BD8119FM-ME2

Power Management IC Series for Automotive Body Control White Backlight LED Driver for Medium to Large LCD Panels (Switching Regulator Type) BD8119FM-M No.10039EAT07 ●Description BD8119FM-M is a white LED driver with the capability of withstanding high input voltage (36V MAX). This driver has 4ch constant-current drivers integrated in 1-chip, which each channel can draw up to 150mA max, so that high brightness LED driving can be realized. Furthermore, a current-mode buck-boost DC/DC controller is also integrated to achieve stable operation against unstable car-battery voltage input and also to remove the constraint of the number of LEDs in series connection. The brightness can be controlled by either PWM or VDAC techniques. ●Features 1) Input voltage range is 5.0 to 30 V 2) Integrated buck-boost current-mode DC/DC controller 3) Four integrated LED current driver channels (150mA max. each channel) 4) PWM Light Modulation (Minimum Pulse Width 25µs) 5) Built-in protection functions (UVLO, OVP, TSD, OCP, SCP) 6) Abnormal status detection function (OPEN/ SHORT) 7) HSOP-M28 package ●Applications Backlight for car navigation, dashboard panels, etc. (※ Recommended Component of Toshiba Matsushita Display Technology Co.,Ltd. ) ●Absolute maximum ratings (Ta=25℃) Parameter Power supply voltage BOOT Voltage SW,CS,OUTH Voltage BOOT-SW Voltage LED output voltage VREG, OVP, OUTL, FAIL1, FAIL2, LEDEN1, LEDEN2, ISET, VDAC, PWM, SS, COMP, RT, SYNC, EN Voltage Power Consumption Operating temperature range Storage temperature range LED maximum output current Symbol VCC VBOOT VSW, VCS, VOUTH VBOOT-SW VLED1～4 VVREG, VOVP, VOUTL, VFAIL1, VFAIL2, VLEDEN1, VLEDEN2, VISET, VVDAC, VPWM, VSS, VCOMP, VRT, VSYNC, VEN Pd Topr Tstg ILED Ratings 36 41 36 7 36 -0.3～7 < VCC 2.20 ※1 Unit V V V V V V W ℃ ℃ mA -40～+95 -55～+150 150 ※2 ※3 ※1 IC mounted on glass epoxy board measuring 70mm×70mm×1.6mm, power dissipated at a rate of 17.6mw/℃ at temperatures above 25℃. ※2 Dispersion figures for LED maximum output current and VF are correlated. Please refer to data on separate sheet. ※3 Amount of current per channel. ●Operating conditions (Ta=25℃) Parameter Power supply voltage Oscillating frequency range External synchronization frequency range External synchronization pulse duty range ※4 ※5 Symbol VCC FOSC FSYNC FSDUTY Ratings 5.0～30 250～550 fosc～550 40～60 Unit V kHz kHz % ※4 Connect SYNC to GND or OPEN when not using external frequency synchronization. ※5 Do not switch between internal and external synchronization when an external synchronization signal is input to the device. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 1/20 2010.08 - Rev.A BD8119FM-M ●Electrical Characteristics (unless otherwise specified, VCC=12V Ta=25℃) Limits Parameter Symbol Min Typ Max. Circuit current Standby current [VREG Block (VREG)] Reference voltage [OUTH Block] OUTH high-side ON resistance OUTH low-side ON resistance Over-current protection operating voltage [OUTL Block] OUTH high-side ON resistance OUTH low -side ON resistance [SW Block] SW low -side ON resistance [Error Amplifie Block] LED voltage COMP sink current COMP source current [Oscillator Block] Oscillating frequency [OVP Block] Over-voltage detection reference voltage OVP hysteresis width SCP Latch OFF Delay Time [UVLO Block ] UVLO voltage UVLO hysteresis width VUVLO VUHYS 4.0 50 4.3 150 4.6 150 V mV VCC : Sweep down VCC : Sweep up VOVP VOHYS TSCP 1.9 0.45 70 2.0 0.55 100 2.1 0.65 130 V V ms VOVP=Sweep up VOVP=Sweep down RT=100kΩ fOSC 250 300 350 KHz RT=100kΩ VLED ICOMPSINK ICOMPSOURCE 0.9 15 -35 1.0 25 -25 1.1 35 -15 V µA µA RON_SW 1.0 2.0 4.0 Ω ION_SW=10mA RONLH RONLL 1.0 0.5 3 2 4.5 3.0 Ω Ω ION=-10mA ION=10mA RONHH RONHL VOLIMIT 1.0 0.5 VCC -0.66 3 2 VCC -0.6 4.5 3.0 VCC -0.54 Ω Ω V ION=-10mA ION=10mA VREG 4.5 5 5.5 V ICC IST 7 4 14 8 Technical Note Unit mA µA Conditions EN=Hi, SYNC=Hi, RT=OPEN PWM=Low, ISET=OPEN, CIN=10µF EN=Low IREG=-5mA, CREG=2.2µF VLED=2V, Vcomp=1V VLED=0V, Vcomp=1V ◎ This product is not designed for use in radioactive environments. