NewsSiC Enables High–Power Density in a Compact Package

SiC Enables High–Power Density in a Compact Package

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Apex Microtechnology has developed a range of devices that have integrated silicon carbide (SiC) MOSFET technology that improves the power density and performance.

Applications for power are shifting to devices with smaller footprints and greater efficiency. To boost efficiency, power, that lets the device be contained in a smaller size, SiC is a good alternative to silicon for power modules and discretes. Because of their superior performance that SiC MOSFETs have, they are widely employed in power applications in where high switching frequency as well as voltage, current and efficiency are needed.

Their capability to function at higher temperatures than those exhibited by silicon additionally allows SiC devices to have greater thermal control This is a further benefit to reduce the size of the die.

Silicon-based high-power components and modules generally require cooling solutions that rely on large heatsinks which can impact the overall size of the solution. However, SiC gives the opportunity to offer unimaginable power density levels in compact footprints without the thermal management being compromised.

Silicon Carbide

In comparison to silicon SiC provides a number of advantages in terms of its lower resistance to on-resistance, both in relation to the current and temperature. A lower R DS(on) results in better current versus voltage performance as well as lower switching losses. Although the price of SiC is more expensive than silicon, its less heat load, simplified cooling, and better reliability make up for the disadvantage.

Beginning with these points, Apex — a supplier of high-power analog monolithic hybrid and open-frame components that are suitable for many industrial testing and measurement as well as aerospace, medical semi-cap, as well as military applications — has developed new products that exploit the characteristics of SiC. The products include the SA110 half-bridge switching module that incorporates a gate driver, as well as the SA310 three-phase power-switching system with built-in gate driver.

A well-designed design can effectively showcase the various features of SiC. When developing its high-power products, Apex has carefully considered the effects of parasitics (which can be greater than the resistance of the on) as well as trace inductance as well as trace resistance. Figure 1 depicts the block diagram for the Apex SA310KR, an three-phase power module based on SiC with an built-in gate drivers.

One of the toughest issues that Apex had to face Apex in the development of SiC-based power electronics was co-packaging the MOSFET driver and MOSFET gate drivers. Because of the high frequency of switching, which is the primary feature provided by SiC this speed of slew (di/dt) is extremely high. This requires careful routing of traces within the PCB layout, and avoiding the possibility of noise or interfering between adjacent tracer (crosstalk).

Furthermore that, when the switching frequency is higher the skin effect can be not insignificant, since it reduces the effective cross-sectional size of the output and input connections, thereby increasing their electrical resistance. The potential problems have been resolved by Apex through the use of a sophisticated thick-film technology for the substrate, printing the traces twice to make them more dense and lessen their impedance.

A additional benefit of Apex’s copackaging solution is the fact that gate driver circuits are placed near to the SiC MOSFETs, thereby reducing the influence of inductance within the gate. This effect becomes noticeable at higher switching speeds. In addition, by paying attention to packaging, thermal pathways, and the materials used, Apex is able to attain an excellent thermal control as per Apex. This allows, for example the SA110 to release the power of 89 W and operate within a temperature range of 40°C to 125°C.

The SA110, offered in a compact footprint 12 pin Power SIP (DP) packaging, comes with an integral gate drive controller, an extremely high (400-kHz maximum) speed of switching, as well as the ability to output 28 amps continuously in the A-grade version. It is ideal for applications like AC/DC and DC/DC converters as well as Power factor correction (PFC) and motor drives.

The SA310 comes in a 16-pin Power DIIP (KR) device, consists of three isolated half-bridges that are independent, that can provide up to A peak current output under the direct microcontroller, and DSC control. It is built on a thermally-conductive yet electrically isolated surface, which provides the greatest flexibility and efficiency in heatsinking. The SA310 is able to meet the needs of various applications, including motor controls (BLDCs) and AC/DC converters, variable frequency drives test equipment, power inverters as well as MRI main coil supply.

Both devices offer protection functions including an undervoltage lockout in addition to active Miller clamping, which helps to reduce the noise of switching and enhance reliability.

Apex SA111

The Arizona-headquartered company has recently announced the SA111, a SiC-based high-power half-bridge module that delivers high levels of power density in a compact proprietary PQ package.

The SA111 is offered with an SMD package that measures only 20 x 20 millimeters The SA111 (Figure 2.) is able to provide constant output currents up to 32A, handle supply voltages as high as 650V and reach switching frequencies as high as 1 MHz (remaining within the safe operating range). The surface-mount device has an extremely high thermal efficiency as well as top-side cooling. This allows users to maximize the layout of the board by placing the heatsink over the device.

Figure 2: The new Apex SA111 (Source: Apex Microtechnology)

Its SiC half-bridge power unit is an perfect solution for projects such as MRI magnet bearings, gradient coil drive motor drives testing equipment, server fan, PFC, AC/DC, or DC/DC converters. SiC MOSFETs additionally allow the SA111 to endure greater thermal stress, allowing junction temperatures up to 175°C.

With the integrated gate driver an undervoltage lockout, as well as active Miller clamping and active Miller clamping, the SA111 SiC Power Module offers an integrated device that provides greater security and control of the device. SiC enhances thermal management since less heat is produced and the module is less reliant to cool the module and the module may be smaller. The power supply for the module may be smaller and less efficient in dissipating heat, and could be more affordable also.

With its surface-mount design and its extremely small footprint the SA111 enables designers to maximize the space on their boards and allows the use of several devices in circuit designs that have the need for high power density. The SA111PQ is available in sample units. SA111PQ are available for customers who have qualified applications and a mass production to begin in the summer of 2022.

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Electronics and Telecommunications engineer with Electro-energetics Master degree graduation. Lightning designer experienced engineer. Currently working in IT industry.