August 2021

Desheng Guo

1-kW, 80 Plus titanium, GaN CCM totem pole bridgeless PFC and half-bridge LLC reference design使用 CCM GaN 圖騰柱和半橋 LLC 實現 80 plus 鈦金牌效率的 1kW AC/DC 系統參考設計

1

Content

• Introduction of the1kW reference design

• Why choose Totem-Pole PFC with TI GaN

• Introduction to LLC resonant converter

• Test Data and waveforms

2

Target application

• Server PSU

3

85%

88%

90%

92%

94%

96%

97.5%OCP V3

20202005

OCP V2

*Open Compute Project (OCP)

1kW, 80plus titanium, AC/DC power supply Reference Design TIDA-010062

4

Tools & Resources

Target Applications

• Merchant network and server PSU

• Merchant telecom rectifiers

Features

• Digital controlled system solution with front stage and end stage;

• GaN for PFC stage & Si SJFET for DCDC stage;

• System peak efficiency: 96.3% @ 60% load;

• High efficiency between 20%~ 100% load, > 95%;

• Low iTHD, <10%@10% load, <5%@20% load, <2%@>50%load

• Over/undershoot <300mV@50% load Tr, 2.5A/us slew rate

• Small form factor, 38mm*66mm*160mm

Benefits

• Super High Efficiency makes thermal design simpler

• Solution with low component count

• Makes compliance with 80 Plus Titanium specs easier

• less than 5% THD for 20% to full load

• Fast load transient response with 2.5A/us slew rate requirement

• Power Density ~41W/in3

• TIDA-010062 and Tools Folder• Design Guide• Design Files: Schematics, BOM, Gerber• Device Datasheets:

‒ TMS320f280049, LMG3410R070, UCC27714, UCC21540,UCC27524, ISO7741FDW, CSD18510Q5B， INA180，TMCS1100

Solution Diagram

5

F280049C/F280025C

F280049C/F280025C

Why choose Totem-Pole PFC

6

+

Active bridge rectifier

Bridgeless

• AC switch

bridgeless

• Totem-pole

bridgeless

Which one is the future

• Technologies to improve PFC efficiency

PFC technology comparison

7

AC switch PFC Totem-pole PFC Active bridge PFC

Block diagram

Details 2 silicon diodes

2 MOSFETs

2 silicon diodes or SiC diodes

1 choke coil

2 GaN FETs or SiC MOSFETs

2 MOSFETs

1 choke coil

5 MOSFETs

1 silicon diodes or SiC diodes

1 choke coil

Cost Middle Lowest in future High

Efficiency On-time: 2 MOSFETs

Off-time: 1 SiC diode + 1

silicon diode

On-time: 1 MOSFET + 1 FET

Off-time: 1 MOSFET + 1 FET

On-time: 3 MOSFETs

Off-time: 2 MOSFETs + 1

diode

~98.7% ~99.0% ~98.5%

Why Choose TI-GaN in Totem-Pole PFC

8

• GaN has >50% lower switching energy

compared to SiC

• GaN has zero reverse recovery losses

• TI-GaN switches at up to 150V/ns

resulting in 5.5x reduction in losses

compared to SiC and 2.7x compared to

discrete GaN

• TI-GaN has 3x lower dead-time losses

compered to SiC and discrete GaN

• TI-GaN has the lowest cost

146

LMG3410: 600V GaN Power Stage

9

LDO,

BB

UVLO,

OC,TEMP

FAULT

VDD

5V

LPM

IN

RDRV

Current

Direct- Drive

Slew Rate

Enable

Switch

600V

GaN

D

S

S

VNEG

Built-in 5V LDO to power

external digital Isolator

Slew rate control by one external

resistor: 30 V/ns to 100 V/ns

High speed over current protection

with <100ns response time

Fault feedback to system controller

50mΩ /70mΩ -600V GaN FET

Integrated direct gate driver with zero common

source inductance

Low power mode for standby

Integrated temperature

protection and UVLO

Digital PWM input

Only +12V unregulated supply

needed

TI-GaN with integrated driver & protection portfolio

10

150mΩ<1kWLMG341xR150

70mΩ 1kWLMG341xR070

50mΩ 2.1kWLMG341xR050

50mΩ- 3kWLMG32xR050

30mΩ - 4kWLMG342xR030 30mΩ - 6kw

LMG352xR030-Q1

2x

the power AECQ-100

8x8 mm

12x12 mm

bottom-sidecooled

12x12 mm

top-sidecooled

6 devices in mass production

Gen-I (LMLG341x,

600V)

Gen-II (LMG342x,

600V)

Gen-IIAutomotive (LMG352x,

650V)

