Français dropdown-ico

Manuel d’utilisation Fairchild RC5050

24 pages 0.52 mb
Télécharger

Aller à la page of 24

Summary
  • Fairchild RC5050 - page 1

    Application Note 50 Implementing the RC5050 and RC5051 DC-DC Conver ters on Pentium ® Pr o Motherboar ds www .fair childsemi.com Intr oduction This document describes how to implement a switching v olt- age regulator using an RC5050 or an RC5051 high speed controller , a po wer inductor , a Schottky diode, appropriate capacitors, and external po w ...

  • Fairchild RC5050 - page 2

    AN50 APPLICATION NOTE 2 T able 2. Intel Pentium Pr o and OverDrive ® Processor P ower Specifications Notes: 1. Maximum power values are measured at typical V CC P to take into account the thermal time constant of the CPU package. 2. Flexible motherboard specifications are recommendations only. Actual specifications are subject to change. CPU Mode ...

  • Fairchild RC5050 - page 3

    APPLICATION NOTE AN50 3 I/O Controls In addition to the V oltage Identification, there are sev eral sig- nals that control the DC-DC con verter or provide feedback from the DC-DC con verter to the CPU. They are Po wer- Good (PWRGD), Output Enable (OUTEN), and Upgrade Present (UP#). These signals will be discussed later . RC5050 and RC5051 Descript ...

  • Fairchild RC5050 - page 4

    AN50 APPLICATION NOTE 4 The HIDR V driver has a po wer supply , VCCQP , supplied from a 12V source as illustrated in Figure 2. The resulting voltage is suf ficient to provide the gate to source voltage to the external MOSFET that is required to achie ve a low R DS,ON . Since the lo w side synchronous FET is referenced to ground, there is no need t ...

  • Fairchild RC5050 - page 5

    APPLICATION NOTE AN50 5 Short Circuit Protection A current sense methodology is implemented to disable the output driv e signal to the MOSFET(s) when an over-current condition is detected. The v oltage drop created by the output current flowing across a sense resistor is presented to an internal comparator . When the v oltage developed across the ...

  • Fairchild RC5050 - page 6

    AN50 APPLICATION NOTE 6 Figure 4. Synchronous DC-DC Converter Application Schematic Using the RC5051 VO GND VID3 VID2 VID1 VID0 8 7 6 5 4 3 2 1 9 10 11 12 13 14 15 16 17 18 19 20 +5V PWRGD RC5051 VCC ENABLE C10 0.1 µ F C11 0.1 µ F 10K C EXT C7 0.1 µ F C6 4.7 µ F DS1 1N5817 C1 1000 µ F C2 C3 1000 µ F 1000 µ F C5 0.1 µ F D1 1N4691 C12 1 µ F ...

  • Fairchild RC5050 - page 7

    APPLICATION NOTE AN50 7 MOSFET Selection Cosiderations MOSFET Selection This application requires N-channel Logic Lev el Enhance- ment Mode Field Effect Transistors. Desired characteristics are as follows: • Low Static Drain-Source On-Resistance, R DS,ON < 37 m Ω (lower is better) • Low g ate driv e voltage, V GS ≤ 4.5V • Power package ...

  • Fairchild RC5050 - page 8

    AN50 APPLICATION NOTE 8 T wo MOSFETs in parallel. W e recommend two MOSFETs used in parallel instead of one single MOSFET . The following significant adv antages are realized using two MOSFETs in parallel: • Significant reduction of P ower dissipation . Maximum current of 14A with one MOSFET : P MOSFET = (I 2 R DS,ON )(Duty Cycle) = (14) 2 (0.0 ...

  • Fairchild RC5050 - page 9

    APPLICATION NOTE AN50 9 Con ver ter Efficiency Losses due to parasitic resistance in the switches, coil, and sense resistor dominate at high load-current lev el. The major loss mechanisms under heavy loads, in usual order of impor - tance, are: • MOSFET I 2 R Losses • Coil Losses • Sense Resistor Losses • gate-charge losses • diode-condu ...

  • Fairchild RC5050 - page 10

    AN50 APPLICATION NOTE 10 Selecting the Inductor The inductor is one of the most critical components to be selected for a DC-DC con verter application. The critical parameters are inductance (L), maximum DC current (I O ), and DC coil resistance (R l ). The inductor core material is a crucial factor in determining the amount of current the inductor ...

