Ti nods on smaller, more efficient satellites with Gan Fet Gate Triver

Texas Instruments (Ti) recently unveiled a family of Gallium Nitrid (GAN) Fet Gate drivers for space applications. These ICS were developed for Satellite Electrical Power Systems (EPS) and are the first GAN FET drivers of the so-called industry, which can support a company of up to 200 V.

The new Gan-Fet from Ti can support complex power supply systems for satellite computer needs.

Design challenges of satellites of electrical power supply systems

Satellite Electrical Power Systems (EPS) consist of various subsystems, including solar collectors, batteries, electricity conditioning and distribution units (PCDU) and backup power supplies. Satellite taverns often use synchronous bock, flyback or full bridge topologies.

Typical satellite power supply systems (EPS) contain several components with individual functions.

With these designs, PWM controllers and gate drivers usually have to operate the MOSFETS or GAN -FETS. In order to optimize the size, weight and performance (swap) of designs, satellite engineers require a special gate driver -ics that is qualified for radiation tolerance, high frequency, efficiency and electricity ratings. Ti aims to meet these strict requirements with its new ICS ICs (radiation hardness).

Room quality with high-voltage fet gate drivers

The new family gives two packaging options: the TPS7H60x5 series in plastic packaging and the previously available TPS7H60X3 series in ceramic packaging (linked data leaves). The Gan Fet Gate drivers support various voltage levels.

All devices can process a 1.3-a-top source current and a 2.5-A top-angle current.

Each device can be operated in two modes: an independent input mode (IIM) and a PWM mode. With the IIM, each output can be controlled by its own input. The PWM mode creates two complementary outputs from a single input with adjustable dead time for each edge. The drivers have an adjustable dead time, a delay in propagation of 30 NS and 5.5 NS typical delay adjustment. Internal LDOs can provide the 5 V drive voltage.

The plastic packages are tested on ASTM E595 and are available in military temperature ranges (-55 ° C-125 ° C). Ti has published accompanying support tools for the Gan Fet Gate driver, including evaluation modules, reference designs and simulation models.

GAN FETS optimized for space missions

The development of electronics for space offers unique restrictions. In contrast to terrestrial electronics, the room electronics with radiation protection must be produced. This applies in particular to satellites in Low Earth Orbit (Leo) and Geostationary Orbit (Geo). The space environment is filled with radiation of enclosed particles in the atmosphere caused by sun and cosmic rays. These particles can cause temporary or permanent damage to electrical components.

NASA lists two main categories of radiation damage. The entire ionizing dose (TID) is the long-term degradation of devices that are exposed to radiation, measured by resistance to a certain grady dosage (Si). One-event effects (lake) are different individual events that can occur when ionized particles hit one device. This is referred to by a linear energy transmission (LET) for destructive individual event effects (Dseer), measured in MEV CM2/mg. Space system designers have to select components that have been characterized in order to survive both the TID and the DSee profiles that are expected in their area.

The new plastic TPS7H60x5 series is available in radiant-hardened QMLP and radiation tolerant spatial amplifiers (SEP). The QMLP devices (TPS7H60X5-SP) are rated up to 100 Krad (Si) for TID and see free to get Let = 75 Mev-cm²/mg. The SEP devices (TPS7H60X5-SEP) are rated up to 50 Krad (Si) for TID and see free to get Let = 43 Mev-cm²/mg.

Radiation reproduction and the Swap Sweet Spot

The size, weight and power (SWAP) are further important considerations for space missions. Starting providers have size restrictions and can calculate from 1,000 to 10,000 US dollars per kilogram according to Ti. This means that the smaller the size and weight, the cheaper the mission. Satellites are based on solar modules for electricity generation. As such, batteries and panels often have to take a large part of the permissible size and weight budget. Designers often strive to optimize the swap as far as possible in order to extend the mission period.

Simplified application diagram of the TPS7H60x5-SP and TPS7H60X5-SEP.

These considerations clearly qualify for the room and offer inherent radiation tolerance and a lower dice size compared to typical scraps of silicon. Gamma radiation, a source of permanent damage in the room, can collide with the gate -oxide layer of FETS and create “holes” in this layer. This leads to voltage shifts that can reduce the performance of the transistor gate. Gan -Fets have no gate oxide layer, which is less susceptible to this form of damage.

Gan is also a wide band gap material, which means that the removal of drain sources can be made much smaller than silicon. These two functions make GAN-FEST-SICHT TIS TPS7H60X5-SP/TPS7H60X5-SEP and TPS7H60X3-SP-Familien-Used candidates for radiation hardness and smaller exchange.