use the FLT pin to monitor fault conditions. This pin is open-drain and will pull low when a fault (e.g., overcurrent or thermal shutdown) occurs. Use a pull-up resistor (e.g., 10 kΩ) to connect FLT to the desired logic level.
5. Bypass Capacitor: Place a bypass capacitor (e.g., 1 µF) close to the VIN pin to stabilize the input voltage and reduce noise.

• Thermal Management: Ensure adequate heat dissipation, especially when operating near the maximum current rating. Use a PCB with good thermal conductivity or add heat sinks if necessary.
• Overcurrent Protection: The TPS22917 includes built-in overcurrent protection. However, avoid designing circuits that consistently operate near the current limit to prevent frequent fault conditions.
• Enable Pin Logic Levels: Ensure the EN pin voltage meets the logic high threshold (0.85 V or higher) to enable the switch. For microcontroller-based systems, connect the EN pin to a GPIO pin.
• Fault Handling: If a fault condition occurs, investigate the cause (e.g., excessive load current or overheating) and resolve it before re-enabling the switch.

The following example demonstrates how to control the TPS22917 using an Arduino UNO. The EN pin is connected to a GPIO pin on the Arduino to enable or disable the switch.

• VIN: Connect to a 5 V power supply.
• VOUT: Connect to the load (e.g., an LED or motor).
• EN: Connect to Arduino digital pin 7.
• GND: Connect to the common ground of the circuit.
• FLT: Connect to Arduino digital pin 8 (optional, for fault monitoring).

// Define pin connections
const int enablePin = 7; // EN pin connected to digital pin 7
const int faultPin = 8;  // FLT pin connected to digital pin 8 (optional)

void setup() {
  // Set up the enable pin as an output
  pinMode(enablePin, OUTPUT);
  
  // Set up the fault pin as an input with pull-up resistor
  pinMode(faultPin, INPUT_PULLUP);
  
  // Initially disable the switch
  digitalWrite(enablePin, LOW);
}

void loop() {
  // Enable the switch
  digitalWrite(enablePin, HIGH);
  delay(1000); // Keep the switch on for 1 second
  
  // Check for fault condition
  if (digitalRead(faultPin) == LOW) {
    // Fault detected, take appropriate action
    Serial.println("Fault detected! Disabling switch.");
    digitalWrite(enablePin, LOW);
    while (1); // Halt execution
  }
  
  // Disable the switch
  digitalWrite(enablePin, LOW);
  delay(1000); // Keep the switch off for 1 second
}

1. Switch Does Not Turn On

   • Cause: EN pin voltage is too low.
   • Solution: Ensure the EN pin is driven high (above 0.85 V). Check the GPIO pin configuration if using a microcontroller.

2. Fault Pin Stays Low

   • Cause: Overcurrent or thermal shutdown condition.
   • Solution: Reduce the load current or improve thermal management. Check for short circuits on the output.

3. High Power Dissipation

   • Cause: Excessive current or poor thermal design.
   • Solution: Ensure the load current is within the specified range. Use a PCB with good thermal conductivity.

4. Output Voltage is Unstable

   • Cause: Insufficient bypass capacitance.
   • Solution: Add a bypass capacitor (e.g., 1 µF) close to the VIN pin.

• Q: Can the TPS22917 handle inductive loads?
  A: Yes, but you should add a flyback diode across the load to protect the switch from voltage spikes.

• Q: What happens if the input voltage exceeds 5.5 V?
  A: The device may be damaged. Always ensure the input voltage stays within the specified range.

• Q: Can I leave the FLT pin unconnected?
  A: Yes, the FLT pin is optional. However, connecting it to a pull-up resistor allows you to monitor fault conditions.

• Q: Is the TPS22917 suitable for battery-powered applications?
  A: Yes, its low quiescent current (19 µA typical) makes it ideal for battery-powered systems.