BACKGROUND OF THE INVENTION

This invention relates to power delivery to electronic circuits in general and

more particularly to an improved power delivery system for supplying power to a power consuming module

Along with the development of higher levels of integration in integrated circuits, power requirements have increased. This is particularly true with current

microprocessor and associated integrated circuits or chips recently developed and

now being developed. These chips, which are operating at higher speeds, consume greater amounts of power than previously.

In a typical computer system, a large printed circuit board known as a

motherboard is provided The motherboard contains a certain number of basic

components and is supplied with voltage from a power supply, typically at a higher

DC level (e.g., 12 volts) than required by the components on the motherboard The motherboard includes connectors for daughter boards which can be plugged in to

provide different capabilities for the computer. Such boards, for example may provide an interface to disk drives and CD ROMs, modem interfaces for local area

networks, etc Typically, these circuits operate on the 12 volts which is on the board

or on reduced voltages of 5 volts Power consumption is not typically very high

Current processors however have been designed to operate at lower voltages, e.g., 3 3 volts Because of the increased capability and speed of these processors they consume a large amount of power despite their lower voltage Their operation at a

lower voltage requires a dc-to-dc power converter to reduce the voltage Typically, this dc-to-dc power converter is soldered to the mother board or plugs into a

connector on the motherboard The lower voltage is then conducted through

conductors or traces on the motherboard to a connector for the component requiring

the lower voltage, e.g., a processor This same connector also provides signal connections In current systems, one or more processors and in some cases associated chips are mounted on a board or module This module then plugs into the connector on the motherboard Since the voltage required by the processor is lower,

and the power consumption is high, the currents which must be supplied to the module become particularly large As a result, it is difficult to establish a low

resistance, low inductance path on the motherboard from the dc-to-dc converter

board to the multi-chip module. This is particularly true since the prior art

arrangement requires that the high current pass through two connectors, one from the dc-to-dc converter into the motherboard and another connector from the motherboard through the module connector to the module Also, the prior art

arrangement presents difficulties in manufacture because the dc-to-dc converter

becomes an additional component that must be tested with the remaining components

on the motherboard.

Thus, there is the need for an improved arrangement for delivering power to a power consuming module requiring high amounts of power at a lower voltage,

which voltage must be converted from a higher voltage

SUMMARY OF THE INVENTION

On a printed circuit board, e.g., a motherboard, a connector, e.g., a socket for

the power consuming module, e.g., a multichip module is provided This connector,

unlike connectors of the prior art, is only a signal connector, it does not provide power connections Spaced from this socket is a higher voltage connection, e.g. , a 12 volt power connector or a pair of contacts across which 12 volts is supplied

These connect to, for example, 12 volt and ground buses on the motherboard Also

provided on the printed circuit board, if necessary, are fasteners, e.g., spring clips, screws, etc , for holding a dc-to-dc converter A dc-to-dc converter within a housing

is provided and includes a pair of pins or contacts, to mate with the higher voltage

connector contacts on the board It has surfaces on the housing for engaging the

fasteners on the board, e.g., the dc-to-dc converter includes recesses on opposite

sides into which fasteners in the form of spring clips on the board snap Extending from the converter housing is a connector which may be rigidly or flexibly mounted,

to the converter housing The connector has contacts, to supply dc power at the

required reduced voltage level These may be upper and lower contacts The power consuming module includes power pads on one edge and plugs into the laterally

extending connector of the dc-to-dc converter so that contact is made along an

extended length For example, with a rectangular module, the power pads can extend

along one edge of the module The power pads connect to power planes on the

power consuming module In the illustrated embodiment these compose a ground

plane on one side and a voltage plane on the other side On its bottom surface, the

power consuming module includes contacts, e.g., pins which mate with the connector

on the board

BRIEF DESCRIPTION OF THE DRAWINGS

FIG 1 is a perspective view showing the major components of the present invention separated from each other

FIG 2a is a side and FIG 2b a top schematic view illustrating the power

planes of a module to which power is being supplied extending into the connector from the dc-to-dc converter

FIG 3 is a rear perspective view of the dc-to-dc converter of FIG 1 showing its higher voltage contacts

FIG 4 is a bottom perspective view of the multi-chip module of FIG 1 showing its pins and bottom power pad

