BD6581GU-E2 Rohm Semiconductor, BD6581GU-E2 Datasheet - Page 12

• Manufacturer Part Number: BD6581GU-E2
• Description: IC LED DVR WHT BCKLGHT VCSP85H2
• Manufacturer: Rohm Semiconductor
• Series: -r

Specifications of BD6581GU-E2

• Constant Current: -
• Constant Voltage: -
• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 6
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 800kHz ~ 1.2MHz
• Voltage - Supply: 2.7 V ~ 22 V
• Voltage - Output: 44.7 V
• Mounting Type: *
• Package / Case: *
• Operating Temperature: -30°C ~ 85°C
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

●Start to Use PWMPOW Terminal for the PWM Control, PWM Operating
BD6581GU
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After RSTB and PWMDRV is changing L → H, input PWM to PWMPOW terminal.
There is no constraint in turn of RSTB and PWMDRV.
And, because it corresponds to PWM drive of shorter ON time than soft start time (1ms), when PWMPOW is input H more
than three times, the soft start is invalidated and it enable to correspond the high-speed drive. Until RSTB is set L,
invalidation of the soft start isn't canceled.
In case of lighting → light off → lighting, when it turns off the lights with PWM=L and It starts without soft start when it sets
PWM modulated light again.
But the peak current of the coil changes owing to discharge of output capacitor, It may flow to the over current limit value, as
follows Fig.35. Because soft start can be used when it turns off the lights with RSTB=L, The peak current of the coil can be
suppressed, as follows Fig.36 and this process of light off is recommended.
Fig.35 Light off control of PWMPOW pin at PWM control on PWM=L
Output Voltage
Output Voltage
Fig.36 Light off control of PWMPOW pin at PWM control on RSTB=L
Current coil
Current coil
PWMPOW
PWMPOW
PWMDRV
PWMDRV
RSTB
RSTB
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2010.03 - Rev.A
Technical Note