LED Driver for LCD Backlights White LED Driver for 4Ch Large LCD Panels (DC/DC converter type) BD9415FS 1.1 ●General Description Key Specifications BD9415FS is a high efficiency driver for white LEDs and designed for large LCDs. This IC has a built-in boost DC/DC converter that employs an array of LEDs as the light source. BD9415FS has various protection functions against fault conditions, such as over-voltage protection (OVP), over current limit protection of DC/DC (OCP), short circuit protection (SCP), over duty protection (ODP) and open detection of LED string. Therefore, BD9415FS is available for the fail-safe design over a wide range of output voltages. Operating power supply voltage： 11.5V to 35.0V Oscillator frequency： 500kHz(RT=30kΩ) Operating current： 6.2mA (Typ) Operating temperature range： -40°C to +105°C 1.2 Package W(Typ) x D(Typ) x H(Max) 13.60mm x 7.80mm x 2.01mm Pin pitch 0.80mm SSOP-A32 Features 4Ch LED constant current driver (external FET) Built-in boost DC/DC converter (external FET) PWM dimming (individual input terminal of 4ch) Analog dimming (Linear) function Low heat generation technology LED protection function (Open/Short protection) Output Short Protection (OCP) Over Duty Protection (ODP) Over Voltage Protection (OVP) Under Voltage Lockout Protection (UVLO) Auto restart function Figure 1. SSOP-A32 Applications TV, Computer Display, Notebook, LCD Backlighting. Typical Application Circuit VIN + VCC CVCC AGND 32 FAILB SSFB 31 3 UVLO RT 30 4 REG90 5 STB 6 N 7 PGND 8 CS 9 DUTYON 10 OVP 11 S1 DUTYP 29 PWM4 28 27 PWM3 26 PWM2 PWM1 25 PWM1 LSP 24 VREF 23 G4 22 12 LED1 LED4 21 13 G1 S4 20 14 S2 G3 19 LED3 18 S3 17 15 LED2 16 G2 PWM4 PWM3 PWM2 REG90 CLSP REG90 BD9415FS STB VCC 2 CV R EF CREG90 1 Figure 2. Typical Application Circuit ○Product structure : Silicon monolithic integrated circuit www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・14・001 ○This product not designed protection against radioactive rays 1/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 1.3 Pin Configuration 1 VCC AGND 32 2 FAILB SSFB 31 3 UVLO RT 30 4 REG90 DUTYP 29 PWM4 28 PWM3 27 PWM2 26 PWM1 25 LSP 24 VREF 23 G4 22 LED4 21 STB 6 N 7 PGND 8 CS 9 DUTYON 10 OVP 11 S1 12 LED1 13 G1 S4 20 14 S2 G3 19 15 LED2 LED3 18 16 G2 S3 17 BD9415FS 5 Figure 3. Pin Configuration 1.4 Pin Descriptions Pin No. Pin Name Pin No. Pin Name 1 VCC Power supply terminal 32 AGND Analog GND 2 FAILB Error detection output pin (open drain) 31 SSFB Soft start pin & Error amplifier pin 3 UVLO Under voltage lockout detection pin 30 RT 4 REG90 9.0V output voltage pin 29 DUTYP Over voltage protection setting pin 5 STB IC ON/OFF pin 28 PWM4 LED4 External PWM dimming signal input pin DC/DC switching output pin 27 PWM3 LED3 External PWM dimming signal input pin Power GND 26 PWM2 LED2 External PWM dimming signal input pin 25 PWM1 LED1 External PWM dimming signal input pin 6 N 7 PGND Function Function DC/DC switching frequency setting pin 8 CS DC/DC output current detect pin, OCP input pin Over duty protection ON/OFF pin 24 LSP Over voltage protection detection pin 23 VREF Analog dimming signal input pin CH1 current detection input pin 22 G4 CH4 dimming signal output pin 9 DUTYON 10 OVP 11 S1 12 LED1 CH1 LED output pin 21 LED4 13 G1 CH1 dimming signal output pin 20 S4 CH4 current detection input pin 14 S2 CH2 current detection input pin 19 G3 CH3 dimming signal output pin 15 LED2 CH2 LED output pin 18 LED3 16 G2 CH2 dimming signal output pin 17 S3 www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 2/30 LED short voltage setting pin CH4 LED output pin CH3 LED output pin CH3 current detection input pin TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 1.5 Block Diagram VIN COUT Di L CIN + VCC LED OPEN / SHORT PROTECT REG 90 STB VREG SCP OVP OVP FILTER UVLO UVLO Auto - Restart Control CONTROL LOGIC REG 90 FAILB N DRIVER CURRENT SENSE RT + OSC SSOK SSFB LED SHORT PROTECT PWM COMP ERROR AMP -+COMP1 + COMP4 4V LSP 2800kΩ 1200kΩ LED OPEN PROTECT DUTYON DUTY P 300kΩ Over Duty Protection LEB + - × 6. 7 COMP1 + COMP4 CS PGND + - LED 1 G1 S1 + - LED 2 G2 S2 + - LED 3 G3 S3 + - LED 4 G4 S4 1/ 5 VREF + PWM 1 300kΩ PWM 4 300kΩ AGND Figure 4. Block Diagram www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 3/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 1.6 Absolute Maximum Ratings (Ta=25°C) Rating Unit -0.3 to +36 V LED1, LED2, LED3, LED4 FAILB, STB, OVP, PWM1, PWM2, PWM3, PWM4, UVLO, VREF, DUTYON N, REG90, G1, G2, G3, G4 S1, S2, S3, S4, DUTYP, RT, SSFB, CS, LSP 60 V 20 V 13 V 7 V Power Dissipation Pd 0.95 *1 W Operating Temperature Range Topr -40 to +105 °C Junction Temperature Tjmax 150 °C Parameter Power Supply Voltage Symbol VCC LED1-4 FAILB, STB, OVP, PWM1-4, UVLO, VREF, DUTYON N, REG90, G1-4 S1-4, DUTYP, RT, SSFB, CS, LSP Storage Temperature Tstg -55 to +150 °C (*1) Derate by 7.6mW/°C when operating above Ta=25°C.. (Mounted on 1-layer 70mm x 70mm x 1.6mm board) 1.7 Recommended Operating Conditions (Ta=25°C) Parameter Rating Symbol Power Supply Voltage VCC DC/DC Oscillating Frequency Fsw Unit 11.5 to 35.0 100 to 1000 V (*1) kHz VREF Input Voltage VREF 0.2 to 2.5 V LSP Input Voltage VLSP 0.8 to 3.0 V PWM Input Frequency FPWM 90 to 2000 Hz The operating ranges above are acquired by evaluating the IC separately. Please take care when using the IC in applications. (*1) When driving external FET as DC/DC, be careful about the input capacity of the FET being used. 1.8 Electrical Characteristics 1/2 (Unless otherwise specified, VCC=24V, Ta=25°C) Parameter 【Total Current Consumption】 Symbol Min Typ Max Unit Condition Circuit Current ICC - 6.2 12.4 mA Standby Current IST - 14 25 μA VSTB=3.0V, LED1-4=2V, RT=30kΩ VSTB=0V N Pin Source ON Resistance RONH - 2.5 3.75 Ω ION=-10mA N Pin Sink ON Resistance RONL - 3.0 4.5 Ω ION=10mA REG90 Output Voltage REG90 8.91 9.0 9.09 V IO=0mA REG90 Available Current IREG90 20 - - mA REG90_UVLO Detect Voltage REG90_TH 4.7 5.4 6.1 V VREG=SWEEP DOWN, VSTB=0V VOCP 0.405 0.450 0.495 V VCS=SWEEP UP Error Amplifier Base Voltage SSFB Source Current (Soft Start) SSFB Sink Current VERR 0.7 0.8 0.9 V VREF=1.5V ISSFBSO_S -13 -10 -7 μA VSSFB=2V ISSFBSINK 80 100 120 μA LED=2.0V、VSSFB=1.0V SSFB source Current ISSFBSOUR -115 -100 -85 µA LED=0V、VSSFB=1.0V Oscillation Frequency FCT 440 500 560 kHz RRT=30kΩ MAX DUTY DUTY_MAX 91 95 99 % 0.05 0.20 0.35 V 【Switching Block】 【REG90 Block】 【Over Current Limit Protection (OCP) Block】 OCP Detect Voltage 【Error Amplifier Block】 【CT Oscillator Block】 【Short Circuit protection (SCP) detect Block】 SCP Detect Voltage VSCP www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 4/30 VOVP=SWEEP DOWN TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 1.8 Electrical Characteristics 2/2 (Unless otherwise specified, VCC=24V, Ta=25°C) Parameter Symbol 【Over Voltage Protection (OVP) Block】 Min Typ Max Unit Condition OVP Detect Voltage VOVP 2.91 3.00 3.09 V OVP Detect Hysteresis VOVP_HYS 50 100 200 mV VOVP=SWEEP DOWN OVP Pin Leak Current IOVP -2 0 2 µA VOVP=4.0V VCC=SWEEP UP VOVP=SWEEP UP 【UVLO Block】 UVLO Unlock Voltage(VCC) VUVLO_VCC 6.5 7.5 8.5 V UVLO Hysteresis(VCC) VUHYS_VCC 150 300 600 mV VCC=SWEEP DOWN UVLO Unlock Voltage VUVLO 2.375 2.5 2.625 V VUVLO=SWEEP UP UVLO Hysteresis VUHYS 50 100 150 mV VUVLO=SWEEP DOWN UVLO Input Resistance RUVLO 360 600 840 kΩ VUVLO=4.0V DTYON_H 1.5 - 18 V DUTYON Pin LOW Voltage DTYON_L DUTYON Pin Pull Down RDTYON Resistance 【Over Duty Protection (ODP) Block】 PWM ODP Protection Detect DODP Duty 【Filter Block】 AUTO Timer TAUTO -0.3 - 0.8 V 180 300 420 kΩ VDUTYON=3.0V - 35 - % FPWM=120Hz, DUTYP=341kΩ - 163 - ms FCT=800kHz - 20 - ms FCT=800kHz 196 200 204 294.6 300 305.4 392.8 400 407.2 【DUTYON Block】 DUTYON Pin HIGH Voltage Abnormal Detection Timer TCP 【LED Driver Block】 VREF=1.0V VS 491 500 509 OPEN Detection Voltage VOPEN 0.12 0.2 0.28 V SHORT Detection Voltage VSHORT 5.6 6.0 6.4 V 2.8 3.0 3.2 V VLED=SWEEP UP -2 0 2 µA VREF=3.0V SHORT Mask Voltage VREF Leak Current VSHORT _MASK IVREF mV VREF=1.5V S Pin Voltage VREF=2.0V VREF=2.5V VLED=SWEEP DOWN VLED=SWEEP UP, VLSP=0.895V 【STB Block】 STB Pin HIGH Voltage STBH 2.0 - 18 V STB Pin LOW Voltage STBL -0.3 - 0.8 V STB Pull Down Resistance RSTB 0.5 1.0 1.5 MΩ PWM Pin HIGH Voltage VPWM_H 1.5 - 18 V PWM Pin LOW Voltage VPWM_L -0.3 - 0.8 V PWM Pin Pull Down Resistance RPWM 180 300 420 kΩ VPWM=3V VFAILB_L 0.25 0.5 1.0 V IFAILB=1mA VSTB=3V 【PWM Block】 【FAILB Block(OPEN DRAIN)】 FAILB LOW Output Voltage www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 5/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 1.9 Typical Performance Curves (Reference data) 8.0 14 7.0 12 10 5.0 VREG90[V] ICC[mA] 6.0 4.0 3.0 8 6 4 2.0 STB=3.0V LED1-4=2.0V Ta=25°C 1.0 STB=3.0V PWM=3.0V STB=3.0V Ta=25°C REG90=-10mA Ta=25°C 2 0.0 0 10 15 20 25 VCC[V] 30 5 35 Figure 5. Operating Circuit Current 15 20 VCC[V] 25 30 35 Figure 6. REG90 Line Regulation 0.6 100 0.5 Sx Feecback Voltage[V] 80 Duty Cycle[%] 10 60 40 20 0.4 0.3 0.2 0.1 VCC=24V Ta=25°C 0 VCC=24V Ta=25°C 0.0 0 1 2 SSFB[V] 3 4 0.0 Figure 7. Duty Cycle vs SSFB Character www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 0.5 1.0 1.5 2.0 VREF[V] 2.5 3.0 Figure 8. S Pin Feedback Voltage vs VREF Character 6/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 2.1 Pin Descriptions ○PIN1：VCC This is the power supply pin of the IC. Input range is from 11.5V to 35V. The operation starts at more than 7.5V(Typ) and shuts down at less than 7.2V(Typ). ○PIN2：FAILB This is FAILB signal output (OPEN DRAIN) pin. At normal operation, NMOS will be in OPEN state, during abnormality detection NMOS will be in ON (500 ohm(Typ))state. ○PIN3：UVLO Under Voltage Lockout pin is the input voltage of the power stage. IC starts boost operation if UVLO is more than 2.5V(Typ) and stops if lower than 2.4V(Typ). It can also be used for reset when latched off by protection. The power of step-up DC/DC converter needs to be set detection level by dividing the resistance. ○PIN4：REG90 The REG pin is used in the DC/DC converter driver block to output 9V. Available current is 20mA(Min). Using the REG pin at current higher than 20mA can affect the IC base voltage, causing the IC to malfunction and leading to heat generation of the IC itself. To avoid this problem, it is recommended to make load setting to the minimum level. The characteristic of VCC line regulation at REG90 is shown as [Figure 6]. VCC must be used in more than 11.5V for stable 9V output. Place the ceramic capacitor connected to REG90 pin (2.2uF to 10uF) closest to REG90-AGND pin. ○PIN5：STB This is the ON/OFF setting terminal of the IC. It is allowed for use to reset the IC from shutdown. ※The IC state is switched according to voltages input in the STB pin. ※Avoid using the STB pin between two states (0.8 to 2.0V). ○PIN6：N The N pin is used to output power to the external NMOS gate driver for the DC/DC converter in the amplitude range of approximately 0V to 9V. Output ON resistance H - side is 2.5Ω (Typ) and L-side is 3.0Ω (Typ). Frequency can be set by the resistor connected to RT. Refer to <RT> pin description for the frequency setting. ○PIN7：PGND The PGND pin is a power ground pin for the driver block of the N output pin. ○PIN8：CS CS pin is current detector for DC/DC current mode inductor current control pin. Current flowing through the inductor is converted into voltage by the current sensing resistor RCS connected to the CS pin and this voltage is compared with voltage set with the error amplifier to control the DC/DC output voltage. The CS pin also incorporates the over current protection (OCP) function. If the CS voltage reaches 0.45V(Typ) or more, switching operation will be forced to stopped. ○PIN9：DUTYON This is the ON/OFF setting terminal of the LED PWM Over Duty Protection (ODP). By adjusting DUTYON input voltage, it is ON/OFF of the ODP adjusted. State DUTYON input voltage ODP=ON DUTYON= -0.3V to +0.8V ODP=OFF DUTYON= +1.5V to +18.0V ○PIN10：OVP The OVP pin is an input pin for over voltage protection and short circuit protection of DC/DC output voltage. When voltage of it exceeds 3.0V(Typ), N pin will stop. This case is not CP count. When OVP pin voltage <0.2V(Typ) or lower, short circuit protection (SCP) function is activated, and output of gate driver will become low immediately. And system is stopped after a CP count. The setting example is separately described in the section ”3.2.6 OVP Setting”. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 7/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS ○PIN11, 14, 17, 20 ：S1-S4, PIN23 ： VREF LED constant current driver is connected to the source of bill FET outside. Output current ILED is inversely proportional to the resistance value. This is the input pin for analog dimming signal. Output current ILED is directly proportional to the input voltage value. VREF pin is high impedance because the internal resistance is not connected to a certain bias. Even if VREF function is not used, pin bias is still required because the open connection of this pin is not a fixed potential. VREF pin voltage is set as 「VVREF」, LED current 「ILED」can be calculated as below. ILED[ A] VREF [V] 0.2 RS[Ω ] LED ILED VREF 1.2V , RS 2[] G + ILED 120[mA] - S 240mV RS Figure 9. ILED setting example For the adjustment of LED current with analog dimming by VREF, note that the output voltage of the DC/DC converter largely changes accompanied by LED VF changes if the VREF voltage is changed rapidly. In particularly, when the VREF voltages changed from high to low, it makes the LED terminal voltage seem higher transiently, which may influence application such as activation of the LED short circuit protection. It needs to be adequately verified with an actual device when analog dimming is used. ○PIN12, 15, 18, 21：LED1-LED4 LED constant current driver output pins. Drain of external NMOS is connected. Setting of LED current value is adjustable by setting the VREF voltage and connecting a resistor to S pin. For details, see the