Akermann Electronic BG JSC Power Management from Texas Instruments Inc. Module 3: Power Management 180 Part II: MOSFET and IGBT Drivers Purpose, Basic Functions, Benefits Replacing discrete Gate Drivers (NPN/PNP Totem pole) with Gate Driver ICs Key Spec/Parameters Types of Gate Drivers Examples 12.October.2017 - Technical seminar 1
MOSFET and IGBT Gate Drivers Everywhere for efficient power conversion!!! 2
For Equipment in your Every Day Life Consumer/Personal/Home/Office/Automotive Electronics For Equipment Behind the Scenes (Think Infrastructure ) IT Infrastructure, Server/Telecom, Industrial, Medical
AC/DC Power Supply - from W to kw Also.DC/DC Isolated Power Supply.Telecom/Industrial AC/DC 24V/ 48V/ Few 100V DC/DC DC/DC DC/DC
Think Power Conditioning/Conversion (DC/AC) Motor/Fan/Pump Power Tools UPS Toys Small Appliances Solar Power Motor Control
What is a Gate Driver?? Gate Driver is a device which enables FAST turn-on & turn-off of power switch Gate Driver device applies voltage signal between Gate & Source (VGS) and provides high-current pulse - To charge/discharge C GS, C GD QUICKLY To turn ON/OFF power MOSFET QUICKLY Gate Driver Gate Driver Switch Turn-On Switch Turn-Off
Gate Driver IC Basic Function Turn ON Turn OFF ON Controller OFF OFF Input Signal Gate Driver Output Signal Output Current Pulse Charge Discharge IN signal from controller, can be logic level Output (OUT pin) of Gate Driver changes state based on Input (IN) signal OUT signal High Level (ON state) ~ VDD OUT signal in Low Level (OFF state) ~ GND High-current pulse delivered by OUT pin for power MOSFET turn ON/OFF Charging current = Source Current Discharging current = Sink Current
Traditional Gate Driver Circuits Based on Discrete Devices (NPN/PNP Totem Pole) Replace with Gate Driver Device NPN/PNP Bipolar transistor in totem pole configuration Power MOSFET or IGBT Gate Driver Devices can effectively replace NPN/PNP Totem Pole: - Reduce BoM component count - Reduce PCB space - Improve reliability 8
Digital Power Application Based on Microcontroller/DSP NPN/PNP Totem Pole Needs ADDITIONAL Level Shifting (3.3V PWM 12V) NPN/PNP Totem Pole + Level Shift circuit Replace with Gate Driver Device 3.3V/5V PWM signal from Microcontroller or DSP Micro/DSP Digikey AUP (50ku): -FMMT618/FMMT718 NPN/PNP =$0.159-2N7002 MOSFETs = $0.022 Level Shifted 12V signal 12V with High, Peak Source/Sink current 9
Change Traditional Gate Driver Circuits Based on Discrete Devices to IC Gate Driver IC Technical Comparison Feature TI UCC2751X Gate Driver NPN/PNP Totem Pole Gate Driver (Discrete or co-pack example Zetex ZXGD3003E6) NPN/PNP Bipolar transistor in totem pole configuration UVLO Feature Yes No Output Current Immaterial of Input current Directly proportional to input Base current & Gain Level-Shifting Capability Yes No, Emitter follower (not compatible with Digital Power trend, see next slide) Internal Shootthrough Protection Yes, Make before break No, add series resistor to limit current from Bias supply Enable Function Yes No Noise Immunity Excellent, choice of CMOS & TTL Poor, can turn-on if IN voltage > 0.7V Size 2.90 mm x 1.60 mm (UCC27517) At least double the IC foot print Prop Delay 12ns (typ) Less than 10ns achievable, depends on load capacitor Recommended Max VDD/Bias 18V Based on choice of NPN/PNP 10