  • Fairchild RC5050 - page 11

    APPLICATION NOTE AN50 11 Therefore, for load current of 14.5A, the peak current through the inductor , I pk , is found to be approximately 15.5A: Therefore, the short circuit detection threshold must be at least 16.5A. The next step is to determine the v alue of the sense resistor . Including sense resistor tolerance, the sense resistor value can b ...

  • Fairchild RC5050 - page 12

    AN50 APPLICATION NOTE 12 Embedded Sense Resistor (PC T race Resistor) Embedded PC trace resistors hav e the advantage of near zero cost implementation. Howe ver , the value of the PC trace resistor has large v ariations. Embedded resistors have 3 major error sources: the sheet resistivity of the inner layer , the mismatch due to L/W , and the tempe ...

  • Fairchild RC5050 - page 13

    APPLICATION NOTE AN50 13 tion. The embedded sense resistor allows the user to choose a plus or a minus delta resistance tap to offset an y large sheet resisti vity change. In this design, the center tap yields 6m Ω , the left tap yields 6.7m Ω , and the right tap yields 5.3m Ω . RC5050 and RC5051 Short Circuit Current Characteristics The RC50 ...

  • Fairchild RC5050 - page 14

    AN50 APPLICATION NOTE 14 Figure 13A. V CCQP Output Waveform for Normal Operation Condition with V out = 3.3V@10A Figure 13B. V CCQP Output Waveform for Output Shorted to Ground Power dissipation on the Schottk y diode during a short cir- cuit condition must also be considered. During normal oper- ation, the Schottky diode dissipates po wer while th ...

  • Fairchild RC5050 - page 15

    APPLICATION NOTE AN50 15 FET . Low Equi valent Series Resistance (ESR) capacitors are best suited for this type of application. Incorrect selection can hinder the con verter's overall performance. The input capacitor should be placed as close to the drain of the FET as possible to reduce the effect of ringing caused by long trace lengths. The ...

  • Fairchild RC5050 - page 16

    AN50 APPLICATION NOTE 16 PCB La yout Guidelines and Considerations PCB Lay out Guidelines • Placement of the MOSFETs relativ e to the RC5050 is critical. Place the MOSFETs (M1 & M2) so that the trace length of the HIDR V pin from the RC5050 to the FET gates is minimized. A long lead length on this pin would cause high amounts of ringing due t ...

  • Fairchild RC5050 - page 17

    APPLICATION NOTE AN50 17 In general, all of the noisy switching lines should be kept aw ay from the quiet analog section of the RC5050. That is, traces that connect to pins 12 and 13 (HIDR V and VCCQP) should be kept far a way from the traces that con- nect to pins 1 through 5, and pin 16. • Place the 0.1 µ F decoupling capacitors as close to th ...

  • Fairchild RC5050 - page 18

    AN50 APPLICATION NOTE 18 Guidelines f or Debug ging and P erformance Ev aluations Debug ging Y our First Design Implementation 1. Note the setting of the VID pins to kno w what voltage is to be expected. 2. Do not connect any load to the circuit. While monitoring the output voltage, apply po wer to the part with current limiting at the power supply ...

  • Fairchild RC5050 - page 19

    APPLICATION NOTE AN50 19 Note: Load regulation is expected to be typically around 0.8%. The load regulation performance for this device under evaluation is excellent. Output V oltag e Load T ransients Due to Load Current Step This test is performed using Intel P6.0/P6S/P6T V oltage T ransient T ester . Note: Transient voltage is recommended to be l ...

  • Fairchild RC5050 - page 20

    AN50 APPLICATION NOTE 20 Input Ripple and P ower on Input Rush Current Note: Excellent input ripple voltage. Input ripple voltage is recom- mended to be less than 5% of the output voltage. Po wer on Input Rush Current w as not measured on the moth- erboard because we did not want to cut the 5V trace and insert a current probe in series with the sup ...

  • Fairchild RC5050 - page 21

    APPLICATION NOTE AN50 21 Attachment C Attachment D Attachment E Attachment F Attachment G ...