explanation of <PIN:11, 14, 17, 20 S1 - S4, Pin23 : VREF >. The abnormal voltage of this pin activates the protection function of LED OPEN detection, LED SHORT detection. Please refer to < 2.2 List of The Protection Function Detection Condition> for details. ○PIN13, 16, 19, 22：G1-G4 This is the output terminal for driving the gate of the boost MOSFET. The high level is REG90. Frequency can be set by the resistor connected to RT. Refer to <RT> pin description for the frequency setting. ○PIN24：LSP LED Short detection voltage setting pin. Resistance voltage divider is internally on IC. It is set as 1.2V. When need to establish the other voltage, use an external resistance voltage divider. LSP pin voltage is set as LED SHORT PROTECTION detection voltage and can be calculated as below. LEDSHORT 6.7 VLSP[V ] LEDSHORT：LSP detection voltage, VLSP：LSP pin voltage Set LSP voltage in the range of 0.8V to 3.0V. In addition to considering the voltage of the internal resistance voltage divider, it's necessary to establish the voltage of the LSP terminal. ○PIN25, 26, 27, 28：PWM1-PWM4 These are the PWM dimming signal input terminals. The high / low level of PWM pins are the following. State PWM pin voltage PWM=H PWM= +1.5V to +18.0V PWM=L PWM= -0.3V to +0.8V www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 8/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS ○PIN29：DUTYP This is the ODP setting pin. The ODP (Over Duty Protection) is the function to limit DUTY of LED PWM frequency fPWM by ODP detection Duty (ODPduty) set by resistance (RDUTY) connected to DUTYP pin. ○Relationship between LED PWM frequency fPWM, ODP Detection Duty and DUTYP resistance (ideal) RDUTYP 1172 ODPduty[%] f PWM [ Hz] [k] The RDUTYP setting ranges from 15kΩ to 600kΩ. The setting example is separately described in section ”3.2.6 ODP Setting”. ○PIN30：RT This is the DC/DC switching frequency setting pin. DCDC frequency is decided by connected resistor. ○The relationship between the frequency and RT resistance value (ideal) RRT 15000 f SW [kHz] [k] ○PIN31：SSFB The SSFB pin is used to make setting of soft start time and duty for soft start, and DC/DC current mode control error amplifier. It performs constant current charge of 10uA to the external capacitor connected to SSFB terminal, which enables soft-start of DC/DC converter. The SSFB pin detects the voltages of LED pins (1 to 4) and controls inductor current so that the pin voltage of the LED located in the row with the highest Vf will come to 0.8V(Typ) (VREF=1.5V). As a result, the pin voltages of other LEDs become higher by Vf variation. After completion of soft start, the SSFB pin is put into high-impedance state with the PWM signal being in the low state, thus maintaining the SSFB voltage. Since the LED protection function (OPEN/SHORT detection) works when it turns to the LED feedback mode. ○PIN32：AGND This is the GND pin of the IC. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 9/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 2.2 List of the Protection Function Detection Condition (Typical Condition) Detection Condition Protection Release Detection Pin Function Condition Detection Condition SS PWM Protection Type (*2) LED Open LEDx LEDx < 0.2V H(4clk) After Soft start LED Short LEDx LEDx > 6.7×VLSP H(4clk) After Soft start LEDx > 0.2V (3clk) LEDx < 6.7xVLSP (3clk) LED Driver FET D-S Short Sx Sx > 0.6V ― ― Sx < 0.6V LED GND Short LEDx LEDx < 0.2V And SSFB > 4.0V H ― LEDx > 0.2V Or SSFB < 3.6V OVP OVP OVP > 3.0V ― ― OVP < 2.9V SCP OVP OVP < 0.2V ― ― OVP > 0.25V VCCUVLO VCC VCC < 7.2V ― ― VCC > 7.5V UVLO UVLO UVLO < 2.4V ― ― UVLO > 2.5V OCP CS CS > 0.45V ― ― ― Over PWM (*1) duty PWM DUTYON = H And PWM interval > setting by DUTYP resistor H ― ― Auto Restart in relevant CH Auto Restart in relevant CH Whole Auto Restart Whole Auto Restart Return immediately. Whole Auto Restart Return immediately. Return immediately. Return immediately. (Pulse by Pulse) Return immediately. The clock number of timer operation corresponds to the boost pulse clock. (*1)When PWM Duty count starts, PWM=H → L is input, when PWM=L → H is input, the ODP is reset. The G (1 to 4) output, the N pin output maintain L until PWM=H → L is input in PWM = 100% again when ODP works once. (*2) The release condition of OPEN protection depends on its release timing. No. The Release Condition The timing of release of LEDx voltage (LEDx > 0.2V) 1 LED pin voltage is released during PWM=H. 2 LED pin voltage is released during PWM=L. LED pin voltage is normal range during 3clk (3 positive edge) As PWM=L, LED pin voltage do not exceed Short protection voltage (VLSP) during more than 3clk or PWM positive edge is input when LED pin voltage do not exceed VLSP for more than 3clk. 2.3 List of Protection function Operation of the Protection Function Protection function STB LED Open DC/DC Gate Output Stop N output Normal operation (Stop when all LED CH stop) LED Short Normal operation LED Driver FET D-S Short Stop after 2 count 14 LED Driver Soft-start FAILB Pin Stop immediately Discharge immediately HiZ Normal operation Low after timer latch Normal operation Low after timer latch Discharge after stop Low after timer latch 14 Stop after 2 count Stop in relevant CH 14 Stop after 2 count Stop in relevant CH 14 Stop after 2 count LED GND Short Stop after * 6 (CP +2 )count VCCUVLO Stop N output Only detected LED ch stops after CP count Other LED ch stop operation * 6 after（CP +2 ）count Stop immediately Discharge immediately HiZ UVLO Stop N output Stop immediately Discharge immediately HiZ OVP Stop N output Normal operation Normal operation SCP * 6 （CP +2 ） Discharge after count Low after timer latch Stop N output Normal operation Normal operation Stop N output OCP Normal operation Normal operation (Pulse by Pulse) Over PWM duty Normal operation Stop in relevant CH Normal operation ※CP ： Count movement after detection of D-S SHORT, LED_OPEN, SHORT. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 10/30 HiZ Low after timer latch HiZ HiZ TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.1 Application Circuit Example An example application using the BD9415FS. 3.1.1 Basic Application Example VIN + VCC CVCC AGND 32 FAILB SSFB 31 3 UVLO RT 30 4 REG90 5 STB 6 N 7 PGND 8 CS 9 DUTYON 10 OVP 11 S1 DUTYP 29 PWM4 28 PWM3 27 PWM3 PWM2 26 PWM2 PWM1 25 PWM1 LSP 24 VREF 23 G4 22 12 LED1 LED4 21 13 G1 S4 20 14 S2 G3 19 15 LED2 LED3 18 16 G2 S3 17 PWM4 REG90 CLSP REG90 BD9415FS STB VCC 2 CV R EF CREG90 1 Figure 10. Basic Application Example 3.1.2 Application Example of Unused CH VCC + ( ) CVCC AGND 32 FAILB SSFB 31 3 UVLO RT 30 4 REG90 5 STB 6 N LEDunused 7 PGND 8 CS 9 DUTYON 10 OVP 11 S1 DUTYP 29 PWM4 28 PWM3 27 PWM3 PWM2 26 PWM2 PWM1 25 LSP 24 VREF 23 G4 22 12 LED1 LED4 21 13 G1 S4 20 14 S2 G3 19 15 LED2 LED3 18 16 G2 S3 17 PWM4 REG90 PWM1 CLSP REG90 BD9415FS STB VCC 2 CV R EF CREG90 1 LEDunused Figure 11. Application Example of Unused CH When an LED terminal was unused, please dispose