Value Added by Gate Driver IC over Discrete Totem Pole Easy System Design Integrated solution shortens design cycle. Reduced BOM count saves assembly and test cost. Excellent noise immunity reduces design uncertainty. Built-in level shift saves additional components. Ease of board layout Reliability Less BOM count reduces the failure rate and improves the MTBF. Internal shoot through protection prevent system in extreme condition. UVLO increase system robustness. Higher Efficiency Current drive capability is not limited to input base current & gain. Size Small form factor saves board size. 11
Layout Example: Discrete vs Integrated BOM of a typical PFC solution with level shift: Discrete 1. 4 Transistors 2. 2 Multi-layer Ceramic Capacitor 3. 1 E-Cap 4. 10 Resistors Total 17 components with 0.84 in 2 PCB space Gate Driver IC 1. 1 Gate driver IC 2. 2 Multi-layer Ceramic Capacitor 3. 1 E-Cap 4. 2 Resistors Total 5 components with 0.33 in 2 PCB space 12
Types of Gate Drivers
2 Types of Gate Drivers Based on Switch Position or Arrangement Low Side Drivers Used to Drive GND referenced switches High side-low Side Drivers Used to Drive 2 switches connected in Bridge Arrangement Low side Gate Driver High side Low side Gate Driver
Low Side Gate Drivers Single Channel GND of Driver IC is same as Source terminal of power switch Reference level for LO output is GND Voltage Level LO LI ~ VDD-GND Dual Channel GND 2 Varieties of Low Side Drivers: Single Channel = 1 input, 1 output Dual Channel = 2 inputs, 2 outputs
High Side - Low Side Gate Drivers High Voltage pins (up to 620V in some PNs) Used to control 2 switches (H, L) arranged in Bridge configuration 2 inputs (HIN, LIN), 2 outputs (HO, LO) LO drives L switch Source of Lower switch L is same as GND H L HO drives H switch Source of Upper switch U is referenced to HS (NOT referenced to GND) High Side Source GND HO ~ HB-HS NOTE: HS Reference level for LO output is GND Reference for HO output is HS (HO is Level Shifted to HS pin) HS, HO, HB are High-Voltage pins in High side-low side Drivers Voltage Level GND LI (same as Low-side Driver) LO ~ VDD-GND HI
High Side - Low Side Gate Drivers (Half-Bridge Drivers) A Special Version of High side-low side Driver is a Half-Bridge Driver Internal circuit ensures HO and LO can never be ON simultaneously No risk of cross-conduction between H and L (also called Shoot-through) Sometimes just 1 IN pin controls both HO and LO state IN High = HO High, LO Low IN Low = HO Low, LO High H L
Both Types of Gate Drivers Needed in Major Power Electronic Topologies Bridge inverter/ rectifier Interleaved Forward, Push-Pull, Boost, Center-tapped rectifier Forward, Flyback, Boost Two-Switch Forward Half-Bridge Active Clamp Asymmetrical H-Br, Synchronous Buck, Boost A B 1 2 C D 1 A 2 B 1 A 2 1 A B A B 1 2 A 1 B A B 1 2 VDD NC 1 INA1 2 - + INA2 3 4 6 Vdd 5 OUT GND ENBA INA GND INB 1 2 3 8 7 6 4 5 ENBB OUTA VDD OUTB LI CONTROL DRIVE HI DRIVE LO HB HO HS LO Single Low Side Driver Dual Low Side Drivers VSS UCC27200/1 High side- Low side Drivers & Half-Bridge Drivers
Key Parameters for LOW SIDE Gate Drivers
Low Side Drivers Parameter # of Outputs Channels Example 1-Channel, UCC27517 2-Channel, UCC27524 Configuration Non-Inverting (IN+) OUT out-of- -phase with IN OUT in-phase with IN Inverting (IN-) # of Inputs/Ch Single Input, UCC27537 (IN or IN+/IN-) Dual Input, UCC27533 (IN+ or IN-) Type of Input Threshold Logic TTL (or CMOS/TTL) Fixed Voltage Threshold CMOS Threshold level is f(vdd)
Low Side Drivers Parameter Example Peak Source/Sink Current SYMMETRICAL (ISRC=ISNK), UCC27524 ASYMMETRICAL (ISRC ISNK), UCC27511 VCC/VDD Supply Range (Min/Max) UCC27517 UCC27533 (higher VDD range suited for IGBTs) Is Enable function Available? (EN pin) When EN pin is Low, OUT pin is Low (no matter what is status of IN pin) Available, UCC27518 Not Available, TPS2828 Single Output OR Split Output? Single Output Source/Sink from OUT pin Split Output Source from OUTH, Sink from OUTL pin
Low Side Drivers Parameter Turn-On, Turn-Off Propagation Delay (t D ) OR Input-to-Output Propagation Delay Rise Time (t r ), Fall Time (t f ) Example Delay Matching Only for Dual Channel Drivers Package Options Single Channel Driver - SOT-23 5-pin, SOT-23 6-pin, DFN 6-pin (with Thermal Pad) Dual Channel Driver - SOIC 8-pin, PDIP 8-pin, MSOP 8-pin (with Thermal Pad), DFN 8-pin (with Thermal Pad)
Low Side Drivers Parameter Example Recommended Operating Temperature Range UCC27524 TPS2814 Input Pin Negative Voltage Capability UCC27524 UCC27524A
Key Parameters for HIGH SIDE-LOW SIDE Gate Drivers
High Side-Low side Drivers Parameter Boot Voltage Examples ABS MAX Voltage Rating of HB pin UCC27211 UCC27714 Peak Source/Sink Current VCC or VDD Range Configuration Types of Input Threshold Logic Similar consideration as Low Side Driver section Similar consideration as Low Side Driver section High side-low side Driver: 2 input pins (HI, LI) Half-Bridge Driver: Single Input pin (IN) TTL (or CMOS/TTL compatible) Fixed voltage threshold Psuedo-CMOS Fixed voltage threshold, higher level, wider hysteresis
High Side-Low side Drivers Parameter Is Bootstrap Diode integrated inside Driver Examples Integrated inside device Not integrated inside device Voltage Slew Rate on HS Propagation Delay Rise/Fall time Delay Matching Similar consideration as Low Side Driver section Similar consideration as Low Side Driver section Similar consideration as Low Side Driver section
High Side-Low Side Drivers Parameter Example Recommended Operating Temperature Range UCC27211 LM5102 Input Pin Voltage Capability UCC27211 UCC27201 Negative Voltage on HS pin (for 600V drivers) IRS212864 UCC27714
EXAMPLEs of Gate Driver Usage in Different Application Schematics
Server/Telecom/industrial AC-DC Power Supply PFC Stage 400V DC/DC Stage AC ~ 1-phase PFC or 2-phase PFC Half-Bridge Converter or Full-Bridge Converter 48V for telecom rectifier 24V/few 100V for industrial 12V for server power 1 channel Gate Driver DC/DC Half Bridge DC/DC Full Bridge 1-phase PFC 2-phase PFC 2- Channel Gate Driver PFC Controller
Example of PARALLELED Switches - PFC 1 channel Gate Driver 1 channel Gate Driver 2 channel Gate Driver
PFC Stage Example: UCC28070 2-Phase PFC EVM (Schematic SLUU312B.pdf) 300W Interleaved PFC pre-regulator 2xPWMs operating 180 out of phase Average CMC Reduces boost inductor volume Reduces EMI filter size 2-Phase PFC converter needs 1X unit of 2-channel gate driver per system for driving 2 PFC MOSFETs Hi-Eff Server and Desktop Power Supplies Telecom Rectifiers White Goods and Industrial Equipment
PFC Stage Example: UCC28070 2-Phase PFC EVM (Schematic SLUU312B.pdf) UCC27324D Dual 4-A Peak High-Speed LS Power-MOSFET Drivers
PFC Stage Example: UCC28070 2-Phase PFC EVM (Schematic SLUU312B.pdf) VOUT Simplified Four-Phase Application Diagram Using 2 x UCC28070 Devices
Example of PARALLELED Switches The basic Boost, Flyback and Buckboost converters have excellent self-pfc capability naturally. Boost and Flyback are especially suitable for DCM PFC usage (most preferable by the designers).
