Texas Instruments Bq2000EVM Manual de usuario

1 Introduction

1.1 Device Background

1.2 EVM Differences

1.3 Performance Specification Summary

User's GuideSLUU270 – June 2007

Using the bq2000EVM

This user’s guide describes the bq2000EVM EVM (an evaluation module for the bq2000 and bq2000T).The EVM provides a convenient method for evaluating the performance of a charge management solutionfor portable applications using either the bq2000 or bq2000T. A complete and tested charger is presented.The charger is designed to deliver up to 1.0A of continuous output current. The DV2000S1 is shipped witha programmed default charging current of 1.0A. Refer to the bq2000/bq2000T data sheet (literature ID“bq2000”) prior to using this EVM for detailed information on the bq2000 or bq2000T device.

The bq2000 is a programmable, monolithic IC for fast-charge management of nickel cadmium (NiCd),nickel metal-hydride (NiMH), or lithium-ion (Li-Ion) batteries in single or multi-chemistry applications. Thebq2000 detects the battery chemistry and proceeds with the optimal charging and termination algorithms.This process eliminates undesirable undercharged or overcharged conditions and allows accurate andsafe termination of fast charge. Depending on the chemistry, the bq2000 provides a number of chargetermination criteria. The bq2000 can terminate charge based on peak voltage detection (PVD) for NiCdand NiMH batteries, minimum charging current for Li-Ion batteries, maximum temperature, or maximumcharge time. For safety, the bq2000 inhibits fast charge until the battery voltage and temperature arewithin user-defined limits. If the battery voltage is below the low-voltage threshold, the bq2000 usestrickle-charge to condition the battery. For NiMH batteries, the bq2000 provides an optional top-off chargeto maximize the battery capacity. The integrated high-frequency comparator allows the bq2000 to be thebasis for a complete, high-efficiency power-conversion circuit for both nickel-based and lithium-basedchemistries.

In addition to this bq2000EVM EVM, there are also DV2000S1 and DV2000TS1 EVMs available forevaluating the performance of the bq2000 or bq2000T. The DV2000S1/TS1 boards make use ofthrough-hole devices while the bq2000EVM board was later developed to utilize all surface-mount devicesand reduce the physical size of the EVM. Both EVMs provide complete evaluation environments for thebq2000/bq2000T, support up to 4 Li-Ion or 10 NiCd/NiMH cells, are user-programmable for other cellcounts, and can operate with or without a charge top-off period. To correctly operate each EVM, consultits corresponding user’s guide.

Specification Min Typ Max Unit

Input DC voltage, V(DC+) – V(DC–) 10 25 VBattery voltage, V(BAT+) – V(BAT–) 18 VBattery charge current, I(BAT+) 1.0 AThermistor voltage, V(TS) 0 5 V

SLUU270 – June 2007 Using the bq2000EVM 1Submit Documentation Feedback

www.ti.com

2 Setup and Configuration

2.1 Connection Descriptions

2.2 Board Setup

Setup and Configuration

This section describes the jumper connections on the bq2000EVM along with the resulting operation. Itdescribes the different ways this EVM can be used with a variety of battery packs.

