ERICSSON POWER MODULES

3E – Enhanced performance, Energy management and increased End-user value with digital POL regulators

Ericsson Power Modules’ new digital POL (point-of-load) regulators establish an innovative approach to

reach the goals of end-user value, flexibility and system performance. These new power supply products

contain several unique concepts and features spanning the disciplines of mechanical packaging, electrical

design, control loop algorithms, power system architecture, power and energy management tools and lo-

gistics during system manufacturing and field support. These POL regulators are the first in a broader line of

Ericsson Power Modules’ digital power products, including isolated DC/DC converters, that will embody these

concepts and features. Because of the wide-ranging impact of these new designs and the resulting benefits

to the customer, it is important that prospective users understand the fundamental principles behind these

products. The user will discover that while the internal design of these POL regulators is quite advanced

relative to the now prevailing analog technology their flexibility is greatly increased and their application to

end-user products can actually be simplified relative to conventional POL regulators. This brochure will

focus on these benefits for the power system designer.

Ericsson Power Modules refers to the high-level end-user benefit of this design approach as “3E”,

the 3 Es being:

• Enhanced Performance

• Energy Management

• End-user Value

We will explore all three of these areas and these new POL regulators will be referred to generically as

“3E POL regulators”.

The next section will describe some of the concepts, terminology and definitions used when working with

the 3E POL regulator designs and power system architectures enabled by the new products. This is fol-

lowed by a description of the 3E POL regulator offerings and then a more detailed treatment of the benefits

to the end-user in the areas of mechanical features, electrical performance, system power and energy

management, and overall value. The last section expands the discussion of the 3E concept and explores its

ramifications for the end-user.

1. Introduction

The internal design of the 3E POL regulators uses digital

power control techniques, and some of the optional

user implementations of these products can benefit

from utilization of system level digital power and energy

management approaches. While these products can be

successfully applied using the same techniques as with

conventional fully analog POL regulators, it is beneficial

for the customer to become somewhat conversant with

the digital approaches to be able to make the optimal

choice for their particular system between conventional

and digital techniques. This section will describe the dis-

tinctions between digital power control and digital power

and energy management. It will also compare them to

conventional completely analog designs. The treatment

here will be very generalized, but references will be cited

so that the reader may explore these areas in more detail

if desired.

This brochure primarily supports the introduction of the

3E POL regulators and does for that reason focus mostly

on this element of the system. The following discussion,

however, will often apply conceptually to other system

elements such as isolated DC/DC converters, front-end

power conditioning hardware and thermal management

devices. During this discussion it will be assumed that a

fairly conventional Intermediate Bus Architecture (IBA) is

used such as that shown in Figure 1. A board-level Inter-

mediate Bus Converter (IBC) feeds multiple POL regula-

tors which are located in proximity to the load circuitry

and supply the final operating voltages. The IBC output

voltage, will typically be between 3.3 and 12 Vdc.

A conventional analog POL regulator uses an analog

PWM (pulse width modulation) control IC to generate the

gate drive waveforms for the power MOSFET switches.

The voltage feedback loop is implemented with analog

comparators, and the stability/compensation circuitry is

composed of linear R, L and C networks. Internal fault

monitoring and detection is done with analog sensors and

comparators. The user configurability of these POL regula-

tors is often rather limited, with resistive trim or output

voltage programming being the most commonly used

modification. These designs have been in use for many

years.

Ericsson Power Modules uses the term “digital power

control” to describe a DC/DC converter or POL regulator

design in which much of the analog control functional-

ity is replaced with digital circuitry. Typically the digital

content will include the feedback loops, MOSFET gate

drive generation, stability control, and fault detection.

The power train with MOSFET switches and the main

output LC filter is similar to what is used in an analog

POL regulator. The main point to be made here is that

digital power control can be transparent to the end-

user. Two power devices, one implemented digitally

and one with analog circuitry, can be plug-compatible

and may even be indistinguishable as far as the user is

concerned. However, as we will see later, using digital

techniques internal to a POL regulator can offer signifi-

cant size and performance advantages to the end-user

as well as drastically increasing the regulator’s flexibility

2. Concepts, Terminology & Definitions

and configurability. The reader is directed to reference

(1) for additional detail on the concepts of digital power

control as it applies to POL regulators.

