BD6067GU

LED Drivers for LCD Backlights White Backlight LED Drivers for Small to Medium LCD Panels (Switching Regulator Type) BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN No.11040ECT19 ●Description Switching Regulator type LED Driver Series for small LCD backlight are boost DC/DC converters possible to drive the white LEDs at constant. It is possible that turning on white LED steadily by a series connection which has no current variation, and by a fast transient response with current mode. And, BD6069GUT/BD6071HFN/BD6072HFN are white LED driver ICs with synchronous rectification. With synchronous rectification (no external schottky diode required) and small package, they can save mount space. BD6071HFN suited over voltage and over current limit from BD6069GUT/BD6072HFN. ●Features 1) Boost DC/DC converter 2) Adjustment of brightness by external PWM pulse 3) Possible to driving 3 LEDs (BD6071HFN ) 4) Possible to driving 4 LEDs (BD6069GUT, BD6072HFN) 5) Possible to driving 8 LEDs (BD6067GU) 6) Soft start function (BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN) 7) Synchronous rectification Boost DC/DC converter (BD6069GUT, BD6071HFN, BD6072HFN) 8) No external schottky diode required (BD6069GUT, BD6071HFN, BD6072HFN) 9) Output Open • Short protect (BD6069GUT, BD6071HFN, BD6072HFN) ●Applications These drivers are applicable for various fields such as mobile phones, portable game machines, Inter-phone camera, audio player, portable DVD player, back light for printer display etc… and support light of the camera for the mobile phone, simple flash. And, these can use power supply for OEL. ●Line up matrix Parameter BD6067GU BD6069GUT BD6071HFN BD6072HFN Input voltage range 2.7 ~ 5.5V 2.7 ~ 5.5V 2.7 ~ 5.5V 2.7 ~ 5.5V Switching frequency 0.8 ~ 1.2MHz 0.8 ~ 1.2MHz 0.8 ~ 1.2MHz 0.8 ~ 1.2MHz White LED number 5~ 4 3 4 8 Operating temperature range -30 ~ +85℃ -30 ~ +85℃ -30 ~ +85℃ -30 ~ +85℃ Package VCSP85H1 VCSP60N1 HSON8 HSON8 www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 1/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6067GU ●Absolute maximum ratings (Ta=25℃) Parameter Power supply voltage 1 Power supply voltage 2 Operating temperature range Storage temperature range Power dissipation Symbol VMAX1 VMAX2 Topr Tstg Pd Ratings 7 *1 40 *1 -30 ~ +85 -55 ~ +150 800 *2 Unit V V ℃ ℃ mW Technical Note Conditions Applicable to Vin, EN, Vfb and VDAC pins Applicable to SW and Vout pins 50mm×58mm×1.75mm Glass epoxy PCB mounting *1 This value is based on GND. *2 This loss decreases approximate 6.4mW/℃ when Ta is 25℃ or more. ●Recommended Operation Range (Ta=-30℃ to +85℃) Parameter Operating supply voltage Symbol VCC Ratings 2.7 ~ 5.5 Unit V Vin pin Conditions ●Electrical characteristics (Unless otherwise stated, Ta is 25℃ and Vin is 3.6V.) Limits Parameter Symbol Min. Min. Min. ‘L’ level input voltage ‘H level input voltage ‘H’ level input current ‘L’ level input current VDAC-Vfb resistance Input voltage range Quiescent current Operating current VFB pin control voltage Over current limit SW transistor ON resistance Switching frequency Maximum duty Output voltage range Over voltage protection Output open protection Startup time *1 The DC current is measured in this item. Unit Conditions VthL VthH IIH IIL 1.4 -2.0 18.3 -0.1 0.4 30.0 - V V μA μA EN=5.5V EN=0V VDAR 56 112 168 kΩ Vin Iq Idd Vfb Icoil Ronn fSW Duty Vo Ovp Ovl Ts 3.1 0.18 450 0.8 92.5 30.0 - 0.1 0.9 0.20 600 0.5 1.0 95.0 31.0 0.7 0.5 5.5 2.0 1.4 0.22 750 1.4 1.2 30.0 32.0 1.4 1.0 V μA mA V mA Ω MHz % V V V ms Vout=24V Vfb=0V Vfb=0V *1 EN=0V EN=3.6V, Vfb=1.0V Isw=200mA www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 2/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6067GU ●Electrical characteristic curves (Reference data) 5.0 4.0 Technical Note 1.0 0.9 Switching freqency [MHz] 0.8 0.7 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 2.5 Ta=85℃ Ta=25℃ Ta=-30℃ Idd [mA] 3.0 Iq [µA] Ta=85℃ Ta=25℃ 0.6 0.5 0.4 0.3 Ta=25℃ Ta=-30℃ Ta=85℃ 2.0 1.0 Ta=-30℃ 0.0 2.5 3 3.5 4 Vin [V] 4.5 5 5.5 0.2 0.1 0.0 2.5 3 3.5 4 Vin [V] 4.5 5 5.5 3 3.5 4 Vin [V] 4.5 5 5.5 Fig.1 Operating current vs. Power Supply Voltage 100 Fig.2 Quiescent current vs. Power Supply Voltage 100 Fig.3 Oscillation Frequency vs. Power Supply Voltage 100 90 Efficiency [%] Vin=5.5V 90 Efficiency [%] Vin=5.5V 90 Efficiency [%] Vin=5.5V 80 80 Vin=3.6V Vin=3.1V 60 80 70 Vin=3.6V Vin=3.1V 70 70 Vin=3.1V 60 Vin=3.6V 60 50 5 15 25 ILED [mA] 35 45 50 5 15 25 ILED [mA] 35 45 50 5 15 25 ILED [mA] 35 45 Fig.4 Efficiency vs. LED Current (6LED) (Ta=25℃) Fig.5 Efficiency vs. LED Current (7LED) (Ta=25℃) Fig.6 Efficiency vs. LED Current (8LED) (Ta=25℃) 3500 3000 Output power [mW ] 230 220 25 Ta=25℃ Ta=-30℃ ILED [mA] 2500 Ta=-30℃ 2000 1500 1000 500 0 2.5 Ta=25℃ 210 20 Vin=3.6V Vfb [mV] 15 200 190 10 Ta=85℃ 180 170 2.5 Ta=85℃ 5 Vin=3.1V Vin=2.7V 0 3 3.5 4 Vin [V] 4.5 5 5.5 0 20 40 60 EN Duty [%] 80 100 3 3.5 4 Vin [V] 4.5 5 5.5 Fig.7 Output Voltage vs. Power Supply Voltage (8LED) 25 Fig.8 VFB Pin Control Voltage vs. Power Supply Voltage (8LED) (ILED=20mA) Fig.9 EN Pin PWM Brightness Control Characteristic (f=100Hz, Ta=25℃) Vin=3.6V 20 ILED [mA] 15 10 Vin=3.1V Vin=2.7V 5 0 0.0 0.5 1.0 VDAC [V] 1.5 2.0 Fig.10 DAC Brightness Control Characteristic www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 3/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6067GU ●Block Diagram and Recommended Circuit Example L1 22µH D1 Technical Note Vin Cin 1µF Vin SW Vout Over voltage protect Thermal Shutdown TSD Output open protect PWMcomp S + + - Cout 1µF 20mA ERRAMP + 14kΩ 98kΩ VFB Q1 Q R Control + Current Sence 300kΩ + OSC VDAC R1 10Ω GND GNDA EN OFF ON Fig.11 Block Diagram and Recommended Circuit Example C1 B1 A1 C2 C3 B3 A2 A3 Fig.12 Pin location diagram VCSP85H1 (Bottom view) ●Pin assignment table