Jumper

DescriptionDesignator

J1: DC+ DC input positive voltage from external supplyJ1: DC– DC input groundJ2: BAT+ Positive terminal of the battery or battery packJ2: BAT– Negative terminal of the battery or battery packJ2: TS Thermistor connectionJ2: BAT– Negative terminal of the battery or battery pack, used for thermistor connectionJ3: C/4, 320, Y Place jumper here for a C/4 charge rate, 320 minute timeout, top-off mode selectedJ3: C/4, 320, N Place jumper here for a C/4 charge rate, 320 minute timeout, top-off mode not selectedJ3: C/3, 240, Y Place jumper here for a C/3 charge rate, 240 minute timeout, top-off mode selectedJ3: C/3, 240, N Place jumper here for a C/3 charge rate, 240 minute timeout, top-off mode not selectedJ3: C/2, 160, Y Place jumper here for a C/2 charge rate, 160 minute timeout, top-off mode selectedJ3: C/2, 160, N Place jumper here for a C/2 charge rate, 160 minute timeout, top-off mode not selectedJ3: C, 80, Y Place jumper here for a C charge rate, 80 minute timeout, top-off mode selectedJ3: C, 80, N Place jumper here for a C charge rate, 80 minute timeout, top-off mode not selectedJ3: USER, Y Place jumper here to select a user-defined charge rate and timeout, uses top-off modeJ3: USER, N Place jumper here to select a user-defined charge rate and timeout, no top-off modeJ4: Top off Y Place jumper between Y and COM to select top-off modeJ4: Top off COM Connect to top-off Y or top-off NJ4: Top off N Place jumper between N and COM to not use top-off modeJ5: USER Place jumper here for a user-defined NiCd/NiMH cell countJ5: 10 Place jumper here when using a battery pack of 10 NiCd/NiMH cells in a series configurationJ5: 8 Place jumper here when using a battery pack of 8 NiCd/NiMH cells in a series configurationJ5: 6 Place jumper here when using a battery pack of 6 NiCd/NiMH cells in a series configurationJ5: 5 Place jumper here when using a battery pack of 5 NiCd/NiMH cells in a series configurationJ5: 4 Place jumper here when using a battery pack of 4 NiCd/NiMH cells in a series configurationJ6: 4 Place jumper here when using a battery pack of 4 Li-Ion cells in a series configurationJ6: 3 Place jumper here when using a battery pack of 3 Li-Ion cells in a series configurationJ6: 2 Place jumper here when using a battery pack of 2 Li-Ion cells in a series configurationJ6: 1 Place jumper here when using a battery pack of 1 Li-Ion cells in a series configuration

The bq2000EVM can be configured as described below.

Number of Cells Selection (JP5, JP6): These jumpers select the number of cells for either Li-Ion orNiCd/NiMH batteries. These jumpers should be changed only if the battery is absent or if the DC supply isnot connected to the board. Only one jumper should be placed on a J5 or J6 connection for proper circuitconfiguration.

Note that there are two USER defined connections provided on J5. This connection can be configured forNiCd/NiMH or Li-Ion cell counts other than what are predefined on the bq2000EVM. Configuration isaccomplished by placing an appropriate resistor in the USER Y or N position according to the desiredbattery pack voltage.

Using the bq2000EVM2 SLUU270 – June 2007Submit Documentation Feedback

www.ti.com

2.3 Setup Procedure – Testing With a Battery Pack

2.4 Setup Procedure – Testing Without a Battery Pack

12 V

Power Supply 1

2.0 V-4.5 V

Power Supply 2

DC+

DC-

BAT+

BAT-

(No Connect)

BAT-

SETUP

Load Card

BQ2000EVM

Setup and Configuration

The following procedure outlines how to set up the bq2000EVM when charging a battery pack:1. Configure the bq2000EVM for the appropriate number and type of cells by placing a single jumper onone of the J5 or J6 connection points.2. Place a jumper between J4’s COM and YES to utilize the bq2000’s top-off mode or between COM andNO to not use the top-off mode.3. Place one jumper on one of the J3 connection points to select a charge rate and timeout duration. Iftop-off mode is being used, only a J3 connection labeled “Y” should be used. A J3 connection labeled“N” should be used if top-off mode is not being used.4. Connect the thermistor between TS and the lower BAT–. If using a thermistor is not desired, a 10-k Ωresistor can be connected between TS and BAT–.5. Connect the battery pack to BAT+ and BAT–.6. Connect the charging supply to J1 while ensuring that it falls within the bq2000EVM’s recommendedDC operating range.

Sometimes it is beneficial to test a battery charger without charging an actual battery due to the long timeneeded to charge/discharge battery packs. An ideal substitute for a battery is a four-quadrant powersupply that can both sink and source current. If a four-quadrant power supply is unavailable, the load cardshown below can be used in parallel with a standard two-quadrant power supply. The load card as shownis designed to charge a one-cell lithium-ion battery at 1A constant current charge.

