APEC 2023 underscores advances in power devices

At the Applied Power Electronics Conference & Exposition (APEC 2023), over 270 component manufacturers showcased their latest innovations and technologies, aimed at system power designers. Power trends continue to focus on improving efficiency and reducing system complexity while driving down cost and package sizes. More highly integrated power devices are also on the upswing.

A big area of development continues to be wide-bandgap (WBG) semiconductors, such as gallium nitride (GaN) and silicon carbide (SiC) power devices for a range of automotive, consumer electronics, communications and industrial applications. Several GaN manufacturers unveiled technology advances that claim higher performance and integration.

Here is a selection of power devices featured at the conference that deliver improved functionality, higher integration and increased efficiency for a wide range of applications.

GaN technology advances

GaN power device manufacturers continue to advance their roadmaps with higher-performance and higher-efficiency devices. A few examples include GaN Systems, Innoscience, Navitas and Rohm.

GaN Systems has announced a new GaN-based 11-kW/800-V on-board charger (OBC) reference design that delivers 36% higher power density and up to 15% lower bill-of-materials (BOM) cost compared with SiC transistors, according to the company. The improved efficiency of the 800-V OBC reference design reduces power losses during electric-vehicle (EV) charging, resulting in higher efficiency and lower cost.

The OBC combines a three-level flying capacitor topology for a bridgeless totem-pole PFC structure and a dual active bridge in the AC/DC and DC/DC, respectively. The GaN transistors, offering high switching performance, reduce the transistor voltage stress to half and allow the 650-V GaN to be used in many 800-V applications, GaN Systems said.

The company said using GaN transistors in an 800-V OBC is a “revolutionary innovation that sets this 11-kW/800-V solution apart from competitors” and is a “game-changing solution.”

Key features include an AC/DC stage peak efficiency of >99%, a DC/DC stage peak efficiency of >98.5%, lower total semiconductor power loss and minimized gate ringing, as well as lower noise and ringing during switching transitions. It also offers improved thermal performance by using an IMS interface.

By reducing switching losses and power dissipation during operation, GaN power semiconductors increase the efficiency of the OBC by reducing power losses during EV charging, GaN Systems said. One benefit cited is a reduction in the complexity and cost of the cooling system, which helps reduce the size and weight of the OBC. As a result, this size and weight savings can be allocated to other areas of the EV design.

Innoscience Technology has launched the first in a new family of SolidGaN integrated GaN devices. The ISG3201 is a complete half-bridge circuit including two 100-V 3.2-mΩ InnoGaN HEMTs and the necessary driver circuitry in an LGA package, measuring 5 × 6.5 × 1.1 mm.

The new solution offers designers a choice between using a discrete solution and a new integrated approach for simplifying the power stage layout, Innoscience said.

The ISG3201 SolidGaN half-bridge consists of two 100-V 3.2-mΩ e-mode GaN HEMTs with a driver, driving resistor and bootstrap and VCC capacitors. Key features include a 34-A continuous-current capability, zero reverse-recovery charge and ultra-low on-resistance (R_DS(on)). “Thanks to the high level of integration, the gate loop and power loop parasitics are kept below 1 nH,” the company said, and “as a result, voltage spikes on switching nodes are minimized.”

The integrated ISG3201 can save up to 20% PCB space on discrete GaN designs and 73% board space on traditional Si implementations, according to the company. Target applications include high-frequency buck converters, half-bridge or full-bridge converters, Class D audio amplifiers, LLC converters and power modules.

The company plans to launch additional products this year, including half-bridge circuits with different voltage ratings.

Navitas Semiconductor also announced a few advances with the launch of a new family of GaNSense Control ICs, which are integrated with the company’s high-performance GaN ICs.

The initial range of GaNSense Control devices features high-frequency quasi-resonant flybacks supporting QR, DCM, CCM and multiple-frequency, hybrid-mode operations, with frequencies up to 225 kHz. These devices are provided in two package options: a single, surface-mount QFN package (NV695x-series) or as a chipset (NV9510x + NV61xx) for greater design flexibility. On the secondary side, integrated synchronous rectifier power ICs (NV97xx) offer maximum efficiency at any load condition compared with conventional rectifiers, the company said.