Pin Pin name number A1 A2 A3 B1 B3 C1 C2 C3 GNDA EN VDAC Vin VFB VOUT SW GND In/Out In In In In In Analog GND Function Enable control (pull-down by internal resistance) Analog signal input for current adjustment Supply voltage input Feedback voltage input Over voltage protection input SBD open protection input Switching pin Power GND www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 4/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN Technical Note ►BD6067GU ●Release Circuit Protection 1) Operation BD6067GU is a constant frequency PWM current mode DC/DC converter. It is shown in the block diagram of Fig.11. In a PWM comparator forming one of the PWM current mode features, one is an error element from the error amplifier and another is an element produced by superimposing the inductor current on a slope waveform that prevents sub-harmonic oscillation. This output controls Q1 via the RS latch. Energy is stored in an external inductor whileQ1 is ON and then it is moved to the COUT capacitor via D1 while Q1 is OFF. In this way, voltage Vout higher than input voltage Vin can be obtained. Because the above operation is performed in a way that the VFB pin voltage equals the Vfb voltage, the boost voltage is dominantly determined by the expression “Vf × number of LEDs.” Vout voltage = (Vf × number of LEDs) + Vfb 2) LED current control The LED current is determined depending on the VFB pin voltage “Vfb” and the resistance connected to VFB. ILED is given below. ILED =200mV/ R1 ILED [mA] 5 10 12 15 20 BD6067GU 39 20 16 13 10 R1 [Ω] 3) Dimming control ▪ Control by PWM signal The startup condition of BD6067GU is controlled via the SHDNB/EN pin. It is powered OFF at 0.4V or less and powered ON at 1.4V or more. As shown in Fig.13, brightness is controlled in the BD6067GU via the PWM signal input the SHDNB/EN pin. In this way, the LED current is controlled in a range from 0 to the maximum current. The average LED current increases in proportion to the Duty cycle of the PWM signal. In the PWM off cycle, no current dissipation takes place in IC and LEDs, resulting in high efficiency. Duties below 5% and above 95% must no be used for brightness control because they significantly affects the leading and trailing edges. BD6067GU standard PWM frequency ranges from 100Hz to 300Hz. L1 22μH Vin Vin SW Vout BD6067GU VFB VDAC GNDA GND EN PWM 100Hz~300Hz D1 1μF ILED R1 10Ω Fig.13 Example of Brightness Control by PWM signal at the EN Pin www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 5/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6067GU Technical Note ▪ Control by DC Voltage BD067GU has a built-in function for LED current control by DC voltage and can control the current by VDAC pin control voltage. L1 22μH Vin Vin SW Vout BD6067GU VFB VDAC GNDA GND EN ILED 5 25 D1 20 Vfb ILED [mA] 1 μF 15 10 DAC R1 10Ω 0 0 0.5 1 1.5 2 2.5 DAC [V] (Vfb=200mV) Fig.14 Brightness Control by BD6067GU DAC Fig.15 DAC Constant Current Characteristics by DAC Control ●Over voltage Protection BD6067GU has an over voltage protection feature. When a fault occurs, for example, IC is disconnected from LED, an excessive voltage rise may cause the SW pin and VOUT pin to exceed the absolute maximum ratings respectively, resulting in IC damage. For this reason, when VOUT is 30V or more, over voltage protection is activated to turn Q1 off so that the SW pin and VOUT pin don’t exceed the absolute maximum ratings. At this time, the IC state changes from active to inactive and the output voltage drops slowly. Then, when the output voltage falls below the over voltage protection hysteresis level, the output voltage continues to rise up to 30V again. This protection circuit is shown in Fig.16. D1 SW Cout Vout Q1 Driver OVER Detector OVER VOLTAGE REF Control Fig.16 Block Diagram for Short-circuit Protection and over voltage Protection www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 6/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN Technical Note ►BD6067GU ●Startup and Rush Current BD6067GU has a built-in soft start function. This function prevents the rush current from being generated at startup time. L1 22µH D1 Cout 1µF Vin Cin 1µF Vin SW Over voltage protect Thermal Shutdown TSD Output open protect + + - Vout ILED Soft start circuit PWMcomp S Q1 Q R Control + ERRAMP + 14kΩ VFB 98kΩ VDAC VDAC 0~1.8V R1 10Ω Current Sence 300kΩ + OSC EN GND GNDA OFF ON Fig.17 Soft Start Circuit ●Application Circuit Example The output maximum voltage range of BD6067GU is 30V. *** When LED has 8 lights, special care should be taken to prevent output voltage (VOUT) from exceeding 30V. VOUT = (LED vf × number of LED lights) + Vfb L1 22µH D1 Vin Cin 1µF Vin SW Over voltage protect Thermal Shutdown TSD Output open protect + + - Vout Cout 1µF ILED S Q1 Q R PWMcomp Control + ERRAMP + 14kΩ 98kΩ VFB R1 10Ω VDAC 1µF R2 10kΩ 1kHz Current Sence 300kΩ + OSC GND GNDA EN OFF ON Fig.18 Example of Dimming Circuit Subject to PWM Control at the VDAC Pin www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 7/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6067GU ●External components Selection Method R1: Determines the LED current ILED at power ON. R1[Ω] ILED (mA) 5 15 20 39 13 10 Technical Note L1: Coil for boost. The recommended value is 22µH. be sure to use a sufficient DC current permissible value and a sufficient low DC resistance coil. Inductance value Model number/manufacturer 22µH NR3015T220M / TAIYO YUDEN Cin: Power supplie bypass capacitor. This capacitor must be provided to remove an instantaneous power supply noise for stable voltage supply to this IC. To obtain good characteristics, the low ESR parts like the ceramics capacitor must be used. The recommended capacitance is 1µF or more. Capacitance value Model number/manufacturer 1.0µF GRM188B11A105KA61B / MURATA C0: Output smoothing capacitor. The capacitance recommended for BD6067GU is 1.0µF. Capacitance value Model number/manufacturer 1.0µF UMK107C105KA-B / TAIYO YUDEN When selecting capacitors for Cin and C0, special care should be taken for rated voltage. The desirable rated voltage is about double the voltage actually applied to the capacitor. When the margin for rated voltage is not sufficient, the capacitance may be a half or less of the nominal value. D1: Schottky barrier diode (SBD) for output rectification. To achieve high conversion efficiency, use a diode characterized by of low Vf, low reverse leak and high current capacity. Model number/manufacturer RB160M-40 / ROHM ●Recommended PCB layout When a PCB designed, the power supply line should be wired in a way that the board impedance can be minimized. If necessary, the bypass capacitor must be connected. In particular, pins around the DC/DC converter must be wired in such a way that the wiring impedance can be minimized. In addition, when a DC/DC converter using a coil is used, it is necessary to place the output capacitor Cout, coil L1, rectification diode D1 and bypass capacitor CIN near this IC and keep the GND impedance low. To cell voltage source CIN GNDA EN VDAC VIN VFB R1 VOUT SW GND COUT D1 L1 To battery GND Fig.19 PCB Layout Image www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 8/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6067GU Technical Note Top surface (Top view) Bottom surface (Top view) Fig. 20 PCB Layout ***Bypass capacitor and GND It is necessary to place bypass capacitor CIN, coil L1 and power ground GND near this IC (CIN2 of Fig.20). To obtain good characteristics, as the need arises power supply, bypass capacitor CIN between analog GNDA must be added. (at LED8 lights). When LED has 8 lights, full assessment is required for characteristics prior to usage. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 9/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6071HFN ●Absolute maximum ratings (Ta=25℃) Parameter Power supply voltage 1 Power supply voltage 2 Power dissipation Operating temperature range Storage temperature rang Symbol VMAX1 VMAX2 Pd Topr Tstg Ratings 7 *1 20 *1 630 *2 -30 ~ +85 -55 ~ +150 Unit V V mW ℃ ℃ Technical Note Conditions Applicable to Vin,EN,VFB, TEST pins Applicable to SW,Vout pins 70mm×70mm×1.6mm at glass epoxy board mounting *1 These values are based on GND and GNDA pins. *2 When it’s used by more than Ta=25℃, it’s reduced by 5.04mW/℃. ●Recommended operating range (Ta=-30℃ ~+85℃) Parameter Operating supply voltage Symbol Vin Ratings Min. 2.7 Typ. 3.6 Max. 5.5 Unit V Conditions ●Electrical characteristic (Unless otherwise specified Ta = +25℃, Vin=3.6V) Limits Parameter Symbol Min. Typ. Max. EN threshold voltage (Low) EN threshold voltage (High) EN terminal input current EN terminal output current Input voltage range Quiescent Current Current Consumption Feedback voltage Inductor current limit SW saturation voltage SW on resistance P Switching frequency Duty cycle limit Output voltage range Over voltage limit Start up time Vin Iq Idd Vfb Icoil Vsat Ronp fSW Duty Vo Ovl Ts 3.1 0.47 200 0.8 82.7 14.0 0.1 1.1 0.50 265 0.14 2.1 1.0 85.0 14.5 0.5 5.5 2.0 1.5 0.53 330 0.28 3.2 1.2 14.0 15.0 1.0 VthL VthH Iin Iout 1.4 -2.0 18.3 -0.1 0.4 30.0 - Unit Conditions V V μA μA V μA mA V mA V Ω MHz % V V ms VFB=0V VFB=0V Vin=3.6V *1 Isw=200mA, Vout=13V Ipch=200mA,Vout=13V EN=0V EN=2.6V,VFB=1.0V,VIN=3.6V EN=5.5V EN=0 *1 This parameter is tested with dc measurement. ●Electrical characteristic curves (Reference data) 5.0 1.0 0.9 1.4 1.3 Switching freqency [MHz] 1.2 1.1 1 0.9 0.8 0.7 0.6 2.5 Ta=85℃ Ta=-30℃ Ta=25℃ 4.0 0.8 0.7 IIN [mA] 3.0 Ta=85℃ 2.0 Ta=25℃ Iin [µA] 0.6 0.5 0.4 0.3 1.0 Ta=-30℃ 0.0 2.5 3 3.5 4 Vin [V] 4.5 5 5.5 Ta=-30, 25, 85℃ 0.2 0.1 0.0 2.5 3 3.5 4 Vin [V] 4.5 5 5.5 3 3.5 4 Vin [V] 4.5 5 5.5 Fig.21 Current Consumption vs. power source voltage Fig.22 Quiescent current vs. power source voltage Fig.23 Oscillation frequency vs. power source voltage www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 10/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6071HFN ●Electrical characteristic curves (Reference data) 90 85 80 75 70 65 60 10 15 20 25 30 ILED [mA] 35 40 Technical Note 90 90 CoilCraft : DO1608C-223 85 85 80 75 70 65 60 10 15 20 25 30 ILED [mA] 35 40 10 15 20 25 30 ILED [mA] 35 40 Efficiency [%] Efficiency [%] Efficiency [%] CoilCraft : DO1608C-223 MURATA:LQH32CN220K53 TDK:VLCF4020T-220MR56 TDK:VLF3012AT-220MR33 80 VIN=5.5V VIN=4.5V VIN=3.6V VIN=3.1V MURATA:LQH32CN220K53 75 TDK:VLCF4020T-220MR56 70 65 60 TDK:VLF3012AT-220MR33 Fig.24 Efficiency vs. LED current in each coil Fig.25 Efficiency vs. LED current in each coil Fig.26 Efficiency vs. LED current < 2LED > (VOUT=7.5V, VIN=3.6V, Ta=25℃) < 3LED > (VOUT=10.5V, VIN=3.6V, Ta=25℃) < 2LED > (VOUT=7.5V, Ta=25℃) 90 85 80 75 70 65 60 10 15 20 25 30 ILED [mA] 35 40 340 320 2000 Ta=-30℃ Output Power [mW ] 1500 300 VIN=3.1V Ta=25℃ Efficiency [%] VIN=5.5V VIN=4.5V VIN=3.6V VIN=3.1V IIN [mA] 280 260 240 220 200 -30 1000 VIN=3.6V VIN=5.5V 500 Ta=85℃ -10 10 30 50 Temparature [℃] 70 90 0 2.5 3 3.5 VIN [V] 4 4.5 Fig.27 Efficiency vs. LED current < 3LED > (VOUT=10.5V, VIN=3.6V, Ta=25℃) Fig.28 Inductor current limits vs. Temperature Fig.29 Output power vs. power source voltage 0.53 0.52 0.51 EN 5V/div Ta=85℃ Ta=25℃ IIN 100mA/dev VOUT 10V/div VFB 0.5V/div ( 100µs/div ) VOUT 1V/div ⊿V=1.57V VFB [V] 0.5 0.49 0.48 0.47 2.5 Ta=-30℃ 10ms IIN 200mA/div Ave IIN =1.5mA ( 4ms/div ) 3 3.5 4 4.5 VIN [V] 5 5.5 Fig.30 Feedback voltage vs. Power source voltage Fig.31 Soft Start ( VIN = 3.6V, Ta = 25℃, 3LED, 20mA Load ) Fig.32 LED Open output voltage EN 2V/div IIN 200mA/div ILED 20mA/div VOUT 5V/div ( 4ms/div ) Fig.33 LED luminance adjustment ( VIN = 3.6V, Ta = 25℃, 