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Rohm BD60A00NUX Скачать руководство пользователя страница 11

Technical Note

11/22

BD60A00NUX, BD60A60NUX

www.rohm.com

2011.12 - Rev.A

© 2011 ROHM Co., Ltd. All rights reserved.

●

Operating of the application deficiency

1) When 1 LED or 1string OPEN during the operating

Since FB terminal is set to 0V when set to OPEN, Output boosts up to the over voltage protection voltage. When over
voltage is detected, the boosting operation stops and then output voltage goes down slowly. Later, if output voltage
becomes less than hysteresis of over current protection, output voltage keeps boosting up to over voltage protection
voltage again.

Fig. 8 LED open detect

2) When LED short-circuited in the plural

Even if one LED short-circuits during boost operation, it usually passes along LED and it is turned on. By making LED
shorted, FB terminal voltage increases by LED VF. Therefore output voltage becomes lower by LED VF, and the
condition turns to be normal.

Fig. 9 One LED shorted

Fig.10 FB terminal – VOUT terminal shorted

FB

FB

output

Vout

FB voltage

LED

connection

normal

Open

LED current

20mA

0mA

Hysteresis voltage

0.7V+

VF of

LED

FB

VOUT

LED current

20mA

0.7V

LED short

VF of

LED

VF of

LED

FB

VOUT

FB

VOUT

LED current 20mA

0.7V

LED short

VIN

5.9V

0.1mA

100uS

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Содержание BD60A00NUX

Страница 1: ... 1ms typ 6 Over voltage protection 42V typ BD60A00NUX 28Vtyp BD60A60NUX 7 SBD open protection and output short protection 8 Over current protection 9 LED terminal over voltage protection 10 UVLO 11 VSON008x2030 package 2 0mm 3 0mm 0 6mm MAX Applications Digital video cameras digital single lens reflexes digital still cameras digital photo frames personal navigations PND mobile phones smart phones ...

Страница 2: ... Ronn 0 5 Ω Isw 80mA SW Transistor Leak Current IqSW 0 1 2 0 μA EN 0V Protection Over Current Limit Icoil 750 mA 1 Over Voltage Limit BD60A00NUX OVP1 40 42 44 V Detect voltage of VOUT terminal Over Voltage Limit BD60A60NUX OVP2 26 28 30 V Detect Voltage of VOUT terminal Over Voltage Limit Hysteresis OVPhy 1 V VOUT Terminal Leak Current IqVOUT 0 1 1 0 μA EN 0V Shot key Diode Open Protection Sop 0 2...

Страница 3: ...ET In LED Current Setting Terminal A 5 FB In Feedback Voltage Input B 6 VOUT In Over Voltage Protection Input B 7 GND GND C 8 SW Out Switching Terminal B Terminal Diagram Fig 2 Terminal Diagram GND C Vin GND PIN B GND PIN A Vin L1 10μH OSC Control S Q R TSD SW EN GND PWMcomp ERRAMP FB Vin Thermal Shutdown Current Sense Over Current protect Cbat 4 7μF Cout 2 2 μF Coil Power 2 3V to 20V D1 Q1 VOUT O...

Страница 4: ...rohm com 2011 12 Rev A 2011 ROHM Co Ltd All rights reserved Main characteristics examples 1 Efficiency BD60A60NUX efficiency ILED LED 6series coil VLF302512MT 100M BD60A00NUX efficiency ILED LED 10series coil VLF302512MT 100M coil VLF302512MT 100M ...

Страница 5: ...S 10M TOKO SBD RB521A 40TR ROHM BD60A00NUXVcoil vsefficiency VIN 5V Ta 25 LED 8灯 26V coil 1094AS 10M TOKO SBDRB060M 60TR ROHM LED電流設定 25mA PWM 100 eff1 Vout ILED Vcoil Icoil 100 eff2 Vout ILED Vcoil Icoil VIN IVIN 100 70 75 80 85 90 95 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Vcoil V efficiency eff1 eff2 BD60A60 Vcoil vs efficiency VIN 5V Ta 25 LED 6灯 20V coil 1094AS 10M TOKO SBD RB521S...

Страница 6: ...Note 6 22 BD60A00NUX BD60A60NUX www rohm com 2011 12 Rev A 2011 ROHM Co Ltd All rights reserved PWM 20kHz Duty 50 VOUT LED current PWM VOUT LED current PWM PWM 20kHz Duty 1 100mV div 100mV div 40µs div 200ns div ...

Страница 7: ...5 0V LED 8serial LED current 25mA PWM frequency 20kHz Ta 25deg coil 1094AS 10M TOKO SBD RB060M 60TR ROHM BD60A00NUX Vcoil vs efficiency VIN 5V Ta 25 LED 8 灯 26V coil 1094AS 10M TOKO SBD RB060M 60TR ROHM LED current 25mA PWM frequency 20kHz 0 01 0 10 1 00 10 00 100 00 0 1 1 0 10 0 100 0 PWM duty LED current mA Possible to Duty 0 4 at PWM 20kHz 0 4 ...

Страница 8: ...gate is ON energy is accumulated in the external inductor and in the period where internal Nch Tr gate is OFF energy is transferred to the output capacitor via external SBD This IC has many safety functions and their detection signals stop switching operation at once 2 Soft Start This IC has soft start function which prevents rush current at turning on After EN and PWM are changed L H soft start b...

Страница 9: ...tion Over current flows the current detection resistor that is connected to between internal switching transistor source and GND Current sense voltage turns more than detection voltage over current protection is operating and it is prevented from flowing more than detection current by reducing ON duty of switching Tr without stopping boost As over current detector of This IC is detected peak curre...

