LED Drivers for LCD Backlights White Backlight LED Drivers for Medium to Large LCD Panels (Switching Regulator Type) BD6066GU, BD6066EKN No.11040EBT26 ●Description BD6066GU/BD6066EKN are white LED driver ICs with PWM step-up DC/DC converter that can boost max 40.5V and current driver that can drive max 30mA. The wide brightness can be adjusted to control by external PWM pulse on power control terminal. And, with extended resolution current driver, a few errors between the lines of the current driver, it is suitable for decreasing the lacking in brightness of the display. BD6066GU, CSP package type, is suited for saving space. BD6066EKN, HQFN package type, is suited for mounting on the flexible board. ●Features 1) High efficiency PWM step-up DC/DC converter (fsw=1MHz) 2) Extended resolution current driver 4ch 3) Driving＊12 series × 4parallel =48 white LEDs (＊white LED Vf=3.2Vmax) 4) Wide input voltage range (2.7V ~ 22V) 5) Rich safety functions ▪ Over-voltage protection (OVP) ▪ Over current limit ▪ External SBD open detect ▪ Thermal shutdown (175 ℃) 6) CSP small & thin package VCSP85H2 2.6 × 2.6 × 0.85mm HQFN28V 5.2 × 5.2 × 0.95mm ●Applications Notebook PC, portable DVD player, car navigation systems ● Absolute maximum ratings (Ta=25 ℃) Parameter Symbol Limits Unit Condition Maximum applied voltage 1 VMAX1 7 V TEST,ISET,VREG,SENSP, SENSN, SW, EN1, EN2, PWM Maximum applied voltage 2 VMAX2 15.5 V LED1, LED2, LED3, LED4 Maximum applied voltage 3 VMAX3 30.5 V VBAT Maximum applied voltage 4 VMAX4 50.5 V VDET Power dissipation 1 (BD6066GU) Pd1 1100 *1 mW Power dissipation 2 (BD6066EKN) Pd2 560 *2 mW Power dissipation 3 (BD6066EKN) Pd3 880 *3 mW Power dissipation 4 (BD6066EKN) Pd4 2650 *4 mW Operating temperature range Topr -30 ~ +85 ℃ Storage temperature range Tstg -55 ~ +150 ℃ (*1) The measurement value which was mounted on the PCB by ROHM. When it’s used by more than Ta=25 ℃, it’s reduced by 8.8mW/ ℃. (*2) Reduced 4.5mW/ ℃ With Ta>25 ℃ when not mounted on a heat radiation Board. (*3) 70mm x 70mm x 1.6mm glass epoxy Board which has 1 layers (60mm x 60mm). When it’s used by more than Ta=25 ℃, it’s reduced by 7.0mW/ ℃. (*4) 70mm x 70mm x 1.6mm glass epoxy Board which has 2 layers (60mm x 60mm). When it’s used by more than Ta=25 ℃, it’s reduced by 21.2mW/ ℃. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 1/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Recommended operating range (Ta=-30 ℃ ~ +85 ℃) Parameter Power supply voltage Symbol BD6066GU BD6066EKN VBAT Limits Min. Typ. Max. 2.7 12.0 22.0 ●Electrical characteristic (Unless otherwise specified, VBAT=12V, Ta = +25 ℃) Limits Parameter Symbol Min. Typ. Max. Unit Condition V Unit Condition [EN Terminal] EN threshold voltage (Low) VthL 0 - 0.2 V EN threshold voltage (High) 1 VthH1 1.4 - 5.0 V VBAT > 5.0V EN threshold voltage (High) 2 VthH2 1.4 - VBAT V VBAT < 5.0V Iin - 8.3 14.0 µA EN=2.5V Iout -2.0 -0.1 - µA EN=0V PWML 0 - 0.2 V High Input Voltage range1 PWMH1 1.4 - 5.0 V VBAT > 5.0V High Input Voltage range2 PWMH2 1.4 - VBAT V VBAT < 5.0V PWM pull down resistor PWMR 300 500 700 kΩ VREG Voltage VREG 4.0 5.0 6.0 V Under Voltage Lock Out UVLO 2.05 2.35 2.65 V Input voltage range Vin 3.1 12.0 22.0 V Quiescent Current 1 Iq1 - 0.6 3.4 µA EN=0V, VBAT=12V Quiescent Current 2 Iq2 - 4.6 10 µA EN=0V, VBAT=22V Current Consumption Idd - 3.4 5.1 mA EN=3.6V, VDET=0V,ISET=24kΩ LED Control voltage VLED 0.4 0.5 0.6 V Over Current Limit voltage Ocp 70 100 130 mV SBD Open Protect Sop - 0.2 1.4 V Switching frequency fSW 0.8 1.0 1.2 MHz Duty cycle limit Duty 92.5 95.0 99.0 % LED1=LED2=LED3=LED4=0V Over Voltage Limit Ovl 40.5 42.0 43.5 V LED1=LED2=LED3=LED4=0V Start up time Ts - 0.5 1.0 ms LED maximum current ILMAX - - 30 mA LED current accuracy ILACCU - - ±5 % ILED=20mA LED current matching ILMAT - - ±3 % - Each LED current / Average (LED1,2,3,4) - ILED=20mA Iset 0.5 0.6 0.7 V ILOCP 35 60 90 mA LEDOVP 12.5 13.5 14.5 V EN terminal input current EN terminal output current [PWM Terminal] Low Input Voltage range [Regulator] [Switching Regulator] *1 *2 Output voltage=24V [Current driver] ISET voltage LED current limiter LED Terminal Over Voltage Protect *1 Electrical characteristics are guaranteed from 3.1V to 22V and operating is guaranteed from 2.7V to 3.1V. *2 This parameter is tested with dc measurement. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 2/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Reference data 20 5 1.3 85℃ Frequency [MHz] 15 3 25℃ -30℃ 2 Ist[µA] Iin [mA] 25 ℃ 1.2 4 85℃ 10 25℃ 1.1 1 -30℃ 0.9 85℃ 5 1 0.8 -30℃ 0 0 0 5 10 15 VBAT [V] 20 0 25 5 10 15 VBAT[V] 20 0.7 25 0 5 10 15 VBAT [V] 20 25 Fig.1 Fig.2 Current Consumption - power source voltage Fig.3 Quiescent current - power source voltage Oscillation frequency - power source voltage 44 0.4 43 0.3 16 15 41 0.2 85℃ 85℃ 11 40 10 0.0 0 5 10 15 VBAT[V] 13 12 85℃ 0.1 25℃ 14 LED[V] VDET[V] VDET[V] 42 -30℃ -30, 25℃ 25℃ -30℃ 20 25 0 5 10 15 VBAT[V] 20 0 25 5 10 15 VBAT[V] 20 25 Fig.4 Fig.5 Fig.6 Over Voltage Limit - power source voltage SBD Open Protect Limit - power source voltage LED terminal Over Voltage Protect vs power source voltage 200 5 Over current detected voltage [mV] 2.5 6 2 4 VBAT [V] VREG[V] 1.5 3 2 0.5 1 0 0 5 10 15 VBAT[V] 20 0 -50 25 -25 0 25 Ta [o C] 50 75 2.7V, 3.1V, 6V 100 Fig.8 UVLO - Temperature 0 -50 100 21.0 21.0 20.8 20.8 20.8 20.6 20.6 20.6 20.4 20.4 20.0 19.8 19.6 20.0 19.8 -30℃ 19.4 19.2 19.2 19.0 0.20 19.0 0.60 0.80 1.00 1.20 1.40 VLED[V] Fig.10 LED current - LED terminal voltage ( Expansion) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 85℃ 0 25 Ta [o C] 50 75 100 -30℃ 25℃ 20.2 20.0 19.8 19.6 19.6 19.4 0.40 20.4 25℃ 20.2 ILED[mA] ILED[mA] 25℃ -25 Over Current Limit Voltage - Temperature 21.0 85℃ 5V 22V 50 Fig.9 Fig.7 VREG - power source voltage 20.2 ILED[mA] 1 150 85℃ 19.4 -30℃ 19.2 19.0 2 3 4 5 6 7 VLED[V] 8 9 10 Fig.11 LED current - LED terminal voltage 3/15 0 5 10 15 VBAT[V] 20 25 Fig.12 LED current - power source voltage 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN 25 100 ISET=27kΩ 20 -30℃ 70 ISET=27kΩ LED current [mA] 85℃ 60 50 40 30 1.5 LED current [mA] 80 Efficiency[%] 2 25℃ 90 15 6V, 7.4V, 10.7V, 22V 10 20 1 22V 10.7V 0.5 16V 5 16V 6V 7.4V 10 0 0 0 0 5 10 15 VBAT[V] 20 25 0 20 40 60 PWM-HI Duty [％] Fig.13 Efficiency - source voltage 25 2 VBAT=7.4V ISET=27kΩ 80 2 100 10 20 Fig.15 100 VBAT=7.4V ISET=27kΩ VBAT=7.4V ISET=27kΩ 90 85℃ 80 70 25℃ 1 0.5 85℃ 5 18 LED current - PWM HI Duty( Expansion) PWM = 200Hz Dispersion [%] LED current [mA] LED current [mA] -30℃ 8 10 12 14 16 PWM-HI Duty [％] Fig.14 1.5 25℃ 6 LED current - PWM HI Duty PWM = 200Hz 20 15 4 60 50 VF Dispersion of LED line interval is 2.6V. 40 30 VF Dispersion of LED line interval is small. 20 -30℃ 10 0 0 20 40 60 PWM-HI Duty [%] 80 100 4 0 6 8 10 12 14 16 18 20 PWM-HI Duty [%] 20 40 60 PWM-HI Duty [%] 80 100 Fig.16 Fig.17 Fig.18 LED current - PWM HI Duty( Expansion) PWM = 200Hz LED current matching - PWM HI Duty PWM = 200Hz 100% 50% 90% 80% 70% 40% VBAT=7.4V ISET=27kΩ 40 30 Dispersion VF Dispersion of LED line interval is 2.6V. VF Dispersion of LED line interval is small. 20 0 -10 0% -10% 10 5 10 15 20 Duty [%] 25 30 Fig.19 LED current matching - PWM HI Duty (Expansion) PWM = 200Hz 6V 7.4V 30% 60% 50% 40% 30% 20% 10% 0 2 LED current - PWM HI Duty PWM = 200Hz 50 Dispersion [%] 0 6V Dispersion 0 -10 0 7.4V 10.7V 16V 10.7V 20% 22V 10% 22V 0% 16V -10% 0 10 20 30 40 50 60 70 80 90 100 PWM-HI Duty [%] Fig.20 LED current matching - PWM HI Duty VF Dispersion of LED line interval is 2.6V. PWM = 200Hz 0 5 10 15 20 Duty [%] 25 30 Fig.21 LED current matching - PWM HI Duty (Expansion) VF Dispersion of LED line interval is 2.6V. PWM = 200Hz Output 10V/div Average current = 0.8mA Coil current 500mA/div Fig.22 LED Open Voltage www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 4/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Block diagram, I/O equivalent circuit diagram VBAT VREG VBAT VBAT VREG EN1 VIN detector UVLO Clump EN2 PIN REG Internal Power suplly Clump PWM SBD Open protect VDET + - PIN PIN GND GND A B VBAT VBAT C TSD over voltage protect S SW Q R ERRAMP + PWMcomp + Control sence + PIN PIN GND + Current Sence SENSN PIN LED1 LED2 SENSP OSC LED TERMINAL Over Voltage Protect GND D LED3 VBAT VREG 5.5V 5.5V Clump Clump E GND F VBAT VREG LED4 PIN ISET Resistor driver Current Driver GND GND ISET GND TEST G Fig.24 I/O equivalent circuit diagram Fig.23 Block diagram ●Pin assignment table PIN Name In/Out PIN number BD6066GU BD6066EKN Function Terminal equivalent circuit diagram SENSN In A1 1 - Side Current sense terminal A GND - A2 2 GND B VDET In C3 3 Detect input for SBD open and OVP C N.C. - - 4 No connect pin - N.C. - - 5 No connect pin - ISET In A3 6 Resistor connection for LED current setting A TEST In A4 7 TEST input (Pull down 100kΩ to GND) G N.C. - - 8 No connect pin - LED4 In A5 9 Current sink for LED4 C LED3 In B5 10 Current sink for LED3 C N.C. - - 11 No connect pin - LED2 In C5 12 Current sink for LED2 C LED1 In D5 13 Current sink for LED1 C N.C. - - 14 No connect pin - EN1 In E5 15 Enable input 1 E N.C. - - 16 No connect pin - EN2 In E3 17 Enable input 2 E N.C. - - 18 No connect pin - VBAT In E4 19 Battery input C VREG Out E2 20 Regulator output / Internal power-supply D PWM In E1 21 PWM input F N.C. - - 22 No connect pin - GND - D1 23 GND B N.C. - - 24 No connect pin - VREG Out - 25 Regulator output / Internal power-supply D SW Out C1 26 