Test method for characterizing currents associated with powered components in an electronic system

#Current draw characterizations of semiconductor power components (e.g., a semiconductor die) within electronic systems have always been difficult to determine. Such characterizations are however needed to appropriately design cooling and power solutions in the system design. By way of example, electronic systems often include thermal dissipation elements, such as heat sinks, to counter heat-generating components such as power supplies and microprocessors. To ensure proper thermal dissipation, the design of the system's heat dissipation capacity is often made to over-compensate uncertainties in power consumption and dissipation relative to the heat-generating components. In one example, a power supply may be rated to a specified power dissipation; however this rating may not represent the actual performance of the supply in operation within the system. In another example, electronic system designers sometimes take temperature measurements of prototype devices and then perform calculations to predict future thermal loads within production systems; however, this technique also does not provide actual performance accuracy during operation because the power characterizations for individual components are not accurately known. Moreover, in this latter example, temperature measurements may be made for several components within the electronic system, causing cumulative errors in the thermal dissipation and power consumption estimates.

#Accordingly, electronic systems are designed with certain thermal dissipation over-capacity to account for actual heat generation within the systems. Likewise, such systems are designed with certain power supply over-capacity to account for current draw and power variations for individual components of the systems. These over-capacities represent an increased cost of manufacture, such as the production cost for the heat sinks and power distribution components within the electronic system; in the world of highly competitive electronic computers and components, increased costs may make the underlying product uncompetitive.

#The invention provides techniques and methods for improving estimation and measurement of transient and steady-state current draw for components within electronic systems. One feature of the invention is to provide methods for designing power and/or cooling solutions for electronic systems. Other features of the invention will be apparent within the description that follows.

#A more complete understanding of the invention may be obtained by reference to the drawings, in which:

#FIG. 1 shows a top view of one current estimation system of the invention;

#FIG. 2 shows a cross-sectional side view of the current estimation system of FIG. 1 and coupled to a power component;

#FIG. 1 shows a top view of one current estimation device 10 of the invention; FIG. 2 shows a cross-sectional side view of device 10, and additionally coupled with a heat sink 32. Device 10 couples with an electronic system 12 including a printed circuit board 14. Printed circuit board 14 has a plurality of vias 16. Certain vias 16 connect to a ground plane 21; certain other vias 16 connect to a power plane 20. A power source 18 connects to power plane 20 to provide system power. Power source 18 may further connect to ground plane 21, as shown; and, though not required, ground plane 21 may further connect to a system ground 19. A power component 22 (shown as a transparent outline in FIG. 1, for purposes of illustration) couples with printed circuit board 14 and operates by obtaining power and ground through vias 16. By way of example, power component 22 may be a semiconductor die and package attached to circuit board 14 by conductive solder joints or sockets 24. One or more pins of component 22 may further connect to system power source 18 by a conductive connection 26A with an appropriate via 16A, which in turn connects with power plane 20 as shown. One or more pins of component 22 also may connect to ground (e.g., system ground 19 and/or other terminal 23 of power source 18) by a conductive connection 26B with an appropriate via 16B, which in turn connects with ground plane 21 as shown. Connections 26A, 26B may be solder or socket connections known in the art.

#Device 10 also includes at least one electrically conductive loop 28 that surrounds, at least in part, at least one relevant via 16A, 16B; for purposes of illustration, loop 28 is shown to surround via 16A. One or more additional electrically conductive loops 28A may surround a like number of additional vias 16C, such as shown; the additional loops 28A are typically included with device 10 to accommodate additional power components 22A or additional power and/or ground vias 16. A power component 22 may have multiple connections to the ground and power planes 21, 20 in order to ensure appropriate current capacity.

#In operation, device 10 characterizes current behavior of component 22 by measuring the current through loop 28. By way of example, transient and/or steady-state current behavior of the associated via 16A may be determined from the measured current. Voltage behavior may also be assessed. Accordingly, a measuring device such as an ammeter 30 couples with loop 28 to assess current behavior. The measured behavior may be converted to power dissipation by a conversion equation VI, where I is the current in via 16A and V is the voltage between ground and power planes 21, 20.