the unused CH as follows. ・Please input lower than 3.0V (typical) of voltage to a LEDx pin (ex. 1.0 to 2.0V). ・Gx pin, Sx pin is short ・Unused PWMx = L www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 11/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.2 External Components Selection 3.2.1 Startup operation and soft start (SSFB) capacitance setting The following section describes the sequence for the startup of this IC. ① 10uA 5V STB Soft-Start(ISS=10uA) VOUT Q D PWM COMP IFB(Sink, Source)=±100uA) DRIVER OSC OSC CS ILED SSFB N PWM LED_OK LEDx SSFB ② PWM=L:STOP N RSSFB VOUT CSSFB Gx ILED ③ Sx LED_ DRIVER LED_OK PWMx ④ ⑤ ⑥ Figure 12. Startup Waveform Figure 13. Circuit Behavior at Startup Description of startup sequence (1) Set the STB and PWM pin to “ON”. (2) Set all systems to “ON”, SSFB charge will be initiated. (3) Since the SSFB pin reach the lower limit of the internal sawtooth wave of the IC, the DC/DC converter operates to start VOUT voltage rising. (4) The VOUT voltage continuously rising to reach a voltage at which LED current starts flowing. (5) When the LED current reaches the set amount of current, the startup operation is completed. (6) After that, conduct normal operation following the feedback operation sequence with the LED pins. If the SSFB pin sink/source current is ±100uA, the LED protection function will be activated. SSFB capacitance setting procedure As aforementioned, this IC stops DC/DC converter when the PWM pin is set to Low level and conducts step-up operation only in the section in which the PWM pin is maintained at High level. Consequently, setting the PWM duty cycle to the minimum will extend the startup time. The startup time also varies with application settings of output capacitance, LED current, output voltage, and others. Startup time at minimum duty cycle can be approximated according to the following method: Make measurement of VOUT startup time with a 100% duty cycle, first. Take this value as “Trise100”. The startup time “Trise_min” for the relevant application with the minimum duty cycle is given by the following equation. Trise _ min Trise _ 100[sec] [sec] Min _ Duty [ratio ] However, since this calculation method is just for approximation, use it only as a guide. Assuming that the SSFB pin voltage is VSSFB, the time is given by the following equation: TSSFB CSSFB[ F ] VSSFB[V ] 10[ A] [ Sec ] As a result, it is recommended to make SSFB capacitance setting so that “TSSFB” will be greater than “Trise_min” www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 12/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.2.2 LED Current Setting (VREF pin, Sx pin) First, VREF pin voltage is determined. When performing Analog dimming, be careful of VREF pin input range(0.2 to 2.5V) and decide typical voltage. In BD9415FS, LED constant current is controlled by Sx pin voltage as a reference point. Sx pin is controlled to become one fifth of the voltage of VREF pin voltage. In the case of VREF=1V, it is set to Sx=0.2V. Therefore, when the resistance to Sx pin versus GND is set to "RS", the relationship between RS, VREF and ILED is as follows R S [ohm] VVREF [V ] I LED [ A] 5 REG90=9V 3.2.3 LED Short Detection Voltage Setting (LSP terminal) The voltage of LED short detection can be arbitrarily set up with LSP pin voltage. It is possible to change the LED short detection voltage, please input (0.8V to 3.0V) to LSP pin. About LED short detection voltage, if "VLEDshort" and LSP pin voltage are set to "VLSP", it is as follows 4V LSP COMP + R3 2800k R4 1200k VLEDSHORT [V ] 6.7 CLSP R2 3700k VLSP R1 LSP LEDx 800k Figure 14. LSP setting example Since the setting range of a LSP pin is set to 0.8V to 3.0V, VLEDshort can be set up in 5.36V to 20.1V. ○ Equation of setting LSP detect Voltage When the detection voltage VLSP of LSP is set up by resistance division of R1 and R2 using REG90, it becomes like the following formula. R2[k] R4[k] REG 90[V ] R3 4[V ] R1[k] LEDSHORT ( 2 ) 6.7 [V ] ( R1[k] R3[k] R2 R4 R2[k] R4[k] R1[k] R3[k] 【Setting example】 Assuming that LSP is approximated by Equation (1) in order to set LSP detection voltage to 6V, R1 comes to 68kΩ. and R2 comes to 7.6kΩ. When calculating LSP detection voltage taking into account internal IC resistance by Equation (2), it will be given as: 7.6[k] 1200[k] 9[V ] 2800[k] 4[V ] 68[k] LEDSHORT ( 2) 6.7 6.078[V ] (68[k] 2800[k] 7.6[k] 1200[k] 7.6[k] 1200[k] 68[k] 2800[k] *Also including the variation in IC, please also take the part variation in a set into consideration for an actual constant setup, and inquire enough to it. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 13/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.2.4 DCDC Oscillation Frequency Setting RRT which connects to RT pin sets the oscillation frequency f SW of DCDC. ○Relationship between frequency fSW and RT resistance (ideal) RRT 15000 f SW [kHz] Frequency (fsw) [k] 【setting example】 When DCDC frequency fSW is set to 200kHz, RRT is as follows. GATE CS RT RRT 15000 15000 75[k] f SW [kHz] 200[kHz] Rcs RRT GND Figure 15. RT terminal setting example 3.2.5 UVLO Setting Under Voltage Lockout pin is the input voltage of the power stage. IC starts boost operation if UVLO is more than 2.5V(Typ) and stops if lower than 2.4V(Typ). Since internal impedance exists in UVLO pin, cautions are needed for selection of resistance for resistance division. Vin detection voltage level can be calculated by the following formula using resistance division of R1 and R2 (unit: kΩ). Vin R1 Zin=610kΩ (typ.) 1400k 530k 125k 480k UVLO R2 1000pF AGND AGND Figure 16. UVLO setting example ○ Equation of Setting UVLO Release R1 R2 1 1 Vin DET 2.5 R1 [V ] 1400k 125k 530k 480k R2 ○ Equation of Setting UVLO Lock R1 R2 1 1 Vinlock 2.4 R1 [V ] 1400k 125k 530k 480k 40k R2 *Also including the variation in IC, please also take the part variation in a set into consideration for an actual constant setup, and inquire enough to it. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 14/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.2.6 OVP Setting The OVP terminal is the input for over-voltage protection of output voltage. The OVP pin is high impedance, because the internal resistance is not connected to a certain bias. Detection voltage of VOUT is set by dividing resistors R1 and R2. The resistor values can be calculated by the formula below. ○ OVP Detect Equation If VOUT is boosted abnormally, VOVPDET, the detect voltage of OVP, R1, R2 can be expressed by the following formula. R1 R2[k] VOVPDET [V ] 3.0[V ] 3.0[V ] [k] ○ OVP Release Equation By using R1 and R2 in the above equation, the release voltage of OVP, VOVPCAN can be expressed as follows. VOVPCAN 2.9[V ] VOUT OVP R1 + OVP COMP - SCP COMP - R1[k] R2[k] + 3.0V/2.9V R2 0.2V R2[k] Figure 17 . OVP setting example 【setting example】 If the normal output voltage, VOUT is 58V, the detect voltage of OVP is 63V, R2 is 20kΩ, R1 is calculated as follows. R1 R2[k] VOVPDET [V ] 3.0[V ] 20[k] 63[V ] 3.0[V ] 400[k] 3.0[V ] 3.0[V ] By using these R1 and R2, the release voltage of OVP, VOVPCAN can be calculated as follows. VOVPCAN 2.9[V ] R1[k] R2[k] 400[k] 20[k] 60.9[V ] 2.9[V ] R2[k] 20[k] 3.2.7 SCP setting 【3.2.6) The SCP setting「VSCPDET」 voltage is calculated as below when R1,R2 is decided above: VSCPDET 0.2[V ] R1[k] R2[k] 400[k] 20[k] 40.2[V ] 0.2[V ] R2[k] 20[k] *Also including the variation in IC, please also take the part variation in a set into consideration for an actual constant setup, and inquire enough to it. 3.2.8 FAILB Logic FAILB signal output pin (OPEN DRAIN); when an abnormality is detected, NMOS is brought into GND Level. The rating of this pin is 20V. State FAILB output In completion of an abnormality ※ （After CP count ） GND Level (500ohm (Typ)) In normal state, In STB OPEN ※CP count ： Count movement after detection of D-S SHORT, LED_OPEN, SHORT, SCP. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 15/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.2.9 ODP setting RDUTYP which connects to ODP pin sets the ODP detection duty. ○Relationship between LED PWM frequency fPWM, ODP Detection Duty and DUTYP resistance (ideal) RDUTYP 1172 ODPduty [%] f PWM [ Hz] [k] N 【setting example】 When LED PWM frequency fPWM, is set to 120Hz and ODP Detection Duty (ODPduty) is set to 35%, RDUTYP is as follows. DUTYP CS RDUTYP RCS Gx RDUTYP 1172 35[%] 341.8[k] 120[ Hz] PWM Sx RS GND Figure 18. ODP setting example fPWM PWM N GATE Gx DIMOUT ODPduty Figure 19. The GATE and the DIMOUT waveform as PWM dimming (ODP) 3.2.10 Timer Latch Time (CP Counter) Setting, Auto-Restart Timer Setting Timer latch time (CP Counter) is set by counting the clock frequency which is set at the RT pin. About the behavior from abnormal detection to latch-off, please refer to the section “3.5.2 and 3.5.3 Timing Chart”. When various abnormal conditions happen, counting starts from the timing, latch occurs after below time has passed. Furthermore, even if PWM=L, if abnormal condition continues, timer count will not reset. LATCHTIME 214 AUTOTIME 217 RRT [] 100[k] 16384 [ s] 10 1.5 10 1.5 107 RRT [] 100[k] 131072 [ s] 10 1.5 10 1.5 107 Here, LATCHTIME = time until latch condition occurs, AUTOTIME = auto restart timer’s time RRT = Resistor value connected to RT pin 【setting example】 Timer latch time when RT=30kohm (500kHz) LATCHTIME 16384 AUTOTIME 131072 www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 RRT [k] 30[k] 16384 32.8[ms] 7 1.5 10 1.5 107 RRT [k] 30[k] 131072 262.1[ms] 7 1.5 10 1.5 107 16/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.3. DCDC Parts Selection 3.3.1. OCP Setting / Calculation Method for the Current Rating of DCDC Parts OCP detection stops the switching when the CS pin voltage is more than 0.45V(Typ). The resistor value of CS pin, RCS needs to be considered by the coil L current. And the current rating of DCDC external parts is required more than the peak current of the coil. Shown below are the calculation method of the coil peak current, the selection method of Rcs (the resistor value of CS pin) and the current rating of the external DCDC parts at Continuous Current Mode. (The calculation method of the coil peak current, IPEAK at Continuous Current Mode) At first, since the ripple voltage at CS pin depends on the application condition of DCDC, the following variables are used. Vout voltage = VOUT [V] LED total current = IOUT [A] DCDC input voltage of the power stage = VIN [V] Efficiency of DCDC =η [%] L VIN fsw VOUT [V ] I OUT [ A] [ A] VIN [V ] [%] GATE And the ripple current of the inductor L (ΔIL[A]) can be calculated by using DCDC the switching frequency, fSW, as follows. IL CS Rcs GND (VOUT [V ] VIN [V ]) VIN [V ] [ A] L[ H ] VOUT [V ] f SW [ Hz] (V) IL[ A] [ A] 2 … (1) N[V] On the other hand, the peak current of the inductor IPEAK can be expressed as follows. I PEAK I IN [ A] Therefore, the bottom of the ripple current IMIN is （A) IL[ A] I IN [ A] or 0 2 (t) Ipeak If IMIN>0, the operation mode is CCM (Continuous Current Mode), otherwise the mode is DCM (Discontinuous Current Mode). (The selection method of RCS at Continuous Current Mode) IPEAK flows into RCS and that causes the voltage signal to CS pin. (Please refer to the timing chart at the right) Peak voltage VCSPEAK is as follows. Imin (t) （V) 0.4V VCS[V] VCS PEAK RCS I PEAK [V ] ΔIL IIN IL[A] I min IOUT IL And then, the average input current IIN is calculated by the following equation. I IN VOUT 0.45V VCSpeak As this VCSPEAK reaches 0.4V (typical), the DCDC output stops the switching. Therefore, RCS value is necessary to meet the condition below. RCS I PEAK [V ] 0.45[V ] (t) Figure 20. Coil Current Waveform (The current rating of the external DCDC parts) The peak current as the CS voltage reaches OCP level (0.4V (Typ)) is defined as IPEAK_DET. I PEAK _ DET 0.45[V ] [ A] RCS [] … (2) The relationship among IPEAK (equation (1)), IPEAK_DET (equation (2)) and the current rating of parts is required to meet the following Ipeak Ipeak _ det The current rating of parts Please make the selection of the external parts such as FET, Inductor, diode meet the above condition. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 17/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 【setting example】 Output voltage = VOUT [V] = 40V LED total current = IOUT [A] = 0.48A DCDC input voltage of the power stage = VIN [V] = 24V Efficiency of DCDC=η [%]=90% Averaged input current IIN is calculated as follows. I IN VOUT [V ] I OUT [ A] 40[V ] 0.48[ A] 0.89[ A] VIN [V ] [%] 24[V ] 90[%] If the switching frequency, fSW = 200kHz, and the inductor, L=100μH, the ripple current of the inductor L (ΔIL [A]) can be calculated as follows. IL (VOUT [V ] VIN [V ]) VIN [V ] (40[V ] 24[V ]) 24[ A] 0.48[ A] L[ H ] VOUT [V ] f SW [ Hz] 100 10 6 [ H ] 40[V ] 200 103[ Hz] Therefore the inductor peak current, IPEAK is I PEAK I IN [ A] IL[ A] 0.48[ A] [ A] 0.89[ A] 1.13[ A] 2 2 …calculation result of the peak current If RCS is assumed to be 0.3Ω VCS PEAK RCS I PEAK 0.3[] 1.13[ A] 0.339[V ] 0.45[V ] …RCS value confirmation The above condition is met. And IPEAK_DET, the current OCP works, is I PEAK _ DET 0.45[V ] 1.35[ A] 0.3[] If the current rating of the used parts is 2A, Ipeak Ipeak _ det The current raying 1.33[ A] 1.35[ A] 2.0[ A] …current rating confirmation of DCDC parts This inequality meets the above relationship. The parts selection is proper. And IMIN, the bottom of the IL ripple current, can be calculated as follows. I MIN I IN [ A] IL[ A] [ A] 1.13[ A] 0.48[ A] 0.65[ A] 0 2 This inequality implies that the operation is continuous current mode. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 18/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.3.2. Inductor Selection The inductor value affects the input ripple current, as shown the previous section 3.3.1. IL ΔIL I IN (VOUT [V ] VIN [V ]) VIN [V ] [ A] L[ H ] VOUT [V ] f SW [ Hz] VOUT [V ] I OUT [ A] [ A] VIN [V ] [%] VIN IL I PEAK I IN [ A] IL[ A] [ A] 2 L VOUT RCS COUT Where L: coil inductance [H] VOUT: DCDC output voltage [V] VIN: input voltage [V] IOUT: output load current (the summation of LED current) [A] IIN: input current [A] fSW: oscillation frequency [Hz] Figure 21. Inductor current waveform and diagram In continuous current mode, ⊿IL is set to 30% to 50% of the output load current in many cases. In using smaller inductor, the boost is operated by the discontinuous current mode in which the coil current returns to zero at every period. *The current exceeding the rated current value of inductor flown through the coil causes magnetic saturation, results in decreasing in efficiency. Inductor needs to be selected to have such adequate margin that peak current does not exceed the rated current value of the inductor. *To reduce inductor loss and improve efficiency, inductor with low resistance components (DCR, ACR) needs to be selected. 3.3.3. Output Capacitance COUT Selection Output capacitor needs to be selected in consideration of equivalent series resistance VIN required to even the stable area of output voltage or ripple voltage. Be aware that set LED current may not be flown due to decrease in LED terminal voltage if output ripple IL component is high. L Output ripple voltage _VOUT is determined by Equation (4): VOUT RESR RCS COUT VOUT IL RESR [V ] (4) When the coil current is charged to the output capacitor as MOS turns off, much output ripple is caused. Much ripple voltage of the output capacitor may cause the LED current ripple. Figure 22. Output capacitor diagram * Rating of capacitor needs to be selected to have adequate margin against output voltage. * To use an electrolytic capacitor, adequate margin against allowable current is also necessary. Be aware that the LED current is larger than the set value transitionally in case that LED is provided with PWM dimming especially. 3.3.4. MOSFET Selection There is no problem if the absolute maximum rating is larger than the rated current of the inductor L, or is larger than the sum of the tolerance voltage of COUT and the rectifying diode VF. The product with small gate capacitance (injected charge) needs to be selected to achieve high-speed switching. * One with over current protection setting or higher is recommended. * The selection of one with small on resistance results in high efficiency. 3.3.5. Rectifying Diode Selection A schottky barrier diode which has current ability higher than the rated current of L, reverse voltage larger than the tolerance voltage of COUT, and low forward voltage VF especially needs to be selected. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 19/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.4 Loop Compensation A current mode DCDC converter has each one pole (phase lag) f P due to CR filter composed of the output capacitor and the output resistance (= LED current) and zero (phase lead) fZ by the output capacitor and the ESR of the capacitor. Moreover, a step-up DCDC converter has RHP zero (right-half plane zero point) fZRHP which is unique with the boost converter. This zero may cause the unstable feedback. To avoid this by RHP zero, the loop compensation that the cross-over frequency fc, set as follows, is suggested. fc = fZRHP /5 (fZRHP: RHP zero frequency) Considering the response speed, the calculated constant below is not always optimized completely. It needs to be adequately verified with an actual device. VIN VOUT ILED L VOUT - RCS FB gm RESR + RFB1 COUT CFB2 CFB1 Figure 23. Output stage and error amplifier diagram i. Calculate the pole frequency fP and the RHP zero frequency fZRHP of DC/DC converter fP I LED [ Hz] 2 VOUT COUT f ZRHP Where I LED the summation of LED current, D ii. VOUT (1 D)2 [ Hz] 2 L I LED VOUT VIN VOUT (Continuous Current Mode) Calculate the phase compensation of the error amp output(fc = fZRHP/5) RFB1 f RHZP RCS I LED [ ] 5 f P gm VOUT (1 D) CFB1 1 5 [F ] 2 RFB1 f C 2 RFB! f ZRHP gm 4.0 104 [S ] Above equation is described for lighting LED without the oscillation. The value may cause much error if the quick response for the abrupt change of dimming signal is required. To improve the transient response, RFB1 needs to be increased, and CFB1 needs to be decreased. It needs to be adequately verified with an actual device in consideration of variation from parts to parts since phase margin is decreased. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 20/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.5. Timing Chart 3.5.1 PWM Start Up VCC STB REG90 UVLO 7.5V 2.0V 0.8V 5.8V 2.5V FAILB (External PullUp) SSFB LED_OK (internal) VOUT PWMx ILEDx LED Open Detection LED Short Detection OFF (*1) (*2) (*3) NORMAL (*4) OFF (*5) Figure 24. Start Up (*1)…REG90 starts up when STB is changed from Low to High. In the state where the PWM signal is not inputted, SS terminal is not charged and DCDC doesn't start to boost, either. (*2)…When REG90 is more than 5.8V(Typ), the reset signal is released. (*3)…The charge of the pin SS starts at the positive edge of PWM=L to H, and the soft start starts. The pin SS continues charging in spite of the assertion of PWM or OVP level. (*4)…The soft start interval will end if the LED_OK = H (internal signal), By this time, it boosts VOUT to the voltage where the set LED current flows. The abnormal detection of FBMAX starts to be monitored. (*5)…As STB=L, the boost operation is stopped instantaneously.( N=L, SSFB=L) www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 21/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.5.2 LED OPEN Detection PWM1~4 LED1=OPEN LED1=Normal Condition LED1≒Vout LED1=OPEN VLED1 OPEN THRFESHOLD 0.2V 0.2V LED1=Normal Condition 3V VLED2~4 Internal signal 5V Pull Up 3V Mask (4count) (OPEN DET) 16384 Ab < normal count Internal signal Mask (3count) 16384count (Abnormal Count) LED1=OFF ILED1 ILED2~4 FAILB Internal signal 131072count AUto Restart Count Start (131072count) (Auto Restart) IC State Normal Abnormal Counting Normal Abnormal Counting LED1 = OFF Normal Judge OK Figure 25. LED OPEN Detection www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 22/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.5.3 LED SHORT Detection PWM1~4 LED1=SHORT LED1=Normal Condition 6V 6V VLED1 VLED2~4 LED1=Normal Condition LED1=SHORT 6V Internal signal (SHORT DET) Mask (4counts) 16384 Ab < count normal Internal signal 16384count 16384count Mask (3counts) (Abnormal Count) ILED1 LED1 = OFF LED1 = OFF ILED2~4 FAILB Internal signal IC State 131072count AUto Restart Count Start (131072count) (Auto Restart) Normal Abnormal Counting Abnormal Counting Normal LED1 = OFF Abnormal Counting Judge Fail 131072count LED1 = OFF Normal Judge OK Figure 26. LED SHORT Detection www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 23/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.5.4 Over Duty Protection PWM1 PWM2 PWM=100% (35%) (30%) dutyH > (35%) PWM3 PWM4 ILED1 ILED2 (35%) (35%) (35%) (30%) ILED3 ILED4 (*1) (*2) (*3) (*4) (*5) (*6) Figure 27. Over Duty Protection ODP=35% setup (*1) …PWM < 35% : Turn on in relevant CH of same time PWM_DutyH. (*2) …PWM > 35% : An LED of relevant CH is turn off by PWM_DutyH=35%. (*3) …PWM=H signal beyond 35% is changed, and that doesn't react to IC in particular. (*4) …PWM > 35% : An LED of relevant CH is turn off by PWM_DutyH=35%. (*5) …ODP Function= ON : When a PWM signal is equivalent to 100%, LED=OFF continues after 35 %. (*6) … When the next PWM=H signal is input, an LED is also turn on at the same time. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 24/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 3.6 I/O Equivalent Circuits OVP UVLO SSFB SSFB 100k OVP UVLO 5V RT PWM1-4 RT DUTYON PWM1-4 100k 300k 5V G1-4 DUTYON 100 k 5V 300k S1-4 LSP 4V G1-G4 2800k S1-S4 LSP 100k 1200k REG90 / N / PGND / CS STB VREF REG90 N 100k STB 20 k VREF 5V 5V 1M GND CS DUTYP FAILB LED1-4 LED1-4 DUTYP FAILB 500 Figure 28. Internal Equivalent Circuits www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 25/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS Operational Notes 1. Reverse Connection of Power Supply Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity when connecting the power supply, such as mounting an external diode between the power supply and the IC’s power supply pins. 2. Power Supply Lines Design the PCB layout pattern to provide low impedance supply lines. Connect a capacitor to ground at all power supply pins. Consider the effect of temperature and aging on the capacitance value when using electrolytic capacitors. 3. Ground Voltage Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition. 4. Ground Wiring Pattern When using both small-signal and large-current ground traces, the two ground traces should be routed separately but connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal ground caused by large currents. Also ensure that the ground traces of external components do not cause variations on the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance. 5. Thermal Consideration Should by any chance the maximum junction temperature rating be exceeded the rise in temperature of the chip may result in deterioration of the properties of the chip. In case of exceeding this absolute maximum rating, increase the board size and copper area to prevent exceeding the maximum junction temperature rating. 6. Recommended Operating Conditions These conditions represent a range within which the expected characteristics of the IC can be approximately obtained. The electrical characteristics are guaranteed under the conditions of each parameter. 7. Inrush Current When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power supply. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of connections. 8. Operation Under Strong Electromagnetic Field Operating the IC in the presence of a strong electromagnetic field may cause the IC to malfunction. 9. Testing on Application Boards When testing the IC on an application board, connecting a capacitor directly to a low-impedance output 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 the test setup during the inspection process. To prevent damage from static discharge, ground the IC during assembly and use similar precautions during transport and storage. 10. Inter-pin Short and Mounting Errors Ensure that the direction and position are correct when mounting the IC on the PCB. Incorrect mounting may result in damaging the IC. Avoid nearby pins being shorted to each other especially to ground, power supply and output pin. Inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins during assembly to name a few. 11. Unused Input Pins Input pins of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance and extremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small charge acquired in this way is enough to produce a significant effect on the conduction through the transistor and cause unexpected operation of the IC. So unless otherwise specified, unused input pins should be connected to the power supply or ground line. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 26/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS 12. Regarding the Input Pin of the IC This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated. P-N junctions are formed at the intersection of the P layers with the N layers of other elements, creating a parasitic diode or transistor. For example (refer to figure below): When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode. When GND > Pin B, the P-N junction operates as a parasitic transistor. Parasitic diodes inevitably occur in the structure of the IC. The operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. Therefore, 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. Resistor Transistor (NPN) Pin A Pin B C E Pin A N P+ P N N P+ N Parasitic Elements N P+ N P N P+ B N C E Parasitic Elements P Substrate P Substrate Parasitic Elements Pin B B GND Parasitic Elements GND GND N Region close-by GND Figure 29. Example of monolithic IC structure 13. Ceramic Capacitor When using a ceramic capacitor, determine the dielectric constant considering the change of capacitance with temperature and the decrease in nominal capacitance due to DC bias and others. 14. Area of Safe Operation (ASO) Operate the IC such that the output voltage, output current, and the maximum junction temperature rating are all within the Area of Safe Operation (ASO). 15. Thermal Shutdown Circuit(TSD) This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always be within the IC’s maximum junction temperature rating. If however the rating is exceeded for a continued period, the junction temperature (Tj) will rise which will activate the TSD circuit that will turn OFF all output pins. When the Tj falls below the TSD threshold, the circuits are automatically restored to normal operation. Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from heat damage. 16. Over Current Protection Circuit (OCP) This IC incorporates an integrated overcurrent protection circuit that is activated when the load is shorted. This protection circuit is effective in preventing damage due to sudden and unexpected incidents. However, the IC should not be used in applications characterized by continuous operation or transitioning of the protection circuit. 17. Disturbance light In a device where a portion of silicon is exposed to light such as in a WL-CSP, IC characteristics may be affected due to photoelectric effect. For this reason, it is recommended to come up with countermeasures that will prevent the chip from being exposed to light. www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 27/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS Ordering Information B D 9 4 1 Part Number 5 F S - Package F: SSOP-A32 E2 Packaging and forming specification E2: Embossed tape and reel Marking Diagrams SSOP-A32(TOP VIEW) Part Number Marking BD9415FS LOT Number 1PIN MARK www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 28/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS Physical Dimension, Tape and Reel Information Package Name www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 SSOP-A32 29/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 BD9415FS Revision History Date Revision 12 May.2016 001 Change New Release www.rohm.com © 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 30/30 TSZ02201-0F2F0C100140-1-2 23.May.2016 Rev.001 Notice Precaution on using ROHM Products 1. Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment, OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you (Note 1) intend to use our Products in devices requiring extremely high reliability (such as medical equipment , transport equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance. Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific Applications. (Note1) Medical Equipment Classification of the Specific Applications JAPAN USA EU CHINA CLASSⅢ CLASSⅡb CLASSⅢ CLASSⅢ CLASSⅣ CLASSⅢ 2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which a failure or malfunction of our Products may cause. The following are examples of safety measures: [a] Installation of protection circuits or other protective devices to improve system safety [b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. Our Products are designed and manufactured for use under standard conditions and not under any special or extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any special or extraordinary environments or conditions. If you intend to use our Products under any special or extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be necessary: [a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents [b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust [c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves [e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items [f] Sealing or coating our Products with resin or other coating materials [g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning residue after soldering [h] Use of the Products in places subject to dew condensation 4. The Products are not subject to radiation-proof design. 5. Please verify and confirm characteristics of the final or mounted products in using the Products. 6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied, confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect product performance and reliability. 7. De-rate Power Dissipation depending on ambient temperature. When used in sealed area, confirm that it is the use in the range that does not exceed the maximum junction temperature. 8. Confirm that operation temperature is within the specified range described in the product specification. 9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in this document. Precaution for Mounting / Circuit board design 1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product performance and reliability. 2. In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products, please consult with the ROHM representative in advance. For details, please refer to ROHM Mounting specification Notice-PGA-E © 2015 ROHM Co., Ltd. All rights reserved. Rev.003 Precautions Regarding Application Examples and External Circuits 1. If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the characteristics of the Products and external components, including transient characteristics, as well as static characteristics. 2. You agree that application notes, reference designs, and associated data and information contained in this document are presented only as guidance for Products use. Therefore, in case you use such information, you are solely responsible for it and you must exercise your own independent verification and judgment in the use of such information contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such information. Precaution for Electrostatic This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron, isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control). Precaution for Storage / Transportation 1. Product performance and soldered connections may deteriorate if the Products are stored in the places where: [a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [b] the temperature or humidity exceeds those recommended by ROHM [c] the Products are exposed to direct sunshine or condensation [d] the Products are exposed to high Electrostatic 2. Even under ROHM recommended storage condition, solderability of products out of recommended storage time period may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is exceeding the recommended storage time period. 3. Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads may occur due to excessive stress applied when dropping of a carton. 4. Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of which storage time is exceeding the recommended storage time period. Precaution for Product Label A two-dimensional barcode printed on ROHM Products label is for ROHM’s internal use only. Precaution for Disposition When disposing Products please dispose them properly using an authorized industry waste company. Precaution for Foreign Exchange and Foreign Trade act Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign trade act, please consult with ROHM in case of export. Precaution Regarding Intellectual Property Rights 1. All information and data including but not limited to application example contained in this document is for reference only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any other rights of any third party regarding such information or data. 2. ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the Products with other articles such as components, circuits, systems or external equipment (including software). 3. No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to manufacture or sell products containing the Products, subject to the terms and conditions herein. Other Precaution 1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM. 2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of ROHM. 3. In no event shall you use in any way whatsoever the Products and the related technical information contained in the Products or this document for any military purposes, including but not limited to, the development of mass-destruction weapons. 4. The proper names of companies or products described in this document are trademarks or registered trademarks of ROHM, its affiliated companies or third parties. Notice-PGA-E © 2015 ROHM Co., Ltd. All rights reserved. Rev.003 Datasheet General Precaution 1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents. ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny ROHM’s Products against warning, caution or note contained in this document. 2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s representative. 3. The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or concerning such information. Notice – WE © 2015 ROHM Co., Ltd. All rights reserved. Rev.001