Samples, EVM and

Documentation: www.www.ti.com/product/LM

G3522R030-Q1

Samples, EVM and

Documentation: https://www.ti.com/product/

LMG3422R030

LMG342x/352x: TI Gen 2 GaN FETs

11

>150 V/ns Drain-Source Slew rate

capability; Adjustable from 30 V/ns to 150 V/ns

V/I/T fault reporting

12mm by 12 mm QFN

LMG342x: bottom-cooled

LMG352x: top cooled QFN with

wettable flanks

LMG342x: 600-V GaN FET

LMG352x: 650-V GaN FET

Overcurrent protection Cycle-by-Cycle

Short circuit protection Latched

Integrated 2.2 MHz gate driver with industry

lowest CSI

GaN FET temperature digital

PWM reporting for active power management

LMG3425/3525 Ideal diode

mode reduces reverse conduction lossesIntegrated gate driver bias

generated from 7.5-18 V unregulated supply supporting

2.2 MHz switching

5-V regulated output for

powering digital isolator

Wettable flanks

NEW

NEW

NEW

Isolated DC-DC

12

Tech Trend: High efficiency, high power density

Increase switching frequency

Reduce switching losses, soft switching

Recycle the leakage of transformer

Isolated DCDC

Phase Shift Full Bridge LLC Resonant

Introduction to LLC resonant converter

13

• HB LLC Resonant Converter is one of the most widely used soft-switching topologies in DC/DC Converters.

Pros:– Primary switches are ZVS on– Secondary switches are ZCS when fs < fr– Better EMI performance

Vsw

ILR

ID1

ZVS turn-on

ZCS turn-on/ turn-off

Cons:– Higher rms current– 2nd side need to use low ESR capacitance– Complicated control

LLC – Below, At and Above Resonance

14

• Above Resonance, ZVS achieved, CCM on sec, Rectifiers not soft

switched. Lower RMS currents for given power

• At Resonance, ZVS achieved, CCM on sec, Rectifiers are soft

switched (ZCS), Optimum efficiency

• Below Resonance, ZVS achieved, DCM on sec, Rectifiers are soft

switched (ZCS), RMS currents higher for given power.

0A

0A

0A

Gain vs FreqFor various Q

‘Sweet Spot’ at Resonance,Frequency almost independent of load

BUT – the difficulty is

Wide gain range requires large frequency variation

Q = 1

Q = 0.4

LLC: Gain vs Frequency Characteristic

15

• Gain curve of LLC

– RE = 8 NT2 RL / 2

(NT = Turns Ratio, RL = Load)

– QE = (√(LR/CR))/RE

– To improve efficiency, LN should be as high as possible

– Resonant frequency is

Peak Gain Curve Vs Q ( LN = 5)

LLC stage gain vs frequency with QE as a

parameter (normalised to f0, resonant frequency )Gain f Q ( )

LN f2

LN f2

f2

1−( ) 1 jf LN Q+( )+

LN

LM

LRQE

LR

CR

RE

f01

2 LR CR

• Gain curve design

– FHA

– Time domain calculation

– Simulation

C2000 strategy – expanding real-time control

16

Co

st-

Op

tim

ize

d

Mid

-ran

ge

Hig

h-P

erf

orm

an

ce

Price/P

erf

orm

ance

Code & Peripheral compatible

Generation 2

Generation 3

F2833x150 MIPS512 kB

F2803x120 MIPS128 kBF2802x

60 MIPS64 kB

F2806x180 MIPS256 kB

F28004x200 MIPS256 kB

ASIL-B

F2807x400 MIPS512 kB

ASIL-B/Sil-2

F2837xS400 MIPS1 MB

ASIL-B/Sil-2

F2838xS525 MIPS

1.5 MB

ASIL-B/Sil-2

F28002x100 MIPS

128 kB

QM

C2000 Portfolio OfferingBroadest Portfolio of Real Time MCUs

• Software Compatible Portfolio

• 60 MIPS to 1000 MIPS

• 32kB to 1.5MB Flash

• 6-32 PWM ch (16 High-Res)

• Up to 40 ADC ch

• I2C, UART, SPI, CAN, CAN-FD, Ethernet, EtherCAT, USB

• Packages from 32 QFN (5x5mm), QFP, to 337 BGA

• Safety Support, Industrial and Automotive

• <$1 to $10 Price Range

Flexible & Innov ativ e Capabilities

• High Precision Analog Sensing & Feature Rich PWMs

• DSP-Efficient CPU, Control Accelerators, & Parallel Multi -

Core Processing

• TMU, FPU, & CLA for More Performance

• CLB for Peripheral Customization, FSI for high-speed

communication, ERAD for Enhanced Diagnostics and

Profi l ing

• Enabling GaN & SiC Technologies

Real-time Control Systems Made Easy

• Over 25 Years of Expertise in Real-Time Control Systems

• Extensive Library of Public Reference Designs

• Software and Hardware Tools to Jump-Start your Design

and Shorten the Time Between Evaluation and Production

Time

F2837xD800 MIPS1 MB

ASIL-B/Sil-2

F2838xD925 MIPS

1.5 MB

ASIL-B/Sil-2

NEW

NEW

NEW

Production

STATUS

PowerSUITE digital power software tools make digital power control easier

17

Get started

adapting TI

code to your

digital power

design!

