LMZ22018 [NSC]

Sharing Evaluation Board power modules are easy-to-use DC-DC; 分享评估板电源模块易于使用DC-DC


型号：	LMZ22018
厂家：	National Semiconductor
描述：	Sharing Evaluation Board power modules are easy-to-use DC-DC 分享评估板电源模块易于使用DC-DC 电源电路
文件：	总16页 (文件大小：2751K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

National Semiconductor

Application Note 2093

Marc Davis-Marsh

April 7, 2010

LMZ23610/8/6 and

LMZ22010/8/6 Current

Sharing Evaluation Board

Introduction

Board Specifications

The LMZ23610/8/6 and LMZ22010/8/6 SIMPLE SWITCH-

ER® power modules are easy-to-use DC-DC solution capa-

ble of driving up to a 10, 8 or 6 ampere load. They are

available in an innovative package that enhances thermal

performance and allows for hand or machine soldering. The

LMZ23610/8/6 can accept an input voltage rail between 6V

and 36V and the LMZ22010/8/6 can accept an input voltage

rail between 6V and 20V.

•

V_IN= 6V to 36V (LMZ23610/8/6)

V_IN= 6V to 20V (LMZ22010/8/6)

V_OUT= 1.2V, 2.5V, 3.3V or 5V (minimum input voltage of

7V required for 5V output)

•

I_OUT= 0 to 10, 8, or 6 Amps

_JA= 8.8 °C / W, θ_JC= 1.0 °C/W

Designed on four layers; Inner are 2 oz copper; Outer are

2 oz copper.

The current sharing evaluation board is designed so that four

modules can be easily connected to supply up to a 40 amp

load. More can be connected as long as care is taken to not

exceed the current capabilities of the banana plug connectors

and the 5-amp per pin rating of the edge board connector.

•

Measures 3.54" x 3.54" (90 mm x 90 mm) and is 62 mils

(1.57 mm) thick of FR4 laminate material

For additional circuit considerations, including additional out-

put voltage options, refer to the Applications Section section

of the LMZ23610/8/6 or LMZ22010/8/6 data sheets. For neg-

ative output voltage connections see AN-2027.

The current sharing evaluation board is highly configurable.

The output voltage can be changed to 5V, 3.3V, 2.5V or 1.2V

with a jumper change. The external soft-start capacitor facil-

itates a controlled and adjustable startup rise time of the

output. The board temperature can be measured with the on-

board resistor. The UVLO can be adjusted by adding one

resistor. To simplify the synchronization of the modules an

onboard 555 timer provides an adjustable frequency clock

from 350 to 600 kHz.

The LMZ23610 and LMZ22010 family is a reliable and robust

solution with the following features: loss-less cycle-by-cycle

valley current limit to protect for over current or short-circuit

fault, thermal shutdown, input under-voltage lockout, and will

start up into a pre-biased output.

Simplified Schematic

30138708

FIGURE 1.

301387

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Test Connections

then the enable clamp zener D1 can be omitted. Pull EN low

to shutdown the module and clock circuitry.

The board should be connected to a power supply and load

as shown below in Figure 2. The EN post is connected to the

UVLO circuit on the back of the board. There is a resistive

divider implemented on the board, with the bottom resistor

unpopulated, that can be used to establish a precision UVLO

level of the board. A common user change to this circuit is to

adjust the value of RENT and RENB to adjust the operating

UVLO to that of the target application. Refer to the respective

data sheet for calculation. Note that if in the end application

the EN pin voltage does not exceed 5.5V at maximum Vin,

The SYNC post is connected to the output of a 555 timer on

the back of the board and is fed to the SYNC pin of the device.

This clock is provided to simplify the testing of the current

sharing features of the device and is not required for stand

alone operation. The frequency of the clock can be adjusted

from 350kHz to 600kHz using the potentiometer labeled

R_freq_adj. Jumper J3 (SLAVE) can be used to disable the

555 timer and allow the use of external clocks from 314 to 600

kHz.

Board Connection Diagram

30138701

FIGURE 2.

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Edge Connector Diagram

30138706

FIGURE 3.

The evaluation board is also compatible with the 44-pin edge

connector shown in Figure 3. The table below explains the

functionality of the pins.

Name

Description

1, 2, 3, 4, 5, 7, 8

VIN

Input supply — Nominal operating range is from 6V to 20V for the LMZLMZ22010/8/6 and from 6V

to 36V for the LMZLMZ23610/8/6.

9, 10, 11, 12, 13,

14, A, B, C, D, E

GND

Power Ground — Electrical path for the power circuits within the module.

15, 16, 18, 19,

20, 21, 22, V, W,

X, Y, Z

VOUT

Output Voltage — Regulated 5, 3.3, 2.5 or 1.2V.

VIN SENSE + Positive Kelvin Sense of Input voltage — Tied to VIN pin of the LMZ module.

VIN SENSE - Negative Kelvin Sense of Input voltage — Tied to PGND (EP) of the LMZ module.

VOUT SENSE + Positive Kelvin Sense of Output voltage — Tied to Vout banana jack.

VOUT SENSE - Negative Kelvin Sense of Output voltage — Tied to AGND of the LMZ module.

