Built-in GaN Half-Bridge Delivers MHz Efficiency

//php echo do_shortcode(‘[responsivevoice_button voice=”US English Male” buttontext=”Listen to Post”]’) ?>

Historically, energy designers needed to construct half-bridge circuits utilizing discrete transistors and several other exterior parts, akin to drivers, level-shifters, sensors, bootstraps, and peripherals. Navitas Semiconductor not too long ago introduced the {industry}’s first GaNSense half-bridge energy ICs, out there in a compact 6×8-mm surface-mount PQFN package deal.  

These next-gen gallium nitride (GaN) half-bridge ICs ship 2-MHz switching frequency, with over 60% discount in parts and circuit measurement, in line with the corporate. That, in flip, reduces the system value and complexity in contrast with current discrete options that require a better variety of parts, are dearer, and ship decrease switching frequency, density, and effectivity. 

As proven in Determine 1, the brand new gadgets combine two GaN FETs with drivers, management, sensing, autonomous safety, and level-shift isolation, forming a whole power-stage constructing block for energy electronics. 

Determine 1: GaNSense half-bridge integrates drive, management, sensing, and safety with stage shifting isolation right into a single 6×8-mm PQFN package deal (Supply: Navitas)

GaN Units 

“Our new GaNSense half-bridge energy ICs are an enormous step that can revolutionize energy electronics, since we combine every part in a single package deal, enabling megahertz switching frequencies in high-speed topologies”, stated Llew Vaughan-Edmunds, a director at Navitas Semiconductor. 

For extra reliability and robustness, the built-in GaNSense expertise permits autonomous safety with loss-less present sensing for better ranges of effectivity and power financial savings. Excessive integration ranges make it potential for quite a lot of AC-DC energy topologies, akin to LLC resonant, uneven half-bridge (AHB), and active-clamp flyback (ACF), to function at megahertz frequencies by eliminating circuit parasitics and delays. The totem-pole PFC and motor-drive functions are likewise perfect suits for the GaNSense half-bridge ICs. 

The degrees {of electrical} energy required by the market are always growing.  Typical energy scores for quick chargers have elevated from 20-30 W to 65 W, and a brand new ultra-fast class launched with >100-W energy—even as much as 200 W delivering 0-100% charging of a 4,700 mAhr battery in lower than 10 minutes, Navitas stated. Equally, a knowledge heart’s goal effectivity goes from 80% to 90% or extra, whereas clients demand quicker charging of EVs, too. 

The important thing options that the market calls for for present and future energy functions are measurement, weight, effectivity, and pace. Through the use of soft-switching topologies, akin to zero voltage switching (ZVS), the GaNSense half-bridge ICs decrease switching losses and improve effectivity, whereas additionally enabling quicker switching and a smaller footprint. 

“We’re enabling the best frequency, effectivity and essentially the most compact design in soft-switching topologies and half-bridge platforms,” Vaughan-Edmunds stated. “Legacy silicon options have decrease frequency, decrease effectivity, and decrease energy density. With GaN, we at the moment are speaking about megahertz and plus switching frequency.” 

Navitas stated its resolution differs from rivals’ options in that it has an built-in gate drive (which eliminates parasitic inductance, turn-off, and false turn-on of eMode gate), safety of the delicate eMode gate node (which protects gadget from system noise and voltage spikes), and the high-feature GaNSense expertise.  

This consists of superior options to simplify design, akin to customary and digital-logic inputs, high-side bootstrapping and level-shifting, and loss-less present sensing for the best effectivity and best probability of first time-right, quickest time-to-market designs—in distinction to advanced, costly, and probably unstable discrete implementations. Shoot-through safety, over-current, over-temperature sensing and autonomous management, 2 kV ESD, and 200 V/ns slew-rate capabilities are all customary with this real IC.  

A comparability between a discrete GaN half-bridge resolution and an equal board designed utilizing GaNSense half-bridge IC is proven in Determine 2, as described by Vaughan-Edmunds.  

“We will see how the GaNSense resolution requires 61% fewer parts, has a considerably decrease footprint and supplies increased integration. Furthermore, it doesn’t require exterior high-voltage bootstrap, high-voltage bypass diodes, and it doesn’t have uncovered gates. As proven in Determine 1, the 2 pads beneath of the 6×8 mm PQFN package deal have a bigger measurement for enhancing thermal administration,” Vaughan-Edmunds stated.  

Determine 2: GaNSense half-bridge IC resolution has a smaller footprint, requires much less parts, and is exempt from ringing and glitching throughout switching transitions (Supply: Navitas)

Among the many totally different safety measures supplied by GaNSense expertise, short-circuit safety is a key issue for motor drive functions. As an alternative of getting 5 microseconds or 10 microseconds of delay because the quick circuit detection, the gadget switches itself off inside 30 nanoseconds—six instances quicker than discretes.  

That is known as autonomous safety, because the GaNSense half-bridge energy IC doesn’t must interrupt the microcontroller to inform it to change it off; it switches off by itself. Footprint discount is a related function for mid-power motor drive functions, as properly.  

The household of GaNSense half-bridge ICs begins with two elements: the NV6247, rated at 650 V, 160 m (twin), and the NV6245C, rated at 275 m (twin). Each can be found in an industry-standard, low profile, low inductance, 6×8-mm PQFN package deal. Each ICs meet the demand coming from totally different energy functions, together with cell quick and ultra-fast chargers, residence home equipment, and motor drive. 

Instantly out there in manufacturing with a 16-week lead time, the NV6247 is appropriate for cell and client functions with energy ranges starting from 100 W to 140 W (like PFC and chargers), and for pumps and followers with energy as much as 400 W. The NV6245C is presently sampling to pick out clients and will probably be broadly out there in manufacturing to all clients by the tip of this yr. The GaNSense half-bridge IC household will then broaden, providing a variety of package deal kinds and energy ranges within the coming quarters. 

Motor Management 

GaNSense half-bridge ICs additionally allow inverter-motor integration. Three half-bridges are usually used to supply a three-phase topology in fashionable variable-speed drives for electrical motors, as utilized in family home equipment, HVAC, industrial equipment, EVs, and robotics. Most of as we speak’s motor-drives are low-frequency and hard-switched. GaN’s low switching capacitance and the absence of a reverse-recovery cost permit switching frequencies to be elevated whereas minimizing losses even in hard-switching functions. 

In response to Navitas, an influence loss comparability amongst IGBT, SJ MOSFET, and GaNFast IC in motor-drives reveals how GaN achieves a 78% discount in whole energy loss, whereas concurrently operating 3× quicker than a legacy Si IGBT design. Through the use of GaN Energy ICs right into a 2-kW motor drive design, the inverter effectivity will increase 2.5% (from 96% to 98.5%), whereas whole losses scale back 50% (from 15 W to six.8 W). 

Determine 3: GaNSense half-bridge ICs allow inverter-motor integration (Supply: Navitas)

“We’re additionally eliminating the heatsinks, and we’re going to place this into the motor shaft,” Vaughan-Edmunds stated. “For the shoppers who need the motor-integrated inverter, this can be a good resolution. We really feel we’ve got the best integration stage.” 

Leave a Reply