Switching Tr drive terminal G SENSP In B1 27 + Side Current sense terminal G GND - - 28 GND B www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 5/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Application example Battery Battery 4.7μH 4.7μH 10LED RB160M-60 10LED RB160M-60 10μF (25V) 10μF (25V) 2.2μF (50V) 2.2μF (50V) C3 C3 RTR020N05 C1 SW RTR020N05 VDET B1 SENSP C1 SW VDET B1 SENSP 68mΩ 68mΩ A1 SENSN A1 SENSN Power ON/OFF LED1 D5 E5 EN1 200Hz PWM E3 EN2 LED2 C5 E1 PWM LED3 B5 200Hz PWM LED4 A5 E4 VBAT GND A2 E3 EN2 LED2 C5 E1 PWM LED3 B5 LED4 A5 E4 VBAT each 20mA E2 VREG 1μF(10V) LED1 D5 E5 EN1 Power ON/OFF E2 VREG 1μF(10V) GND TEST ISET D1 A4 GND GND TEST ISET A2 A3 D1 A4 A3 24kΩ 24kΩ Fig.25 LED current 20mA setting example (10 series × 4parallel) Fig.26 LED current 20mA setting example (10 series × 3parallel) Battery Battery 4.7μH 4.7μH 10LED RB160M-60 12LED RB160M-60 10μF (25V) 10μF (25V) 2.2μF (100V) 2.2μF (50V) C3 RTR020N05 C1 SW C1 SW VDET B1 SENSP 39mΩ 68mΩ A1 SENSN A1 SENSN LED1 D5 E5 EN1 E3 EN2 LED2 C5 200Hz PWM E1 PWM LED3 B5 3.1 to 5.5V E4 VBAT LED4 A5 Power ON/OFF 200Hz PWM GND A2 LED1 D5 E5 EN1 E3 EN2 LED2 C5 E1 PWM LED3 B5 LED4 A5 E4 VBAT each 20mA Each 20mA E2 VREG E2 VREG 1μF(10V) 270kΩ C3 VDET B1 SENSP Power ON/OFF each 20mA 1μF(10V) GND TEST ISET D1 A4 GND A2 A3 GND TEST ISET D1 A4 A3 24kΩ 24kΩ Fig.27 Separated power supply of IC and coil setting example Fig.28 Over voltage 48.1V(typ) by external resistor, LED current 20mA setting example (12 series (VF3.6Vmax) × 4parallel) ●Terminal processing TEST pin = Connect to GND N.C. = Nothing specified in particular. Open is recommended. VREG = When IC is driving from the outside of 3.1~5.5V, short VBAT and VREG, and put the voltage to VREG EN1, 2 = Connect to GND in case of fixing at L level LED1, 2 = When each LED driver are not used at EN setting, connect to VREG terminal or the power supply of more than 1V. GND = Each GND is connecting inside IC. Connect to GND of all PCB www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 6/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Description of Functions 1) PWM current mode DC/DC converter While BD6066GU/EKN is power ON, the lowest voltage of LED1, 2, 3, 4 is detected, PWM duty is decided to be 0.5V and output voltage is kept invariably. As for the inputs of the PWM comparator as the feature of the PWM current mode, one is overlapped with error components from the error amplifier, and the other is overlapped with a current sense signal that controls the inductor current into Slope waveform to prevent sub harmonic oscillation. This output controls external Nch Tr via the RS latch. In the period where external Nch Tr gate is ON, energy is accumulated in the external inductor, and in the period where external Nch Tr gate is OFF, energy is transferred to the output capacitor via external SBD. BD6066GU/EKN has many safety functions, and their detection signals stop switching operation at once. 2) Soft start and off status BD6066GU/EKN has soft start function and off status function. The soft start function and the off status function prevent large coil current. Rush current at turning on is prevented by the soft start function, and invalid current at turning off is prevented by the off status function. 3) External SBD open detect and over voltage protection BD6066GU/EKN has over boost protection by external SBD open and over voltage protection. This function will stop the switching. Details are as shown below. ▪ External SBD open detect In the case of external SBD is not connected to IC, the coil or external Tr may be destructed. Therefore, at such an error as VOUT becoming 0.2V or below, the Under Detector shown in the figure works, and turns off the output Tr, and prevents the coil and the IC from being destructed. And the IC changes from activation into non-activation, and current does not flow to the coil (0mA). ▪ Over voltage protection At such an error of output open as the output DC/DC and the LED is not connected to IC, the DC/DC will boost too much and the VDET terminal exceed the absolute maximum ratings, and may destruct the IC. Therefore, when VDET becomes sensing voltage or higher, the over voltage limit works, and turns off the output Tr, and the pressure up made stop. At this moment, the IC changes from activation into non-activation, and the output voltage goes down slowly. And, when the output voltage becomes the hysteresis of the over voltage limit or below, the output voltage pressure up to sensing voltage once again and unless the application error is recovered, this operation is repeated. This protection action is shown in Fig.29. Cout VDET SW OVER Detector OVER VOLTAGE REF SBD Open Detector SBD Open VOLTAGE REF Control Fig.29 Block diagram of external SBD open detect and over voltage 4) Thermal shut down BD6066GU/EKN has thermal shut down function. The thermal shut down works at 175C or higher, and while holding the setting of EN control from the outside, the IC changes from activation into non-activation. And at 175C or below, the IC gets back to its normal action. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 7/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN 5) Over Current Limit Over current flows the current detection resistor that is connected to switching transistor source and between GND, SENSP pin 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 BD6066GU/EKN is detected peak current, current more than over current setting value does not flow. And, over current value can decide freely by changing over current detection voltage. <Derivation sequence of detection resistor> Detection resistor =Over current detection voltage / Over current setting value TYP value of over current detection voltage is 100mV, MIN = 70mV and MAX = 130mV and after the current value which was necessary for the normal operation was decided, detection resistor is derived by using MIN value of over current detection value. For example, detection resistor when necessary current value was set at 1A is given as shown below. Detection resistor =70mV / 1A = 70mΩ MAX current dispersion of this detection resistor value is MAX current = 130mV / 70mΩ = 1.86A <The estimate of the current value which need for the normal operation > As over current detector of BD6066GU/EKN is detected the peak current, it have to estimate peak current to flow to the coil by operating condition. In case of, Supply voltage of coil = VIN Reactance value of coil = L Switching frequency = fsw MIN=0.8MHz, Typ=1MHz, MAX=1.2MHz Output voltage = VOUT Total LED current = IOUT Average current of coil = Iave Peak current of coil = Ipeak Efficiency = eff (Please set up having margin, it refers to data on p.4.) ON time of switching transistor = Ton Ipeak = (VIN / L) × (1 / fsw) × (1-(VIN / VOUT)) Iave=(VOUT × IOUT / VIN) / eff 1/2 Ton=(Iave × (1-VIN/VOUT) × (1/fsw) × (L/VIN) × 2) Each current is calculated. As peak current varies according to whether there is the direct current superposed, the next is decided. (1-VIN/VOUT) × (1/fsw) < Ton→ peak current = Ipeak /2 + Iave (1-VIN/VOUT) × (1/fsw) > Ton→ peak current = Ipeak (Example 1) In case of, VIN=6.5V, L=4.7µH, fsw=1MHz, VOUT=39V, IOUT=80mA, Efficiency=85% Ipeak = (6.5V / 4.7µH) × (1 / 1MHz) × (1-(6.5V / 39V)) =1.08A Iave = (39V × 80mA / 6.0V) / 85% = 0.61A 1/2 Ton = (0.61A × (1-6.0V / 39V) × (1 / 1MHz) × ( 4.7µH /6.0V) × 2) = 0.90µs (1-VIN/VOUT) × (1/fsw)=0.85µs < Ton Peak current = 1.08A/2+0.61A = 1.15A (Example 2) In case of, VIN=12.0V, L=4.7µH, fsw=1MHz, VOUT=39V, IOUT=80mA, Efficiency=85% Ipeak = (12.0V / 4.7µH) × (1 / 1MHz) × (1-(12V / 39V)) =1.77A Iave = (39V × 80mA / 12.0V) / 85% = 0.31A 1/2 Ton = (0.31A × (1-12 V / 39V) × (1 / 1MHz) × ( 4.7µH /12 V) × 2) = 0.41µs (1-VIN/VOUT) × (1/fsw)=0.69µs > Ton Peak current = 12V/4.7µH × 0.41µs = 1.05A www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 8/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Start control and select constant current driver BD6066GU/EKN can control the start conditions by EN1, 2 terminal and PWM terminal, and sets 0.2V or below EN1, 2 terminal or sets 0.2 or below PWM terminal and IC can power off by being 0V LED terminal selected EN1, 2. PWM, EN power on at more than 1.4V, constant current can select ON/OFF by the combination of EN as shown below table. When there is unused constant current driver, connect unused LED terminal to VREG terminal or connect to fixed voltage of more than 1V. And, EN1, 2 are changed with PWM=H and it is prohibited to change a constant current driver. Enable Constant current driver EN1 EN2 PWM LED1 LED2 LED3 LED4 H L H L H L H L H H L L H H L L H H H H L L L L OFF OFF ON OFF ON ON ON ON ON ON ON ON OFF (As for these setups, power-off IC.) ●Off sequence Off sequence controls power off timing of each block, LED terminal may not exceed the pressure. After EN or PWM terminal set H→L, it continues electric current by the current value decided with ISET terminal until all the LED terminals selected with EN are less than 40mV and output voltage reduces. On that occasion, the DC/ DC power-off is given and it doesn't have a charge to the output capacitor. After that, LED driver is turned off, built-in REG is turned off, and power-off is completed. If the VF tolerance of the LED is large, it doesn't need to examine VF not to exceed pressure of the LED terminal by this sequence. EN DCDC_EN DRV_EN REG_EN Terminal voltage