While digital power control only applies to circuitry con-

tained within a power supply and is designed and con-

trolled by the power supply manufacturer, digital power

management and energy management extends beyond

the physical boundaries of a DC/DC converter or POL

regulator and into the end-use system. This extension

significantly increases the capabilities of the end-use

system, but will also require the power system designer

to participate in the implementation of the system man-

agement structure. The term “digital power manage-

ment” is used by Ericsson Power Modules to describe a

concept where digital communication between DC/DC

converters and/or POL regulators or other elements in

the system, for the purposes of monitoring and con-

trolling the status of the power supplies, minimizes the

system power and energy consumption and optimizes

the overall performance of the system. This digital com-

munication is typically used for the functions of power

monitoring, power on/off, output voltage setting, fault

handling, and power sequencing and is facilitated by a

digital interface, referred to as the power management

bus (PMBus™).

The analog-based hard-wired circuitry and multi-con-

ductor wiring used for these functions in a conventional

system are replaced with a digital communication bus

structure that simplifies the interconnections and allows

for programmable rather than fixed functionality. Refer-

ence (2) explains how a digital interface for this purpose

can be added to a POL regulator without impacting

the cost. While digital power control must operate on a

cycle-by-cycle basis to control the energy flow, digital

power management usually operates on a slower time

scale to react to changes within the system.

The efficiency of DC/DC converters and POL regula-

tors has always been a key performance criterion, and

is receiving even more attention in recent years as more

emphasis is placed on power and energy consump-

tion and the environmental impacts of large scale data

processing and telecom installations. Digital power adds

another dimension and the synergy between digital

power control and digital power management results in

further system efficiency improvements and lower energy

consumption. Digital power control allows for “on-the-fly”

reconfiguration of operating parameters within a power

supply. In a conventional DC/DC converter or POL regu-

lator many operating parameters are fixed, resulting in an

efficiency that is a compromise based on the expected

range of operating conditions in the system. If a digitally

controlled POL regulator or DC/DC converter is oper-

ated in a system with digital power management, the

system status can be used to dynamically program the

operating conditions of the power supply. For example,

the PWM dead-time can be varied as a function of the

regulator’s input and the load voltage and output current

to optimize the real time efficiency over a broad variety of

operating conditions.

Similarly, the output voltage of an IBC can be dynamically

varied to optimize the overall efficiency of the combina-

tion of IBC and POL regulator as a function of the current

system operating condition. Effects of power conversion

component variations due to ageing may also be com-

pensated for in this way. Ericsson Power Modules refers

to this combined usage of digital power management

and digital power control for the purpose of optimizing

the overall power efficiency of the end-use equipment

as a function of actual operating conditions as “digital

energy management”. Impressive savings in energy

consumption can be achieved in this way. In effect, digital

energy management replaces compromise with optimiza-

tion. Reference (3) describes these possibilities in greater

depth. References (4) and (5) discuss similar concepts as

applied to DC/DC converters.

48V/24V DC

3.3 V

1.8 V

1.5 V

12V/9V/5V/3.3V

Figure 1 In an Intermediate Bus Architecture (IBA) a board-level Intermediate Bus Converter (IBC) feeds multiple POL regulators which are located in proximity to the load circuitry and provides a well regulated supply voltage.

2. Concepts, Terminology & Definitions

This section will discuss the benefits of the new

3E POL regulators in some detail. It starts with an over-

view of the planned initial product offerings, which will

cover the output current range of 20 A and 40 A. Later

introductions will expand this current range. These 3E

POL regulators are extremely flexible, with the capability

of efficiently spanning an input voltage range of 4.5 to

14 V and an output voltage range of 0.6 to 5.5 V. Each

3E POL regulator includes a connector that is used for

the purpose of interfacing to the PMBus, see 3.3.2.

Each POL will be available in either SMT or PTH (plated-

through-hole) packages with a common interconnection

footprint to allow easy system scalability. A photograph

of the initial 3E POL regulators is shown in Figure 2.

3.1 MECHANICAL FEATURES

Ericsson Power Modules has shipped more than

50 million BMPS (board mounted power supplies)

over the years, and has developed an industry leading

expertise in designing packages that are cost effective

in manufacturing and extremely reliable in the field. A

new packaging and interconnect concept was required

for the 3E POL regulators since a power management

interface needed to be included. We looked upon this

new requirement as an opportunity to optimize the entire

POL regulator physical package and incorporate several

features that provide substantial benefit to the end-user.