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 2/20 2010.08 - Rev.A BD8119FM-M ●Electrical Characteristics – Continued (unless otherwise specified, VCC=12V Ta=25℃) Limits Parameter Symbol Unit Min Typ Max. [LED Output Block] LED current relative dispersion width LED current absolute dispersion width ISET voltage PWM minimum pulse width PWM maximum duty PWM frequency VDAC gain Open detection voltage LED Short detection Voltage LED Short Latch OFF Delay Time PWM Latch OFF Delay Time △ILED1 △ILED2 VISET Tmin Dmax fPWM GVDAC VOPEN VSHORT TSHORT TPWM -3 -5 1.96 25 0.2 4.4 70 70 2.0 25 0.3 4.7 100 100 +3 +5 2.04 100 20 0.4 5.0 130 130 % % V µs % KHz mA/V V V ms ms Technical Note Conditions ILED=50mA, ΔILED1=(ILEDILED_AVG-1)×100 ILED=50mA, ΔILED2=(ILED50mA-1)×100 RISET 1=120kΩ FPWM=150Hz, ILED=50mA FPWM=150Hz, ILED=50mA Duty=50%, ILED=50mA VDAC=0～2V, RISET=120kΩ ILED=VDAC÷RISET×Gain VLED= Sweep down VOVP= Sweep up RT=100kΩ RT=100kΩ [Logic Inputs (EN, SYNC, PWM, LEDEN1, LEDEN2)] Input HIGH voltage Input LOW voltage Input current 1 Input current 2 [FAIL Output (open drain) ] FAIL LOW voltage VOL 0.1 0.2 V IOL=0.1mA VINH VINL IIN IEN 2.1 GND 20 15 35 25 5.5 0.8 50 35 V V µA µA VIN=5V (SYNC, PWM, LEDEN1, LEDEN2) VEN=5V (EN) ◎ This product is not designed for use in radioactive environments. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 3/20 2010.08 - Rev.A BD8119FM-M ●Reference data (unless otherwise specified, Ta=25℃) 5.5 SWITCHING FREQUENCY:FOSC [kHz] 400 Technical Note 55 OUTPUTCURRENT :ILED [mA] OUTPUT VOLTAGE:VREG [V] 5.3 360 53 VCC=12V 5.1 VCC=12V 320 VCC= 12V 51 4.9 280 49 4.7 240 47 4.5 -40 -15 10 35 60 TEMPERATURE:Ta [℃] 85 200 -40 -15 10 35 60 TEMPERATURE:Ta [℃] 85 45 0.5 1.5 2.5 3.5 LED VOLTAGE:VLED[V] 4.5 Fig.1 VREG temperature characteristic 55 OUTPUTCURRENT :ILED [mA] OUTPUTCURRENT :ILED [mA] 50 Fig.2 OSC temperature characteristic 5 OUTPUTCURRENT :ILED [mA] 0 0.5 1 1.5 VDAC VOLTAGE:VDAC[V] 2 Fig.3 ILED depend on VLED 53 VCC= 12V 51 40 4 30 3 49 20 2 47 10 1 45 -40 -15 10 35 60 TEMPERATURE:Ta [℃] 85 0 0 0 0.02 0.04 0.06 0.08 VDAC VOLTAGE:VDAC[V] 0.1 Fig.4 ILED temperature characteristic 100 100 Fig.5 VDAC Gain① Fig.6 VDAC Gain② 10.0 85 70 VCC=12V 55 VCC=30V 70 VCC=30V 55 VCC=15V OUTPUT CARRENT:Icc [mA] 85 8.0 EFFICIENCY [%] EFFICIENCY [%] 6.0 VCC=12V 4.0 40 VCC=5V 25 25 150 275 400 525 OUTPUT CURRENT [mA] 40 VCC=4V 25 25 150 275 400 525 OUTPUT CURRENT [mA] 2.0 0.0 0 6 12 18 24 30 SUPPLY VOLTAGE:Vcc [V] 36 Fig.7 Efficiency (Depend on input voltage) 0.66 0.64 OUTPUT VOLTAGE:Vcc-Vcs [V] 0.62 0.60 0.58 Fig.8 Efficiency (Depend on output voltage) 10 10 Fig.9 Circuit Current (Switching OFF) OUTPUT VOLTAGE:VREG [V] 6 OUTPUTCURRENT :ILED [mA] 0 1 2 3 4 EN VOLTAGE:VEN [V] 5 8 8 6 4 4 VCC=12V 0.56 0.54 -40 -15 10 35 60 TEMPERATURE:Ta [℃] 85 2 2 0 0 0 1 2 3 4 PWM VOLTAGE:VEN [V] 5 Fig.10 Overcurrent detecting voltage temperature characteristic Fig.11 EN threshold voltage Fig.12 PWM threshold voltage www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 4/20 2010.08 - Rev.A BD8119FM-M ●Block diagram Vin CIN VCC VREG COUT OVP Technical Note UVLO TSD OVP VREG EN Timer Latch OCP PWM ＋ － CS FAIL1 BOOT Control Logic OUTH DRV － PWM SW CTL SYNC RT CRT RT SLOPE OSC ＋ VREG DGND OUTL ERR AMP COMP RPC CPC SS CSS － － － － ＋ GND Ccomp OCP OVP LED1 SS LED2 Current driver PWM LED3 LED4 VDAC ISET PGND ISET RISET Open Short Detect Open Det Timer Latch Short Det FAIL2 LEDEN1 LEDEN2 Fig.13 ●Pin layout COMP SS VCC EN RT SYNC GND 1 2 3 4 5 6 7 28 27 26 25 24 23 22 PWM FAIL1 FAIL2 LEDEN1 LEDEN2 LED1 LED2 8 9 10 11 12 13 14 21 20 19 18 17 16 15 Fig.14 ●Pin function table Pin Symbol 1 COMP VREG 2 SS BOOT 3 VCC CS 4 EN OUTH 5 RT SW 6 SYNC 7 GND DGND 8 PWM OUTL 9 FAIL1 10 FAIL2 11 LEDEN1 12 LEDEN2 13 LED1 14 LED2 15 LED3 N.C. 16 LED4 PGND 17 OVP ISET 18 VDAC VDAC 19 ISET 20 PGND OVP 21 LED4 22 OUTL LED3 23 DGND 24 SW 25 OUTH 26 CS 27 BOOT 28 VREG Function Error amplifier output Soft start time-setting capacitance input Input power supply Enable input Oscillation frequency-setting resistance input External synchronization signal input Small-signal GND PWM light modulation input Failure signal output LED open/short detection signal output LED output enable pin 1 LED output enable pin 2 LED output 1 LED output 2 LED output 3 LED output 4 Over-voltage detection input DC variable light modulation input LED output current-setting resistance input LED output GND N.C. Low-side external MOSFET Gate