is detected, and turned off. LED Terminal Voltage is high. LED Terminal Voltage is low. Power Control REG_EN REG LED 10 lights 5V EN1, 2,PW M DCDC_EN DCDC LED 9 lights SW … … … … LED4 LED3 DRV_EN DRV LED2 Terminal voltage is low LED1 Terminal voltage is high Fig.30 Block diagram of off sequence www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 9/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Setting of LED current and current range LED current can set up resistance value (RISET) connecting to ISET, LED current setting range is 4mA~30mA. ISET setting example RISET 24.0 kΩ (E24) 25.5 kΩ (E96) 27.0 kΩ (E12) 28.0 kΩ (E96) 30.0 kΩ (E24) 33.0 kΩ (E6) Setting of LED current is given as shown below. LED current = 20mA × ( 24kΩ / RISET) The current in the standard application is as shown below. RISET=24kΩ, LED current=20mA LED current 20.0mA 18.8mA 17.8mA 17.1mA 16.0mA 14.5mA ●Brightness control PWM brightness adjustment is made by inputting PWM pulse to PWM pin. The electric current select setting with ISET in the Hi section, and the Lo section turns off the electric current. Lo. The average current increases in proportion with the duty cycle of PWM signal. By this method, IC can power off at the OFF time, the IC and LED both consume no currents, thus providing a high-efficiency operation. The recommended PWM frequency is 100Hz ~ 300Hz. <ON time limit> On time is necessary more than 750μs (at the time of 200Hz, 15%) to require the start up-time of 750μs. < OFF time limit > OFF time is approximated by the following parameter. External output capacitor : Cvout LED current setting : ILED (worst = +5%) LED sequence number : NPLED LED series number : NSLED VF tolerance of LED terminal : ∆VF Reaction time of internal circuit : 10μs (worst = 15μs) Necessary time for OFF (typ) = Cvout × ((∆VF × NSLED) + 0.5V)/(ILED × NPLED)+10μs (example) Necessary time for OFF (typ) = 2μF × ((0.2V × 10 lights) + 0.5V)/(20mA × 4)+10μs = 72.5μs <PWM=200Hz, duty1.5% equivalent> Please use worst value of each parameter when you calculate the worst time. (example) Necessary time for OFF (worst) = (2μF × 1.3) × ((0.26V × 10 lights) + 0.7V)/((20mA × 1.05) × 4)+15μs =117μs <PWM=200Hz, duty2.3% equivalent > And please don’t use ON time under 750μs or under OFF time calculated in the above of current setting for the brightness control, because power-on/off has very influential. ●Noise of ceramic capacitor by PWM brightness control In order to use a ceramic capacitor as the output capacitor, noise of capacitor occurs by the kind of the circuit board and mounted method, the mounting place. As for the noise cause, the resonant of ceramic capacitor and the board give cause by output voltage fluctuation. Measures of this trouble are shown. (1) Ceramic capacitor is changed to tantalum capacitor. By changing to tantalum capacitor, noise is stopped because of changing ceramic capacitor itself bringing about the noise. But, as the output ripple increases by ESR that is characteristic of the tantalum, it needs to select tantalum with low ESR. Also, it recommends connecting parallel capacitor for the noise measure of 0.1µF Recommended capacitor is shown next page. (2) Ceramic capacitor is floated from the top of the circuit board. Reducing the contact surface of the ceramic capacitor and the circuit board can reduce the noise. Capacitor that can float a capacitor from the circuit board are as shown below. This capacitor is connected the metal cap both electrodes of the capacitor, so It can have the effect which be floated because the metal cap is connected to the circuit board. Recommended capacitor is shown next page. The metal cap CKG45NX7R2A225N (TDK) The circuit board Fig.31 The metal cap capacitor www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 10/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Selection of external parts Recommended external parts are as shown below. When to use other parts than these, select the following equivalent parts. Coil Size Vertical Horizontal Height DC current (mA) DCR (Ω) Use power voltage range B1015AS-4R7N 8.4 8.3 4.0 3300 0.038 2.7 ~ 22V 4.7μH TAIYO YUDEN NR4012T4R7M 4.0 4.0 1.2 960 0.14 2.7 ~ 22V 4.7μH TAIYO YUDEN NR4018T4R7M 4.0 4.0 1.8 1200 0.11 2.7 ~ 22V 6.8μH TAIYO YUDEN NR4012T6R8M 4.0 4.0 1.2 840 0.18 7.0 ~ 22V Value Manufacturer Product number 4.7μH TOKO Capacitor Value Pressure Manufacturer Product number Size Temperature range Vertical Horizontal Height 3.2 1.6 1.6 -25deg ~ +85deg [ Power supply capacitor ] 10μF 25V MURATA GRM31CB31E106KA75 [ Smoothing capacitor for built-in regulator ] 1μF 10V MURATA GRM188B10J105KA01 1.6 0.8 0.8 -25deg ~ +85deg [ Output capacitor ] 1μF 50V MURATA GRM31MB31H105KA87 3.2 1.6 