The incorporation of digital control techniques and the

new package design provides increases in footprint areal

current density (A/cm²) of up to 300% and a correspond-

ingly significant increase of the power density. The low

building height also allow these devices to be used in

systems with a board pitch down to 15 mm. The physical

dimensions of the new 3E POL regulator products are:

Current Rating Overall L x W x H (mm)

20 A 25.7 x 12.9 x 8.2

40 A 30.9 x 20.0 x 8.2

3. Benefits of new POL offerings

40 A

20 A

10 A

Figure 2 40 A and 20 A 3E POL regulators.

Figure 3 The footprint layouts of the 10 A, 20 A and 40 A 3E POL regulators are scalable. A single PCB layout can accommodate any of these products.

Most conventional BMPS use connection pins with the

same design regardless of the pin function. Pins carrying

20 A could be the same physical size as pins carrying

a couple of mA. This is obviously not cost-effective and

is a waste of valuable PWB real estate. For the 3E POL

regulator products Ericsson Power Modules took a fresh

look at the interconnection issues and created a new

optimized header design. For power input and output

pins carrying large amount of current thick low resistance

pins are used. For other interfaces such as remote sens-

ing, clock and data lines that conduct minimal current

an industry standard connector header is selected. This

selection, in addition to reducing the footprint dimen-

sions, results in cost savings to the end user. The low

current connector header is widely used in the industry

with high production volumes and low cost. This selec-

tion also eliminates the technical risk of developing a new

pin design.

A major design decision was to make the footprint

layouts of the different 3E POL regulators scalable.

The power system designer can create a single board

layout that will accommodate any of these products.

This is especially valuable in terms of minimizing costly

and time-consuming layout changes during the product

development cycle when the exact current requirements

are not well defined. This concept is depicted in Figure

3. Note that the digital power management interface pins

on the right side of the drawing remain the same for any

of the three regulator families. The larger input and output

power pins to the left can be bussed together on the

user’s PWB to provide connection to any 3E POL regula-

tor with an output current rating from 20 A to 40 A.

The selected pin layout has an added advantage during

the customer’s manufacturing process. Notice in Figure 3

that the pins are bunched into three groups – the power

management connector on the right and the upper and

lower group of high current pins on the left. This grouping

forms a “three legged stool” structure which minimizes

coplanarity problems during SMT reflow soldering pro-

cesses. Sizeable components, such as POL regulators,

with pins in each of four corners can potentially present

difficulties in this regard. The reader need only compare

experiences in the amount of wobble in three legged

stools vs. four legged tables to be convinced of this

benefit!

All POL regulators in the 3E families feature an output

inductor with a flat surface oriented to the top of the

package. This is intentionally designed as a convenient

attachment point for vacuum nozzle pick and place

equipment. Both tray and tape & reel device packaging

will be available to maximize compatibility to the user’s

manufacturing process. Both SMT and PTH options will

also be offered. Figure 4 is a photograph showing more

detail of the interconnection offerings.

3.2 ELECTRICAL PERFORMANCE

This section summarizes the fundamental electrical

performance characteristics of the 3E POL regulators. As

will be seen in the next section, these fundamental per-

formance parameters can in some cases be enhanced

when using digital power management and digital energy

management at the system level.

The broad input voltage range (4.5 V to 14 V) of the 3E

POL offerings allow them to operate with the most com-

monly used intermediate bus voltages of 5 V, 9 V and

12 V. The output voltage range extends from 0.6 V up to

5.5 V.

The efficiency of these products is in line with the best

solutions currently available and it can be improved even

further by use of digital control and power management

Figure 4 The 3E POL regulators are designed for either surface mount or plated through-hole mount manufacturing processes, giving the user a flexibility of choice.

techniques. Efficiency data both in a “stand-alone” mode

and when operating with digital power management

feedback from the system will be given in the next sec-

tion. Similarly, the excellent dynamic response character-

istics of the 3E POL regulators can be further optimized

by means of system-level feedback, and comparative

data will be shown.