Drive out put Low-side internal MOSFET Source out put High-side external MOSFET Source pin High-side external MOSFET Gate Drive out pin DC/DC Current Sense Pin High-side MOSFET Power Supply pin Internal reference voltage output www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 5/20 2010.08 - Rev.A BD8119FM-M Technical Note ●5V voltage reference (VREG) 5V (Typ.) is generated from the VCC input voltage when the enable pin is set high. This voltage is used to power internal circuitry, as well as the voltage source for device pins that need to be fixed to a logical HIGH. UVLO protection is integrated into the VREG pin. The voltage regulation circuitry operates uninterrupted for output voltages higher than 4.5 V (Typ.), but if output voltage drops to 4.3 V (Typ.) or lower, UVLO engages and turns the IC off. Connect a capacitor (Creg = 2.2µF Typ.) to the VREG terminal for phase compensation. Operation may become unstable if Creg is not connected. ●Constant-current LED drivers If less than four constant-current drivers are used, unused channels should be switched off via the LEDEN pin configuration. The truth table for these pins is shown below. If a driver output is enabled but not used (i.e. left open), the IC’s open circuit-detection circuitry will operate. Please keep the unused pins open. The LEDEN terminals are pulled down internally in the IC, so if left open, the IC will recognize them as logic LO. However, they should be connected directly to VREG or fixed to a logic HI when in use. LED LED EN 〈1〉 〈2〉 1 2 3 4 L L ON ON ON ON H L ON ON ON OFF L H ON ON OFF OFF H H ON OFF OFF OFF ・Output current setting LED current is computed via the following equation: ILED = min[VDAC , VISET(=2.0V)] / RSET x GAIN [A] (min[VDAC , 2.0V] = the smaller value of either VDAC or VISET; GAIN = set by internal circuitry.) In applications where an external signal is used for output current control, a control voltage in the range of 0.1 to 2.0 V can be connected on the VDAC pin to control according to the above equation. If an external control signal is not used, connect the VDAC pin to VREG (do not leave the pin open as this may cause the IC to malfunction). Also, do not switch individual channels on or off via the LEDEN pin while operating in PWM mode. The following diagram illustrates the relation between ILED and GAIN. ILED vs GAIN 3350 3300 3250 3200 GAIN 3150 3100 3050 3000 2950 0 20 40 60 80 ILED[mA] 100 120 140 160 ILED[mA] 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 GAIN 3215 3080 3030 2995 3000 3020 3040 3070 3105 3140 3175 3210 3245 3280 3330 In PWM intensity control mode, the ON/OFF state of each current driver is controlled directly by the input signal on the PWM pin; thus, the duty ratio of the input signal on the PWM pin equals the duty ratio of the LED current. When not controlling intensity via PWM, fix the PWM terminal to a high voltage (100%). Output light intensity is greatest at 100% input. PWM PWM ILED(50mA/div) ILED PWM=150Hz Duty=0.38% PWM=150Hz Duty=50% www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 6/20 2010.08 - Rev.A BD8119FM-M Technical Note ●Buck-Boost DC/DC controller ・Number of LEDs in series connection Output voltage of the DCDC converter is controlled such that the forward voltage over each of the LEDs on the output is set to 1.0V (Typ.). DCDC operation is performed only when the LED output is operating. When two or more LED outputs are operating simultaneously, the LED voltage output is held at 1.0V (Typ.) per LED over the column of LEDs with the highest VF value. The voltages of other LED outputs are increased only in relation to the fluctuation of voltage over this column. Consideration should be given to the change in power dissipation due to variations in VF of the LEDs. Please determine the allowable maximum VF variance of the total LEDs in series by using the description as shown below: VF variation allowable voltage 3.7V(Typ.) = short detecting voltage 4.7V(Typ.) - LED control voltage 1.0V(Typ.) The number of LEDs that can be connected in series is limited due to the open-circuit protection circuit, which engages at 85% of the set OVP voltage. Therefore, the maximum output voltage of the under normal operation becomes 30.6 V (= 36 