1. Configure the bq2000EVM for the appropriate number and type of cells by placing a single jumper onone of the J5 or J6 connection points.2. Place a jumper between J4’s COM and YES to utilize the bq2000’s top-off mode or between COM andNO to not use the top-off mode.3. Place one jumper on one of the J3 connection points to select a charge rate and timeout duration. Iftop-off mode is being used, only a J3 connection labeled “Y” should be used. A J3 connection labeled“N” should be used if top-off mode is not being used.4. Connect the load card as shown above. A 10-k Ωthermistor or 10-k Ωresistor can be added to the loadcard for convenience. The JP1 header and 4.99-k Ωresistor are added to demonstrate the temperaturesensing feature of the bq2000EVM. When the jumper is removed, the EVM will charge as normal.Installing the jumper simulates an over-temperature condition and the charger will turn off.5. Connect the second power supply to the load card as shown. The series diode is added to protect thepower supply from sinking current and potential damage. Turn power supply two on so that it is withinthe voltage range set in step one (4.2V/cell if simulating a lithium-ion battery is desired, or 1.2V/cell if anickel-based battery is desired).6. Connect the charging supply to J1 while ensuring that it falls within the bq2000EVM’s recommendedDC operating range.

The load card allows a two-quadrant power supply to be used because it sinks current to BAT– throughthe shunt resistors. The above load card is designed for charging a single lithium-ion battery at 1Aconstant current. The charge range for a one-cell lithium-ion battery is 2.7 V to 4.2 V. Whenever thevoltage on power supply two is less than 2.7 V, the bq2000EVM will be off and power supply two will

SLUU270 – June 2007 Using the bq2000EVM 3Submit Documentation Feedback

www.ti.com

Setup and Configuration

source current through the shunt resistors. The charging algorithm for the bq2000EVM depends on thecharge voltage that it sees on BAT+. As the voltage on power supply two is increased to within the setcharge range of the bq2000EVM, the bq2000EVM will turn on into constant current mode and will sourceits set charge current (1A) into the load card. As the voltage provided by power supply two is increased, itwill source enough current into the load card such that:V

ps2

= R

load

x (I

ps2

+ I

charge

), where I

charge

is the constant current charge sourced by the bq2000EVM,I

ps2

is the current sourced by power supply two, R

load

is the parallel resistance between BAT+ andBAT–, and V

ps2

is the voltage on power supply two.

Once the voltage on power supply two goes above the termination point set on the bq2000EVM, thebq2000EVM will shut off and all current will be sourced by power supply two. To design a load card for anarbitrary battery pack, the following procedure can be used.1. Determine the minimum (V

min

) and maximum (V

max

) charging voltages for the desired battery pack.2. Determine the desired constant current charge (I

chg

)3. Calculate the resistance (R

load

) needed between BAT+ and BAT– by the following equation:R

load

= V

min

/ I

chg4. Calculate the power that will be dissipated by the shunts resistance (P

shunt

):P

shunt

= V

max

/ R

load5. Choose a combination of parallel resistors that meet the equivalent resistance and overall powerdissipation rating needed to satisfy the above equations. NOTE: Make sure power resistors are heatsunk properly to handle the amount of power to avoid overstressing the components.

Using the bq2000EVM4 SLUU270 – June 2007Submit Documentation Feedback

www.ti.com

3 Schematic

Schematic

SLUU270 – June 2007 Using the bq2000EVM 5Submit Documentation Feedback

www.ti.com

4 Physical Layouts

Physical Layouts

Top Assembly

6Using the bq2000EVM SLUU270 – June 2007Submit Documentation Feedback

www.ti.com

Physical Layouts

Layer 1

SLUU270 – June 2007 Using the bq2000EVM 7Submit Documentation Feedback

www.ti.com

5 Bill of Materials

Bill of Materials

Layer 2

Table 1. HPA250A Bill of MaterialsCount RefDes Value Description Size Part Number MFR

2 C1, C2 0.1 µF Capacitor, Ceramic, X7R, 0.1 µF 0603 {std}

1 C10 0.15 µF Capacitor, Ceramic, X7R, 0.15 µF, 16V 0603 {std}

2 C3, C5 10 µF Capacitor, Aluminum, 10 µF, 25V, 20% 0.177 ×0.177 EEV-FK1E100R Panasonic

2 C4, C9 1000pF Capacitor, Ceramic, 1000pF, 50V, X7R 0805 {std} {std}

Capacitor, Aluminum, SM, 330 µF, 25V,1 C6 330 µF 8 ×10 mm EEV-FK1E331P Panasonic0.16 Ω(FK series)