Perhaps the biggest improvement in electrical perfor-

mance visible to the casual observer is in the realm of

physical size and power density. This is primarily due to

the significantly lower parts count inherent in a POL regu-

lator designed with digital power control techniques. The

table below summarizes the power and current densities

of the 3E POL products compared with a traditional

18 A analog POL regulator. These data assume an output

voltage setting of 3.3 V at max rated current and an input

voltage of 12 V. Keep in mind that these improvements

were made in spite of including the new interface for

digital power management.

DEvICE POWER DENSITy AREAL CURRENT

W/cm³ DENSITy A/cm²

18 A Analog POL 7.4 2.1

20 A 3E POL 24.3 6.0

40 A 3E POL 26.1 6.5

A photograph showing the relative size difference of

the above products is shown in Figure 5. While steady

power and current density improvements have been

common in the POL regulator market, the step function

packaging density gains shown by the 3E digital POL

regulator designs are unprecedented.

While the digital power management connector was added

primarily for that purpose, it also contains some pins that

may be used to obtain more conventional analog func-

tions. Remote sense connections are provided for both the

positive and negative POL output terminals. These can be

used to regulate the POL output voltage accurately at the

load. The digital power management connector may also

be used for other features like current share and synchro-

nization. A direct current share connection can be made

between 3E POLs through another pin on this connector.

With this connection the POLs will automatically current

share without further need for external control. For ex-

ample, two 40 A POL regulators can power a load with a

requirement of up to 80 A. Another pin may be used for al-

lowing two or more 3E POL regulators to synchronize their

Synchronization

Remotesense

Currentshare

out0.6 – 5.5 V

3.3 / 5 /9 / 12 V in

out0.6 – 5.5 V

Figure 6 The digital power management connector may be used for many well-known features such as remote sense, current share and synchronization.

Figure 5 From left to right relative size difference of a traditional 18 A ana-log POL regulator compared to the 20 A and 40 A 3E POL regulators.

POL-to-POL bus 3.3 V

1.8 V

1.5 V

switching activity with each other or with an external oscilla-

tor. This feature could be used to facilitate filter design and

reduce the input ripple current. Figure 6 depicts a system

in which three POLs are synchronized and interleaved and

two of them are configured in a current sharing arrange-

ment.

3.3 SySTEM POWER AND ENERGy MANAGEMENT

3.3.1 Power Management Methodologies

The 3E POL regulator offerings are extremely flexible in

terms of available management methodologies that can

be applied during the life cycle of the end-use applica-

tion. In order of increasing functionality they can be sum-

marized as follows:

1. The 3E POL regulator can be treated the same as a

conventional POL with internal analog circuitry. Con-

necting the POL to the input voltage bus and selecting

the output voltage by means of an external trimming re-

sistor is all that is required to operate the 3E device as a

conventional POL regulator. The digital power manage-

ment interface can be ignored. This would enable the

3E POL regulators to be utilized in systems that have

no need for a more sophisticated control system or that

have an existing analog-based control implementation.

Note that with this scenario many of the performance

benefits of the 3E products such as increased efficiency

and power density could still be realized.

2. A dedicated POL to POL bus can be used without

having the PMBus connected to a host controller dur-

ing system operation. The POL to POL bus is a single

wire connection via a dedicated pin. An example of

this is found in the previous section when current

sharing and POL switching synchronization capabili-

ties were discussed. This control methodology will

provide some degree of power management based

on a pre-configured set of 3E POL regulators. For

example, the start-up and shut-down sequencing can

be defined, current sharing established, or a selected

group of regulators could be tied together so that they

all would shut down in response to a fault condition

on any one of them.

3. The PMBus can be used for digital communication

between the 3E POL regulators and a host controller.

This host controller can be a part of each board-level

power system or can be only a temporary connection

to an external host during the product development

and/or manufacturing process. This is by far the most

flexible option in terms of obtaining maximum benefit

and optimization by means of digital power manage-

ment.

A drawing showing these three levels of control implemen-

tation is shown in Figure 7.

Figure 7c The PMBus can be used for digital communication between the 3E POL regulators and a host controller.

Figure 7a The 3E POL regulator can be treated the same as a conven-tional POL using an external trimming resistor for adjusting the output voltage.

Figure 7b A dedicated POL to POL bus can be used for power management without having the PMBus connected to a host controller during system operation.