3LED, 20mA Load ) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 11/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6071HFN ●Block diagram, recommended circuit example, pin location diagram CIN 1μF VIN L 22μH SW Q2 over voltage protect + - Technical Note VOUT TSD short protect PWMcomp + + COUT 1μF white LED ERRAMP VFB Q Q1 Q S R Control + Current Sence + OSC RFB 24Ω 300kΩ GND GNDA EN TEST Fig.34 Block diagram and recommended circuit diagram 8 7 6 5 1 2 3 4 Fig.35 Pin location diagram HSON8 (Top view) ●Pin assignment table PIN Name GNDA EN TEST VIN VFB VOUT SW GND In/Out In In In In Out In Pin number 1 2 3 8 4 7 6 5 Analog GND Enable control(pull down is integrated on resistance) TEST input (pull down is integrated on resistance) Power supply input Feedback input voltage Output Switching terminal Power GND Function ●Operation BD6071HFN is a fixed frequency PWM current mode DC/DC converter, and adopts synchronous rectification architecture. 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 for sub harmonic oscillation prevention. This output controls Q1 and Q2 via the RS latch. Timing of Q1 and Q2 is precisely adjusted so that they will not turn ON at the same time, thus putting them into non-overlapped relation. In the period where Q1 is ON, energy is accumulated in the external inductor, and in the period where Q1 is OFF, energy is transferred to the capacitor of VOUT via Q2. Further, BD6071HFN has many safety functions, and their detection signals stop switching operation at once. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 12/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN Technical Note ►BD6071HFN ●Description of Functions 1) Soft starts and off status BD6071HFN has soft start function and off status function. The soft start function and the off status function prevent large current from flowing to the IC via coil. Occurrence of rush current at turning on is prevented by the soft start function, and occurrence of invalid current at turning off is prevented by the off status function. 2) Isolation control BD6071HFN has isolation control to prevent LED wrong lighting at power off. The cause of the LED wrong lighting is leak current from VIN to the white LED. Therefore, when BD6071HFN gets in power off (EN = L), the isolation control cuts the DC path between SW and Vout, thereby the leak current from VIN to LED is prevented. VIN White LED VFB SW Vout Fig.36 Isolation control 3) Short-circuit protection and over voltage protection BD6071HFN has short-circuit protection and over voltage protection. These detect the voltage of VOUT, and at error, they stop the output Tr. Details are as shown below. ・Short-circuit protection In the case of short-circuit of the DC/DC output (VOUT) to GND, the coil or the IC may be destructed. Therefore, at such an error as VOUT becoming 0.7V 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 its action condition into its non-action condition, and current does not flow to the coil (0mA). ・Over voltage protection At such an error as the IC and the LED being cut off, over voltage causes the SW terminal and the VOUT terminal exceed the absolute maximum ratings, and may destruct the IC. Therefore, when VOUT becomes 14.5V or higher, the over voltage limit works, and turns off the output Tr, and prevents the SW terminal and the VOUT terminal from exceeding the absolute maximum ratings. At this moment, the IC changes from its action condition into its non action condition, 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 goes on up to 14.5V once again. This protection action is shown in Fig.37. Cout SW Vout OVER Detector OVER VOLTAGE REF driver UNDER Detector UNDER VOLTAGE REF Control Fig.37 Block diagram of short-circuit protection and over voltage 4) Thermal shut down BD6071HFN has thermal shut down function. The thermal shut down works at 175℃ or higher, and while holding the setting of EN control from the outside, the IC changes from its action condition into its non action condition. And at 175℃ or below, the IC gets back to its normal action. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 13/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN Technical Note ►BD6071HFN ●Start control and brightness control BD6071HFN can control the start conditions by its EN terminal, and power off at 0.4V or below, and power on at 1.4V or higher. And by changing the duty of power on and off by PWM control, the LED brightness can be adjusted. Two techniques are available for the brightness adjustment. One is discrete time (PWM) adjustment, and the other is continuous time adjustment. 1) PWM brightness adjustment is made by giving PWM signal to EN as shown in Fig.38. The BD6068GU/BD6071HFN T power on/off are according to the PWM signal. By this method, LED current is controlled from 0 to the maximum current. The average LED current increases in proportion with the duty cycle of PWM signal. While in PWM off-cycle mode, the IC and LED both consume no currents, thus providing a high-efficiency operation. And please don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment because of the influence of turning on and off operating is large. The recommended PWM frequency is 100Hz ~ 300Hz. 22µH VIN VIN PWM EN TEST GNDA GND VFB 24Ω SW VOUT 1µF Fig.38 The brightness adjustment example of EN terminal by PWM (fPWM = 100Hz ~ 300Hz) 2-1) The continuous time the brightness adjustment is made by giving DC control voltage to VFB pin of BD6068GUT / BD6071HFN via a series resistor as shown in Fig.39. LED luminance (current) changed by giving DC voltage to VFB directly. DC voltage is given from filtered one of DAC signal, or PWM signal shown in Fig.41. The advantage of this approach is that the PWM signal to be used to control the LED brightness can be set to a high frequency (1kHz or higher). And please don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment. LED current (ILED) is approximated by the following equation. ILED = [{(VFB-DAC) / R1} × R2 + VFB ] / RFB 22μH VIN VIN EN TEST GNDA GND VFB 22kΩ SW VOUT 1μF ILED 4.7kΩ R2 R1 24Ω RFB 30 30 25 25 20 20 ILED [mA] 15 15 10 10 55 00 -5 5 DAC 0 0 0.5 0.5 1.5 2 2.5 1.5DAC [V] 2.5 2 (VFB=500mV) 1 1 3 3 3.5 3.5 4 4 Fig.39 The brightness adjustment example by DAC 22μH VIN VIN EN TEST GNDA GND SW VOUT 20 25 Fig.40 DAC adjustment 1 μF ILED ILED [mA] 15 VFB 100kΩ 33kΩ 47kΩ 30Ω 10 5 PWM 10kHz 0～2.85V 47nF 0 0 10 20 30 40 50 60 70 80 90 100 HI Duty [%] Fig.41 The brightness adjustment example of VFB terminal by PWM (fPWM=10kHz) Fig.42 VFB PWM Control www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 14/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6071HFN Technical Note 2-2) The brightness adjustment of below is done in adjusting of R2 ON time by R1 and Duty cycle of PWM. The minimum value of the LED current is decided by VFB / R1 at the PWM 0%, the maximum value of the LED current is decided by VFB / R2 at the PWM 100%. ILED is given as shown below. ILED=VFB / R1 + VFB / R2 × HI Duty Standard PWM frequency is 100Hz~1kHz. And please don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment. 22μH VIN 20 25 VIN EN TEST GNDA GND SW VOUT 1μF ILED [mA] 15 10 VFB R2 47Ω PWM 1kHz R1 47Ω 5 0 0 10 20 30 40 50 60 70 80 90 100 HI Duty [%] Fig.43 The brightness adjustment example of VFB terminal by PWM (fPWM=100Hz ~ 1kHz) ●Setting range of LED current LED current is determined by the voltage of VFB and the resistor connected to VFB terminal. ILED is given as shown below. ILED=VFB/RFB The current in the standard application is as shown below. VFB=0.5V, RFB=24Ω ILED=20.8mA VIN 1μF Fig.44 VFB PWM Control 22μH VIN EN TEST GNDA GND SW VOUT 1μF ILED VFB RFB 24Ω PWM Fig.45 Recommended circuit diagram The shaded portion in the figure below is the setting range of LED current to become the standard. In case of using 2LED, LED current might increase due to over boosting when VOUT is less than 5.5V. Therefore some ICs may not be used at desired currents. Consequently, for the proper setting of LED current, thoroughly check it for the suitability under use conditions including applicable power supply voltage and temperature. 80 70 60 ILED [mA] VIN=5.5V 80 70 60 ILED [mA] VIN=3.1V ~ 4.2V 50 40 30 20 10 0 7 8 9 10 11 12 13 14 VOUT [V] 50 40 30 20 10 0 5.5 7 8.5 10 VOUT [V] 11.5 13 14 2LED 3LED 2LED 3LED Fig.46 LED Setting range of LED current www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 15/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6071HFN ●Selection of external parts Recommended external parts are as shown below. When to use other parts than these, select the following equivalent parts. ・Coil Value 22μH 22μH 22μH 22μH Tolerance ±10% ±20% ±20% ±20% Manufacturer MURATA TDK Coil Craft TDK Product number LQH32CN220K53 VLF3012AT220MR33 DO1608 VLF3010AT220MR33 Size (mm) W 2.5 2.6 4.45 2.6 L 3.2 2.8 6.6 2.8 H 1.55 1.2 2.92 1.0 Technical Note DCR(Ω) 0.71 0.66 0.37 1.30 Please refer to the reference data of p.11 for the change in the efficiency when the coil is changed. ・Capacitor Value 1µF 1µF ・Resistor Value Tolerance Manufacturer Product number 24Ω ±1% ROHM MCR006YZPF24R0 0.6 0.3 0.23 Size (mm) L W H MURATA GRM188B31E105K 1.6 0.8 0.8 -25deg~+85deg MURATA GRM188B11A105K 1.6 0.8 0.8 -25deg~+85deg Manufacturer Product number Size (mm) L W H Temperature range 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. The BD6068GUT/BD6071HFN is designed for the inductance value of 22µH. Do not use other inductance value. Select a capacitor of ceramic type with excellent frequency and temperature characteristics. Further, select Capacitor to be used for CIN/COUT with small direct current resistance, and pay sufficient attention to the PCB layout shown in the next page. ●PCB Layout To battery power source CIN GNDA EN TEST VIN VOUT SW COUT L1 VFB RFB GND To battery GND Fig.47 PCB Layout Image 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, which please note carefully. Connect the input bypath capacitor CIN nearest to between VIN and GNDA pin, as shown in the upper diagram. Thereby, the input voltage ripple of the IC can be reduced. And, connect the output capacitor COUT nearest to between VOUT and GND pin. Thereby, the output voltage ripple of the IC can be reduced. Connect the current setting RFB nearest to VFB pin. Connect the GND connection side of RFB directly to GND pin. Connect the GNDA pin directly to GND pin. When those pins are not connected directly near the chip, influence is given to the performance of BD6068/BD6071HFN 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. And keep the pins that are subject to the influence like VFB pin away from the wire to SW. The PCB layout in consideration of these is shown in the Fig.49. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 16/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6071HFN VOUT Technical Note 112mVpp (VBAT=3.6V, Ta=25℃, VOUT=14V, 20mA Load) Fig.48 Output noise ●Recommended PCB layout Front surface (Top view) Bottom surface (Top view) Fig.49 PCB Layout www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 17/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6069GUT, BD6072HFN ●Absolute maximum ratings (Ta=25℃) Parameter Power supply voltage 1 Power supply voltage 2 BD6069GUT Power dissipation BD6072HFN Operating temperature range Storage temperature range Topr Tstg Pd Symbol VMAX1 VMAX2 Ratings 7 *1 20 *1 800 * 2 Technical Note Unit V V mW mW ℃ ℃ Conditions Vin,EN,VFB,TEST SW,Vout 50mm×58mm×1.75mm At glass epoxy board mounting. 70mm×70mm×1.6mm At glass epoxy board mounting. 