The Future of Power: High-Frequency Systems Enabled by GaN

The Future of Power: High-Frequency Systems Enabled by GaN

April 2021

Dong Lin, Sr. Director, Applications, dong.lin@navitassemi.com

Stephen Oliver, VP Corp. Mktg. & IR, stephen.oliver@navitassemi.com

World’s first and only GaN power IC company Over 18Mu shipped and zero failures

 Energy to revolutionize power electronics

 Energy to accelerate change

 Energy to make a sustainable difference for our world

GaN is a high-speed semiconductor that switches up to 100x faster than Si and enables more efficient, smaller, lighter, cooler and lower cost systems; delivering 30-40% in energy savings.

Leonardo da Vinci
1452-1519

Frustrated Genius:

Strong ideas…

…Weak tools

The Enabling Force

Power GaN Technologies

 Power ICs: Single, Half-Bridge

• Monolithic integration, 650V/800V, 2MHz

• GaN Power FET(s) + Driver + Control + Protection
• Features: on-board regulators, hysteretic input, level-shift, bootstrap, dV/dt control, UVLO, shoot-through & ESD protection

• “Digital In, Power Out”

2x Energy Savings at 27-40 MHz

The evolution of Flyback Frequency

QR Flyback Losses

• Quasi-Resonant (QR) Flyback

• Frequency-dependent losses
• Frequency-dependent losses
• Leakage inductance
• Snubber/clamp
• Partial hard-switching at high line
• Slow turn-on to minimize EMI
• Difficult to improve efficiency at high frequency

Mass Production: ACF

No Cap, Thin Transformer

• 60% thinner/smaller transformer

• 80% smaller output caps

• No electrolytic bulk cap

• Easier EMI

• 10x increased frequency
• Planar shield layer
• More consistent parameters

Pulsed-ACF

• Topology:

• Rectified AC 100Hz feeds directly into high-frequency ACF
• ACF maintains 100 Hz smooth pulse output to charge the phone’s battery, even if input voltage range is wide
• Stability, and accurate current and voltage monitor critical
• Eliminates electrolytic bulk capacitor
• OPPO-proprietary ‘direct-charge’ means during each pulse gap, polarization effect in the phone battery is eliminated, reducing wear-out mechanisms and extending battery life

• Powertrain:

• 2x Navitas NV6115 (170mOhm GaNFast power ICs)
• Low RDS(ON to minimize ‘on-state’ losses
• Minimal COSS for best ‘switching’ performance

• Control:

• TI UCC28782 ACF + On Semi NCP51530
• High-speed, soft-switching (~500 kHz)

 

The evolution of Front-End Frequency

Rectifier on Fire!

Rectifier on Fire!

2016: 1MHz CrCM Totem-Pole

300W Totem-Pole PFC

• Output : 400V (300W)utput : 400V (300W)
• Fast FETs : NV6117 (110mΩ) GaN Power ICs
• Slow FETs : Si Superjunction (62mΩ)
• Frequency : 300-1,200 kHz
• Size : 53.3 x 57.5 x 20 mm = 62 cc uncased (DSP controller board not included)
• Power Density: 4.9 W/cc (80 W/in3) uncased
• Target Efficiency : 98.5% @ 220VAC, 98% @ 110VAC, 97.5% at 90VAC, full load

Dr. Weijing Du, Navitas, 2018

NV6128: 70mΩ GaNFast Power IC

Integration Drives Performance

Only GaNFast is Fast… and Safe

Double-Pulsed Test (Sync Boost Circuit)

“Best GaN We Tested!”

Partner Feedback:

“Protected gate removes external parts without restricting switching speeds”

“Minimal ringing optimizes EMI”

“No gate-loop risks”

“Fast and very clean switching”

“Easy to control slew rates”

“Integrated gate allows fast switching”
(dV/dt > 200 V/ns, di/dt >10 A/ns)

High-Frequency HVDC

Quarter (¼) Brick, 400 VIN