7 a 7 b

7 c

3.3 V

1.8 V

1.5 V

Analogresistor trim

3.3.2 The PMBus

The PMBus is a bidirectional serial multi-node interface

that utilizes 4 conductors with the following functions:

• Clock (SCL)

• Data (SDA)

• Control (CTRL)

• Alert (SALERT)

The clock and data lines are used for the bidirectional

transfer of data between the host and the controlled

nodes (3E POL regulators in this case) in the network.

The Control line is hardwired to a regulator pin for the

purpose of enabling the output. The Alert line is used, as

an alarm, by the connected POL regulators to gain the

attention of the host controller.

Individual 3E POL regulators are identified to the host

controller by means of an assigned address. These ad-

dresses are physically assigned at each POL regulator

used in the system by means of resistive programming.

One or two pins in the power management connector are

available on each 3E POL for this purpose, and chip re-

sistors are connected from these pins to Gnd to establish

the programming. Twentyfive pre-defined discrete values

of resistance are used per pin, providing a total of up to

625 combinations, which is more than enough since the

PMBus specification is limited to 128 unique addresses.

Note that in a typical system some of these addresses

would be used by other power system components such

as DC/DC converters, fans and AC/DC rectifiers.

3.3.3 Usage of the PMBus

While usage of the PMBus is optional, its use will greatly

increase the flexibility of the end application’s power

system. If BMPS products with PMBus connectivity are

used in the system, it really only requires the bussing of

the 4 conductors previously identified to a host location

in order to take advantage of the benefits of digital power

management. One common misconception is that the

host controller must be resident in the end system. While

this is one option, it is not the only one. The following

three scenarios show how the PMBus could be used

during various phases of the end-use system develop-

ment, manufacture and deployment.

1. The PMBus is used during product development and

evaluation. The host controller in this case could be

an external PC connected to the prototype system or

sub-system. This is an extremely convenient and fast

way to experiment with such things as voltage set-

tings, overcurrent limits, power sequencing routines,

voltage margining, fault handling, etc. without the

need for hardware changes in the system. Ericsson

Power Modules has an evaluation kit for the 3E POL

regulators that contains an extensive Configuration

Monitoring and Management (CMM) software and is

an excellent way to begin exploring this type of capa-

bility. No host controller is required in the system itself.

2. The PMBus is used during system manufacturing and

test, and the host controller could be part of the Auto-

mated Test Equipment (ATE). In this scenario the ATE

could automatically configure the 3E POL regulators

during the system’s manufacturing process. Param-

eters such as output voltage, start-up delay and over

temperature/current/voltage limits can be established

during this process. No host controller is required in

the system itself.

3. The scenario with the most capability and flexibility

is to include the host controller into each board-level

power system. With this configuration the same

host controller can be used for all three phases of a

system’s lifetime – development, manufacture, and

field deployment. Another misconception is that the

host controller needs to be powerful and expensive. In

reality, its specifications are very modest and in many

systems it can be as simple as a general purpose

microcontroller or some spare gates of an FPGA that

may already be resident in the system. A representa-

tion of a system power board using 3E POL regulators

and connection to a system-level host via the PMBus

is shown in Figure 8.

3.3.4 Examples of optimization using

Power/Energy Management

This section assumes that the power system designer

has decided to use the PMBus in one of the implemen-

tations described above, and will give some examples

of how the power system may be optimized by digital

power management techniques. These are only a very

few of the many possibilities. The reader is encouraged to

think about other ways to use these capabilities in his/her

own systems.

Today’s circuitry often operates at very low static voltage

levels, below one volt in some cases, and still requires

tight power supply regulation, such as +/- 1%. Providing

these tolerances at low voltage levels is a severe chal-

lenge when considering distribution paths, component

variability, changing current demands and even tempera-

ture changes. Using a host controller in the manufactur-

ing ATE or even in the end product itself can greatly facili-

tate making these voltage level adjustments automatically

while optimizing the setting for each particular system.

The 3E POL regulator is an ideal solution for such situa-

tions. See Figure 9.

Using the PMBus in conjunction with a host controller in

the manufacturing ATE makes for fast and reliable setting

of power sequencing routines. This represents a vast

improvement in complexity relative to traditional systems

that used analog-based power controllers for this pur-

pose. It is also easy to implement voltage margin testing

during manufacturing to verify system operation over the

extremes of the design space. See Figure 10.

