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2009.04 - Rev.B

Hi-performance Regulator IC Series for PCs

2ch Switching Regulators

for Desktop PC

BD9540EFV

●Description

BD9540EFV is a 2ch switching regulator synchronous controller that can generate low output voltages (0.75V to 5.5V). High

efficiency for the switching regulator can be achieved due to its external N-MOSFET power transistor. The IC also

incorporates a new technology called H

Reg

, a Rohm proprietary control method which facilitates ultra-high transient

response against changes in load. For protection and ease of use, the IC also incorporates soft start, and short circuit

protection with timer latch functions. This switching regulator is designed for DRAM and power supplies for graphics chips.

●Features

1) 2ch H

Reg

DC/DC converter synchronous controller

2) Thermal Shut Down (TSD), Under-Voltage Lock-Out (UVLO),

Adjustable Over Current Protection (OCP) : detected Low side FET Ron, Over Voltage Protection (OVP),

Short Circuit Protection (SCP) built-in

3) Soft start function to minimize rush current during startup

4) HTSSOP-B28 package

5) Built-in 5V power supply for FET driver

6) Integrated bootstrap diode

●Applications

LCD-TV, Game Consoles, Desktop PCs

●Maximum Absolute Ratings (Ta=25℃)

Parameter Symbol Limit Unit

Input Voltage VIN 24

BOOT Voltage BOOT1,BOOT2 30

BOOT-SW Voltage BOOT1-SW1, BOOT2-SW2 7

HG-SW Voltage HG1-SW1, HG2-SW2 7

LG Voltage LG1, LG2 5VReg V

Output Voltage VOUT1, VOUT2 7

Output Feedback Voltage FB1, FB2 5VReg V

5VReg Voltage 5VReg 7

Current Limit Setting Voltage ILIM1, ILIM2 5VReg V

Logic Input Voltage 1 EN1, EN2 24

Logic Input Voltage 2 CTL1, CTL2 7

Power dissipation 1 Pd1 1.45

Power dissipation 2 Pd2 1.85

Power dissipation 3 Pd3 3.30

Power dissipation 4 Pd4 4.70

Operating Temperature Range Topr -20～+100 ℃

Storage Temperature Range Tstg -55～+150 ℃

Junction Temperature Tjmax +150 ℃

*1 Not to exceed Pd.

*2 Reduced by 11.6mW for each increase in Ta of 1℃ over 25℃

(when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB, 1layer, no copper foil area.)

*3 Reduced by 14.8mW for increase in Ta of 1℃ over 25℃.

(when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB, 2layers, copper foil area : 15mm×15mm.)

*4 Reduced by 26.4mW for increase in Ta of 1℃ over 25℃.

(when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB, 2layers, copper foil area : 70mm×70mm.)

*5 Reduced by 37.6mW for increase in Ta of 1℃ over 25℃.

(when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB, 4layers, copper foil area : 70mm×70mm.)

No.09030EBT07

Summary of content (18 pages)

