Monolithic Power Systems, Inc. · NASDAQ:MPWR
Monolithic Power Systems — Technical Presentation (September 2020)
32 slides from Monolithic Power Systems's technical presentation, September 2020
Slide 1: Driving Power MOSFETs
Driving Power MOSFETs Pete Millett Senior Technical Marketing Engineer September 2020
Slide 2: Pete Millett – Senior Technical Marketing Engineer
Pete Millett – Senior Technical Marketing Engineer 2014–Present • MPS Senior Technical Marketing Engineer for motor driver ICs • Responsible for new product definitions as well as application engineering 2005–2013 • Systems Engineer and Systems Manager at Texas Instruments • Product definition and s
Slide 3: Driving power MOSFETs
Driving power MOSFETs MOSFET Basics Driving Loads: H-Bridges and Half-H-Bridges Driving the Gate Effects of MOSFET Switching Speed Conclusion
Slide 4: Power MOSFETs
Power MOSFETs Drain (D) Drain (D) Gate (G) Source (S) P-channel “4 ,, mrS
Slide 5: Power Drive Circuits
Power Drive Circuits V+ V+ V+ V+ Out On Off Low side Half Bridge H-Bridge Red: PWM On Blue: PWM Off
Slide 6: Half Bridges: N and P
Half Bridges: N and P VIN VIN On: VIN - Vg On: VIN + Vg Off: V+ P-channel Off: Out N-channel Out On: Vg N-channel On: Vg N-channel Off: 0V Off: 0V VIN – Load Supply Voltage VG – Gate Drive Voltage
Slide 7: MOSFET Structure
MOSFET Structure Source Gate Oxide
Slide 8: Simplified Model of an N-channel Power MOSFET
Simplified Model of an N-channel Power MOSFET
Slide 9: Datasheet Specs and Total Gate Charge
Datasheet Specs and Total Gate Charge IPP015N04N VDS max 40.0 V RDS (on) (@10V) max 1.5 mΩ ID (@25°C) max 120.0 A Ptot max 250.0 W Ciss 15000.0 pF Coss 4000.0 pF QG (typ @10V) 188.0 nC VGS(th) min / max2.0 V / 4.0 V Q = CV (Charge = Capacitance x Voltage) CISS – Input capacitance (gate-to-source + g
Slide 10: Driving the Gate
Driving the Gate IPP015N04N VDS max 40.0 V RDS (on) (@10V) max 1.5 mΩ ID (@25°C) max 120.0 A Ptot max 250.0 W Ciss 15000.0 pF Coss 4000.0 pF Gate drive voltage QG (typ @10V) 188.0 nC VGS(th) min / max2.0 V / 4.0 V Load resistance Supply voltage Gate series resistance
Slide 11: Low Resistance Gate Drive
Low Resistance Gate Drive Red: Drain Voltage Green: Gate Voltage Blue: Gate Current
Slide 12: Low Resistance Gate Drive
Low Resistance Gate Drive Red: Drain Voltage Green: Gate Voltage Blue: Gate Current
Slide 13: Adding Series Resistance
Adding Series Resistance Red: Drain Voltage Green: Gate Voltage Blue: Gate Current
Slide 14: Adding Series Resistance
Adding Series Resistance Red: Drain Voltage Green: Gate Voltage Blue: Gate Current
Slide 15: Too Much Series Resistance?
Too Much Series Resistance? Red: Drain Voltage Green: Gate Voltage Blue: Gate Current
Slide 16: Too Much Series Resistance?
Too Much Series Resistance? Red: Drain Voltage Green: Gate Voltage Blue: Gate Current
Slide 17: False Turn-On
False Turn-On Red: Drain Voltage Blue: Gate Voltage Green: Drain Current
Slide 18: Asymmetric Gate Drive
Asymmetric Gate Drive Blue: Drain Voltage Green: Gate Voltage
Slide 19: MOSFET Switching Speed
MOSFET Switching Speed Yes MOSFET Waveforms Power Loss Turn-on Turn-off Turn-on Turn-off switching loss ° switching loss t (a) mrS
Slide 20: Why Slow the Gate Down?
Why Slow the Gate Down? Fast Slow Green: Gate Voltage Blue: Drain Voltage Red: Source Voltage
Slide 21: EMI Concerns
EMI Concerns mrS
Slide 22: Body Diode Reverse Recovery
Body Diode Reverse Recovery High dI/dt IRR1 IRR1 Equal Areas >> IRR2 Low dI/dt IRR2
Slide 23: Summary
Summary • Key takeaways: • Understand how MOSFETs work to implement a successful power circuit • Optimize the gate drive to control slew rate, transients, and EMI • Carefully design the PCB with consideration of parasitic inductances and impedances
Slide 24: Q&A
Q&A Please submit questions through the “Q&A” menu option in the Zoom app This webinar and others will be available for on-demand streaming at: MonolithicPower.com/webinars
Slide 25: The Body Diode
The Body Diode Source Body Diode
Slide 26: DC Current Needed for Gate Drivers
DC Current Needed for Gate Drivers IPP015N04N VDS max 40.0 V RDS (on) (@10V) max 1.5 mΩ ID (@25°C) max 120.0 A Ptot max 250.0 W Gate driver current Ciss 15000.0 pF Coss 4000.0 pF Gate drive QG (typ @10V) 188.0 nC supply VGS(th) min / max2.0 V / 4.0 V
Slide 27: DC Current Needed for a Gate Driver
DC Current Needed for a Gate Driver
Slide 28: MOSFET Ratings and Breakdown
MOSFET Ratings and Breakdown
Slide 29: Avalanche
Source Gate Emax(0s) ak Avalanche starts when Em: exceeds the E, of the structure Ey Drain mrS
Slide 30: High-Side Gate Drive
High-Side Gate Drive V+ V+ Charge Pump HS in Driver N-channel HS in Driver N-channel LS in Driver N-channel LS in Driver N-channel Isolated High-Side Supply Charge Pump High-Side Supply
Slide 31: Bootstrap Gate Drive
Bootstrap Gate Drive VIN LS In 3.3 0 12 VG LS Out 0 BST HS In 3.3 0 HS in Driver VIN+VG HS Out 0 LS in Driver VIN+VG BST VIN VG Out 0 Bootstrap High-Side Supply
Slide 32: Driving the Gate: Constant Current vs. Series Resistance
Driving the Gate: Constant Current vs. Series Resistance 1 Amp Constant Current Gate Drive 12V Gate Drive with 12Ω Series Resistance (100nC - Red = gate, purple = drain, 200nS/div) (100nC - Red = gate, purple = drain, 200nS/div)
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