Accuracy and set-point improvement

V

+ 5 %

- 5 %

out

+ 1 %

- 1 %

Voltage margining

V

+ 5 %

- 5 %

out

Sequencing(V)

Figure 8 Including a host controller into each board-level power system means that the PMBus could be used during various phases of the end-use system development, manufacture and deployment.

Figure 9 The 3E POL regulator shows its worth by allowing voltage rails to be fine-tuned per board assembly to offset varia-tions in component and distribution paths, minimizing voltage rail tolerances at the actual payload circuitry.

Figure 10 The PMBus interface facilitates voltage margin testing during manufacturing as well as to configure sequencing start-up and shut-down of multiple voltage rails in a power system.

Fault detection and handling can be easily optimized.

The host controller can be programmed to set custom-

ized limits on each of the fault sensors (temperature,

voltage and current) not only for absolute limits but also

for “warning” conditions, as shown in Figure 11. In ad-

dition to these classic indicators of a major parameter

gone awry, it is also possible to predict future failures by

monitoring indicators such as operating efficiency. A pat-

tern of continuously declining efficiency allows for a Field

Replaceable Unit (FRU) to be replaced before an actual

equipment failure occurs. For systems with high availabil-

ity requirements this capability is quite valuable. The host

controller may be used to store a user selectable history

of performance parameters for the purpose of facilitating

root cause analysis in the event of a failure. This operat-

ing parameter data can also be used to collect reliability

data for the purpose of improving robustness in future

designs. A host controller is required for these types of

capabilities.

Traditional POL regulators are designed with the best pos-

sible efficiency characteristics over the expected range of

use. This range includes the input voltage selection, the

programmable output voltage range and the variation in

possible output current. Obviously, the overall efficiency

curve must be a compromise. If the POL designer was de-

signing for one particular combination of input voltage, out-

put voltage and operating current, then the efficiency could

be optimized for this particular operating condition. This is

exactly what can be accomplished by using the PMBus

in conjunction with a host controller in the manufacturing

ATE or in the system itself. The already excellent efficiency

depicted in Figure 12 can be improved even further by

configuration and optimization of the power system for it’s

intended line and load conditions. This is described more

in detail in reference (3).

A similar situation exists with the POL dynamic response

characteristics. These are dependent not only on the

circuitry inside the POL, but also on the dynamic load

profile in the application and on the amount and type of

decoupling capacitance in the end system. Knowledge of

these factors can allow a 3E POL regulator to operate in

an optimized manner as shown in Figure 13. The default

configuration allows for stable operation with a wide

range of capacitance on the output, but this inevitably

leads to compromises in performance. The optimized

configuration exemplifies how the dynamic performance

can be improved by reconfiguring the POL regulator for

its intended use with a known output capacitance. Using

this technique could allow the removal of a significant

amount of output capacitance and result in system cost

savings. These last two examples show just how power-

ful the concept of digital power management can be. You

no longer need to accept compromise – you can have

optimization!

Con�guration

Fault

Warning

Warning

Fault

Figure 11 Warning and fault thresholds for temperature, voltage and current can be individually configured on each 3E POL regulator.

Figure 12 The already excellent efficiency of a 3E POL regulator can be improved even further by configuration and optimization of the power system for its intended line and load conditions.

4.5 V in, 3.3 V out

5 V in, 3.3 V out

12 V in, 3.3 V out

%

A

14 V in, 3.3 V out

100

95

90

85

80

75

0 4 8 12 16 20

3.4 END-USER vALUE

This paper has so far concentrated on how the 3E POL

regulators can provide measurable benefits to the user in

terms of the design, manufacturing and operation phases

of the product lifecycle. These benefits have been mostly

technical in nature, relating to electrical and mechani-

cal performance. In this section other benefits of the 3E

concept are explored. These are perhaps secondary in

nature but still quite important to most all designers of

contemporary power systems and create value for the

end-user as depicted in Figure 14.

The most striking change when comparing a 3E POL

to a more traditional design is the drastic reduction in

the number of passive components used. In addition to

the resultant density enhancements, this reduced parts

count has another significant benefit – higher reliability.

Since the techniques discussed here also will allow for

optimization of system operating efficiency, the average

operating temperature in the 3E POL regulators and other

system components can be lower. Fewer parts operating

at lower temperatures equates to lower failure rate and

higher system MTBF. This in turn leads to reduced sys-

tem maintenance and down time and most importantly, it

leads to fewer site visits and lower total cost of ownership

(TCO) which means higher end-user satisfaction.

