Smart FET Protection Features 1 Agenda • Current Limit • Over Temperature Protection • Over Voltage Protection • ESD Protection • Diagnostic Output • High and Low Side Portfolio and Applications 2 SmartFET Capability Smart Power Solutions Integrated Protection & Diagnostics Self Protected MOSFET High-side MOSFET E-FET Temp Sense Current Sense ESD Active Clamp Protection Features Power MOSFETs Features: Charge Pump Loss of Ground Low-side Current Limit Features: Temp Limit + shutdown G-D Active Clamp Diagnostic Output Current Limit Over/Under volt Temp Limit + shutdown Reverse Batt. Batt Prot. Auto Restart G-S ESD protection Self Protected MOSFET Clamp/Temp/ Current Sense Features: Multi Chip Module SmartFET enables integration of analog circuit elements in Power MOSFET devices for cost effective solutions 3 $ Value Smart FET Protection Features • ON Semiconductor’s Smart FET’s Feature 4 Main Protection Functions – – – – • Current Limit Protection Over Temperature Protection Overvoltage Protection ESD Protection ON Semiconductor’s High Side NCV8460 Adds Diagnostic Features – Open Load Detection 4 Current Limit Protection • Current from the Drain is mirrored into a smaller device anywhere from 1/200th to 1/1000th the size of the main power device 5 Current Limit Protection • The current through the smaller device develops a voltage across RS • As VRS increases, a pulldown FET turns on, and pulls down on the voltage of the main power FET, which reduces output current 6 Current Limit Protection • The current limit will vary with temperature • As can be seen above, as the device heats up, current limit decreases 7 Over Temperature Protection • • On Semiconductor’s Smart FET’s include Over Temperature Protection, which shuts down the device when the temperature exceeds a predetermined threshold If the TSD structure indicates a high temperature, the TLIM Pulldown device pulls the voltage down on the main power device. 8 Over Temperature Protection Location of Thermal Sense Device • A reference voltage is compared to the TSD structure, a diode structure, located in the die’s ‘hot spot’ 9 Over Temperature Protection • Once the TSD structure indicates the temperature has dropped, the pulldown device turns off, allowing the main power device to turn back on • The typical hysteresis is 15 C 10 Over Voltage Protection • A Gate to Drain Zener Clamp provides overvoltage protection • The clamp allows the Gate to turn on, spreading the energy more evenly across the active area 11 Over Voltage Protection On Input Off Voltage Across DUT V(Br) VDD IAR Current Through DUT tav • Voltage across DUT is clamped during an inductive flyback event • When the input is turned off, the voltage across DUT increases until it reaches the clamp level, typically around 45 V 12 ESD Protection • • • Back to Back diodes on the Gate pin clamp the voltage to 13 V This combined with the internal series resistance allow a minimum of 4000 V Human Body Model and 400 V Machine Model ESD capability The Source and Drain are inherently protected through the device structure itself 13 Diagnostics • The NCV8460 offers diagnostic features and a status pin – Normal Operation- Status Pin High – Undervoltage• Status Pin Undefined • Output Turns Off 14 Diagnostics • The NCV8460 offers diagnostic features and a status pin – Overvoltage • Status Pin Stays High • Output Shuts Off – Over Temperature • Status Pin Goes Low • Output Turns Off 15 Diagnostics • The NCV8460 offers diagnostic features and a status pin – Open Load With External Pull Up • Input High- Status Pin Goes Low When Open Load Detected • Input Low- Status Pin Goes Low When Open Load Detected – Open Load Without External Pull Up • Input High- Status Pin Goes Low When Open Load Detected • Input Low- Status Pin Stays High Regardless of Load Condition 16 Potential Failure Modes and Mitigation Strategies 17 ON Semiconductor Low Side Portfolio – NCV8401 • 33 A Current Limit, 23 mOhm RDSOn, 42 V Clamp, and 175 C TSD – NCV8402 and NCV8402 Dual • 2 A Current Limit, 165 mOhm RDSOn, 42 V Clamp, and 175 C TSD – NCV8403 • 15 A Current Limit, 53 mOhm RDSOn, 42 V Clamp, and 175 C TSD – NCV8405 • 6 A Current Limit, 90 mOhm RDSOn, 42 V Clamp, and 175 C TSD – NCV8440 • 95 mOhm RDSOn • 52 V Clamp Only, No TSD, or Current Limit – NIMD6001 (Dual) • 110 mOhm RDSOn • No Clamp, TSD or Current Limit • Over Voltage Diagnostic Signal 18 Low Side Applications – Split Cooling Valve Sensor- NCV8403 • The Drain is used to drive a heater resistor to control a thermostat • As the resistive load heats up, the thermostat heats up causing it to be over-ridden • A 3 kΩ gate resistor is used to slew the switching speed. 16 V 15 Ω 3 kΩ 0 – 5 V, 80 Hz 19 NCV8403 Low Side Applications – Lambda Sensor- NCV8403 • A lambda sensor is a resistive load • The sensor measures the oxygen content in the exhaust gas • A 3 kΩ gate resistor is used to slew the switching speed 16 V 3.2 Ω 3 kΩ 0 – 5 V, 100 Hz 20 NCV8403 ON Semiconductor High Side Portfolio – NCV8450 • • • • • Released 1 A Current Limit, 1 Ohm RDSOn No Diagnostic Features Cross to BTS4140 Voltage Clamped to 45 V, 175 C TSD – NCV8460 • Currently in Design • Diagnostic Features – On State Open Load Detection – Off State Open Load Detection – Diagnostic Output • Under Voltage and Over Voltage Shutdown • 9 A Current Limit, 60 mOhm RDSOn • Cross to VN750 • Voltage Clamped to 42 V, 175 C TSD 21 High Side Applications – Power Train Application- NCV8450 • Evaporation Leak Detection Solenoid 22 High Side Applications – Brake Light Application- NCV8450 • Open Collector Hall Sensor Used to Drive NCV8450 NCV8450 23 Conclusion • ON Semiconductor’s SmartFET offers 4 main protection functions – – – – Current Limit Over Temperature Protection Over Voltage Protection ESD Protection • ON Semiconductors’ new NCV8460 adds a Diagnostic Output Feature 24 For More Information • View the extensive portfolio of power management products from ON Semiconductor at www.onsemi.com • View reference designs, design notes, and other material supporting automotive applications at www.onsemi.com/automotive 25