BD6067GU-E2 Rohm Semiconductor, BD6067GU-E2 Datasheet - Page 21

• Manufacturer Part Number: BD6067GU-E2
• Description: IC LED DRIVR WHITE BCKLGT 8-VCSP
• Manufacturer: Rohm Semiconductor
• Type: Backlight, White LEDr

Specifications of BD6067GU-E2

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 800kHz ~ 1.2MHz
• Voltage - Supply: 2.7 V ~ 5.5 V
• Voltage - Output: 30V
• Mounting Type: Surface Mount
• Package / Case: 8-VCSP
• Operating Temperature: -30°C ~ 85°C
• Current - Output / Channel: 30mA
• Internal Switch(s): Yes
• Led Driver Application: Mobile Phones
• No. Of Outputs: 1
• Output Current: 30mA
• Output Voltage: 36V
• Input Voltage: 2.7V To 5.5V
• Operating Temperature Range: -30°C To +85°C
• Driver: RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Efficiency: -
• Lead Free Status / Rohs Status: Details
• Other names: BD6067GU-E2TR

© 2011 ROHM Co., Ltd. All rights reserved.
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
►BD6069GUT, BD6072HFN
●Description of Functions
www.rohm.com
1) Soft starts and off status
2) Isolation control
3) Short-circuit protection and over voltage protection
4) Thermal shut down
BD6069GUT/BD6072HFN has soft start function and off status function.
The soft start function and the off status function prevent large current from flowing to the IC via coil.
Occurrence of rush current at turning on is prevented by the soft start function, and occurrence of invalid current at turning
off is prevented by the off status function.
BD6069GU/BD6072HFN T has isolation control to prevent LED wrong lighting at power off.
The cause of the LED wrong lighting is leak current from VIN to the white LED.
Therefore, when BD6069GUT/BD6072HFN gets in power off (EN = L), the isolation control cuts the DC path between SW
and Vout, thereby the leak current from VIN to LED is prevented.
BD6069GUT/BD6072HFN has short-circuit protection and over voltage protection. These detect the voltage of VOUT, and
at error, they stop the output Tr. Details are as shown below.
・Short-circuit protection
・Over voltage protection
BD6069GUT/BD6072HFN has thermal shut down function.
The thermal shut down works at 175℃ or higher, and while holding the setting of EN control from the outside, the IC
changes from its action condition into its non action condition. And at 175℃ or below, the IC gets back to its normal action.
In the case of short-circuit of the DC/DC output (VOUT) to GND, the coil or the IC may be destructed.
Therefore, at such an error as VOUT becoming 0.7V or below, the Under Detector shown in the figure works, and turns
off the output Tr, and prevents the coil and the IC from being destructed.
And the IC changes from its action condition into its non action condition, and current does not flow to the coil (0mA).
At such an error as the IC and the LED being cut off, over voltage causes the SW terminal and the VOUT terminal
exceed the absolute maximum ratings, and may destruct the IC. