Bridging Theory in Practice

1. Bridging Theory in Practice Transferring Technical Knowledge to Practical Applications

2. Protected High Side Drivers

3. Overvoltage Protection Power Stage Current Control Overvoltage Logic Charge Pump Temperature Sensor Power Output Stage Overvoltage Protection Logic ESD Protection Protected High Side Drivers

4. Protected High Side Drivers Intended Audience: • Electrical engineers with a knowledge of simple electrical circuits • An understanding of MOSFETs and high side drivers is assumed Topics Covered: • What is a PROFET? • What type of protection does a PROFET have? • What type of diagnostics does a PROFET have? • How does a PROFET impact system EMI? • How is a PROFET circuit implemented? • PROFET Selection Questions Expected Time: • Approximately 90 Minutes

5. Protected High Side Drivers • Introduction to PROFETs • PROFET Protection Features • PROFET Diagnostic Features • EMI/EMC Considerations • System Implementation • Frequently Asked Questions

6. Gate Source Source n+ n+ p+ p+ N-Channel D n- MOSFET ( Enhancement) ( n+ G S Drain MOSFET Review MOSFET Metal Oxide Semiconductor Field Effect Transistor D G VGS S VSG S G P-Channel MOSFET (Enhancement) D

7. VGS increases MOSFETRegions of Operation • A positive (for N-Channel) or negative (for P-Channel) VGS produces a conducting channel between the Drain and Source • The MOSFET is then able to operate in two regions: • 1)Linear region: The MOSFET behaves like a resistance. • 2) Saturation region: The MOSFET behaves like a current source. VDS = VGS-VT VGS > 0V N-Channel MOSFET (NMOS) IDS VDS

8. High Side Drive (HSD) Configuration To turn on the HSD, the MOSFET gate is pulled high 14V VS ~ 13V VGS ~ 1V But, the maximum voltage at the MOSFET source is VG - VT ILOAD The low value of VGS translates into a small ILOAD (saturation region) The switch is on the “HIGH” side of the load 14V MOSFET Switch Load

9. To turn on the HSD, the MOSFET gate is pulled high 26V VS ~ 14V VGS ~ 14V The source voltage is now approximately Vsupply ILOAD The high value of VGS translates into a large value of ILOAD (linear region) High Side Drive (HSD)Configuration The switch is on the “HIGH” side of the load 14V MOSFET Switch If the MOSFET gate is pulled to a higher voltage… Load

10. PROFETs = PROtected FETs Over Voltage Protection Reverse Battery Protection Integrated Charge Pump Current Limit Diagnostics Over Temperature Protection Short Circuit Protection MOSFET PROFET

11. Voltage Controlled PROFET Block Diagram Voltage Controlled IN

12. Current Controlled Current Controlled Current ControlledPROFET Block Diagram Current ControlledPROFET Block Diagram IN IIN

13. Introduction to PROFETs • Introduction to PROFETs • PROFET Protection Features • PROFET Diagnostic Features • EMI/EMC Considerations • System Implementation • Frequently Asked Questions

14. Rugged vs. Protected Rugged MOSFETs Achieved through process & manufacturing technology Protection Not Built in Protected • PROFETs • Achieved through design and utilization of more advanced integrated circuit technologies • Available CMOS, DMOS and Bipolar devices allow for the integration of ESD protection, active clamping, current limit, temperature sensing, etc. • Protection Built in Protected • PROFETs • Achieved through design and utilization of more advanced integrated circuit technologies • Available CMOS, DMOS and Bipolar devices allow for the integration of ESD protection, active clamping, current limit, temperature sensing, etc. • Protection Built in Protected • PROFETs • Achieved through design and utilization of more advanced integrated circuit technologies • Available CMOS, DMOS and Bipolar devices allow for the integration of ESD protection, active clamping, current limit, temperature sensing, etc. • Protection Built in

15. PROtected FET(PROFET)Protection Features Electrostatic Discharge (ESD) Protection Overvoltage / Load Dump Protection Overvoltage Shutdown Protection and Restart Undervoltage Shutdown Protection and Restart Reverse Battery Protection Reversave™ Battery Protection Inductive and Overvoltage Output Clamp Protection Thermal Shutdown Protection Current Limit Protection Short Circuit Shutdown Protection Inversave™ Inverse Current Protection Loss of Ground Protection Loss of Supply Voltage Protection

16. Block Diagram Including Protection Features

17. ESD Protection

18. Overvoltage Protection VAZ

19. Overvoltage Shutdown Protection and Restart

20. Undervoltage Shutdown Protection and Restart

21. The rated load dump voltage is a function of the generator impedance (RG) and the load resistance (RL) As RG and RL increase, less energy is dissipated in the PROFET, and the maximum allowable load dump voltage increases Load Dump Protection

22. Reverse Battery Protection 4) The over temperature protection is not active during reverse current operation! The PROFET will requires a 150 resistor in the GND connection to limit the reverse supply current.

23. The reverse load current through the intrinsic drain- source diode has to be limited by the connected load. Power dissipation is higher compared to normal operating conditions due to the voltage drop across the drain-source diode. Reverse Battery Protection 4) The temperature protection is not active during reverse current operation!

