BD8381EFV-E2 Rohm Semiconductor, BD8381EFV-E2 Datasheet

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... BD8381EFV-M ●Description BD8381EFV white LED driver with the capability of withstanding high input voltage (50V MAX). A current-mode buck-boost DC/DC controller is also integrated to achieve stable operation against 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 linear. The PWM brightness signal generation circuit is built into, and the control without microcomputer is also possible. ● ...

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... BD8381EFV-M ●Electrical characteristics (unless otherwise specified, VCC=12V Ta=25℃) Parameter 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] OUTL high-side ON resistance OUTL low –side ON resistance [SW Block] ...

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... BD8381EFV-M ●Electrical characteristic curves (Reference data) (unless otherwise specified, Ta=25℃ VCC VOLTAGE [V] Fig.1 VREG Temperature characteristic 8.0 6.0 4.0 2.0 0 SUPPLY VOLTAGE:Vcc [V] Fig.4 Circuit current (Switching OFF) 250 200 150 100 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 THM VOLTAGE:THM[V] Fig ...

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... BD8381EFV-M ●Block diagram and pin configuration Vin VCC VREG EN SYNC RT COMP OCP OVP SS VREG THM DRLIN VREG DISC VTH ● Pin layout BD8381EFV-M（HTSSOP-B28） Fig.11 www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. VREG FAIL1 UVLO TSD OVP OCP Timer ...

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... BD8381EFV-M ● 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 ...

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... BD8381EFV-M ● Buck-Boost DC/DC controller ・ 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 ...

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... BD8381EFV-M ・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. UVLO TSD OVP OCP S SCP ...

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... BD8381EFV-M ・LED Short Detection When the voltage between LEDR-pin and LEDC-pin ≥ 0.2 (TYP), the internal counter starts operating, and approximately after 100ms (when FOSC = 300kHz) the operation latches off. With the PWM brightness control, the detecting operation is processed only when PWMOUT-pin = High. If the condition of the detection operation is released before 100ms (when FOSC = 300kHz), then the internal counter resets ...

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... BD8381EFV-M ●Error all condition Protection UVLO VREG<4.3V TSD OVP VOVP>2.0V OCP VCS≦ VCC-0.6V SCP (140ms delay when LED open & VOVP>1.7V lVLEDR-VLEDCl>0.2V LED short (100ms delay when FOSC=300kHz) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. Detecting Condition [Detect] [Release] VREG> ...

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... BD8381EFV-M ●Protection sequence Vcc EN VREG UVLO THM (Input by the resistance division of VREG. ) SYNC DRLIN SS OUTL VOUT Power supply turning on sequence ① Please turn on EN with Vcc≧4.5V or more after impressing Vcc. ② Please fix the potential of DRLIN and THM before turning on EN. ...

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... BD8381EFV-M ●Operation in error circumstances of LED ① LED open detection VCC OUTH SW OUTL PWMOUT FB Fig.17 ②LED short detection VCC OUTH SW OUTL PWMOUT Fig.18 ③ LED anode/cathode land GND short detection VCC OUTH SW OUTL PWMOUT Fig.19 www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. ...

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... BD8381EFV-M ● Procedure for external components selection Follow the steps as shown below for selecting the external components 1. Work out IL_MAX from the operating conditions. 2. Select the value of RSC such that IOCP > IL_MAX 3. Select the value of L such that 0.05[V/µs] < ...

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... VIN is when the minimum, and thus the minimum value should be applied in the equation. ・The L value of 10µF ∼ 47µF is recommended. The current-mode type of DC/DC conversion is adopted for BD8381EFV-M, which is optimized with the use of the recommended L value in the design stage. This recommendation is based upon the efficiency as well as the stability ...

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... BD8381EFV-M 5. Selection of the output capacitor Select the output capacitor Cout based on the requirement of the ripple voltage Vpp. Iout Vout × Vpp = Cout Vout+V Choose Cout that allows the Vpp to settle within the requirement. Allow some margin also, such as the tolerance of the external components ...

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... BD8381EFV-M 8. 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 ∼ 0.1uF. For the capacitance less than 0.001uF may cause overshoot of the output voltage. For the capacitance greater than 0.1uF may cause massive reverse current through the parasitic elements of the IC and damage the whole device ...

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... BD8381EFV-M ●Power consumption calculation 1 Pc(N) = ICC*VCC + *Ciss*VREG*Fsw*VREG×2×2+ 2 ICC ： Current of the maximum circuit VCC ：Power-supply voltage Ciss ： External FET capacity Vsw ： SW gate voltage Fsw ： SW frequency F ： PWM frequency PWM ＜Calculation example＞ When assuming Pc(4) = 10mA × 30V + 500pF × 5V × 300kHz × 5V×2×2+ it becomes Pc = about 300mW ...

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... BD8381EFV-M ●Application circuit 1 Vin VCC EN SYNC RT COMP SS VREG THM INP1 INP2 DRLIN VREG DISC VTH Buck application composition (It is INP1, INP2, and two input selector function. ) ●Application circuit 2 Vin VCC EN SYNC RT COMP SS VREG THM DRLIN VREG DISC VTH Boost application composition (When invalidating short detection. ) www.rohm.com © ...

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... BD8381EFV-M ●Input/output Equivalent Circuits 1. COMP VREG VREG COMP 5. RT VREG VREG VREG VCC FB 12. DRLIN VCC DRLIN ※The values are all Typ. value. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved VREG VCC SS 6. SYNC 8. THM SYNC 10. DISC 11. VTH VREG DISC 13,14 ...

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... BD8381EFV-M ●Input/output Equivalent Circuits(Continuation) 16,17. LEDC, LEDR LEDC LEDR 24. SW VCC SW 27. BOOT VREG BOOT ※The values are all Typ. value. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 19,22. PWMOUT, OUTL VREG VREG 25. OUTH BOOT BOOT OUTH 28. VREG VREG VCC ...

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... BD8381EFV-M ●Notes for use 1．Absolute maximum ratings We are careful enough for quality control about this IC. So, there is no problem under normal operation, excluding that it exceeds the absolute maximum ratings. However, this IC might be destroyed when the absolute maximum ratings, such as impressed voltages or the operating temperature range(Topr), is exceeded, and whether the destruction is short circuit mode or open circuit mode cannot be specified ...

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... BD8381EFV-M www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 21/20 Technical Note 2010.10 - Rev.0.11 ...