SYNC +

Synchronization Positive Input — This is the positive probe point for viewing the clock generated

by the 555 timer and is connected to the SYNC pin of the LMZ module. If the 555 timer is shutdown

using J3 then an external clock can be used. The external clock must provide a CMOS logic level

square wave whose frequency is between 314 kHz and 600 kHz.

SYNC -

Synchronization Negative Input — Tied to AGND of the LMZ module.

SHARE +

Share Positive Input — Connect this pin to the share pin of other LMZ modules to share the load

between the devices.

SHARE -

Share Negative Input — Tied to AGND of the LMZ module.

Enable — Input to the precision enable comparator of the LMZ Module. Also tied to a pull-up resistor

to enable the 5v bias supply and the 555 timer.

TEMP SENSE Connected to top of the Rts temperature sensing resistor. Temperature measurements can be made

by measuring the temperature dependant resistance between TEMP SENSE and VIN SENSE -.

Convert the resistance to temperature with the following equation: Temperature (C) ≊ 2.6245 x

Resistance (Ω) - 262.7

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vided on the slave board (J2). The slave module's switching

frequency will now be controlled by the clock on the master

board. Turning the R_freq_adj pot counter clockwise lowers

the clock frequency and turning the pot clockwise increases

the frequency. By placing an additional jumper on J3 (SLAVE)

of the master board, the 555 timer is disabled on both boards.

With the clock disabled you can observe the parts perfor-

mance when the devices are not synchronized, or you can

supply an external clock through the SYNC post. J3 must be

in place (555 disabled) on all boards to use an external clock

on sync. The Sync pin of the slave can also be disconnected

from the master board by removing the RSHORT resistor.

This allows the user to provide a multiphase clock of their

choosing to the boards.

Adjusting the Output Voltage

The output voltage of the evaluation board is adjusted to ei-

ther 5V, 3.3V, 2.5V, or 1.2V by moving jumper J1. For other

voltage options see the datasheet for adjusting the feedback

resistors.

Current Sharing

Current sharing is easy to evaluate. The next steps should be

implemented only while the power to the device is off.

Select which board will be the master. This is usually the

board closer to the load. Connect the master board as de-

scribed above in Test Connections. Insert the slave board into

the socket on the master. If there is no socket, connect a 44-

pin board-edge extender to the top of the master board and

solder the pins. The board-edge connector will connect Vin,

Gnd, Vout, Enable, Sync and the Share pin between the

boards to split the current demand between multiple boards.

The advantage to running the clocks out of phase is to reduce

the current stress on the input and output capacitors. For two

modules the clocks should be run 180 degrees out of phase,

for three modules the clocks should be run 120 degrees out

of phase an so on. Although local input bypass capacitors are

still required, the bulk capacitance required for a given ripple

voltage can be greatly reduced.

On the slave board(s) remove the jumper J1 (MASTER) and

move it to jumper J2 (SLAVE). This disconnects the FB pin of

the slave converter(s) (J1) and disables the clock that is pro-

Output Voltage Ripple with Two Boards Synchronized to Output Voltage Ripple with Two Boards Synchronized with

350Khz 180° Phase Shift

30138709

30138710

FIGURE 4.

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Master Slave Connection

30138702

FIGURE 5.

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30138707

FIGURE 6. Evaluation Board Schematic

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TABLE 1. Current Sharing Evaluation Board Bill of Materials, V_IN= 6V to 36V (20V), V_OUT= 1.2 / 3.3V / 5V, I_{OUT (MAX)}

10/08/06A

Designator

Description

Case Size

Manufacturer

Manufacturer P/N

Quantity

SIMPLE SWITCHER®

TO-PMOD-11

National

Semiconductor

LMZ23610/08/06 or

LMZ22010/08/06

Timer, 8-pin Narrow

SOIC, Pb-Free

TSSOP-8

SOT23

National

Semiconductor

LMC555CM/NOPB

300 mA/600 mA up to

42V Input Step-Down

DC/DC Regulator

National

Semiconductor

LM2841XMK-ADJL/NOPB

Cin1

Cin6

Co1

Co5

0.047uF, X7R, 50V

0805

1210

Kemet

TDK

C0805C473K5RACTU

C3225X7S1H106M

Cin_b

Cin2

Cin3

Cin4

10 µF, X7S, 50V

Cin5

150 µF, Aluminum

Electrolytic, 50V

Panasonic

Murata

EEE-FK1H151P

Co2

Cout_b

47uF, X5R, 10V

1210

2917

GRM32ER61A476KE20L

T520D337M006ATE015

Co3

Co4

330µF, 6.3V, 0.015 ohm,

Kemet

Cff

4700 pF, X7R, 50V

0.15uF, X7R, 10V

0805

0603

Kemet

Murata

C0805C472K5RACTU

Css

Cbt

GRM188R71A154KA01D

Cbyp, Cbyp2

0.1uF, X7R, 50V

470pF, C0G/NP0, 50V

4.7V, 500mW

0805

TDK

AVX

C2012X7R1H104K

08055A471FAT2A

MMSZ4688-V-GS08

B140-13-F

SOD-123

SMA

Vishay

Diode, Schottky, 40V, 1A

Diode, Schottky, 20V, 1A

1.0k ohm, 5%, 0.125W

Diodes Inc.

ON Semiconductor

Vishay-Dale

SOD_123FL

0805

MBR120LSFT1G

CRCW08051K00JNEA

Rent

Rrst2

Rsync

Renb

Rtop

Not Populated

0805

5.62k ohm, 1%, 0.125W

1.02k ohm, 1%, 0.125W,

1.07k ohm, 1%, 0.125W

576 ohm, 1%, 0.125W

9.53 ohm, 1%, 0.125W

3.74k ohm, 1%, 0.125W

84.5 ohm, 1%, 0.125W

8.06k ohm, 1%, 0.125W

169 ohm, 1%, 0.125W

5.6k ohm, 1%, 0.125W

73.2 ohm, 1%, 0.125W

Vishay-Dale

Vishay

CRCW08055K62FKEA

CRCW08051K02FKEA

CRCW08051K07FKEA

CRCW0805576RFKEA

CRCW08059R53FKEA

CRCW08053K74FKEA

CRCW080584R5FKEA

CRCW08058K06FKEA

CRCW0805169RFKEA

CRCW08055K60FKEA

CRCW080573R2FKEA

CRCW080520R0FKEA

CRCW0805200RFKEA

CRCW08050000Z0EA

PTS08051B100RP 100

Rbtm

Rfbb

Rfbt_1.2

Rfbt_1.2b

Rfbt_2.5

Rfbt_2.5b

Rfbt_3.3

Rfbt_3.3b

Rfbt_5

Rfbt_5b

RFB_LP

Rpull

20 Ω

200 ohm, 1%, 0.125W

Rshrt

0 ohm, 5%, 0.125W

Rts

100 ohm,Temp Sense

Resistor

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Designator

Description

Case Size

Manufacturer

Manufacturer P/N

Quantity

R_freq_adj

ADJ, 100K ohm, 0.5W

Round - 0.350" Dia x

0.150" H

Bourn

3352T-1-104LF

3.48k ohm, 1%, 0.125W

0805

Vishay-Dale

CRCW08053K48FKEA

744043220

Inductor, Shielded Drum

Core, Ferrite, 22uH,

0.7A, 0.155 ohm

SMD

Wurth Elektronik

SYNC

Test Point, TH,

Miniature, Red

Keystone Electronics

5000

5001

575-8

GND

Test Point, TH,

Miniature, Black

GND

VIN

Banana Jack Connector

VOUT

Header, 4x2, Gold

plated, 230 mil above

insulator

TH, 100mil

Samtec Inc.

Amp

TSW-104-07-G-D

TSW-102-07-G-S

382811-6

Header, 2x1, Gold

plated, 230 mil above

insulator

SH-1

SH-2

SH-3

Shunt, 100mil, Gold

plated, Black

Machine Screw, Round,

#4-40 x 1/4, Nylon,

Philips panhead

B and FFastener

Supply

NY PMS 440 0025 PH

Standoff, Hex, 0.5"L

#4-40 Nylon

Keystone

EDAC

1902C

44-Pin Edge Connector

Not Populated

305-044-555-201

Rrst1

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Performance Characteristics

Efficiency, V_OUT= 5.0V

Thermal Derating, V_OUT= 5.0V

100

10A

10 Vin

12 Vin

16 Vin

20 Vin

-40 -20

20 40 60 80 100 120

OUTPUT CURRENT (A)

AMBIENT TEMPERATURE (°C)

30138720

30138721

Startup, V_IN= 12V, V_OUT= 3.3V

30138722

PCB Layout Diagrams

Gerber and CAD files can be downloaded from the associated product folder.

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30138714

FIGURE 7. Top Layer

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30138715

FIGURE 8. Internal Layer I (Ground)

Heat Sinking Layer

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30138716

FIGURE 9. Internal Layer II (Routing)

Heat Sinking Layer

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30138717

FIGURE 10. Bottom Layer (Ground and Routing)

Heat Sinking Layer

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30138718

FIGURE 11. Top Silkscreen

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30138719

FIGURE 12. Bottom Silkscreen

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Notes

For more National Semiconductor product information and proven design tools, visit the following Web sites at:

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Products

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Design Support

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Amplifiers

WEBENCH® Tools

App Notes

Audio

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www.national.com/adc

www.national.com/interface

www.national.com/lvds

www.national.com/power

www.national.com/appnotes

www.national.com/refdesigns

www.national.com/samples

www.national.com/evalboards

www.national.com/packaging

www.national.com/quality/green

www.national.com/contacts

www.national.com/quality

www.national.com/feedback

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Clock and Timing

Data Converters

Interface

Reference Designs

Samples

Eval Boards

LVDS

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Distributors

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LDOs

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www.national.com/led

www.national.com/vref

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Quality and Reliability

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Design Made Easy

Applications & Markets

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LED Lighting

Voltage References

PowerWise® Solutions

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Serial Digital Interface (SDI) www.national.com/sdi

Temperature Sensors

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PowerWise® Design

University

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