V x 0.85, where (30.6 V – 1.0 V) / VF > N [maximum number of LEDs in series]). ・Over-voltage protection circuit (OVP) The output of the DCDC converter should be connected to the OVP pin via a voltage divider. In determining an appropriate trigger voltage of for OVP function, consider the total number of LEDs in series and the maximum variation in VF. Also, bear in mind that over-current protection (OCP) is triggered at 0.85 x OVP trigger voltage. If the OVP function engages, it will not release unless the DCDC voltage drops to 72.5% of the OVP trigger voltage. For example, if ROVP1 (output voltage side), ROVP2 (GND side), and DCDC voltage VOUT are conditions for OVP, then: VOUT ≥ (ROVP1 + ROVP2) / ROVP2 x 2.0 V. OVP will engage when VOUT > 32 V if ROVP1 = 330 kΩ and ROVP2 = 22 kΩ. ・Buck-boost DC/DC converter oscillation frequency (FOSC) The regulator’s internal triangular wave oscillation frequency can be set via a resistor connected to the RT pin (pin 26). This resistor determines the charge/discharge current to the internal capacitor, thereby changing the oscillating frequency. Refer to the following theoretical formula when setting RT: fosc = 30 × 106 RT [Ω] x α [kHz] 6 30 x 10 (V/A/S) is a constant (±16.6%) determined by the internal circuitry, and α is a correction factor that varies in relation to RT: { RT: α = 50kΩ: 0.98, 60kΩ: 0.985, 70kΩ: 0.99, 80kΩ: 0.994, 90kΩ: 0.996, 100kΩ: 1.0, 50kΩ: 1.01, 200kΩ: 1.02, 300kΩ: 1.03, 400kΩ: 1.04, 500kΩ: 1.045 } A resistor in the range of 62.6kΩ～523kΩ is recommended. Settings that deviate from the frequency range shown below may cause switching to stop, and proper operation cannot be guaranteed. 550K 450K Frequency [kHz] 周波数 350K 250K 150K 50K 0 100 200 300 400 RT [kΩ] 500 600 700 800 Fig.15 RT versus switching frequency ・External DC/DC converter oscillating frequency synchronization (FSYNC) Do not switch from external to internal oscillation of the DC/DC converter if an external synchronization signal is present on the SYNC pin. When the signal on the SYNC terminal is switched from high to low, a delay of about 30 µS (typ.) occurs before the internal oscillation circuitry starts to operate (only the rising edge of the input clock signal on the SYNC terminal is recognized). Moreover, if external input frequency is less than the internal oscillation frequency, the internal oscillator will engage after the above-mentioned 30 µS (typ.) delay; thus, do not input a synchronization signal with a frequency less than the internal oscillation frequency. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 7/20 2010.08 - Rev.A BD8119FM-M Technical Note ・Soft Start Function The soft-start (SS) limits the current and slows the rise-time of the output voltage during the start-up, and hence leads to prevention of the overshoot of the output voltage and the inrush current. ・Self-diagnostic functions The operating status of the built-in protection circuitry is propagated to FAIL1 and FAIL2 pins (open-drain outputs). FAIL1 becomes low when UVLO, TSD, OVP, or SCP protection is engaged, whereas FAIL2 becomes low when open or short LED is detected. FAIL2 FAIL1 OPEN UVLO TSD OVP OCP SHORT MASK S Q R SCP Counter S Q R EN=Low UVLO/TSD EN=Low UVLO/TSD ・Operation of the Protection Circuitry ・Under-Voltage Lock Out (UVLO) The UVLO shuts down all the circuits other than REG when VCC  4.3V (TYP). ・Thermal Shut Down (TSD) The TSD shuts down all the circuits other than REG when the Tj reaches 175℃ (TYP), and releases when the Tj becomes below 150℃ (TYP). ・Over Current Protection (OCP) The OCP detects the current through the power-FET by monitoring the voltage of the high-side resistor, and activates when the CS voltage becomes less than VCC-0.6V (TYP). When the OCP is activated, the external capacitor of the SS pin becomes discharged and the switching operation of the DCDC turns off. ・Over Voltage Protection (OVP) The output voltage of the DCDC is detected with the OVP-pin voltage, and the protection activates when the OVP-pin voltage becomes greater than 2.0V (TYP). When the OVP is activated, the external capacitor of the SS pin becomes discharged and the switching operation of the DCDC turns off. ・Short Circuit Protection (SCP) When the LED-pin voltage becomes