1 C7 4.7pF Capacitor, Ceramic, 4.7pF, 50V, NPO 0603 {std} {std}

1 C8 0.047 µF Capacitor, Ceramic, X7R, 0.047 µF, 25V 0603 {std}

1 D1 Red Diode, LED, Red, 1.7V, 40mcd, SM 1210 SML-LX2832SRC-TR Lumex

2 D2, D4 B230-13 30V, 2A Diode, Schottky, 2A, 30V SMB B230-13 Diodes, Inc.

2 D3, D5 BAT54 Diode, Schottky, 200mA, 30V SOT23 BAT54 Vishay-Liteon

1 D6 5.6V Diode, Zener, 5.6V, 350mW SOT23 BZX84C5V6T Diodes, Inc.

1 D7 MMSZ5234BT1 Diode, Zener, 6.2V, 500mW SOD-123 MMSZ5234BT1 On Semi

1 J1 Terminal block, 2pin, 6A, 3,5 mm 0.27 ×0.25" ED1514 OST

1 J2 Terminal block, 4pin, 6A, 3,5 mm 0.55 ×0.25" ED1516 OST

Header, 2x10pin, 100mil spacing (36-pin1 J3 0.100 ×10 ×2" PTC36DAAN Sullinsstrip)

1 J4 Header, 3pin, 100mil spacing, (36-pin strip) 0.100 ×3" PTC36DAAN Sullins

8Using the bq2000EVM SLUU270 – June 2007Submit Documentation Feedback

www.ti.com

6 References

References

Table 1. HPA250A Bill of Materials (continued)Count RefDes Value Description Size Part Number MFR