UCC25600 Half-Bridge 8-Pin High-Performance Resonant Mode LLC Controller OR Applications: 100-W to 1kW Power Supplies LCD, Plasma, DLP TVs Adaptors, Computing and ATX Power Supplies Home Audio Systems Electronic Lighting Ballasts
UCC25600 Half-Bridge (Schematic SLUR403.pdf) Replace NPN/PNP Totem Pole with Gate Driver
DC/DC Stage Example: UCC28950 FULL Bridge EVM (Schematic SLUU421A.pdf) Green Phase-Shifted Full-Bridge Controller with Synchronous Rectification UCC27324D Dual 4-A Peak High-Speed LS Power-MOSFET Drivers
DC/DC Stage Example: UCC28950 FULL Bridge EVM (Schematic SLUU421A.pdf) Green Phase-Shifted Full-Bridge Controller With Synchronous Rectification Current Sensing Transformer (for sensing current) Main Power Transformer (for sending power) 390VDC In / 12VDC Out 2A INPUT / 50A OUTPUT POUT = 600W Sync rectification (Secondary side) => High Eff 2-Channel Gate Driver for Gate Drive Transformer 2-Channel Gate Driver for Gate Drive Transformer Gate Drive Transformer (for sending signal) 2-Channel Gate Driver for SR MOSFET FULL Bridge converter needs 3X units of 2-channel gate driver per system - 2X units for 2 Gate Drive Transformers - 1X Units for 2 SR MOSFETs Phase-Shifted Full-Bridge Converters Datacom, Telecom, and Wireless Base-Station Power Server, Power Supplies Industrial Power Systems High-Density Power Architectures Solar Inverters, and Electric Vehicles
Single Channel Gate Driver IC for POWER TOOLs DC Brush Motor Chopper Motors V BATTERY Battery Input Voltage Freewheel Diode Single Channel Low Side Driver ICs Power MOSFET 39
High side-low side Gate Driver IC in Bridge-type Motors Battery Voltage High side-low side Gate Driver IC Power MOSFET Power MOSFET Battery Voltage High side-low side Gate Driver IC High side-low side Gate Driver IC
Gate Driver in 3-Phase Inverter Motors PMSM AC Induction 15V Bias Supply Generation Block 1-ph or 2-ph PFC IC* Low Side Gate Driver IC *In newer architectures, PFC control function is delivered by C/DSP, eliminating need for a discrete analog PFC controller 3X C/ DSP 700V Half-Bridge Gate Driver IC 41
Isolated MOSFET and IGBT Drivers A conceptual power drive system block diagram Electronic devices and integrated circuits (ICs) used for isolation are called isolators 42
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Isolated MOSFET and IGBT Drivers ( CMTI Common-Mode Transient Immunity ) 46
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Isolated MOSFET and IGBT Drivers Type C ISO Driver Applications Isolated Converters in Offline AC-to-DC Power Supplies Server, Telecom, IT and Industrial Infrastructures Motor Drive and DC-to-AC Solar Inverters LED Lighting Inductive Heating Uninterruptible Power Supply (UPS) HEV and BEV Battery Chargers 4-A Peak Source, 6-A Peak Sink, 5,7-kVRMS Isolated Dual-Channel Gate Driver 48
Isolated MOSFET and IGBT Drivers Type C ISO Driver 4-A Peak Source, 6-A Peak Sink, 5,7-kVRMS Isolated Dual-Channel Gate Driver Common Mode Transient Immunity (CMTI) is one of three key characteristics associated with digital isolators as well as optocouplers. CMTI is important because high SR (high frequency) transients can corrupt data transmission across the isolation barrier. The capacitance across the barrier (i.e., between the isolated ground planes) provides the path for these fast transients to cross the isolation barrier and corrupt the output waveform. 49
Isolated MOSFET and IGBT Drivers Type C ISO Driver During CMTI testing, a pulsed transient is applied across the isolated ground planes and the outputs of the device are monitored for data disruptions. The key characteristic of this transient is its slew rate. In the case shown in the figure a transient pulse is applied to the ground on the left hand side of the isolation barrier while the outputs of the DUT on the right hand side of the barrier are monitored. 50
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