The main topics of most discussions at the event were digital power and the improvement of power efficiency, also underlined by the new products released at the show. This article describes some of them in detail.
ABB Switzerland launched a new generation of high-power IGCTs (Integrated Gate-Commutated Thyristors) with substantially increased turn-off capability. The new generation, called High Power Technology (Figure 1), is capable of switching nearly 50% more current than the current series while still fitting within the mechanical dimensions of the currently produced devices. Initially, two new products will enter production in the 4th quarter of 2007: 5.5kA/4.5kV and 4.2kA/6.5kV; these will be followed in 2008 by a third device rated 5kA/5.5kV. The new generation exhibits increased turn-off at low temperature. Consequently, the datasheets will henceforth show a constant-current capability over the usual industrial temperature range of 0 to +125°C. This increased SOA (Safe Operating Area) has been achieved by both a new silicon design (which exploits some of the patented techniques developed for SPT IGBTs) and a completely new gate-driver design. IGCTs are supplied - by definition- complete with their gate units. This is possible because the gate unit is not used to control switching characteristics as is the case with IGBTs. Thus one gate-unit can be designed for a family of GCT devices, provided they are of the same mechanical dimensions.
Fairchild Semiconductor introduced the Green FPS e-Series (Figure 2), a new family of FPS (Fairchild Power Switch) products that provide high energy efficiency and system reliability in DVD-player, set-top-box, LCD-monitor and other 25W and lower power-supply designs. Based on the proprietary valley-switching technique, the Green FPS products raise power-conversion efficiency by 1% and reduce EMI up to 5dB compared to conventional hard-switch converter topologies. This valley-switching operation also enables these converters to perform soft switching, therefore increasing power-conversion efficiency by 1% while reducing heat generation. These highly integrated FPS devices combine the functionality of a fully avalanche-rated SenseFET, a current-mode PWM IC and various protection functions. Utilising advanced-burst-mode operation, the family's devices meet standby-power regulations by reducing standby-power consumption to below 0.2W at no load conditions (below 1W at 0.5W load). Designs employing these products provide system reliability and space benefits compared to discrete MOSFET/controllers, RCC switching converters, or conventional hard-switching solutions thanks to space-saving 8-lead DIP and 8-lead LSOP packaging and the inclusion of several sorts of protection circuitry. This circuitry includes OVP (over-voltage protection), OLP (over-load protection), AOCP (abnormal over-current protection) and TSD (thermal shutdown protection). Additional features include an integrated fixed oscillator, UVLO (under-voltage lockout), optimised blanking and gate turn-on/turn-off driver, and temperature-compensated precision-current sources for loop compensation. These products meet or exceed the requirements of the joint IPC/JEDEC standard J-STD-020C and are compliant with European Union regulations now in effect.
International Rectifier introduced a series of 200V ICs for low- and mid-voltage motor-drive applications, including power tools, lowvoltage servo drives, electric garden equipment, and electric vehicles such as cranes, golf carts, and scooters. The IRS200x family of half-bridge, high-side and low-side drivers is tailored for low-voltage (24, 36 and 48V) and mid-voltage (60, 80 and 100V) motor-drive applications, which include both three-phase inverter and half-bridge. UVLO protection is a standard feature provided across the family, while the IRS2003 and IRS2004 also include deadtime protection. In addition, the IRS2004 features a shutdown input pin. These new ICs feature low quiescent current that enables a low-cost bootstrap power supply for the high-side circuitry, eliminating the need for large and expensive auxiliary power supplies that discrete optocoupler- or transformer-based designs typically require. This makes them well-suited for low-voltage applications that require a small footprint. The devices are offered in 8-pin SOIC and DIP packages and feature gate voltage (Vout) up to 20V, typical turn-on current (Io+) of 290 mA, typical turn-off (Io-) current of 600 mA, and accept input-logic levels of 3.3, 5 and 15V.
National Semiconductor introduced a PoE (Power-over-Ethernet) PD (powered-device) controller (Figure 3) with an adjustable outputcurrent level and the ability to interface with any DC/DC converter topology. The LM5073 integrates a programmable interface port including a hot-swap controller that exceeds the standard IEEE 802.3af specifications, allowing designers to operate PoE appliances at power levels of 30W or more. For greater flexibility, the device separates the PD interface from the DC/DC converter to support a wide variety of isolated and non-isolated converter topologies. Applications include IP telephony, remote security cameras, card readers, wireless access points, PoE-enabled industrial-automation systems and point-of-sale terminals. Offered in a 14-pin TSSOP with an exposed pad for improved thermal performance, the controller integrates a 100V, 700mOhm, N-channel MOSFET as well as the PD signature and UVLO resistors. It also provides configurable front and rear auxiliary inputs that accept power from AC adapters to reduce the power draw on the PoE power-sourcing equipment. Complementary control outputs provide a flexible interface to the best power-conversion topology for the particular application.
Semikron introduces a 100% solder-free IGBT module for 22 to 150kW train-drive converters in electric and hybrid vehicles (Figure 4). SKiM has a temperature cycling capability five times higher than that of soldered modules. The solder-free pressure system and an internal laminated bus bar cause a homogeneous current distribution. Every IGBT and diode chip has its own connection to the main terminal. The result is a low module resistance of 0.3mOhm - in comparison, soldered modules feature approximately 1.1mOhm. The connection to the driver board is also solder-free with springs for high-temperature cycling and fast solder-free mounting. The chips are not soldered but sintered to achieve the high-power cycling capability. The sinter joint is a thin silver layer that has a thermal resistance superior to that of a soldered joint and that, due to the high melting point of silver, exhibits no joining fatigue; this leads to an increased service life. Since there is no base plate, the connection of the DCB to the heat sink has the ability to "move" with no limitation of temperature-cycling reliability. SKiM withstands the stringent automotive standards as it is highly resistant against shock and vibration stress. The packaging and connection technology of the module fully exploits the silicon capabilities, resulting in a cost-efficient solution. Two case sizes are available: SKiM 63 (120x160 mm2) and SKiM 93 (150x160 mm2).
Texas Instruments introduced the single-chip, interleaved, transition-mode PFC (power-factor-correction) control circuit that helps lower power system cost and save energy in consumer applications, such as digital TVs, personal computers and entry-level server platforms. The two-phase high-performance controller for 75 to 800W applications simplifies power-system design, minimises switching losses, and saves system cost and valuable board space compared to traditional single-phase, transition-mode topologies or CCM (continuous-conduction mode) topologies. The device meets the world's most stringent power-factor requirements for consumer electronic systems. It features Natural Interleaving technology, which reduces the amount of input- and output-current ripple, distributes magnetics to improve thermal management, and provides light-load phase management. The UCC28060's ripple-cancellation feature significantly reduces ripple current compared to single-phase or alternative master-slave interleaved solutions. In addition, the feature allows a designer to reduce capacitor size by 27% and it gives designers the ability to use a smaller, less expensive electromagnetic-interference filter. The PFC controller's light-load phase management enables a power supply to operate at high efficiency over the range of the load, enhancing system performance and aiding OEMs' efforts to achieve 80 Plus and Energy Star compliance. Phase management allows the user to turn on or off phases of the power supply so that only the phases required to power the load are enabled.