PAGE 1
Hi-performance Regulator IC Series for PCs 2ch Switching Regulators for Desktop PC No.09030EBT07 BD9540EFV ●Description BD9540EFV is a 2ch switching regulator synchronous controller that can generate low output voltages (0.75V to 5.5V). High efficiency for the switching regulator can be achieved due to its external N-MOSFET power transistor.
PAGE 2
Technical Note BD9540EFV ●Operating Conditions (Ta=25℃) Parameter Input voltage BOOT voltage SW Voltage BOOT-SW voltage Logic Input Voltage 1 Logic Input Voltage 2 Output Voltage MIN ON Time Symbol VIN BOOT1, BOOT2 SW1, SW2 BOOT1-SW1, BOOT2-SW2 EN1, EN2 CTL1, CTL2 VOUT1, VOUT2 tonmin Min. 7.5 4.5 -0.7 4.5 0 0 0.7 - Max. 20 25 20 5.5 20 5.5 5.5 100 Unit V V V V V V V ns *This product should not be used in a radioactive environment. *The range of the VOUT is limited by the voltage between VIN and VOUT.
PAGE 3
Technical Note BD9540EFV ●Block Diagram VIN 23 22 5VReg 5VReg Thermal TSD Protection VOUT1 VOUT1 VIN 4 VIN BOOT1 EN1/UVLO TSD/OVP 1 5VReg 28 27 3 EN1 FB1 5VReg H Reg Controller Block SS1 Soft Start REF1 SS1 5 TM - EN1 3 12 26 25 1.02 FB1 + - 24 CTL1 8 CTL2 9 EN1 Delay UVLO 0.90 FB2 ILIM1 REF2×0.7 FB2 EN2 OVP2 REF1 PGND1 FB1 + - OVP DAC LG1 REF1×0.
PAGE 4
Technical Note BD9540EFV ●Pin Function PIN No. PIN name 1 BOOT1 2 NC 3 EN1 4 VOUT1 5 FB1 PIN Function HG Driver Power Supply Pin 1 Non connection Pin Enable Input Pin 1 (0～0.3V:OFF, 2.2～20V:ON) Output Voltage Sence Pin 1 Output Voltage Feedback Pin 1 6 NC 7 GND Sense GND Non connection Pin 8 CTL1 1ch Reference Voltage Setting Control Pin 1:See P12/17 9 CTL2 1ch Reference Voltage Setting Control Pin 2:See P12/17 10 FB2 11 VOUT2 12 EN2 Enable Input Pin 2 (0～0.3V:OFF, 2.
PAGE 5
Technical Note BD9540EFV ●Reference Data VOUT2 50[mV/div] VOUT2 50[mV/div] VOUT1 50[mV/div] SW1 10[V/div] SW1 10[V/div] SW1 10[V/div] SW2 10[V/div] SW2 10[V/div] SW2 10[V/div] IOUT2 2[A/div] IOUT2 2[A/div] IOUT2 2[A/div] (2μs/div) (2μs/div) (2μs/div) Fig.3 Transient Respnse (VIN=12V VOUT1=3.3V) Fig.2 Transient Respnse (VIN=12V VOUT2=1.05V) Fig.1 Transient Respnse (VIN=12V VOUT2=1.05V) VOUT1 50[mV/div] EN 50[V/div] SW1 10[V/div] VOUT 0.
PAGE 6
Technical Note BD9540EFV ●Reference Data 10 VCC=VREG5V EN1=EN2=0V 8 5 5.1 4 5VREG [V] 4 6 5VREG [V] IIN_STB [μA] 6 5.2 5 2 4.9 2 1 4.8 0 0 4 8 12 16 0 -20 20 0 20 40 60 80 100 0 Fig.13 VIN-IIN_STB Fig.14 Ta-5VREG 5 5 4 4 3 3 2 2 1 1 0 4 8 12 16 VEN [V] Fig.16 VEN‐IEN www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 20 20 VOUT2 [V} VOUT1 [V] 15 0 16 6 20 5 12 Fig.15 VIN-5VREG 6 10 8 VIN [V] 25 0 4 Ta [℃] VIN [V] IEN [μA] 3 7.
PAGE 7
Technical Note BD9540EFV ●Pin Descriptions ・EN1 (3 pin) / EN2 (12 pin) When the input voltage on the EN pin reaches at least 2.2V, the switching regulator becomes active. At voltages less than 0.3 V, the switching regulator becomes inactive, and the input current drops to 10μA or less. Thus the IC can be controlled from 2.5V, 3.3V or 5V power supplies. ・5VReg (22 pin) 5.0V reference voltage output pin. If at least 2.2V is supplied to either the EN1 or EN2 pin, the reference output is switched on.
PAGE 8
Technical Note BD9540EFV ●Explanation of Operation The BD9540EFV is a 2ch switching regulator controller incorporating ROHM’s proprietary H3RegTM CONTROLLA control system. When VOUT drops due to a rapid load change, the system quickly restores VOUT by extending the TON time interval. H3RegTM control (Normal operation) FB When FB falls below the threshold voltage (REF), a drop 3 TM is detected, activating the H Reg CONTROLLA system.
