## Overview of the TPS1663 eFuse The **TPS1663** is a high-voltage, integrated eFuse designed by Texas Instruments. It is used to protect circuits from overvoltage, overcurrent, and reverse polarity. Unlike traditional fuses, the TPS1663 is resettable and provides precision control over power delivery. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Operating Voltage** | 4.5 V to 60 V | | **Max Output Current** | 6 A | | **On-Resistance ($R_{DS(on)}$)** | 31 mΩ (typical) | | **Current Limit Accuracy** | ±7% at 6 A | | **Package** | 24-pin VQFN (4 mm x 4 mm) | --- ### 2. Core Functional Blocks The electronic internal structure of the TPS1663 consists of several critical components: * **Integrated N-Channel MOSFET:** This is the primary switch that controls the power flow. Its low $R_{DS(on)}$ minimizes power loss during normal operation. * **Current Sensing Circuitry:** Uses an internal sense resistor to monitor current. The current limit is adjustable via an external resistor on the `ILIM` pin. * **Voltage Comparators:** Monitors the `UVLO` (Under-Voltage Lockout) and `OVP` (Over-Voltage Protection) pins to ensure the input voltage stays within safe limits. * **Charge Pump:** Since it uses an N-Channel MOSFET on the high side, an internal charge pump generates a gate voltage higher than the input voltage to fully turn on the FET. --- ### 3. Protection Mechanisms The TPS1663 provides multiple layers of electronic safeguarding: #### Overcurrent Protection (OCP) The device limits the output current to a level set by the $R_{ILIM}$ resistor. If the load attempts to draw more current, the device either limits the current or shuts down (depending on the specific sub-version, TPS16630 or TPS16632). #### Overvoltage Protection (OVP) Users can set an overvoltage threshold using a resistor divider on the `OVLO` pin. If the input voltage exceeds this threshold, the internal MOSFET turns off instantly to protect the downstream load. #### Thermal Shutdown If the internal junction temperature exceeds approximately **150°C**, the device disables the power PATH to prevent permanent damage to the silicon. --- ### 4. Pin Configuration and Functions | Pin Name | Function | | :--- | :--- | | **IN / OUT** | Input power supply and protected output. | | **EN/UVLO** | Enable input and programmable Under-Voltage Lockout. | | **ILIM** | Connection for a resistor to set the current limit ($I_{OL} \approx 120 / R_{ILIM}$). | | **FLT** | Open-drain output that pulls low during a fault (Overcurrent, OVP, Thermal). | | **dVdt** | Connection for a capacitor to control the output voltage ramp rate (soft-start). | --- ### 5. Application Circuit Example To configure the TPS1663, you typically use a series of resistors to define the operational boundaries: ```python # Simplified calculation logic for TPS1663 settings def calculate_ilim(r_ilim_kohm): # Standard formula: I_limit (A) = 120 / R_ilim (kOhms) return 120 / r_ilim_kohm # Example: If R_ilim is 20k current_limit = calculate_ilim(20) print(f"Current Limit: {current_limit} Amps") ```