Isolated Synchronous Half-Bridge DC/DC Controller Provides Greater Than 90% Efficiency at 500 kHz for Step-Down Power Conversion; Two-Chip Solution Saves on Components for Servers and Telecom Power Supplies.MALVERN, Pa. -- Vishay Intertechnology Inc. (NYSE NYSE See: New York Stock Exchange : VSH VSH Vegetarian Society of Houston (USA) VSH Vertical Split Head (railway defect) VSH Video Sensor Head VSH Virus Shield VSH Virtual Software House VSH Virtual Switch Header ) today released a new 500-kHz half-bridge dc-to-dc controller and synchronous rectifier rectifier, component of an electric circuit used to change alternating current to direct current. Rectifiers are made in various forms, all operating on the principle that current passes through them freely in one direction but only slightly or not at all in the driver that work together as a chipset A group of chips designed to work as a unit to perform a function. For example, a modem chipset contains all the primary circuits for transmitting and receiving. A PC chipset provides the electronic interfaces between all subsystems (see PC chipset for illustration). to enable more efficient 25-W to 300-W telecom and computer power supplies. The new Si9122A half-bridge controller and SiP11203/11204 secondary synchronous rectifier driver offer greater than 90% dc-to-dc conversion efficiency -- even for output voltages below 3.3 V -- in power supply modules and network cards for fixed telecom systems, central office switching equipment, distributed power systems, intermediate bus converters and brick converters. Links to product datasheets: www.vishay.com/doc?73492 (Si9122A) www.vishay.com/doc?73868 (SiP11203 and SiP11204) Si9122A Half-Bridge Controller Designed to operate within the fixed telecom voltage range of 36 V to 75 V and withstand 100-V, 100-ms transients, the Si9122A is capable of controlling and driving both the low and high-side switching devices of a half-bridge circuit and the synchronous rectifier MOSFETs on the secondary side of the bridge. The Si9122A uses a pulse transformer transformer, electrical device used to transfer an alternating current or voltage from one electric circuit to another by means of electromagnetic induction. to drive these low-on-resistance secondary MOSFETs, enabling much better conversion efficiency compared to implementations using Schottky diode The Schottky diode (named after German physicist Walter H. Schottky; also known as hot carrier diode) is a semiconductor diode with a low forward voltage drop and a very fast switching action. rectifiers. On-chip control of the dead-time delays between the primary and secondary synchronous signals keeps efficiencies high and prevents shorting of the power transformer. An external resistor resistor, two-terminal electric circuit component that offers opposition to an electric current. Resistors are normally designed and operated so that, with varying levels of current, variations of their resistance values are negligible (see resistance). sets the switching frequency from 200 kHz to 500 kHz. Advanced monitoring and control circuitry in the Si9122A enables users to set the maximum current in the primary circuit and allows the system to operate a constant current into a short circuit. This same circuitry also provides constant current into large capacitive loads during start-up or when paralleling multiple power supplies. The Si9122A is available in TSSOP-20 or MLP (Meridian Lossless Packing) The compression technique used in DVD-Audio that provides the highest audio quality. It delivers two channels at 192 kHz with 24-bit samples or six channels at 96 kHz. 65-20 packages. SiP11203 and SiP11204 Secondary Synchronous Rectifier Drivers The SiP11203/11204 integrate seven functions typically implemented with discretes in isolated converters: the synchronous rectifier drivers, the error amplifier, the precision voltage reference A voltage reference is an electronic device (circuit or component) that produces a fixed (constant) voltage irrespective of the loading on the device, power supply variation and temperature. , the opto-isolator driver, control of the start-up, control of the shutdown and overvoltage protection. As such, they enable a simpler compact power supply module when used in conjunction with the Si9122A and other isolated dc-to-dc controllers. The SiP11203/11204 and Si9122A interface via a pulse transformer to provide isolated control of the synchronous MOSFETs. The error signal, supplied by the SiP11203/11204, is fed to the Si9122A via an opto-isolator. Together, the transformers and the opto-isolator provide isolation between the input and the output. Both ICs are capable of being powered via conventional bias supplies (output inductor inductor, electric device consisting of one or more turns of wire and typically having two terminals. An inductor is usually connected into a circuit in order to raise the inductance to a desired value. winding or power transformer winding), or from the same pulse transformer supplying the gate timing signals, and both parts generate a regulated supply for powering the error amplifier and control circuitry. The two product versions provide a choice of synchronous rectifier turn-off (SiP11203) or turn-on (SiP11204) in the event of an overvoltage condition. During power-up, the SiP11203/11204 ensure that the synchronous rectifiers are held off until the supply voltages are sufficient to guarantee effective operation of the driver circuits. During the soft-start interval, a gradual ramp-up of the synchronous rectifier conduction conduction, transfer of heat or electricity through a substance, resulting from a difference in temperature between different parts of the substance, in the case of heat, or from a difference in electric potential, in the case of electricity. time is assured. The ICs also allow control of the discharge rate of the synchronous rectifier driver outputs during power-down. Both devices are rated for a 5.5-V to 13-V operating range, feature a regulated internal logic voltage of 5 V and provide a 2.2-A source and 4-A sink drive capability. They are designed for high-current applications in any topology topology, branch of mathematics, formerly known as analysis situs, that studies patterns of geometric figures involving position and relative position without regard to size. requiring secondary-side drivers. Each driver is available in a compact MLP44-16 package. Availability Samples and production quantities of the Si9122A and SiP11203/4 are available now, with lead times of eight weeks for larger orders. Vishay Intertechnology Inc., a Fortune 1,000 company listed on the NYSE (VSH), is one of the world's largest manufacturers of discrete semiconductors (diodes, rectifiers, transistors, and optoelectronics and selected ICs) and passive electronic components (resistors, capacitors, inductors, sensors and transducers). Vishay's components can be found in products manufactured in a very broad range of industries worldwide. Vishay is headquartered in Malvern, Pa., and has operations in 17 countries employing more than 26,000 people. Vishay can be found on the Internet at http://www.vishay.com. |
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