Consumer demand for smaller form factor and higher power, plus government efficiency regulations, are driving innovation in the USB adapter market. The USB-C power delivery standards are a further driver for innovation in this market. The emergence of GaN-based devices in this market is one feature of the innovation.

The Oppo Reno Ace smartphone, launched in October of 2019, is powered by a 4000 mAh battery and supports their proprietary Super VOOC fast charging. Figure 1 shows a photograph of the inside of the back of the Reno Ace smartphone. Two 2000 mAh batteries can be seen.

Figure 1 Inside the Oppo Reno Ace (model PCLM10)

The VCA7GACH charger provided with the Oppo Reno Ace is able to drive 6.5 A and 10 V, giving a maximum 65 W power, apparently allowing the Reno Ace to be charged in half an hour. TechInsights has acquired samples and has subjected the charger to a detailed teardown analysis.

Figure 2 shows the VCA7GACH USB-C charger. The charger is 5.5 cm x 5.5 cm x 3.1 cm giving a power density of 11.4 W/in3, which is significantly higher than the density achieved by the Apple A1720 charger and comparable to that obtained by the RAVPower RP-PC104 USB-C charger.

Figure 2 Oppo Reno Ace Super V00C Charger (model VCA7GACH)

Figure 3 shows the front and backside of the main PCB found inside the VCA7GACH charger. Various inductors and capacitors are seen on the front side of the PCB, while a Power Integrations SC1923 device is observed on the backside of the PCB. The full list of the IC’s found in the VCA7GACH is shown in Table 1.

Figure 3 Oppo Reno Ace Super V00C Charger Main PCB

Table 1 Oppo Reno Ace Charger Design Wins

X-ray analysis of the Power Integrations SC1923 device shows that it contains four separate dies mounted in a conventional plastic lead frame surface mount package. Decapsulation reveals that the device contains the four dies listed in Table 2. The DX101C1 and DX121C are gate drive ASIC dies, the SB190C is a GaN power FET and the DX120B3 is a Si MOSFET that is driving the GaN power FET in a Cascode configuration.

Figure 4 Power Integration SC1923C Package X-Ray

Table 2 Power Integrations SC1923 Dies

A high resolution photograph of the SG190C die is presented in Figure 5, with the location of the source, drain and gate pads indicated. This die was almost certainly fabricated with Power Integrations PowiGaN process. Apparently, Power Integrations started developing this process in 2010, when they acquired Velox Semiconductor. Cross sectional analysis, shown in Figure 6, of the SG190C die reveals a three-aluminum metal process, fabricated on a GaN-on-Sapphire substrate. The use of a sapphire substrate is unusual in the power electronics market space, where most vendors are using GaN-on-Si substrates. It is likely that a benefit of the sapphire (Al2O3) substrate is higher quality GaN material with simpler epitaxial growth requirements, albeit with higher initial substrate costs. An aluminum nitride (AlN) gate dielectric is likely used beneath the metal gate, consistent with normally-on (depletion-mode) operations, as expected given the Cascode configuration.

Figure 5 Power Integrations SG190C GaN Die

Figure 6 Power Integrations SG190C GaN-on-Sapphire Die General Structure

TechInsights has now identified Power Integrations devices in three different USB charger devices. The Anker 30 W PowerPort Atom PD 1 charger was found to contain the Power Integrations SC1933C device with a SG250F GaN-on-Sapphire die. One version of the Aukey PA-U50 charger was found to contain a Power Integrations INN3166C device. The INN3166C did not contain a GaN-based die. Curiously, an earlier version of the Aukey PA-U50 was found by our lab to contain Navitas NV6252 devices. Finally, the VCA7GACH discussed here contains the SG190C GaN-based device.

TechInsights has recently procured samples of the Power Integrations INN3370C-H302-TL InnoSwitch3-Pro Family Digitally Controllable Off-Line CV/CC QR Flyback Switcher IC. Comparison of the package X-ray images followed by decapsulation of this device shows that the SC1923 found in the VCA7GACH charger from the Oppo Reno Ace can be identified to be the same as the INN3370C-H302-TL we procured.

Power Integrations market strategy is clearly paying off and they are almost certainly one of the leaders for the application of GaN-based devices in the USB adapter market. In October, they claim to have passed a milestone, having shipped over 1 million GaN-based devices to Anker.