Digital Power SDK – Supported Solutions

18

EVM / TI Design C2000 Series Support Description

TIDM-1007F28004x

(CLA Support Enabled)Single-Phase Totem Pole CCM PFC

TIDM-02008F28004x

(CLA Support Enabled)Bi-directional Single-Phase Totem Pole CCM PFC

TIDM-DC-DC-BUCK F28004x DC/DC Synchronous Buck Converter

TIDM-HV-1PH-DCAC F28004x, F2837x Voltage source inverter & Grid Connected Inverter

TIDA-00961 F28004x Single-Phase Totem Pole CrM PFC

TIDM-1000F28004x, F2837x, F2838x

(CLA Support Enabled)Three Phase PFC: Vienna Rectifier

TIDM-1001 F28002x Two Phase Interleaved LLC Resonant Converter

TIDM-1022F28004x

(CLA support enabled)Valley Switching Boost PFC

TIDA-01604F28004x

(CLA support enabled)6.6-kW Single-Phase Totem Pole CCM PFC

TIDM-02002F28004x

(CLA support enabled)CLLLC: Bi-Directional Resonant Dual Active Bridge

TIDM-02000 F28004x Phase Shifted Full Bridge Bidirectional DC/DC Converter

TIDM-02011F28004x

(CLA support included)Live firmware update (LFU) solution

TIDM-02009F2838x

(CLA support included)EV traction with bi-directional DC-DC converter

TIDA-01606/TIDA-010039F2837x

(CLA support included)10-kW three phase AC-DC, T type inverter/ T type PFC

Design parameters and Test data of TIDA-010062

19

System efficiency test result

20

Pin Vo Io /A Posystem

eff.130.6 12.117 10 121.17 92.78%

252.9 12.076 20 241.52 95.50%

375.2 12.034 30 361.02 96.22%

498.1 12.004 40 480.16 96.40%

621 11.973 50 598.65 96.40%

745 11.939 60 716.34 96.15%

869 11.906 70 833.42 95.91%

993 11.873 80 949.84 95.65%

1044 11.859 84 996.156 95.42%

89.00%

90.00%

91.00%

92.00%

93.00%

94.00%

95.00%

96.00%

97.00%

0 200 400 600 800 1000 1200

230Vac Titanium

PFC Stage Design Parameters

21

L Q1 Q3

Q4Q2

C

Parameters Spec

AC Input voltage range 100Vac ~ 264Vac

Nominal input voltage 230Vac

DC link voltage 385Vdc

Maximum power 1050W

Frequency 80kHz

GaN HEMET (Q1/Q2) LMG3410R070 (TI)

SR MOSFET (Q3/Q4) TK39A60W (Toshiba)

Inductor (L) 300uH

Bus Capacitor (C) 680uF450V

• PFC Design Parameters

Design Reference:• PMP20873 – 99% Efficient 1kW GaN-based CCM Totem-pole Power Factor Correction (PFC) Converter Reference Design• TIDM-1007 – Interleaved CCM Totem Pole Bridgeless PFC Reference Design Using C2000™ MCU

PFC Stage

22

96.50%

97.00%

97.50%

98.00%

98.50%

99.00%

99.50%

0 200 400 600 800 1000 1200

PFC Stage w/EMC 300uH, EQ 34*30*22，w/ 100uH DMC(Pctrl = 0.5W; Pdrv= 0.84W;)

Vin /Vac Iin /Aac Pin /W Vout /V Iout /A Pout /W Eff

(w ctrl & drv)

230.18 0.412 91.3 387.3 0.232 89.8536 96.99%

230.08 0.828 188.9 387.3 0.4818 186.6011 98.09%

230.05 1.2503 286.6 387.4 0.7319 283.5381 98.47%

229.88 1.674 384.1 387.4 0.9818 380.3493 98.68%

229.81 2.0963 481.2 387.4 1.2307 476.7732 98.80%

229.74 2.52 578 387.4 1.4806 573.5844 99.01%

229.66 2.946 676 387.3 1.7307 670.3001 98.96%

229.67 3.366 772 387 1.9807 766.5309 99.12%

229.51 3.802 872 387.4 2.2311 864.3281 98.97%

229.53 4.224 969 387.4 2.4811 961.1781 99.06%

229.55 4.574 1049 387.4 2.6813 1038.736 98.90%

(Including ctrl & drv loss)

