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PDF BD8113EFV Data sheet ( Hoja de datos )
| Número de pieza | BD8113EFV | |
| Descripción | White Backlight LED Driver | |
| Fabricantes | ROHM Semiconductor | |
| Logotipo |  |
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LED Drivers for LCD Backlights
White Backlight LED Driver
for Medium to Large LCD Panels
(Switching Regulator Type)
BD8113EFV
No.11040EAT04
●Description
BD8113EFV is a white LED driver with the capability of withstanding high input voltage (36V MAX). This driver has 2ch
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 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 5.0 – 30 V
2) Integrated buck-boost current-mode DC/DC controller
3) Two integrated LED current driver channels (150 mA max. each channel)
4) PWM Light Modulation(Minimum Pulse Width 25µs)
5) Oscillation frequency accuracy ±5%
6) Built-in protection functions (UVLO, OVP, TSD, OCP, SCP)
7) LED abnormal status detection function (OPEN/ SHORT)
8) HTSSOP-B24 package
●Applications
Backlight for display audio, small type panels, etc.
●Absolute maximum ratings (Ta=25℃)
Parameter
Symbol
Ratings
Power supply voltage
VCC
36
BOOT ,OUTH Voltage
VBOOT, VOUTH
41
SW,CS Voltage
VSW, VCS
36
BOOT-SW Voltage
VBOOT-SW
7
LED output voltage
VREG, OVP, OUTL, FAIL1, FAIL2, LEDEN,
ISET, VDAC, PWM, SS, COMP, RT,
SYNC, EN voltage
Power Consumption
VLED1,2
VVREG, VOVP, VOUTL, VFAIL1, VFAIL2,
VLEDEN, VISET, VVDAC, VPWM, VSS,
VCOMP, VRT, VSYNC, VEN
Pd
36
-0.3～7 < VCC
1.10 ※1
Operating temperature range
Topr -40～+105
Storage temperature range
LED maximum output current
Tstg
ILED
-55～+150
150 ※2 ※3
Junction temperature
Tjmax
150
*1 IC mounted on glass epoxy board measuring 70mm×70mm×1.6mm, power dissipated at a rate of 8.8mw/℃ 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.
Unit
V
V
V
V
V
V
W
℃
℃
mA
℃
●Operating conditions (Ta=25℃)
Parameter
Symbol
Ratings
Power supply voltage
VCC 5.0～30
Oscillating frequency range
External synchronization frequency range ※4 ※5
FOSC
FSYNC
250～600
fosc～600
External synchronization pulse duty range
FSDUTY
40～60
*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.
Unit
V
kHz
kHz
%
www.rohm.com
© 2011 ROHM Co., Ltd. All rights reserved.
1/19
2011.07 - Rev.A
1 page  
BD8113EFV
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 4.0 V (Typ.) or lower, UVLO engages and turns the IC off. Connect a capacitor (Creg = 2.2uF
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 EN
LED
12
L ON ON
H ON 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 0.0 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
3150
3100
3050
3000
2950
2900
2850
0
20 40 60 80 100 120 140 160
ILED[mA]
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
© 2011 ROHM Co., Ltd. All rights reserved.
5/19
2011.07 - Rev.A
5 Page 
BD8113EFV
Technical Note
1. Computation of the Input Peak Current and IL_MAX
① Calculation of the maximum output voltage (Vout_max)
To calculate the Vout_max, it is necessary to take into account of the VF variation and the number of LED
connection in series.
Vout_max = (VF + ΔVF) × N + 1.0V ΔVF: VF Variation N: Number of LED connection in series
② Calculation of the output current Iout
Iout = ILED × 1.05 × M
M:Number of LED connection in parallel
③ Calculation of the input peak current IL_MAX
IL_MAX = IL_AVG + 1/2ΔIL
IL_AVG = (VIN + Vout) × Iout / (n × VIN)
ΔIL= VIN
L
×1
Fosc
×
Vout
VIN+Vout
n: efficiency Fosc: switching frequency
・The worst case scenario for VIN is when it is at 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
BD8113EFV, 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. The L values outside this recommended range may cause
irregular switching waveform and hence deteriorate stable operation.
・n (efficiency) is approximately 80%
VIN
IL Rcs
CS
M1
L
D2
Vout
M2
D1 Co
External Application Circuit
2. The setting of over-current protection
Choose Rcs with the use of the equation Vocp_min (=0.54V) / Rcs > 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] < L < 0.3 [V/µs]
Vout×Rcs
The smaller
allows stability improvement but slows down the response time.
L
4. Selection of coil L, diode D1 and D2, MOSFET M1 and M2, and Rcs
Current rating
Voltage rating
Coil L
> IL_MAX
―
Diode D1
> Iocp
> VIN_MAX
Diode D2
> Iocp
> Vout
MOSFET M1
> Iocp
> VIN_MAX
MOSFET M2
> Iocp
> Vout
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.
Heat loss
> Iocp2 × Rcs
www.rohm.com
© 2011 ROHM Co., Ltd. All rights reserved.
11/19
2011.07 - Rev.A
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet BD8113EFV.PDF ] | |
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