FIG 5 is a perspective view showing the components of the present invention

in an assembled condition

FIG 6 is a cross section through the rear portion of the dc-to-dc converter

and motherboard showing the spring clip attachment and the contacting of the

contacts of the dc-to-dc converter with the contacts on the motherboard

DETAILED DESCRIPTION

FIG 1 is a perspective view illustrating the basic components which make up

the present invention The three basic elements are a motherboard 1 1 , a power

consuming module 13, and a dc-to-dc power converter 15 In the illustrated

embodiment, the module 13 is a multi-chip module However, the present invention

is equally applicable to a module with only one chip The converter 15 includes

conventional voltage conversion circuits within a housing having a rectangular cross

section The motherboard has mounted thereon a first connector 17 in the form of a socket for receiving pins 19 on the multi-chip module 13 The connector 17 is a

signal connector only As compared to prior art connectors, the number of pins

required on the power consuming module is reduced, thereby lowering the package insertion and removal forces required In the illustrated embodiment, the connector

is what is known as a PGA connector An LGA or BGA or other type connector

could equally well be used. In conventional fashion the connector 17 includes rows

of receptacles to receive pins along the lateral edges thereof Although the multi-chip

module 13 can contain any type of electronic component which requires large amounts of power, in a typical embodiment, this module will contain one or more

high speed processors and possibly associated circuits

Also mounted on the motherboard is a connector 20 with two terminals 21 and 23 into which mating pins may be plugged. Other types of connectors, including contacts directly on the motherboard 11 may be used as terminals. These terminals

connect to buses (not shown) on motherboard 11 and supply a voltage higher than

that required by the module 13, e.g., +12 volts and ground. The connector 20 is

spaced from the rear edge 25 of the connector 17 In the illustrated embodiment,

between the connector 17 and the connector 20 are fasteners 27 which can be in the

form of spring clips Other forms of fastening may also be used, if fasteners are

required The module 13 has upper and lower power planes, in the illustrated

embodiment, on its top and bottom surfaces 29 and 31 These terminate in planar

power pads 33 and 35 on the top and bottom surfaces of its rear lateral edge Other

arrangements are also possible such as side-by-side power pads, etc The key

requirement is a structure which provides a low inductance, low resistance current

path The dc-to-dc converter includes an extending connector 37 which can be mounted to the housing in a flexible or rigid manner This connector 37 has, for example, upper and lower contact surfaces which mate with the power pads 33 and 35 on the multi-chip module These upper and lower contact surfaces can be a power plane and a ground plane

This connection is further illustrated in the schematic views of FIGS 2a and b which are respectively a side view and top view of the dc-to-dc converter 15 and the module 13 illustrating schematically the manner in which the power planes 33a and

35a of the multi-chip module extend into the dc-to-dc converter contact surfaces 39 and 41 This results in an interconnect that is a contained, low resistance, low inductance path between the dc-to-dc converter and the multi-chip module Also,

power is advantageously provided to a power consuming module 13 through a

connector 37 that is separate and independent from the signal connector 17 The

increased dc currents to the power consuming module never flow on the motherboard Instead of two interfaces, there is a single interface connector and the power converter is separable from the motherboard

FIG. 3 is a view of the dc-to-dc converter 15 rotated such that the rear surface of its housing is visible As illustrated, it includes, at the back of the dc-to-dc converter, extending from the bottom of the housing thereof, pins 43 and 45 which

mate with the terminals 21 and 23 in the connector 20 when the dc-to-dc converter

15 is inserted onto the motherboard 1 1 The force of the pins 21 and 23 may be

sufficient to hold the dc-dc converter 15 in place However, in the illustrated

embodiment an additional fastener is also provided Thus, also visible in this view is one of the indentations or recesses 47 found on the sides of the dc-to-dc converter housing into which the spring clips 27 snap when the dc-to-dc converter is mounted

on the motherboard 1 1 The spring force of the spring clips holds the dc-to-dc

power converter securely on the motherboard 1 1 If fastening beyond that provided by the connector 20 and pins 43 and 45 is needed, alternative fasteners such as screws, can equally well be used In a manner known to those skilled in the art,

circuits in the dc-to-dc power converter 15 then convert this higher voltage to a

lower voltage which is supplied at its contacts 39 and 41 and thence to the power pads 33 and 35 of the multi-chip module.

FIG 4 is a view of the module 13 turned upside down so that the bottom

power pad 35 is visible along with the pins 19

FIG 5 is a perspective view showing the components assembled The

module 13, after having its edge inserted into the connector 37 has the pins 19 on the

bottom thereof inserted into the connector 17 As illustrated, this manner of

installing the dc-dc converter provides manufacturing advantages in that the dc-to-dc converter can be separately tested and simply inserted onto the motherboard, the need to construct and test the dc-to-dc converter on the motherboard is eliminated The dc-to-dc converter 15 is held in contact with the motherboard 11 by the spring

clips 27 engaging in the recesses 47 Although spring clips are illustrated, other forms of fastening are possible such as screws passing through tabs having

corresponding holes on the dc-dc converter, into threaded bores in the circuit board

As illustrated by the rear view of FIG 6, the fastening assembly described

above maintains the dc-to-dc converter 15 in good contact with the motherboard 1 1 , and prevents the connection between pins 43 and 45 and the terminals in connector 20 from being broken