power

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CREA - SEMICONDUCTOR TEST EQUIPMENTS

 

Power is defined as current multiplied by voltage:

P=Vx I
where P is the power measured in watts (W) (also joules per second), V is the steady state voltage measured in volts (V), and I is the steady state current measured in amps (A).

Energy is defined as current multiplied by voltage, multiplied by time:

E=IxVxT
where "E" is the energy measured in joules (also watt-seconds), "V" is the instantaneous voltage measured in volts, "i" is the instantaneous current measured in amps, and "T" is the time period measured in seconds.

To calculate power, given energy and frequency, multiply energy by the frequency. For example, if an IGBT has a total switching energy loss of 1.4mJ under a given set of operating conditions, and is operated at 20kHz, the total power loss due to switching will be 28W.
E (1.4mJ) x f (20kHz) = P (28W)

power BiMOS

Circuits with the capability of interfacing higher voltages and current levels than conventional BiMOS circuits. See BiMOS. An advanced Intersil wafer process that combines analog, digital and power capabilities in a single IC. This Double-Layer-Metal (DLM) process is being developed in Findlay, Ohio. It features complementary vertical MOS power output transistors and 16V operation to support commercial and industrial applications in plastic packages. See DLM.

power control circuit

System power supply control functions and output drive, allowing electronic systems to do actual work for such diverse applications as motors, video, and computer disk drives. Examples of Intersil power control ICs are voltage regulators, rectifiers, and high current drivers.

power discrete

See discrete device and intelligent discrete.

power MOSFET

A MOSFET circuit capable of handling current ratings of more than 1 ampere. Intersil power MOSFETs have current-handling capabilities as high as 100A and voltage-handling capabilities up to 1200V. See MOSFET.

power transistor

A transistor capable of being used at current ratings of more than 1 ampere. Intersil bipolar and MOS power transistors have current handling capabilities up to 100A and voltage handling capabilities to 1200V.

Direct current (dc) has a constant magnitude. In contrast, alternating current (ac) has a magnitude dependent on time. it follows a sinusoidal waveform, shown below. ac is generated by moving a copper winding through a magnetic field. This causes a voltage to be developed on the winding. Generators in the United States operate at 60Hz, but many places in the world, 50Hz is the standard.
Hz is the abbreviation for Hertz, which is the unit of measure for frequency.
Frequency is only defined for regular waveforms that repeat indefinitely. Frequency is how many times per second the same position on the waveform occurs. Thus, in the figure below, sixty peaks will pass in one second if the frequency is 60Hz. T is the period, while 1/T is the frequency.

Nearly all current starts off as ac, which is generated through an electromechanical process, and is then converted to dc. It is difficult to generate dc directly, as it requires either a dynamo or a chemical reaction such as the one within in a solar cell which converts sunlight into dc voltage. In applications where dc is present, there is usually a nearby ac source. For example, in your automobile the battery that drives the lights, all the electronics, and all the motors are typically 12 volts dc. This battery is charged by the alternator which is basically a small generator driven by the engine. A three-phase diode bridge is responsible for converting the ac output of the alternator to be compatible with the dc battery.

The last important concept is the role of frequency on magnetics. It is beyond the scope of this training module to explain why, but as the operating frequency of a circuit increases, the physical size of the magnetics (remember this means both inductors and transformers) shrinks. This is one of the reasons designers are constantly increasing the frequency of their designs. In the power supply world, one of the benchmarks of a design is how many watts per cubic inch the power supply delivers. One way to substantially increase this number is by moving to higher frequency, and hence, physically smaller magnetic components. The tradeoff of higher frequency operation is increased switching losses in the semiconductor devices, whether it be a diode, IGBT, or power MOSFET.

 

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