  • Fairchild RC5050 - page 22

    AN50 APPLICATION NOTE 22 Summary This application note cov ers many aspects of the RC5050 and RC5051 for implementation of a DC-DC con verter a on Pentium Pro motherboard. A detailed discussion includes the processor power requirements, a description of the RC5050 and RC5051, design considerations and compo- nents selection, layout guidelines and c ...

  • Fairchild RC5050 - page 23

    APPLICATION NOTE AN50 23 Appendix A Directory of Component Suppliers Dale Electronics, Inc. E. Hwy . 50, PO Box 180 Y ankton, SD 57078-0180 PH: (605) 665-9301 Fuji Electric Collmer Semiconductor Inc. 14368 Proton Rd. Dallas, T exas 75244 PH: (214)233-1589 General Instrument Power Semiconductor Di vision 10 Melville Park Road Melville, NY 11747 PH: ...

  • Fairchild RC5050 - page 24

    AN50 APPLICATION NOTE 2/98 0.0m Stock#AN30000050  1998 Fairchild Semiconductor Corporation LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support de ...

Fabricant Fairchild Catégorie Computer Hardware

Les documents que nous recevons du fabricant de l'appareilFairchild RC5050 peuvent être divisés en plusieurs groupes. Ceux-ci sont, entre autres:
- dessins techniques Fairchild
- manuels d’utilisations RC5050
- fiches produit Fairchild
- dépliants
- ou étiquettes-énergie Fairchild RC5050
Tous sont importants, mais les informations les plus importantes du point de vue de l'utilisation de l'appareil se trouvent dans le manuel d’utilisation Fairchild RC5050.

Un groupe de documents appelé manuels d’utilisation est également divisé en types plus spécifiques, tels que: Manuels d’installation Fairchild RC5050, manuels d’entretien, brefs manuels ou manuels de l’utilisateur Fairchild RC5050. Selon vos besoins, vous devriez chercher le document dont vous avez besoin. Sur notre site, vous pouvez voir le manuel le plus populaire d’utilisation du produit Fairchild RC5050.

Manuels d’utilsiation similaires

Manuel d’utilisation complet de l’appareil Fairchild RC5050, quelle devrait-elle être?
Le manuel d’utilisation, également appelé le mode d’emploi, ou tout simplement le manuel, est un document technique destiné à aider à utiliser Fairchild RC5050 par les utilisateurs. Des manuels sont généralement écrits par un rédacteur technique, mais dans un langage accessible à tous les utilisateurs Fairchild RC5050.

Le manuel d’utilisation complet Fairchild, devrait inclure plusieurs éléments de base. Certains d'entre eux sont moins importants, tels que: la couverture / page de titre ou pages d'auteur. Cependant, la partie restante, devrait nous fournir des informations importantes du point de vue de l'utilisateur.

1. Introduction et des conseils sur la façon d'utiliser le manuel Fairchild RC5050 - Au début de chaque manuel, nous devrions trouver des indices sur la façon d'utiliser le document. Il doit contenir des informations sur l'emplacement de la table des matières Fairchild RC5050, FAQ ou des problèmes les plus fréquents - les points qui sont les plus souvent recherchés par les utilisateurs de chaque manuel
2. Table des matières - index de tous les conseils pour lFairchild RC5050 qui peuvent être trouvés dans le document courant
3. Conseils sur la façon d'utiliser les fonctions de base de l’appareil Fairchild RC5050 - qui devraient nous aider dans les premières étapes lors de l'utilisation Fairchild RC5050
4. Troubleshooting - séquence systématique des activités qui nous aideront à diagnostiquer et ensuite résoudre les principaux problèmes de Fairchild RC5050
5. FAQ - questions fréquemment posées
6. Détails du contact Informations sur l'endroit où chercher le contact avec le fabricant / service Fairchild RC5050 dans un pays donné, si le problème ne peut être résolu par nous-mêmes.

Avez-vous une question à propos de Fairchild RC5050?

Utiliser le formulaire ci-dessous

Si vous n’avez pas résolu votre problème avec Fairchild RC5050, avec l'aide du manuel que vous avez trouvé, posez une question en utilisant le formulaire ci-dessous. Si un utilisateur a eu un problème similaire avec Fairchild RC5050 il est probable qu’il a envie de partager la façon de le résoudre.

Réécrire le texte de l'image

Captcha
Nouvelle image

Commentaires (0)