The 3E POL regulators are programmable and very flex-

ible, with each part number handling a multitude of differ-

ent input and output voltage combinations. Their ability

to be paralleled allows for a single part number POL to

handle a very wide range of output current if needed.

All this leads to terrific flexibility and system capability

with a relatively few part numbers of 3E POL regulators.

Purchasing volume can be concentrated on a few parts

types for maximum unit cost savings while logistics man-

agement costs are minimized.

Figure 13 The dynamic performance can be improved by reconfiguring the 3E POL regulator for its intended use with a known output capacitance. Using this technique could allow the removal of a significant amount of output capacitance and result in system cost savings.

Output voltage response to load current stepchange (5-15-5 A). Resistive load with slewrate > 7 A/µs at:Tref = +25°C, vl = 12 v, Cout = 470 µF.

Top trace: output voltage (50 mv/div.). Bottom trace: load current (10 A/div.). Time scale: (0.1 ms/div.).

Default robust dynamic configuration Load optimal dynamic configuration

Figure 14 Power supplies with a lower com-ponent count and higher efficiency improve reliability, which in turn reduces the total cost of ownership of the equipment.

Because of the very high flexibility of these 3E products

and the programmable nature of the digital power man-

agement concept, Ericsson Power Modules has realized

the need for a partly different quality assurance

and design/manufacturing verification processes com-

pared to analog products. In addition to the traditional

quality assurance provisions of a hardware manufactur-

ing process, we have instituted stringent controls on the

software and firmware elements associated with this new

manufacturing environment. Ericsson Power

Modules’ approach to these important parts of this

product introduction is discussed in reference (6). The

net result is that usage of these 3E POL regulators will

provide the user with pre-validated products. Compared

with custom designed POL regulator solutions, usage of

the 3E POL regulator will result in substantially reduced

technical risk and shorter time-to-market.

The small physical size of these new products brings

other benefits to the system. The small footprint, in par-

ticular, will be a very big advantage for most users. Board

real estate is a valuable commodity in all end-user equip-

ment and systems. Less board space taken by

POL regulators means more real estate available for

payload circuitry.

The digital power management concept can be a power-

ful tool. While saving a few mW in one small subassembly

may not seem terribly important, the cumulative power

savings in a system of even moderate size can add

up quickly. When several of these systems are oper-

ated many hours a day, the resultant energy savings is

substantial. Building heat load and air conditioning costs

go down. The electrical utility bill goes down. It can be

shown that one watt saved at board level will reduce the

operating energy cost with approximately 10 USD over

a five year period (0.1 USD/kWh). Adding all board level

savings up to the system level will result in substantial

savings of operational expenditures (OPEX) for the end-

user. Fewer natural resources are consumed for power

generation purposes. Everyone wins.

As digital power/energy management becomes more

commonplace it will become an enabling technology, with

ramifications beyond the specific system it is installed in.

It can easily become a powerful tool for the purposes of

data collection and analysis. The result will be increased

knowledge of reliability and failure root cause analysis

that will be invaluable in the design of next-generation

systems.

The above examples are a few ways in which the 3E

POL regulators can enhance the value of your system

and the value of the design experience when using them.

User value is, after all, one of the key elements of the 3E

concept.

The preceding pages have hopefully conveyed much

of the flavor of the 3E concept as applied to these new

POL regulators and what it delivers to the end-user. It

has been shown that the 3 Es provide important ben-

efits – many of them new or best-of-breed for the power

conversion industry:

Enhanced performance

• Significantly higher power and current densities

• Scalable footprint

• Industry-leading efficiency

• Maximum efficiency for all application

• Optimization of dynamic response to actual application

• Excellent feature set for “stand alone” operation

• Flexible fault detection and error handling

Energy management

• Simple and cost-efficient PMBus

• Powerful system development tools

• Many levels of possible power

management methodology

• Unparalleled flexibility during field deployment

• Adaptable systems possible

• Reduced power dissipation

• Reduced energy consumption and utility costs

• Reduced environmental impact

End-User value

• Reduced number of POLs to stock

• Enhanced reliability and higher system availability

• Major advantages during

manufacturing and test

• Increased customer satisfaction

• Comprehensive prevalidation

• Reduced technical risk

• Reduced time-to-market

• More board real estate for payload circuitry

• Enabling technology for data collection and analysis

The list is already a long one, and could be added to.