24. PROFETs with ReverSaveTM protection overcome this problem… Reverse Battery Protection 4) The temperature protection is not active during reverse current operation!

25. ReverSave™ Reverse Battery Protection In PROFETs with ReverSaveTM protection, the MOSFET is turned on by the voltage drop across the resistor Rbb. Rbb With the MOSFET conducting the reverse load current (instead of the intrinsic diode), the power dissipation is greatly reduced under reverse battery conditions.

26. Inductive and Overvoltage Output Clamp Protection

27. Thermal Shutdown Protection Input Voltage Load Current Junction Temperature A B C D E F

28. Current Limit Protection IL(SCp) IL(SCr)

29. Short CircuitShutdown Protection VON(SC)

30. Short CircuitShutdown Protection

31. Inversave™Inverse Current Protection Devices with Inversave™ can be operated in inverse current mode. When the device is off, only the intrinsic diode conducts with high power dissipation. When device on, MOSFET turns on for lower power dissipation.

32. Loss of Ground Protection With Loss of Ground Protection, Vbb, VIN, and VST are still referenced to ground through the output This ensures the device will be safely shut off if the ground pin is opened

33. Loss of Supply Voltage Protection All PROFETs are protected against a loss of supply voltage for non-inductive loads Most PROFETs are also protected against a loss of supply voltage for inductive loads by handling the recirculation current through the GND pin VOUT goes negative I

34. Introduction to PROFETs • Introduction to PROFETs • PROFET Protection Features • PROFET Diagnostic Features • EMI/EMC Considerations • System Implementation • Frequently Asked Questions

35. PROFET Diagnostic Feedback Digital vs. Analog STATUS ISTATUS GND

36. Digital Diagnostic Feedback The type of fault is determined by a diagnostic truth table 14V Input Output Status Normal Operation L L L Input H H L Short Circuit to GND L L L PROFET H L H Status Short Circuit to Vbb L H H H H L Output Overcurrent L L L H H L Overtemperature L L L H L H Load Open Load L H H H H L

37. Analog Diagnostic Feedback The type of fault is determined by a diagnostic truth table AND a sense ratio parameter Normal Operation Overcurrent Short Circuit to Ground Overtemperature Short Circuit to Vbb Open Load Input Current L H L H L H L H L H L H Output Voltage L H L H L L L L H H Z H Current IIS IIS(LL) nominal IIS(LL) IIS,FAULT IIS(LL) IIS,FAULT IIS(LL) IIS,FAULT IIS(LL) < nominal IIS(LL) IIS(LH) 14V Input PROFET IIS Output RIS Load

38. Analog Load Current FeedbackVia IIS Current Under normal operation, IIS is proportional to the output current KILIS = IL / IIS ~ 10,000 For example: IL = 25A IIS ~ 2.5mA

39. IIS Current Sense Ratio The accuracy of IIS improves with increasing output current KILIS (IL / IIS)

40. IIS Current Sense Ratio The accuracy of IIS improves with increasing output current More Accurate Less Accurate

41. Status Signal Settling Time The Status signal is not valid during a settling time after turn-on, turn-off, or after change of load current This is true of PROFETs with analog or digital diagnostic feedback

42. Open Load Detection Three Different PROFET strategies Open load detection via Sense pin on HiC (High Current) PROFETs and some PROFETs Open load detection while PROFET is turned on (for some PROFETS---mostly older types) Open load detection while PROFET is turned off (for most PROFETs---mainly newer types)

43. Open Load Detection – Via Sense Pin Under an open load condition, the PROFET will maintain IIS below 1A (maximum). Current Sense

44. Open Load Detection – PROFET On An open load is detected if the PROFET is on and the voltage across the MOSFET is VON < RdsonIL(OL)

45. Open Load Detection - PROFET Off Using an external resistor, an open load is identified if the PROFET is turned off and VOUT > 3.2V (typ.)

46. Introduction to PROFETs • Introduction to PROFETs • PROFET Protection Features • PROFET Diagnostic Features • EMI/EMC Considerations • System Implementation • Frequently Asked Questions

47. MOSFET High Side Drive Recall, the gate of the N-Channel MOSFET must be at a voltage higher than the transistor’s source to turn the MOSFET on: With VSUPPLY being the highest voltage in the system, where does VGATE come from? 14V MOSFET Switch 26V VS ~ 14V VGS ~ 12V ILOAD Load

48. Charge Pump Gate Voltage A charge pump is used to raise (pump) the gate voltage to an acceptable level to turn on the MOSFET VSUPPLY DA DB VOUT Switch B CB CA Switch A

49. Charge Pump Gate Voltage • Initially, Switch A is closed, and CA is charged to VSUPPLY - VDA VSUPPLY = 14V DA DB VOUT Switch B CB CA Switch A ~13V

50. Charge Pump Gate Voltage • Next, Switch B is closed, and current flows from CA, through DB to charge CB VSUPPLY = 14V DA DB VOUT Switch B CB CA Switch A ~13V