630 *3 -30 ~ +85 -55 ~ +150 *1 These values are based on GND and GNDA pins. *2 When it’s used by more than Ta=25℃, it’s reduced by 6.4mW/℃. *3 When it’s used by more than Ta=25℃, it’s reduced by 5.04mW/℃. ●Recommended operating range (Ta=-30℃ ~ +85℃) Parameter Operating supply voltage BD6069GUT BD6072HFN Symbol Vin Ratings Min. 2.7 Typ. 3.6 Max. 5.5 Unit V Conditions ●Electrical characteristics (Unless otherwise specified Ta = +25℃, Vin=3.6V) Limits Parameter Symbol Min. Typ. Max. EN threshold voltage (Low) EN threshold voltage (High) EN terminal input current EN terminal output current Input voltage range Quiescent Current Current Consumption Feedback voltage Inductor current limit SW saturation voltage SW on resistance P Switching frequency Duty cycle limit Output voltage range Over voltage limit Start up time *1 This parameter is tested with dc measurement. Unit Conditions VthL VthH Iin Iout Vin Iq Idd Vfb Icoil Vsat Ronp fSW Duty Vo Ovl Ts 1.4 -2.0 3.1 0.47 270 0.8 82.7 18.0 - 18.3 -0.1 0.1 1.1 0.50 350 0.14 2.1 1.0 85.0 18.5 0.5 0.4 30.0 5.5 2.0 1.5 0.53 430 0.28 3.2 1.2 18.0 19.0 1.0 V V μA μA V μA mA V mA V Ω MHz % V V ms VFB=0V VFB=0V Vin=3.6V *1 Isw=200mA, Vout=13V Ipch=200mA,Vout=13V EN=0V EN=2.6V,VFB=1.0V,VIN=3.6V EN=5.5V EN=0 www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 18/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6069GUT, BD6072HFN ●Electrical characteristic curves (Reference data) 5.0 4.0 Technical Note 1.0 0.9 1.4 1.3 Switching freqency [MHz] 0.8 0.7 1.2 1.1 1 0.9 0.8 0.7 0.6 2.5 Ta=85℃ Ta=-30℃ Ta=25℃ IIN [mA] Ta=85℃ 2.0 Ta=25℃ IIN [µA] 3.0 0.6 0.5 0.4 0.3 1.0 Ta=-30℃ 0.0 2.5 3 3.5 4 Vin [V] 4.5 5 5.5 Ta=-30, 25, 85℃ 0.2 0.1 0.0 2.5 3 3.5 4 VIN [V] 4.5 5 5.5 3 3.5 4 4.5 VIN [V] 5 5.5 Fig.50 Current Consumption vs Power source voltage 90 85 80 75 70 65 60 10 15 20 25 30 ILED [mA] 35 40 90 Fig.51 Quiescent current vs power source voltage 90 Fig.52 Oscillation frequency vs. power source voltage CoilCraft : DO1608C-223 85 80 75 85 80 75 70 65 60 10 15 20 25 30 ILED [mA] 35 40 10 15 20 25 30 ILED [mA] 35 40 Efficiency [%] Efficiency [%] Efficiency [%] CoilCraft : DO1608C-223 MURATA:LQH32CN220K53 TDK:VLCF4020T-220MR56 TDK:VLF3012AT-220MR33 VIN=5.5V VIN=4.5V VIN=3.6V VIN=3.1V TDK:VLCF4020T-220MR56 70 65 60 MURATA:LQH32CN220K53 TDK:VLF3012AT-220MR33 Fig.53 Efficiency vs. LED current in each coil < 3LED > (VOUT=10.5V, VIN=3.6V, Ta=25℃) 90 85 80 75 70 VIN=3.6V VIN=5.5V VIN=4.2V IIN [mA] Fig.54 Efficiency vs. LED current in each coil < 4LED > (VOUT=14V, VIN=3.6V, Ta=25℃) 430 410 2000 Fig.55 Efficiency vs. LED current in each coil < 3LED > (VOUT=10.5V, VIN=3.6V, Ta=25℃) Ta=-30℃ 1500 VIN=3.1V 370 350 330 310 290 Output Power [mW ] 390 Efficiency [%] Ta=25℃ 1000 VIN=3.6V VIN=5.5V 500 Ta=85℃ 65 60 10 15 VIN=3.1V 20 25 30 35 40 270 -30 -10 ILED [mA] 10 30 50 Temparature [℃] 70 85 0 2.5 3 3.5 VIN [V] 4 4.5 Fig.56 Efficiency vs. LED current in each coil < 4LED > (VOUT=14V, VIN=3.6V, Ta=25℃) 0.53 0.52 0.51 VFB [V] 0.5 0.49 0.48 Fig.57 Inductor current limits vs. Temperature Fig.58 Output power vs. Power source voltage VOUT 1V/div Ta=85℃ Ta=25℃ ⊿V=1.57V EN 2V/div IIN 200mA/div ILED 20mA/div Ta=-30℃ 10ms IIN 200mA/div Ave IIN =1.5mA ( 4ms/div ) VOUT 5V/div 0.47 2.5 ( 4ms/div ) 3 3.5 4 4.5 VIN [V] 5 5.5 Fig.59 Feedback voltage vs. Power source voltage (ILED=20mA) Fig.60 LED Open output voltage Fig.61 LED luminance adjustment ( VIN = 3.6V, Ta = 25℃, 3LED, 20mA Load ) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 19/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6069GUT, BD6072HFN ●Block diagram, recommended circuit example, pin location diagram CIN 1µF VIN L 22µH SW Q2 over voltage protect + - Technical Note VOUT TSD short protect PWMcomp + + COUT 1µF white LED ERRAMP VFB Q Q1 Q S R Control + Current Sence + OSC RFB 24Ω 300kΩ GND GNDA EN TEST Fig.62 Block diagram and recommended circuit diagram 8 7 6 5 C1 B1 A1 C2 C3 B3 A2 A3 1 2 3 4 Fig.63 Pin location diagram VCSP60N1 (Bottom view) ●Pin assignment table PIN Name GNDA EN TEST VIN VFB VOUT SW GND In/Out In In In In Out In Ball number BD6069GUT A1 A2 A3 B1 B3 C1 C2 C3 BD6072HFN 1 2 3 8 4 7 6 5 Fig.64 Pin location diagram HSON8 (Top view) Function Analog GND Enable control (pull down is integrated on resistance) TEST input (pull down is integrated on resistance) Power supply input Feedback input voltage Output Switching terminal Power GND ●Operation BD6069GUT is a fixed frequency PWM current mode DC/DC converter, and adopts synchronous rectification architecture. 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 for sub harmonic oscillation prevention. This output controls Q1 and Q2 via the RS latch. Timing of Q1 and Q2 is precisely adjusted so that they will not turn ON at the same time, thus putting them into non-overlapped relation. In the period where Q1 is ON, energy is accumulated in the external inductor, and in the period where Q1 is OFF, energy is transferred to the capacitor of VOUT via Q2. Further, BD6069GUT/BD6072HFN has many safety functions, and their detection signals stop switching operation at once. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 20/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN Technical Note ►BD6069GUT, BD6072HFN ●Description of Functions 1) Soft starts and off status BD6069GUT/BD6072HFN has soft start function and off status function. The soft start function and the off status function prevent large current from flowing to the IC via coil. Occurrence of rush current at turning on is prevented by the soft start function, and occurrence of invalid current at turning off is prevented by the off status function. 