less than 0.3V (TYP), the internal counter starts operating and latches off the circuit approximately after 100ms (when FOSC = 300kHz). If the LED-pin voltage becomes over 0.3V before 100ms, then the counter resets. When the LED anode (i.e. DCDC output voltage) is shorted to ground, then the LED current becomes off and the LED-pin voltage becomes low. Furthermore, the LED current also becomes off when the LED cathode is shorted to ground. Hence in summary, the SCP works with both cases of the LED anode and the cathode being shorted. ・LED Open Detection When the LED-pin voltage  0.3V (TYP) as well as OVP-pin voltage  1.7V (TYP) simultaneously, the device detects as LED open and latches off that particular channel. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 8/20 2010.08 - Rev.A BD8119FM-M Technical Note ・LED Short Detection When the LED-pin voltage  4.7V (TYP) as well as OVP-pin voltage  1.6V (TYP) simultaneously the internal counter starts operating, and approximately after 100ms (when FOSC = 300kHz) the only detected channel (as LED short) latches off. With the PWM brightness control, the detecting operation is processed only when PWM-pin = High. If the condition of the detection operation is released before 100ms (when FOSC = 300kHz), then the internal counter resets. ※ The counter frequency is the DCDC switching frequency determined by the RT. The latch proceeds at the count of 32770. Protection Detecting Condition [Detect] VREG4.5V Operation after detect UVLO All blocks shut down All blocks (but except REG) shut down SS discharged TSD Tj>175℃ Tj2.0V VOVP IL_MAX When investigating the margin, it is worth noting that the L value may vary by approximately ±30%. 3. The selection of the L In order to achieve stable operation of the current-mode DC/DC converter, we recommend selecting the L value in the range indicated below: Vout×Rcs 0.05 [V/µS] < < 0.3 [V/µS] L The smaller Vout×Rcs L allows stability improvement but slows down the response time. 4. Selection of coil L, diode D1 and D2, MOSFET M1 and M2, and Rcs Current rating Voltage rating Coil L Diode D1 Diode D2 MOSFET M1 MOSFET M2 Rcs > IL_MAX > Iocp > Iocp > Iocp > Iocp ― ― > VIN_MAX > Vout > VIN_MAX > Vout ― Heat loss > Iocp2 × Rcs ※ Allow some margin, such as the tolerance of the external components, when selecting. ※ In order to achieve fast switching, choose the MOSFETs with the smaller gate-capacitance. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 12/20 2010.08 - Rev.A BD8119FM-M 5. Selection of the output capacitor Select the output capacitor Cout based on the requirement of the ripple voltage Vpp. Vpp = Iout × Cout 1 Vout × Fosc Vout+VIN + IL_MIN × RESR Technical Note Choose Cout that allows the Vpp to settle within the requirement. Allow some margin also, such as the tolerance of the external components. 6. Selection of the input capacitor A capacitor at the input is also required as the peak current flows between the input and the output in DC/DC conversion. We recommend an input capacitor greater than 10µF with the ESR smaller than 100m. The input capacitor outside of our recommendation may cause large ripple voltage at the input and hence lead to malfunction. 7. Phase Compensation Guidelines In general, the negative feedback loop is stable when the following condition is met: ・Overall gain of 1 (0dB) with a phase lag of less than 150º (i.e., a phase margin of 30º or more) However, as the DC/DC converter constantly samples the switching frequency, the gain-bandwidth (GBW) product of the entire series should be set to 1/10 the switching frequency of the system. Therefore, the overall stability characteristics of the application are as follows: ・Overall gain of 1 (0dB) with a phase lag of less than 150º (i.e., a phase margin of 30º or more) ・GBW (frequency at gain 0dB) of 1/10 the switching frequency Thus, to improve response within the GBW product limits, the switching frequency must be increased. The key for achieving stability is to place fz near to the GBW. Vout Phase-lead fz = Phase-lag fp1 = 1 2πCpcRpc 1 [Hz] 2πRLCout [Hz] LED FB A COMP Rpc Cpc Good stability would be obtained when the fz is set between 1kHz～10kHz. In buck-boost applications, Right-Hand-Plane (RHP) Zero exists. This