Features including loss-less current sensing, high-voltage startup, frequency hopping, low standby power and wide VDD input voltage contribute to more efficient and cool-running systems with fewer components and no RSENSE hotspot, Navitas said. The devices also integrate protection features including 800-V transient voltage and 2-kV ESD as well as overvoltage, overcurrent and overtemperature protection.

Initial applications cover 20–150 W, including smartphone, tablet and laptop chargers, consumer and home appliances, point-of-sale, and auxiliary supplies in high-power data center power and 400-V EV systems. In the future, the company will target higher-power applications in renewable energy, energy storage and EVs.

Also addressing control ICs, Rohm Semiconductor has developed an ultra-high–speed control IC technology that is said to deliver higher energy savings and miniaturization by combining GaN devices and control ICs.

Rohm said the speed of the control ICs, which drive the GaN devices, has becoming challenging, resulting in the company’s development of its Nano Pulse Control ultra-high–speed control IC technology. The new technology reduces the control pulse width to 2 ns, compared with the conventional 9 ns, thanks to a unique circuit configuration, thus maximizing the performance of GaN power ICs. This enables the devices to step down from high voltages up to 60 V to low voltages down to 0.6 V with a single power supply IC in 24-V and 48-V applications.

In addition, to further miniaturize the power supply circuit, “it’s also necessary to reduce the size of the peripheral components through high-speed switching,” and that “requires a control IC that can take advantage of the drive performance of high-speed switching devices like GaN devices,” Rohm said.

Smaller drive peripheral components for high-frequency switching of GaN devices decreases the mounting area by approximately 86% over conventional solutions when combined with Rohm EcoGaN GaN devices.

The commercialization of the control ICs using the new technology is underway. The company plans to start sample shipment of 100-V, one-channel DC/DC control ICs in the second half of 2023. Used in combination with Rohm’s EcoGan series, it is expected to result in significant energy savings and miniaturization for a variety of applications, including base stations, data centers, factory automation equipment and drones.

SiC devices improve

SiC device manufacturers also announced several improvements. For example, Qorvo Inc. introduced a new surface-mount TO-leadless (TOLL) package for its 5.4-mΩ 750-V SiC FETs. It is the first product in a family of 750-V SiC FETs that will be released in the TOLL package with R_DS(on) ranging from 5.4 mΩ to 60 mΩ. Applications include AC/DC power supplies ranging from several hundreds of watts to multiple kilowatts, as well as solid-state relays and circuit breakers up to 100 A.

In the TOLL package, the Gen 4 SiC FET 5.4-mΩ devices have a 4× to 10× lower R_DS(on) than competing best-in-class Si MOSFETs, SiC MOSFETs and GaN transistors, Qorvo said. The 750-V rating is also 100–150 V higher than the alternative technologies, which provides a higher design margin for managing voltage transients, the company added.

The Gen4 SiC FETs use Qorvo’s unique cascode circuit configuration, in which a SiC JFET is co-packaged with a Si MOSFET, which combines the efficiency advantages of WBG switch technology and the simpler gate drive of Si MOSFETs.

The TOLL package offers a 30% smaller footprint and half the height at 2.3 mm compared with alternative D2PAK surface-mount devices. Despite the smaller size, the devices also achieve 0.1°C/W thermal resistance from junction to case thanks to advanced manufacturing techniques.

The DC current rating is 120 A up to case temperatures of 144°C, while the pulsed current rating is 588 A up to 0.5 ms.

Qorvo said the combination of the ultra-low R_DS(on) and excellent transient thermal behavior results in an “I²T” rating about 8× better than a Si MOSFET in the same package, which helps with robustness and immunity to transient overloads while also simplifying the design. A Kelvin source connection is provided in the TOLL package for reliable high-speed switching.

Cissoid and Silicon Mobility announced a partnership to develop a modular SiC inverter reference design that supports electric motors up to 350 kW/850 V. The reference design leverages Cissoid’s high-voltage SiC-based power module, integrated gate-driver board and control board and Silicon Mobility’s ultra-fast OLEA T222 field-programmable control unit, DC and phase-current sensors, DC-link capacitor and EMI filtering with integrated liquid cooling.

Under the partnership, Cissoid will also sell Silicon Mobility’s OLEA App Inverter Software for EV powertrain control, providing customers with a complete SiC inverter reference design and development platform. The fully integrated reference design is expected to simplify the design process and reduce time to market. The company will also provide technical support to integrate the inverter into the end application.