1 J5 Header 2x6 pin, 100mil spacing (36-pin strip) 0.100 ×2×6" PTC36DAAN Sullins

1 J6 Header 2x4 pin, 100mil spacing (36-pin strip) 0.20 ×0.40 PTC36DAAN Sullins

1 L1 100 µH Inductor, SMT, 100 µH, 1.3A, 160m Ω0.472 sq CDRH125-101 Sumida

1 Q1 Si3455DV MOSFET, Pch, –30V, 2.3A, 190m ΩMicro6 Si3455DV Vishay-Liteon

1 Q2 MMBT3906 Bipolar, PNP, 40V, 200mA, 0.22W SOT23 MMBT3906-7 On Semi

2 Q3, Q4 MMBT3904 Bipolar, NPN, 40V, 200mA, 250mW SOT23 MMBT3904 Fairchild

1 R1 100k ΩResistor, Chip, 100k Ω, 1/16W, 1% 0603 Std Std

1 R11 330 ΩResistor, Chip, 330 Ω, 1/16W, 1% 0603 Std Std

1 R12 499 ΩResistor, Chip, 499 Ω, 1/16W, 1% 0603 Std Std

1 R13 604 ΩResistor, Chip, 604 Ω, 1/16W, 1% 0603 Std Std

1 R14 249k ΩResistor, Chip, 249k Ω, 1/16W, 1% 0603 Std Std

2 R15, R32 187k ΩResistor, Chip, 187k Ω, 1/16W, 1% 0603 Std Std

1 R16 150k ΩResistor, Chip, 150k Ω, 1/16W, 1% 0603 Std Std

1 R17 107K Resistor, Chip, 107k Ω, 1/16W, 1% 0603 Std Std

1 R18 681k ΩResistor, Chip, 681k Ω, 1/16W, 1% 0603 Std Std

2 R19, R31 143k ΩResistor, Chip, 143k Ω, 1/16W, 1% 0603 Std Std

1 R2 2k ΩResistor, Chip, 2k Ω, 1/16W, 1% 0603 Std Std

1 R20 232k ΩResistor, Chip, 232k Ω, 1/16W, 1% 0603 Std Std

1 R21 102k ΩResistor, Chip, 102k Ω, 1/16W, 1% 0603 Std Std

1 R22 82.5k ΩResistor, Chip, 82.5k Ω, 1/16W, 1% 0603 Std Std

1 R24 47.5k ΩResistor, Chip, 47.5k Ω, 1/16W, 1% 0603 Std Std

1 R25 95.3k ΩResistor, Chip, 95.3k Ω, 1/16W, 1% 0603 Std Std

1 R27 14.7k ΩResistor, Chip, 14.7k Ω, 1/16W, 1% 0603 Std Std

1 R28 29.4k ΩResistor, Chip, 29.4k Ω, 1/16W, 1% 0603 Std Std

1 R29 44.2k ΩResistor, Chip, 44.2k Ω, 1/16W, 1% 0603 Std Std

1 R3 0.05 ΩResistor, Chip, 0.05 Ω, 1/10W, 1% 0805 Std Std

1 R30 59k ΩResistor, Chip, 59k Ω, 1/16W, 1% 0603 Std Std

1 R4 14.7k ΩResistor, Chip, 14.7k Ω, 1/16W, 1% 0603 Std Std

1 R10 10k ΩResistor, Chip, 10k Ω, 1/16W, 1% 0603 Std Std

1 R5 31.6k ΩResistor, Chip, 31.6k Ω, 1/16W, 1% 0603 Std Std

1 R6 750k ΩResistor, Chip, 750k Ω, 1/16W, 1% 0603 Std Std

R7, R23,0 spare Resistor, Chip, Ohms, 1/16W, 1% 0603 Std StdR26

1 R9 1k ΩResistor, Chip, 1k Ω, 1/16W, 1% 0603 Std Std

1 U1 BQ2000PW IC, Fast Charge, Multi-chemistry TSSOP-8 BQ2000PW TI

Circuit1 HPA250 Circuit board HPA250 Anyboard

1 RT1 Thermister, 10k Ω0.095 x 1.150 In NTC103AT Semitec

Notes: 1. These assemblies are ESD sensitive, ESD precautions shall be observed.

2. These assemblies must be clean and free from flux and all contaminants. Use of no clean flux is not acceptable.

3. These assemblies must comply with workmanship standards IPC-A-610 Class 2.

Ref designators marked with an asterisk ('**') cannot be substituted.4.

All other components can be substituted with equivalent MFG's components.

5. After testing RT1 is taped to the bottom of UUT with ESD tape.

1. bq2000 data sheet, http://focus.ti.com/lit/ds/symlink/bq2000.pdf

2. Using the bq2000/T to Control Fast Charge, http://focus.ti.com/lit/an/slua064b/slua064b.pdf

SLUU270 – June 2007 Using the bq2000EVM 9Submit Documentation Feedback

www.ti.com

References

FCC Warning

This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT,DEMONSTRATION, OR EVALUATION PURPOSES ONLY and is not considered by TI to be afinished end-product fit for general customer use. It generates, uses, and can radiate radiofrequency energy and has not been tested for compliance with the limits of computing devicespursuant to part 15 of FCC rules, which are designed to provide reasonable protection againstradio frequency interference. Operation of this equipment in other environments may causeinterference with radio communications, in which case the user at his own expense will berequired to take whatever measures may be required to correct this interference. - SSZZ017A -February 2006

EVALUATION BOARD/KIT IMPORTANT NOTICE

Texas Instruments (TI) provides the enclosed product(s) under the following conditions:This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT,DEMONSTRATION, OR EVALUATION PURPOSES ONLY and is not considered by TI to be afinished end-product fit for general consumer use. Persons handling the product(s) must haveelectronics training and observe good engineering practice standards. As such, the goods beingprovided are not intended to be complete in terms of required design-, marketing-, and/ormanufacturing-related protective considerations, including product safety and environmentalmeasures typically found in end products that incorporate such semiconductor components orcircuit boards. This evaluation board/kit does not fall within the scope of the European Uniondirectives regarding electromagnetic compatibility, restricted substances (RoHS), recycling(WEEE), FCC, CE or UL, and therefore may not meet the technical requirements of thesedirectives or other related directives.Should this evaluation board/kit not meet the specifications indicated in the User’s Guide, theboard/kit may be returned within 30 days from the date of delivery for a full refund. THEFOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY SELLER TO BUYERAND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY,INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULARPURPOSE.