Zero has no gain but a pole characteristic in terms of phase. As this Zero would cause instability when it is in the control loop, so it is necessary to bring this zero before the GBW. fRHP= Vout+VIN/(Vout+VIN) [Hz] 2πILOADL ILOAD: Maximum Load Current It is important to keep in mind that these are very loose guidelines, and adjustments may have to be made to ensure stability in the actual circuitry. It is also important to note that stability characteristics can change greatly depending on factors such as substrate layout and load conditions. Therefore, when designing for mass-production, stability should be thoroughly investigated and confirmed in the actual physical design. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 13/20 2010.08 - Rev.A BD8119FM-M Technical Note 8. Setting of the over-voltage protection We recommend setting the over-voltage protection Vovp 1.2V to 1.5V greater than Vout which is adjusted by the number of LEDs in series connection. Less than 1.2V may cause unexpected detection of the LED open and short during the PWM brightness control. For the Vovp greater than 1.5V, the LED short detection may become invalid. Vo － ＋ ROVP2 2.0V/1.45V OVP － ＋ 1.7V/1.6V ROVP1 9. Setting of the soft-start The soft-start allows minimization of the coil current as well as the overshoot of the output voltage at the start-up. For the capacitance we recommend in the range of 0.001  0.1µF. For the capacitance less than 0.001µF may cause overshoot of the output voltage. For the capacitance greater than 0.1µF may cause massive reverse current through the parasitic elements of the IC and damage the whole device. In case it is necessary to use the capacitance greater than 0.1µF, ensure to have a reverse current protection diode at the Vcc or a bypass diode placed between the SS-pin and the Vcc. Soft-start time TSS TSS = CSSX0.7V / 5µA [s] CSS: The capacitance at the SS-pin 10 Verification of the operation by taking measurements The overall characteristic may change by load current, input voltage, output voltage, inductance, load capacitance, switching frequency, and the PCB layout. We strongly recommend verifying your design by taking the actual measurements. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 14/20 2010.08 - Rev.A BD8119FM-M ●Power Dissipation Calculation Power dissipation can be calculated as follows: Pc(N) = ICC*VCC + 2*Ciss*VREG*Fsw*Vcc+[VLED*N+△Vf*(N-1)]*ILED ICC VCC Ciss Vsw Fsw VLED N ΔVf ILED Maximum circuit current Supply power voltage External FET capacitance SW gate voltage SE frequency LED control voltage LED parallel numeral LED Vf fluctuation LED output current Technical Note Sample Calculation: Pc(4) = 10mA × 30V + 500pF × 5V × 300kHz × 30V + [1.0V × 4 + △Vf × 3] × 100mA △Vf = 3.0V, Pc (4) = 322.5mW + 1.3W = 1622.5mW Power Dissipation 4 2500 Power Dissipation Pd[Ｗ] (3) 3.50W 3 (1) θja=56.8℃/W (Substrate copper foil density 3%) (2) θja=39.1℃/W (Substrate copper foil density34%) (3) θja=35.7℃/W (Substrate copper foil density60%) 2000 (2) 3.20W (1) 2.20W Pd [mW] 1500 1000 500 0 0 0.5 1 1.5 2 2.5 3 3.5 LEDバラツキ⊿Vf[V] LED Fluctuation ΔVf [V] ILED=5 0mA ILED=1 00mA ILED=1 50mA 2 1 0 25 50 75 95 100 125 150 Ambient Temperature Ta[℃] Fig.16 Note 1: Power dissipation calculated when mounted on 70mm X 70mm X 1.6mm glass epoxy substrate (1-layer platform/copper thickness 18µm) Note 2: Power dissipation changes with the copper foil density of the board. The area of the copper foil becomes the total area of the heat radiation fin and the foot pattern (connected directly with IC) of this IC. This value represents only observed values, not guaranteed values. Pd=2200mW ( 968mW): Substrate copper foil density 3% Pd=3200mW (1408mW): Substrate copper foil density 34% Pd=3500mW (1540mW): Substrate copper foil density 60% (Value within parentheses represents power dissipation when Ta=95°C) Note 3: Please design so that ambient temperature + self-generation of heat may become 150℃ or less because this IC is Tj=150℃. Note 4: Please note the heat design because there is a possibility that thermal resistance rises from the examination result of the temperature cycle by 20% or less. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 15/20 2010.08 - Rev.A BD8119FM-M VCC CPC2 CIN1 CIN2 CPC1 RPC1 CCS RCS1 RCS2 RCS3 VREG Technical Note VCC 1. COMP CSS 28. VREG 27. BOOT RCS5 CREG D G M1 D1 S CBT 2. SS 3. VCC EN SW1 26. CS 25. OUTH 24. SW 23. DGND 22. OUTL FIN. FIN 4. EN 5. RT VOUT L1 D G M2 S COUT1 COUT2 ROVP1 D2 SYNC CRT RRT CIN3 6. SYNC 7. GND FIN. FIN ROVP2 VREG PWM RFL2 RFL1 FAIL1 FAIL2 VREG SW2 8. PWM 9. FAIL1 10. FAIL2 11. LEDEN1 12. LEDEN2 13. LED1 14. LED2 21. FBR CISET 20. PGND 19. ISET RISET RDAC VREG VDAC 18. VDAC 17. OVP 16. LED4 15. LED3 LED4 LED3 SW3 LED1 LED2 ● The coupling capacitors CVCC and CREG should be mounted as close as possible to the IC’s pins. ● Large currents may pass through DGND and PGND, so each should have its own low-impedance routing to the system ground. ● Noise should be minimized as much as possible on pins VDAC, ISET,RT and COMP. ● PWM, SYNC and LED1-4 carry switching signals, so ensure during layout that surrounding traces are not affected by crosstalk. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 16/20 2010.08 - Rev.A BD8119FM-M ●Application Board Part List serial No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 component name CIN1 CIN2 CIN3 CPC1 CPC2 RPC1 CSS RRT CRT RFL1 RFL2 CCS RCS1 RCS2 RCS3 RCS5 CREG CBT M1 M2 D1 D2 L1 COUT1 COUT2 ROVP1 ROVP2 RISET CISET RDAC component value 10µF － － 0.1µF － 510Ω 0.1µF 100kΩ － 100kΩ 100kΩ － 620mΩ 620mΩ － 0Ω 2.2µF 0.1µF － － － － 33µH 10µF 10µF 30kΩ 360kΩ 120kΩ － 0Ω GRM188B31A225KE33 GRM188B31H104KA92 RSS070N05 RSS070N05 RB050L-40 RF201L2S CDRH105R330 GRM31CB31E106KA75B GRM31CB31E106KA75B MCR03 Series MCR03 Series MCR03 Series MCR100JZHFSR620 MCR100JZHFSR620 MCR03 Series MCR03 Series GRM188B31H104KA92 MCR03 Series product name GRM31CB31E106KA75B Technical Note Manufacturer murata murata murata Rohm Rohm Rohm Rohm Rohm murata murata Rohm Rohm Rohm Rohm Sumida murata murata Rohm Rohm Rohm ・The above values are fixed numbers for confirmed operation with the following conditions: VCC = 12V, four parallel channels of five series-connected LEDs, and ILED=50mA. ・Optimal values of external components depend on the actual application; these values should only be used as guidelines and should be adjusted to fit the operating conditions of the actual application. When performing open/short tests of the external components, the open condition of D1 or D2 may cause permanent damage to the driver and/or the external components. In order to prevent this, we recommend having parallel connections for D1 and D2. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 17/20 2010.08 - Rev.A BD8119FM-M ●Input/output Equivalent Circuits (terminal name follows pin number) 1. COMP 2. SS VREG VREG VREG Vcc Technical Note 4. EN Vcc EN 2K 2K COMP 1K SS 10k 175k 135k 5. RT VREG 6. SYNC, 8. PWM 3.3V 10K RT 150K SYNC PWM 9. FAIL1, 10. FAIL2 FAIL1 1K FAIL2 167 11. LEDEN1, 12. LEDEN2 3.3V 13. LED1, 14. LED2, 15. LED3, 16. LED4 17. OVP Vcc 5K 10K 150K 10K LEDEN1 LEDEN2 2.5K LED1～4 10K OVP 5K 18. VDAC VREG Vcc 19. ISET VREG Vcc 22. OUTL VREG VREG 500 VDAC 500 12.5 ISET 100K OUTL 24. SW Vcc 25. OUTH BOOT BOOT 26. CS Vcc 5K SW 100K SW SW SW OUTH CS 27. BOOT VREG BOOT 28. VREG VREG Vcc 21. VREG 205K N.C. SW ※All values typical. 100K N.C. = no connection (open) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 18/20 2010.08 - Rev.A BD8119FM-M ●Notes for use Technical Note 1) Absolute maximum ratings Use of the IC in excess of absolute maximum ratings (such as the input voltage or operating temperature range) may result in damage to the IC. Assumptions should not be made regarding the state of the IC (e.g., short mode or open mode) when such damage is suffered. If operational values are expected to exceed the maximum ratings for the device, consider adding protective circuitry (such as fuses) to eliminate the risk of damaging the IC. 2) GND potential Ensure that the GND pin is held at the minimum potential in all operating conditions. 3) Thermal Design Use a thermal design that allows for a sufficient margin for power dissipation (Pd) under actual operating conditions. 