Страница 10: ...acitor on a parallel with LED and decreasing LED current At that time LED terminal voltage protection works after condition of FB terminal 5 9V keeps more than 100us LED terminal voltage protection might stop current driver and DC DC and also turns off LEDs so that please set up coil selection and LED current setting less than 100us until FB terminal 5 9V Low voltage detect protection UVLO Supply ...

Страница 11: ...tput voltage keeps boosting up to over voltage protection voltage again Fig 8 LED open detect 2 When LED short circuited in the plural Even if one LED short circuits during boost operation it usually passes along LED and it is turned on By making LED shorted FB terminal voltage increases by LED VF Therefore output voltage becomes lower by LED VF and the condition turns to be normal Fig 9 One LED s...

Страница 12: ...put each control signal after VIN exceeds 2 2V and UVLO is off When input Enable and PWM the standup time should be placed as Min 100µs from 2 2V to stable voltage for VIN Since a soft start function stops working at the time of following PWM H when EN H is held with PWM L After EN H should input a PWM signal within 10ms Start control EN and select LED current driver PWM This IC can control the IC...

Страница 13: ...possible to brightness control until 0 4µs MIN1 at 25kHz And don t use for the brightness control because effect of ISET changeover is big under 0 4µs ON time and under 3µs OFF time Typical PWM frequency is 100Hz 25kHz 2 Analog dimming can be operated by applying voltage to ISET terminal via resistor as the below figure shows ISET terminal voltage works to become 0 6V regardless of the connected r...

Страница 14: ...nance current changed by giving DC voltage to VFB directly DC voltage is given from filtered one of DAC signal or PWM signal shown in under figure LED current ILED is next expression ILED FB DC R1 R2 FB RFB SW Vin Cin 4 7μF Cout 2 2μF Vin 2 7V to 4 6V Vout FB L1 10μH ISET GND EN PWM RESET DC RFB 6 49Ω R2 6 8kΩ 3s7p R1 22kΩ SW Vin Cin 4 7μF Cout 2 2μF Vin 2 7V to 4 6V Vout FB L1 10μH ISET GND EN PW...

Страница 15: ... Otherwise phase margin of DC DC decreases and might oscillate Output Voltage consists of Charge FET ON and Discharge LED current So Output voltage has Output ripple Voltage every FET switching Output ripple voltage is calculated as following Output ripple Voltage Switching cycle T Total LED current ILED Switching ON duty D Output ripple Voltage Vripple Output Capacitor COUT Output Capacitor real ...

Страница 16: ...The number of available LEDs by each power supply voltage condition SW Vin Cin 1μF R1 24kΩ Cout 2 2μF 25mA Coil Power 2 3V to 20V Vout FB L1 10μH ISET GND EN PWM RESET PWM Input IC Power 2 7V to 4 6V Step down DC DC 2 3cell Battery Ccoil 4 7μF SW Vin Cin 4 7μF R1 24kΩ Cout 2 2μF 25mA Vout FB L1 10μH ISET GND EN PWM RESET PWM Input IC Power 2 3V to 4 6V １cell Battery ＰＷＭ dimming LED current setting...

Страница 17: ...ted first At the time of power supply OFF Please turn off after make EN terminal L If power supply voltage of coil power becomes low coil current increases due to high boosting which leads to over current limit In order to avoid this state before turning off a power supply it is necessary to surely set EN to L Input voltage 5V BD60A00NUX The GND noise become big by impedance of PCB boards so that ...

Страница 18: ...ting resistor RISET 24kΩ as close as possible between ISET pin and GND There is possibility to oscillate when capacity is added to ISET terminal So pay attention that capacity isn t added Heat radiation of back side PAD PAD is used for improving the efficiency of IC heat radiation Solder PAD to GND pin Moreover connect ground plane of board using via as shown in the patterns of next page The effic...

Страница 19: ...Technical Note 19 22 BD60A00NUX BD60A60NUX www rohm com 2011 12 Rev A 2011 ROHM Co Ltd All rights reserved Recommended PCB layout ...

Страница 20: ...value is 2 2µF When choosing capacitors such as Cin and C0 please be careful of pressure The base line of pressure is about 2 times of actual applying voltage If pressure margin decreases it might be happened that capacity value becomes almost a half of nominal value Value Pressur e Manufactur e Product number Size Vertical Horizontal Height Cin Power supply voltage capacitor 1 0µF 10V MURATA GRM1...

Страница 21: ...arge from the set PCB by each process Furthermore in order to mount or dismount the set PCB to from the jig for the inspection process be sure to turn OFF the power supply and then mount the set PCB to the jig After the completion of the inspection be sure to turn OFF the power supply and then dismount it from the jig In addition for protection against static electricity establish a ground for the...

Страница 22: ... tape and reel Order quantity needs to be multiple of the minimum quantity Tape and Reel information Embossed carrier tape Tape Quantity Direction of feed The direction is the 1pin of product is at the upper right when you hold reel on the left hand and you pull out the tape on the right hand 4000pcs TR Direction of feed Reel 1pin Unit mm VSON008X2030 5 1 8 4 1 4 0 1 0 25 1 5 0 1 0 5 0 3 0 1 0 25 ...

Страница 23: ...nical information The Products specified in this document are intended to be used with general use electronic equipment or devices such as audio visual equipment office automation equipment commu nication devices electronic appliances and amusement devices The Products specified in this document are not designed to be radiation tolerant While ROHM always makes efforts to enhance the quality and re...

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