The reader has probably already thought of other advan-

tages in the end-user equipment that 3E can provide.

To define 3E more succinctly, it is about flexibility - more

importantly, user-defined flexibility. It is about optimization

– namely, user-defined optimization. Past products have

been based on some degree of compromise. Much of

this compromise is no longer required.

3E = Maximal Configurability with Minimal

Compromise

4. 3E – Flexibility and Optimization without Compromise

This brochure has presented several ways in which the

new Ericsson Power Modules 3E POL regulators can be

used to add value to the end-user system while achieving

state-of-the-art performance. Many of these advantages

can be achieved without a commitment to utilize a digital

power management bus in the end application system.

For users who adopt that approach, application of the

3E regulators will be quite similar to using conventional

analog POLs, and the design and testing process will

seem very familiar.

Many users will elect to take advantage of the increased

functionality, flexibility and opportunity for system optimi-

zation that the PMBus offers by using it as an interface

during system development, manufacturing testing or in

the field environment. For some of these users, this will

represent their first power system design using digital

power management techniques. One of Ericsson Power

Modules’ goals is to make the transition from analog to

digital power management systems as convenient as

possible for the end-user by supporting the new products

with a wide variety of applications assistance. In addition

to the references cited earlier in the paper, references (7)

and (8) are recommended as a source of more gener-

alized information about digital approaches to power

conversion design.

The 3E POL regulators are the first Ericsson Power

Modules products containing the PMBus digital interface.

To give the customers an opportunity to easily experience

the benefits to be derived from digital power manage-

ment, a development platform for the 3E POL regulators

is introduced in parallel with the products. This evalua-

tion kit, shown in Figure 15, consists of a demonstration

board with provision for hosting up to 6 pcs of 3E POL

regulators, USB cable, CMM software on CD, device driv-

ers, sample configuration files and complete documenta-

tion. Using this evaluation kit in conjunction with a PC and

commonly available basic lab equipment will allow the

prospective user to conveniently experiment with the digi-

tal development environment. This evaluation kit is highly

recommended as a first step for customers that may be

considering exploring usage of the 3E POL regulators or

designing a power system configured with a PMBus.

The new Ericsson Power Modules 3E POL regulators will

eliminate many of the compromises inherent in current

designs and create exciting opportunities for power sys-

tem designers in terms of system performance, flexibility,

configurability, optimization and end-user value. Further-

more, system design using these products should be a

fun and rewarding experience!

5. Summary

Figure 15 An evaluation kit has been developed to give the customers an opportunity to easily experience the benefits to be derived from digital power management.

ATE Automated Test Equipment

BMPS Board Mounted Power Supply

CD Compact Disk

CMM Configuration Monitoring Management

FPGA Field Programmable Gate Array

FRU Field Replaceable Unit

GUI Graphical User Interface

IBA Intermediate Bus Architecture

IBC Intermediate Bus Converter

IC Integrated Circuit

MicroTCA™ Micro Telecommunications Computing Architecture

MOSFET Metal Oxide Semiconductor Field Effect Transistor

MTBF Mean Time Between Failure

PC Personal Computer

PWB Printed Wired Board

PMBus™ Power Management Bus POL Point of Load

PTH Plated through hole

PWM Pulse Width Modulation

SMT Surface Mount Technology

3E Enhanced Performance, Energy Management, End-user Value

Glossary

All referenced papers can be found at Ericsson Power Modules web site:

http://www.ericsson.com/powermodules

1. Digital Power Forum 2006 – Performance Improvements for OEM System Designers

2. PCIM 2007 – Digital Control Techniques Enabling Power Density Improvements and Power Mgmt Capabilities

3. Digital Power Forum 2007 – Intelligent Energy Management for Improved Efficiency

4. APEC 2007 – Implications of Digital Control and Management for a High Performance Isolated DC/DC

5. Digital Power Europe 2007 – Digital Control in a MicroTCA Power System

6. Digital Power Forum 2007 – Qualification and Verification Considerations for Digital Power Supplies

7. Digital Power Forum 2007 – From Digital Confusion to Digital Conversion

8. Digital Power – Technical Brief

References

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