Once the design is completed, customers can either purchase the entire inverter BOM from Cissoid or just the SiC intelligent power module and control board, allowing them to buy the other components and inverter housing from their preferred suppliers. Customers can integrate the inverter into their motor-drive system before moving to production, Cissoid said.

Power devices

Power IC makers also unveiled several new higher-performance products designed to help simplify design. One example is Alpha and Omega Semiconductor Ltd.’s duo of new protection switches for Type-C extended power range (EPR) 3.1. The AOZ13937DI Type-C sink and AOZ15333DI Type-C source protection switches enable safe implementation of USB Type-C PD3.1 EPR up to 140 W.

The AOZ13937DI is suited for 28-V Type-C sinking applications, while the AOZ15333DI is capable of Type-C sourcing applications. Both the sink and source switches can increase the power-delivery capability of USB Type-C ports up to 140 W. Target Type-C EPR implementations include high-performance laptops, personal computers, monitors and docking.

The AOZ13937DI is designed to isolate and protect downstream components from abnormal VBUS voltage and current conditions. Key features include an ultra-low 20-mΩ resistance with programmable soft-start as well as overvoltage, short-circuit, overcurrent, overtemperature and ESD protection.

It also includes ideal diode fast reverse-current protection, which allows multiple power paths to be connected in parallel without interference, the company said. Other features include a 3.3-V to 32-V operating temperature and a 7-A continuous-current capability: 18 A peak for 10 ms @ 2% duty cycle.

The AOZ15333DI companion source switch IC is capable of sourcing 5 V @ 3 A while blocking up to 28 V. It is UL 2367– and IEC 62368-1:2018 (3rd Edition)–certified as a current-limiting switch. The device is protected against numerous fault conditions, such as V_IN overvoltage protection, startup short-circuit protection and overtemperature protection, and has a programmable ILIMIT pin.

Other features of the AOZ15333DI include an operating temperature range of 3.3 V to 5.5 V, 3.5-A current capability and true reverse-current blocking. It offers a 45-mΩ R_DS(on) in a DFN3×3-12L package.

Both the AOZ15333DI and AOZ13937DI are available in production quantities with a lead time of 16 weeks.

Analog Devices Inc. (ADI) launched an ultra-low–noise dual-output DC/DC μModule regulator for noise-sensitive applications. Operating from up to a 40-V input, the LTM8080’s front end is a high-efficiency synchronous Silent Switcher step-down regulator with two low-noise, low-dropout (LDO) regulators. The integrated Silent Switcher architecture minimizes EMI emissions and enables the device to pass CISPR22 Class B and CISPR25 Class 5 without an input filter, ADI said.

For further noise-switching suppression, the packaging of the LTM8080 integrates an EMI barrier wall or shield. The result is low noise values of <1 µVRMS (10 Hz to 100 kHz), 2-nV/√Hz (10 kH) spot noise and 80-dB PSRR (100 kHz), ADI said.

In addition, the LTM8080 reduces output ripple voltage by up to 70% for a simplified and quiet design, compared with discrete solutions without an EMI shield. The LTM8080 is designed to power digital loads that are susceptible to switching regulator noise, such as data converters, RF transmitters, FPGA I/O and clock, op amps, transceivers and medical scanners.

The devices offer a dual 500-mA or single 1-A output current and are parallelable for lower noise and higher current. Other features include an adjustable switching frequency (200 kHz to 2 MHz), selectable operation modes to minimize the risk of frequency interference, a 0-V to 8-V output voltage range, voltage tracking to minimize power loss and 100-μA SET pin current with ±1% initial accuracy.

The LTM8080EY#PBF and LTM8080IY#PBF are in full production. They are housed in 9 × 6.25 × 3.32-mm BGA packages.

Discrete semiconductors

Discrete semiconductor manufacturers also rolled out new devices aimed at shrinking board space, increasing power density and reducing cost in power applications. A few examples include new products from Nexperia, onsemi and Taiwan Semiconductor.

Nexperia has released its first 80-V and 100-V application-specific MOSFETs (ASFETs) for hot swapping with enhanced safe operating area (SOA) in a small 8 × 8-mm LFPAK88 package. The ASFETs are suited for hot-swapping and soft-start applications and are qualified to 175°C for use in advanced telecom and computing equipment. The company first introduced its ASFET devices in 2020, with optimized features for specific applications.