The user assumes all responsibility and liability for proper and safe handling of the goods. Further,the user indemnifies TI from all claims arising from the handling or use of the goods. Due to theopen construction of the product, it is the user’s responsibility to take any and all appropriateprecautions with regard to electrostatic discharge.EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER PARTYSHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, ORCONSEQUENTIAL DAMAGES.TI currently deals with a variety of customers for products, and therefore our arrangement with theuser is not exclusive.TI assumes no liability for applications assistance, customer product design, softwareperformance, or infringement of patents or services described herein.Please read the User’s Guide and, specifically, the Warnings and Restrictions notice in the User’sGuide prior to handling the product. This notice contains important safety information abouttemperatures and voltages. For additional information on TI’s environmental and/or safetyprograms, please contact the TI application engineer or visit www.ti.com/esh .

10 Using the bq2000EVM SLUU270 – June 2007Submit Documentation Feedback

Tabla de contenidos

Otros manuales de Placa madre de Texas Instruments

Texas Instruments

Texas Instruments TPA6404-Q1 Manual de usuario

Texas Instruments

Texas Instruments TPD4S214EVM Manual de usuario

Texas Instruments

Texas Instruments ADS7861EVM Manual de usuario

Texas Instruments

Texas Instruments DRV10963 Manual de usuario

Texas Instruments

Texas Instruments TSW12D1620 Manual de usuario

Texas Instruments

Texas Instruments bq76PL536PGM-1 Manual de usuario

Texas Instruments

Texas Instruments TLV751-EVM Manual de usuario

Texas Instruments

Texas Instruments AWR1843AOP EVM Manual de usuario

Texas Instruments

Texas Instruments TLV320AIC23 Manual de usuario

Texas Instruments

Texas Instruments TPS25810EVM-745 Manual de usuario

Texas Instruments

Texas Instruments TMDSCNCD263-PMIC Manual de usuario

Texas Instruments

Texas Instruments BQ77207 Manual de usuario

Texas Instruments

Texas Instruments DS90UB934-Q1EVM Manual de usuario

Texas Instruments

Texas Instruments bq2589EVM Manual de usuario

Texas Instruments

Texas Instruments BQ24450EVM Manual de usuario

Texas Instruments

Texas Instruments AN-2154 Manual de usuario

Texas Instruments

Texas Instruments LM63635DNEVM Manual de usuario

Texas Instruments

Texas Instruments ADC121S101EVM Manual de usuario

Texas Instruments

Texas Instruments LMK04808B Manual de usuario

Texas Instruments

Texas Instruments bq2512 Series Manual de usuario

Texas Instruments

Texas Instruments Stellaris LM3S6965 Manual de usuario

Texas Instruments

Texas Instruments HDC2022EVM Manual de usuario

Texas Instruments

Texas Instruments TIO 1 2 Series Manual de usuario

Texas Instruments

Texas Instruments TPS7A87 Manual de usuario

Manuales populares de Placa madre de otras marcas

DFI

DFI SD170 Manual de usuario

ASROCK

ASROCK ROMED8-2T Manual de usuario

Asus

Asus P2L97A Manual de usuario

Winmate

Winmate IC70 Manual de usuario

Asus

Asus MES-B Manual de usuario

Grantech

Grantech SYS8F377VGGA-3OMN Manual de usuario

Telit Wireless Solutions

Telit Wireless Solutions SL869-3DR Manual de usuario

Gigabyte

Gigabyte GA-9IVDT Manual de usuario

Commell

Commell MS-C73 Manual de usuario

IBT Technologies

IBT Technologies MB860 Manual de usuario

Nvidia

Nvidia TEGRA DG-04927-001_V01 Manual de usuario

Biostar

Biostar M7VIT Bravo Instrucciones de funcionamiento e instalación

Intel

Intel D33217CK Manual de usuario

Asus

Asus F1A55-M LX PLUS R2.0 Manual de usuario

EPC

EPC EPC9147C Manual de usuario

Asus

Asus EX-B760M-V5 D4 Manual de usuario

EPOX

EPOX MU-8KHA0010 Manual de usuario

Ski-Doo

Ski-Doo Bombardier MPEM 219 700 090 Manual de usuario

Texas Instruments bq2000EVM Manual de usuario

Manuales populares de Placa madre de otras marcas