Pctrl = 0.5W;

Pdrv = 0.84W;

DC-DC Stage Design Parameters

23

• LLC Design Parameters

Parameters Spec

DC link voltage 385Vdc

Maximum power 1000W

Switching Frequency 80kHz ~ 250kHz

Pri. MOSFET (Q5/Q6) TK39A60W (Toshiba)

SR MOSFET (S1/S2) CSD18510Q5B (TI)

Magnetic inductance (Lm) 200uH

Resonant Inductor (Lr) 13uH

Resonant Capacitance (Cr) 33nF*2

Output Capacitor 3300uF*2

LrQ5

S1 S2Q6

T1

Cr

Lm

Co

Design Reference:• TIDM-1001 – Two-Phase Interleaved LLC Resonant Converter Design With C2000™ Microcontrollers

LLC Stage

24

* Including driving loss & ctrl loss

Transformer, PQ3230, 16:1:1,Toshiba SK39A50,Fs=161kHz,openloop

Vin /V Iin /A Vo /V Io /A Po Eff w/ ctrl&drv

386.1 0.324 12.182 10 122 96.32%

386 0.641 12.149 20 243 97.66%

386 0.959 12.127 30 364 97.92%

386 1.276 12.103 40 484 98.02%

385.9 1.594 12.07 50 604 97.89%

385.9 1.911 12.038 60 722 97.76%

385.8 2.227 12 70 840 97.61%

385.8 2.5481 11.99 80 959 97.44%

385.7 2.6751 11.96 84 1005 97.24%96.20%

96.40%

96.60%

96.80%

97.00%

97.20%

97.40%

97.60%

97.80%

98.00%

98.20%

0 200 400 600 800 1000 1200

LLC Stage w/o Oring

Efficiency improvement with LMG3422R050

25

97.00%

97.20%

97.40%

97.60%

97.80%

98.00%

98.20%

98.40%

98.60%

0 200 400 600 800 1000

η

Pout /W

Eff. @166kHz LLC

TK39A60W

LMG3422R050

Conditions TIDA-010062, fs=166kHz, Toshiba TK39A60W(600V 55mR)

Vin /V Iin /A Vout /V Iout /A Pout /W Eff.

384.67 0.3206 11.975 10 119.75 97.10%

384.64 0.6339 11.944 20 238.88 97.97%

384.62 0.9475 11.920 30 357.60 98.13%

384.6 1.2611 11.898 40 475.92 98.12%

384.6 1.5748 11.874 50 593.70 98.02%

384.58 1.8861 11.835 60 710.10 97.90%

384.57 2.1963 11.791 70 825.37 97.72%

384.55 2.5058 11.745 80 939.60 97.51%

Conditions TIDA-010062, Fs=166kHz,LMG3422R050 (600V 50mR)

Vin /V Iin /A Vout /V Iout /A Pout /W 效率

384.73 0.32 11.992 10 119.92 97.41%

384.71 0.6327 11.961 20 239.22 98.28%

384.69 0.9447 11.929 30 357.87 98.47%

384.67 1.2570 11.898 40 475.92 98.43%

384.65 1.5692 11.869 50 593.45 98.32%

384.63 1.8811 11.837 60 710.22 98.16%

384.61 2.1915 11.795 70 825.65 97.96%

384.6 2.5011 11.748 80 939.84 97.70%

Load transient

26

• No load / 50% load, 2.5A/us

250mV

280mV

Ch4 – Iin, Ch2 – Vlink, Ch4 – Vout(ac coupled)

（230Vac input）

Ch4 – Iin, Ch2 – Vlink, Ch4 – Vout(ac coupled)

Load transient

27

• 50% Load/100 Load, 2.5A/us

200mV

300mV

（230Vac input）

Ch4 – Iin, Ch2 – Vlink, Ch4 – Vout(ac coupled) Ch4 – Iin, Ch2 – Vlink, Ch4 – Vout(ac coupled)

Output ripple

28

（230AC input）

Ch4 – Vout(ac)100% load50% load

System startup

29

• 230Vac no load

Ch1 – Vac, Ch2 – Iac, Ch3 – Vbus, Ch4 – Vout

• 230Vac 50% load

EMI - CE Test result

30

• 230Vac, 800W load

Summary

31

• 80 plus titanium efficiency, =>95.4% @ 25%-100% load

• Fast load transient, Vo change within 300mV @ 2.5A/us slew rate

• Low iTHD, <10%@10% load, <5%@20 load, <2%@>50% load

• Power Density 41W/in3, 38mm*66mm*160mm

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