The new additions include the PSMN2R3-100SSE (100 V, 2.3 mΩ) and the PSMN1R9-100SSE (80 V, 1.9 mΩ). The PSMN2R3-100SSE offers a low R_DS(on) of 2.3 mΩ, which is at least a 40% reduction on currently available devices and high linear-mode (SOA) performance, meeting requirements for hot-swapping applications, Nexperia said.

The 40% lower R_DS(on) results in higher power density of 58×, while the smaller package delivers 2× higher I_D (max) current rating and ultra-low thermal and electrical resistance, the company said.

The PSMN1R9-100SSE targets 48-V power rails in computing servers and other industrial applications in which environmental conditions allow for MOSFETs with a lower BVDS rating, the company said.

Strong linear-mode performance is essential to manage in-rush current when capacitive loads are introduced to the live backplane, Nexperia said, while low R_DS(on) is important to minimize I²R losses when the ASFET is fully turned on.

Nexperia said that even with the low R_DS(on) and small package, the third generation of its enhanced SOA technology achieves a 10% SOA improvement compared with previous generations in D2PAK packages (33 A versus 30 A @ 50 V @ 1 ms). In addition, the LFPAK88 package offers a 60% space savings versus the D2PAK.

The new ASFETs for hot swapping also have fully characterized SOA at both 25°C and 125°C, with hot SOA curves provided in the datasheets, so design engineers don’t have to perform thermal derating calculations.

Onsemi introduced a new range of ultra-efficient 1,200-V insulated-gate bipolar transistors (IGBTs) that minimize conduction and switching losses for industrial markets. Aimed at improving efficiency in fast-switching applications, the new devices target energy infrastructure like solar inverters, uninterruptible power supplies, energy storage and EV charging power conversion.

Onsemi focused on reducing the turn-off switching losses and providing the best switching performance in these devices to meet the high-efficiency requirements in high-switching–frequency energy infrastructure.

The low switching losses of the new 1,200-V Trench Field Stop VII (FS7) IGBTs are said to enable higher switching frequencies that reduce the size of magnetic components, increasing power density while reducing system cost. In addition, the positive temperature coefficient of the FS7 devices enables easy parallel operation for high-power energy-infrastructure applications, onsemi said.

The FS7 devices include high-speed (S-series) and medium-speed (R-series) options. All devices include an optimized diode for low V_F and tuned switching softness and can operate with junction temperatures up to 175°C.

The S-series devices, such as the FGY75T120SWD, are said to offer the best switching performance among currently available 1,200-V IGBTs in the market. They are tested with currents up to 7× the rated value and offer best-in-class latch-up immunity.

The R-series targets medium-speed switching applications, such as motor control and solid-state relays. For example, the FGY100T120RWD shows a V_CE(SAT) as low as 1.45 V at 100 A, an improvement of 0.4 V over previous-generation devices, according to the company.

The FS7 devices are available in several packages, including TO247-3L, TO247-4L, Power TO247-3L and as bare die for greater design flexibility.

Taiwan Semiconductor Corp. has expanded its line of fast-recovery epitaxial diodes (FREDs) that now include 600-V devices. The new PUUPxJ Series are SMPC4.6U-packaged wettable flank devices that offer high efficiency and power density for applications like switching power supplies and power conversion, DC/DC converters, battery-charging systems and offline LED lighting power supplies, snubbers and freewheeling diodes.

The series offers a maximum repetitive reverse-voltage (V_RRM) rating of 600 V with selectable device current ratings of 3 A/600 V, 6 A/600 V, 8 A/600 V, 10 A/600 V and 12 A/600 V. These 600-V FREDs are also said to exceed stringent AEC-Q100 automotive requirements for reliability and manufacturability. AEC-Q100 qualification is in progress.

The devices feature low reverse leakage, which improves efficiency and offers a more controlled switching response between forward- and reverse-conduction modes, TSC said. They also offer low reverse-recovery charge, which lowers the parasitic ringing and EMC, reducing the need for snubbers, along with increasing switching speed and lowering losses.

These devices are RoHS-, WEEE- and REACH-compliant and are halogen-free. They also meet California Prop. 65 and JESD-201 Class 2 Whisker Test.