4) Inter-pin shorts and mounting errors Use caution when orienting and positioning the IC for mounting on printed circuit boards. Improper mounting may result in damage to the IC. Shorts between output pins or between output pins and the power supply and GND pins caused by poor soldering or foreign objects may result in damage to the IC. 5) Operation in strong electromagnetic fields Exercise caution when using the IC in the presence of strong electromagnetic fields as doing so may cause the IC to malfunction. 6) Testing on application boards When testing the IC on an application board, connecting a capacitor directly to a low-impedance pin may subject the IC to stress. Always discharge capacitors completely after each process or step. The IC’s power supply should always be turned off completely before connecting or removing it from a jig or fixture during the evaluation process. To prevent damage from static discharge, ground the IC during assembly and use similar precautions during transport and storage. 7) Ground wiring patterns When using both small-signal and large-current GND traces, the two ground traces should be routed separately but connected to a single ground potential within the application in order to avoid variations in the small-signal ground caused by large currents. Also ensure that the GND traces of external components do not cause variations on GND voltage. 8) IC input pins and parasitic elements This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated. PN junctions are formed at the intersection of these P layers with the N layers of other elements, creating parasitic diodes and/or transistors. For example (refer to the figure below): Resistance Pin A Pin A N P+ N P P+ N N N P+ P P+ N P substrate Parasitic Element Parasitic Element GND Parasitic Elements GND GND GND Other Adjacent Elements Transistor (NPN) Pin B C B E B C E Parasitic Elements Pin B P Substrate Example of IC Structure ・When GND > Pin A and GND > Pin B, the PN junction operates as a parasitic diode ・When GND > Pin B, the PN junction operates as a parasitic transistor Parasitic diodes occur inevitably in the structure of the IC, and the operation of these parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. Accordingly, conditions that cause these diodes to operate, such as applying a voltage lower than the GND voltage to an input pin (and thus to the P substrate) should be avoided. 9) Over-current protection circuits An over-current protection circuit (designed according to the output current) is integrated into the IC to prevent damage in the event of load shorting. This protection circuit is effective in preventing damage due to sudden and unexpected overloads on the output. However, the IC should not be used in applications where operation of the OCP function is anticipated or assumed 10) Thermal shutdown circuit (TSD) This IC also incorporates a built-in TSD circuit for the protection from thermal destruction. The IC should be used within the specified power dissipation range. However, in the event that the IC continues to be operated in excess of its power dissipation limits, the rise in the chip's junction temperature Tj will trigger the TSD circuit, shutting off all output power elements. The circuit automatically resets itself once the junction temperature Tj drops down to normal operating temperatures. The TSD protection will only engage when the IC's absolute maximum ratings have been exceeded; therefore, application designs should never attempt to purposely make use of the TSD function. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 19/20 2010.08 - Rev.A BD8119FM-M ●Ordering part number Technical Note B D 8 Part No. 1 1 9 F M - M Type E 2 Part No. Package FM: HSOP-M28 Packaging and forming specification E2: Embossed tape and reel HSOP-M28 18.5 ± 0.2 (MAX 18.85 include BURR) 28 15 Tape +6° 4°−4° Embossed carrier tape 1500pcs E2 The direction is the 1pin of product is at the upper left when you hold Quantity Direction of feed 9.9 ± 0.3 7.5 ± 0.2 1.25 1 5.15 ± 0.1 14 +0.1 0.27 −0.05 S 2.2 ± 0.1 0.11 0.8 0.37 ± 0.1 0.1 S 0.5 ± 0.2 1.2 ± 0.15 ( reel on the left hand and you pull out the tape on the right hand ) 1pin (Unit : mm) Reel Direction of feed ∗ Order quantity needs to be multiple of the minimum quantity. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 20/20 2010.08 - Rev.A 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 © 2010 ROHM Co., Ltd. All rights reserved. R1010A