1.15 -25deg ~ +85deg 2.2μF 50V MURATA GRM31CB31H225KA87 3.2 1.6 1.6 -25deg ~ +85deg [ Output capacitor ] Noise measure 1 of ceramic capacitor (tantalum capacitor +0.1µF) 0.1μF 50V MURATA GRM188B31H104KA92 1.6 0.8 0.8 -25deg ~ +85deg 1.0μF 50V KYOCERA TAJW105M050 6.0 3.2 1.5 -55deg ~ +125deg 2.2μF 50V KYOCERA TAJC225M050 6.0 3.2 2.6 -55deg ~ +125deg 5.5 -55deg ~ +125deg [ Output capacitor ] Noise measure 2 of ceramic capacitor (capacitor with the metal cap) 2.2μF 100V TDK CKG45NX7R2A225N Tolerance Manufacturer Product number 5.5 4.0 Resistor Value [ Resistor for LED current decision 24kΩ ±0.5% ROHM [ Resistor for over current decision 47mΩ ±1% Size Vertical Horizontal Height 0.6 0.3 0.23 2.0 1.25 0.55 <ISET pin> ] MCR006YZPD243 <SENSP pin> ] ROHM MCR10EZHFLR047 Pressure Manufacturer Product number 60V ROHM RB160M-60 Pressure Manufacturer Product number 45V ROHM RTR020N05 Vertical 3.5 Horizontal 1.6 Height 0.8 SBD Size Vertical Horizontal Height 3.5 1.6 0.8 MOS FET Nch Size Current ability Driving voltage 2A 2.5V 60V ROHM 2SK2503 9.5 6.5 2.3 5A 4.0V 60V FAIR CHILD NDT3055L 6.5 7.0 1.8 4A 2.0V The coil is the part that is most influential to efficiency. Select the coil whose direct current resistor (DCR) and current inductance characteristic is excellent. BD6066GU/EKN are designed for the inductance value of 4.7µH or 6.8µH. Do not use other inductance value. Select a capacitor of ceramic type with excellent frequency and temperature characteristics. Further, select Capacitor to be used with small direct current resistance, and pay sufficient attention to the PCB layout shown in the next page. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 11/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●PCB Layout In order to make the most of the performance of this IC, its PCB layout is very important. Characteristics such as efficiency and ripple and the likes change greatly with layout patterns, which please note carefully. Reset PWM CBAT RSENSE NC EN2 NC VREG NC SW LED3 SENSP GND LED4 SENSN ISET SBD LED2 NC Tr NC NC CREG LED1 VDET to Cathode of LED L EN1 NC GND GND COUT VBAT PWM NC CIN VREG to Power supply to GND to Anode of each LED NC TEST RISET Fig.32 PCB Layout Connect the input bypath capacitor CIN(10µF) nearest to coil L, as shown in the upper diagram. Wire the power supply line by the low resistance from CIN to VBAT pin. And, when it can't be wired by the low resistance, connect the input capacitor CBAT(1µF) nearest to between VBAT and GND pin, as shown in the upper diagram. Thereby, the input voltage ripple of the IC can be reduced. Connect smoothing capacitor CREG of the regulator nearest to between VREG and GND pin, as shown in the upper diagram. Connect schottky barrier diode SBD of the regulator nearest to between coil L and switching transistor Tr. And connect output capacitor COUT nearest to between CIN and GND pin. Thereby, the output voltage ripple of the IC can be reduced. Connect switching transistor Tr nearest to SW pin. Wire coil L and switching transistor Tr, current sensing resistor RSENSE by the low resistance. Wiring to the SENSP pin isn't Tr side, but connect it from RSENSE side. Over current value may become low when wiring from Tr side. Connect RSENSE of GND side isolated to SENS pin. Don’t wire between RSENSE and SNESN pin wiring from SNESN pin to GND pin. After via SENSN pin, connect GND pin, as shown in the upper diagram. Connect LED current setting resistor RISET nearest to ISET pin. There is possibility to oscillate when capacity is added to ISET terminal, so pay attention that capacity isn't added. And, connect RISET of GND side directly to GND pin. When those pins are not connected directly near the chip, influence is given to the performance of BD6066GU/EKN, and may limit the current drive performance. As for the wire to the inductor, make its resistance component small so as to reduce electric power consumption and increase the entire efficiency. The PCB layout in consideration of these is shown in the next page. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 12/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Recommended PCB layout Cin L Cout SBD CBAT Tr Creg Rsense RISET Fig.33 BD6066EKN Component side（Top view） Fig.34 BD6066EKN Back side（Top view） ●Attention point of PCB layout In PCB layout design, the wiring of power supply line should be low Impedance, and put the bypass capacitor if necessary. Especially the wiring impedance must be lower around the DC/DC converter. ●About heat loss In heat design, operate the DC/DC converter in the following condition. (The following temperature is a guarantee temperature, so consider the margin.) 1. Periphery temperature Ta must be less than 85℃ 2. The loss of IC must be less than dissipation Pd. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 13/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Notes for use (1) Absolute Maximum Ratings An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can break down devices, thus making impossible to identify breaking mode such as a short circuit or an open circuit. If any special mode exceeding the absolute maximum ratings is assumed, consideration should be given to take physical safety measures including the use of fuses, etc. (2) Operating conditions These conditions represent a range within which characteristics can be provided approximately as expected. The electrical characteristics are guaranteed under the conditions of each parameter. (3) Reverse connection of power supply connector The reverse connection of power supply connector can break down ICs. Take protective measures against the breakdown due to the reverse connection, such as mounting an external diode between the power supply and the IC’s power supply terminal. (4) Power supply line Design PCB pattern to provide low impedance for the wiring between the power supply and the GND lines. In this regard, for the digital block power supply and the analog block power supply, even though these power supplies has the same level of potential, separate the power supply pattern for the digital block from that for the analog block, thus suppressing the diffraction of digital noises to the analog block power supply resulting from impedance common to the wiring patterns. For the GND line, give consideration to design the patterns in a similar manner. Furthermore, for all power supply terminals to ICs, mount a capacitor between the power supply and the GND terminal. At the same time, in order to use an electrolytic capacitor, thoroughly check to be sure the characteristics of the capacitor to be used present no problem including the occurrence of capacity dropout at a low temperature, thus determining the constant. (5) GND voltage Make setting of the potential of the GND terminal so that it will be maintained at the minimum in any operating state. Furthermore, check to be sure no terminals are at a potential lower than the GND voltage including an actual electric transient. (6) Short circuit between terminals and erroneous mounting In order to mount ICs on a set PCB, pay thorough attention to the direction and offset of the ICs. Erroneous mounting can break down the ICs. Furthermore, if a short circuit occurs due to foreign matters entering between terminals or between the terminal and the power supply or the GND terminal, the ICs can break down. (7) Operation in strong electromagnetic field Be noted that using ICs in the strong electromagnetic field can malfunction them. (8) Inspection with set PCB On the inspection with the set PCB, if a capacitor is connected to a low-impedance IC terminal, the IC can suffer stress. Therefore, be sure to discharge 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 assembly process and pay thorough attention to the transportation and the storage of the set PCB. (9) Input terminals In terms of the construction of IC, parasitic elements are inevitably formed in relation to potential. The operation of the parasitic element can cause interference with circuit operation, thus resulting in a malfunction and then breakdown of the input terminal. Therefore, pay thorough attention not to handle the input terminals, such as to apply to the input terminals a voltage lower than the GND respectively, so that any parasitic element will operate. Furthermore, do not apply a voltage to the input terminals when no power supply voltage is applied to the IC. In addition, even if the power supply voltage is applied, apply to the input terminals a voltage lower than the power supply voltage or within the guaranteed value of electrical characteristics. (10) Ground wiring pattern If small-signal GND and large-current GND are provided, It will be recommended to separate the large-current GND pattern from the small-signal GND pattern and establish a single ground at the reference point of the set PCB so that resistance to the wiring pattern and voltage fluctuations due to a large current will cause no fluctuations in voltages of the small-signal GND. Pay attention not to cause fluctuations in the GND wiring pattern of external parts as well. (11) External capacitor In order to use a ceramic capacitor as the external capacitor, determine the constant with consideration given to a degradation in the nominal capacitance due to DC bias and changes in the capacitance due to temperature, etc. (12) Thermal shutdown circuit (TSD) When junction temperatures become 175℃ (typ) or higher, the thermal shutdown circuit operates and turns a switch OFF. The thermal shutdown circuit, which is aimed at isolating the LSI from thermal runaway as much as possible, is not aimed at the protection or guarantee of the LSI. Therefore, do not continuously use the LSI with this circuit operating or use the LSI assuming its operation. (13) Thermal design Perform thermal design in which there are adequate margins by taking into account the permissible dissipation (Pd) in actual states of use. (14) Selection of coil Select the low DCR inductors to decrease power loss for DC/DC converter. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 14/15 2011.06 - Rev.B Technical Note BD6066GU,BU6066EKN ●Ordering part number B D 6 Part No. 0 6 6 G Part No. 6066 U - Package GU : VCSP85H2 EKN : HQFN28V E 2 Packaging and forming specification E2: Embossed tape and reel VCSP85H2 (BD6066GU) <Tape and Reel information> 2.60±0.1 1.0MAX 0.25± 0.1 2.60± 0.1 1PIN MARK Tape Embossed carrier tape Quantity 3000pcs Direction of feed 0.08 S 17- φ 0.3±0.05 0.05 A B B 1 2 3 4 5 1pin P=0.5×4 0.3±0.1 ) P=0.5 × 4 A E D C B A (φ0.15)INDEX POST The direction is the 1pin of product is at the upper left when you hold ( reel on the left hand and you pull out the tape on the right hand 0.3± 0.1 S E2 Reel (Unit : mm) Direction of feed ∗ Order quantity needs to be multiple of the minimum quantity. HQFN28V 15 14 22 7 0.05 M Embossed carrier tape (with dry pack) Quantity 2500pcs E2 The direction is the 1pin of product is at the upper left when you hold ( reel on the left hand and you pull out the tape on the right hand ) 0.05 ) .5 (0 3(0 0.5 (3.1) .2 2) 5) .3 (0 (3.1) 0.22±0.05 0.22±0.05 0.95MAX 1 Tape Direction of feed 8 28 +0.03 0.02 -0.02 5.0±0.1 5.2±0.1 21 +0.1 0.6 -0.3 <Tape and Reel information> 5.2±0.1 5.0±0.1 (1.1) Notice : Do not use the dotted line area for soldering (Unit : mm) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 1pin Reel 15/15 Direction of feed ∗ Order quantity needs to be multiple of the minimum quantity. 2011.06 - Rev.B 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. Examples of application circuits, circuit constants and any other information contained herein illustrate the standard usage and operations of the Products. The peripheral conditions must be taken into account when designing circuits for mass production. Great care was taken in ensuring the accuracy of the information specified in this document. However, should you incur any damage arising from any inaccuracy or misprint of such information, ROHM shall bear no responsibility for such damage. The technical information specified herein is intended only to show the typical functions of and examples of application circuits for the Products. ROHM does not grant you, explicitly or implicitly, any license to use or exercise intellectual property or other rights held by ROHM and other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the use of such technical 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, communication 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 reliability of its Products, a Product may fail or malfunction for a variety of reasons. Please be sure to implement in your equipment using the Products safety measures to guard against the possibility of physical injury, fire or any other damage caused in the event of the failure of any Product, such as derating, redundancy, fire control and fail-safe designs. ROHM shall bear no responsibility whatsoever for your use of any Product outside of the prescribed scope or not in accordance with the instruction manual. The Products are not designed or manufactured to be used with any equipment, device or system which requires an extremely high level of reliability the failure or malfunction of which may result in a direct threat to human life or create a risk of human injury (such as a medical instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuelcontroller or other safety device). ROHM shall bear no responsibility in any way for use of any of the Products for the above special purposes. If a Product is intended to be used for any such special purpose, please contact a ROHM sales representative before purchasing. If you intend to export or ship overseas any Product or technology specified herein that may be controlled under the Foreign Exchange and the Foreign Trade Law, you will be required to obtain a license or permit under the Law. Thank you for your accessing to ROHM product informations. More detail product informations and catalogs are available, please contact us. ROHM Customer Support System http://www.rohm.com/contact/ www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. R1120A