2) Isolation control BD6069GU/BD6072HFN T has isolation control to prevent LED wrong lighting at power off. The cause of the LED wrong lighting is leak current from VIN to the white LED. Therefore, when BD6069GUT/BD6072HFN gets in power off (EN = L), the isolation control cuts the DC path between SW and Vout, thereby the leak current from VIN to LED is prevented. VIN White LED VFB SW Vout Fig.65 Isolation control 3) Short-circuit protection and over voltage protection BD6069GUT/BD6072HFN has short-circuit protection and over voltage protection. These detect the voltage of VOUT, and at error, they stop the output Tr. Details are as shown below. ・Short-circuit protection In the case of short-circuit of the DC/DC output (VOUT) to GND, the coil or the IC may be destructed. Therefore, at such an error as VOUT becoming 0.7V 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 its action condition into its non action condition, and current does not flow to the coil (0mA). ・Over voltage protection At such an error as the IC and the LED being cut off, over voltage causes the SW terminal and the VOUT terminal exceed the absolute maximum ratings, and may destruct the IC. Therefore, when VOUT becomes 18.5V or higher, the over voltage limit works, and turns off the output Tr, and prevents the SW terminal and the VOUT terminal from exceeding the absolute maximum ratings. At this moment, the IC changes from its action condition into its non action condition, 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 goes on up to 18.5V once again. This protection action is shown in Fig.66. Cout SW Vout OVER Detector OVER VOLTAGE REF driver UNDER Detector UNDER VOLTAGE REF Control Fig.66 Block diagram of short-circuit protection and over voltage 4) Thermal shut down BD6069GUT/BD6072HFN has thermal shut down function. The thermal shut down works at 175℃ or higher, and while holding the setting of EN control from the outside, the IC changes from its action condition into its non action condition. And at 175℃ or below, the IC gets back to its normal action. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 21/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN Technical Note ►BD6069GUT, BD6072HFN ●Start control and brightness control BD6069GUT/BD6072HFN can control the start conditions by its EN terminal, and power off at 0.4V or below, and power on at 1.4V or higher. And by changing the duty of power on and off by PWM control, the LED brightness can be adjusted. Two techniques are available for the brightness adjustment. One is discrete time (PWM) adjustment, and the other is continuous time adjustment. 1) PWM brightness adjustment is made by giving PWM signal to EN as shown in Fig.67. The BD6069GUT/BD6072HFN power on/off is according to the PWM signal. By this method, LED current is controlled from 0 to the maximum current. The average LED current increases in proportion with the duty cycle of PWM signal. While in PWM off-cycle mode, the IC and LED both consume no currents, thus providing a high-efficiency operation. And please don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment because of the influence of turning on and off operating is large. The recommended PWM frequency is 100Hz ~ 300Hz. 22µH VIN VIN PWM EN TEST GNDA GND VFB 24Ω SW VOUT 1µF Fig.67 The brightness adjustment example of EN terminal by PWM (fPWM = 100Hz ~ 300Hz) 2-1) The continuous time the brightness adjustment is made by giving DC control voltage to VFB pin of BD6069GUT / BD6072HFN via a series resistor as shown in Fig.68. LED luminance (current) changed by giving DC voltage to VFB directly. DC voltage is given from filtered one of DAC signal, or PWM signal shown in Fig.70. The advantage of this approach is that the PWM signal to be used to control the LED brightness can be set to a high frequency (1kHz or higher). And please don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment. LED current (ILED) is approximated by the following equation. ILED = [{(VFB-DAC) / R1} × R2 + VFB ] / RFB 22µH VIN VIN EN TEST GNDA GND VFB 22kΩ SW ILED [mA] 30 30 25 25 20 20 VOUT 1µF ILED 4.7kΩ R2 R1 24Ω RFB 15 15 10 10 55 00 -5 5 0 0 0.5 0.5 1 1 1.5 1.5 2 2 2.5 2.5 3 3 3.5 3.5 4 4 DAC [V] DAC (VFB=500mV) Fig.68 The brightness adjustment example by DAC 22µH VIN VIN EN TEST GNDA GND SW VOUT 1µF ILED VFB 100kΩ PWM 10kHz 0～2.85V 47nF 33kΩ 47kΩ 30Ω ILED [mA] 25 Fig.69 DAC adjustment 20 15 10 5 0 0 10 20 30 40 50 60 70 80 90 100 HI Du ty [%] Fig.70 The brightness adjustment example of VFB terminal by PWM (fPWM=10kHz) Fig.71 VFB PWM Control www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 22/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6069GUT, BD6072HFN Technical Note 2-2) The brightness adjustment of below is done in adjusting of R2 ON time by R1 and Duty cycle of PWM. The minimum value of the LED current is decided by VFB / R1 at the PWM 0%, the maximum value of the LED current is decided by VFB / R2 at the PWM 100%. ILED is given as shown below. ILED=VFB / R1 + VFB / R2 × HI Duty Standard PWM frequency is 100Hz~1kHz. And please don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment. 22µH VIN VIN EN TEST GNDA GND VFB R2 47Ω PWM 1kHz R1 47Ω 5 25 SW VOUT ILED [mA] 20 1µF 15 10 0 0 10 20 30 40 50 60 70 80 90 100 HI Duty [%] Fig.72 he brightness adjustment example of VFB terminal by PWM (fPWM=100Hz~1kHz) ●Setting range of LED current LED current is determined by the voltage of VFB and the resistor connected to VFB terminal. ILED is given as shown below. ILED=VFB/RFB The current in the standard application is as shown below. VFB=0.5V, RFB=24Ω ILED=20.8mA Fig.73 VFB PWM Control 22µH VIN 1µF VIN EN TEST GNDA GND SW VOUT PWM 1µF ILED VFB RFB 24Ω Fig.74 Recommended circuit diagram The shaded portion in the figure below is the setting range of LED current to become the standard. Depending on coils and white LEDs to be used, however, some ICs may not be used at desired currents. Consequently, for the proper setting of LED current, thoroughly check it for the suitability under use conditions including applicable power supply voltage and temperature. 