PAGE 9
Technical Note BD9540EFV ●Timing Chart ・Over current protection circuit tON tON tON During normal operation, when FB falls below REF, HG switches high during for the period of time tON (P8). However, if the current of the low-side FET exceeds the ILIMIT threshold, HG will switch off until it becomes below ILIMIT. tON HG LG IL ILIMIT ・Timer Latch Type Short Circuit Protection REF×0.7 Short protection engages when output falls to or below REF × 0.7.
PAGE 10
Technical Note BD9540EFV ●External Component Selection 1. Inductor (L) selection The inductance value has a major influence on output ripple current. As formula (3) below indicates, the greater the inductance or switching frequency, the lower the ripple current. ΔIL ΔIL= VIN HG (VIN-VOUT)×VOUT L×VIN×f [A]・・・(3) The proper output ripple current setting is about 30% of maximum output current. IL ΔIL=0.3×IOUTmax.
PAGE 11
Technical Note BD9540EFV 4.
PAGE 12
Technical Note BD9540EFV 6. Output Voltage Setting The IC will try to maintain output voltage such that REF≒VFB. However, the actual output voltage will also reflect the average ripple voltage value. The output voltage is set via a resistive voltage divider between the output and the FB pin.
PAGE 13
Technical Note BD9540EFV 7. Relationship between output voltage and Ton duration Both 1ch and 2ch of BD9540EFV are synchronous rectification type of switching controllers operated at fixed-frequency. The Ton duration for each channel depends on the output voltage settings, as described by the following formulas. Ton1 = VOUT1 ×2μ+130n [ns]・・・(14) VIN Ton2 = VOUT2 ×0.
PAGE 14
Technical Note BD9540EFV ●I/O Equivalent Circuits 1pin, 14pin (BOOT1, BOOT2) 3pin, 12pin (EN1, EN2) 22pin (5VReg) VIN 1MΩ 2MΩ HG SW 5VReg BOOT 8pin 9pin (CTL1, CTL2) 28pin, 15pin (HG1, HG2) BOOT 27pin, 16pin (SW1, SW2) BOOT BOOT HG 300KΩ SW 26pin, 17pin (LG1, LG2) 20pin (TEST) 24pin, 19pin (ILIM1, ILIM2) 5pin, 10pin (FB1, FB2) 5VReg 300KΩ 300KΩ 100KΩ 21pin (VCC) 4pin, 11pin (VOUT1, VOUT2) 23pin (VIN) 400KΩ 5VReg www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 14/17 2009.
PAGE 15
Technical Note BD9540EFV ●Operation Notes (1) Absolute Maximum Ratings Use of the IC in excess of absolute maximum ratings (such as the input voltage or operating temperature range) may result in damage to the IC. Assumptions should not be made regarding the state of the IC (e.g., short mode or open mode) when such damage is suffered.
PAGE 16
Technical Note BD9540EFV (11) Regarding input pins of the IC This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated. PN junctions are formed at the intersection of these P layers with the N layers of other elements, creating parasitic diodes and/or transistors.
PAGE 17
Technical Note BD9540EFV ●Ordering part number B D 9 Part No. 5 4 0 E Part No. F V - Package EFV : HTSSOP-B28 E 2 Packaging and forming specification E2: Embossed tape and reel HTSSOP-B28 9.7±0.1 (MAX 10.05 include BURR) (5.
PAGE 18
Notice Notes No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. The content specified herein is subject to change for improvement without notice. The content specified herein is for the purpose of introducing ROHM's products (hereinafter "Products"). If you wish to use any such Product, please be sure to refer to the specifications, which can be obtained from ROHM upon request.