80 70 60 ILED[mA] 50 40 30 20 10 0 7 8 9 10 11 12 13 14 15 16 17 18 VOUT[V] Fig.75 Setting range of LED current www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 23/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6069GUT, BD6072HFN ●Selection of external parts Recommended external parts are as shown below. When to use other parts than these, select the following equivalent parts. ・Coil Value 22μH 22μH 22μH 22μH Tolerance ±10% ±20% ±20% ±20% Manufacturer MURATA TDK Coil Craft TDK Product number LQH32CN220K53 VLF3012AT220MR33 DO1608 VLF3010AT220MR33 Size (mm) W 2.5 2.6 4.45 2.6 L 3.2 2.8 6.6 2.8 H 1.55 1.2 2.92 1.0 Technical Note DCR (Ω) 0.71 0.66 0.37 1.30 Please refer to the reference data of p.20 for the change in the efficiency when the coil is changed. ・Capacitor Value 1µF 1µF ・Resistor Value 24Ω ±1% ROHM MCR006YZPF24R0 0.6 0.3 0.23 Tolerance Manufacturer Product number Size (mm) L W H MURATA GRM188B31E105K 1.6 0.8 0.8 -25deg~+85deg MURATA GRM188B11A105K 1.6 0.8 0.8 -25deg~+85deg Manufacturer Product number Size (mm) L W H Temperature range 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. The BD6069GUTT/BD6072HFN is designed for the inductance value of 22µH. Do not use other inductance value. Select a capacitor of ceramic type with excellent frequency and temperature characteristics. Further, select Capacitor to be used for CIN/COUT with small direct current resistance, and pay sufficient attention to the PCB layout shown in the next page. ●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 PCB layout, which please note carefully. To battery power source To battery power source CIN CIN GNDA EN TEST GNDA VIN VOUT SW RFB VIN VFB EN TEST COUT L1 VOUT SW GND COUT L1 To battery GND RFB VFB GND To battery GND Fig.76 BD6069GUT PCB Layout Image Fig.77 BD6072HFN PCB Layout Image www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 24/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6069GUT, BD6072HFN Technical Note Connect the input bypath capacitor CIN nearest to between VIN and GNDA pin, as shown in the upper diagram. Thereby, the input voltage ripple of the IC can be reduced. And, connect the output capacitor COUT nearest to between VOUT and GND pin. Thereby, the output voltage ripple of the IC can be reduced. Connect the current setting RFB nearest to VFB pin. Connect the GND connection side of RFB directly to GND pin. Connect the GNDA pin directly to GND pin. When those pins are not connected directly near the chip, influence is given to the performance of BD6069GUT /BD6072HFN, 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. And keep the pins that are subject to the influence like VFB pin away from the wire to SW. The PCB layout in consideration of these is shown in the Fig.79 to 82. VOUT 112mVpp (VBAT=3.6V, Ta=25℃, VOUT=14V, 20mA Load) Fig.78 Output noise ●Recommended PCB layout GNDA Ci n EN １ ２V Cout RFB FB L ED GND １ １G LED １ ２V １ １G SW L1 L ED SW VOUT VOUT VB AT GND VOUT Fig.80 BD6069GUT Bottom surface (Top view) Fig.79 BD6069GUT Front surface (Top view) VOUT www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 25/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ►BD6069GUT, BD6072HFN ●Recommended PCB layout Technical Note Fig.81 BD6072HFN Front surface (Top view) Fig.82 BD6072HFN Bottom surface (Top view) ●Attention point of PCB layout In PCB 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. 26/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN Technical Note ●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. 27/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN ●Ordering part number Technical Note B D 6 Part No. 0 6 7 G U - E 2 Part No. Package GU : VCSP85H1 Packaging and forming specification E2: Embossed tape and reel VCSP85H1 (BD6067GU) 1PIN MARK 1.68±0.1 Tape Quantity 0.25±0.1 1.0MAX Embossed carrier tape 3000pcs E2 The direction is the 1pin of product is at the upper left when you hold 1.68±0.1 Direction of feed S ( reel on the left hand and you pull out the tape on the right hand ) 0.08 S 8-φ0.3±0.05 0.05 A B (φ0.15)INDEX POST C B A 1 2 3 A B P=0.5×2 0.34±0.1 0.34±0.1 P=0.5×2 1pin Direction of feed (Unit : mm) Reel ∗ Order quantity needs to be multiple of the minimum quantity. B D 6 Part No. 0 6 9 G U T - E 2 Part No. Package GUT : VCSP60N1 Packaging and forming specification E2: Embossed tape and reel VCSP60N1 (BD6069GUT) 1PIN MARK 1.68±0.05 Tape Quantity 0.21±0.05 0.6±0.08 Embossed carrier tape 3000pcs E2 The direction is the 1pin of product is at the upper left when you hold 1.68±0.05 Direction of feed S ( reel on the left hand and you pull out the tape on the right hand ) 8-φ0.3±0.05 0.05 A B (φ0.15)INDEX POST C B A 1 2 A B 3 P=0.5×2 0.34±0.05 0.08 S 0.34±0.05 P=0.5×2 1pin Direction of feed (Unit : mm) Reel ∗ Order quantity needs to be multiple of the minimum quantity. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 28/29 2011.01 - Rev.C BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN Technical Note B D 6 0 7 1 H F N - T R Part No. Part No. 6071 6072 Package HFN : HSON8 Packaging and forming specification TR: Embossed tape and reel HSON8 2.9 ± 0.1 (MAX 3.1 include. BURR) 0.475 87 6 5 (2.2) 5 6 7 8 (0.05) (0.3) (0.15) Tape Quantity Direction of feed +0.1 0.13 –0.05 Embossed carrier tape 3000pcs TR The direction is the 1pin of product is at the upper right when you hold 3.0 ± 0.2 2.8 ± 0.1 (1.8) (0.45) (0.2) ( reel on the left hand and you pull out the tape on the right hand 1pin ) 1PIN MARK +0.03 0.6MAX 0.02 –0.02 S 0.1 S 0.32±0.1 0.08 0.65 (0.2) 1 2 3 4 4 3 2 1 M Direction of feed (Unit : mm) Reel ∗ Order quantity needs to be multiple of the minimum quantity. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 29/29 2011.01 - Rev.C 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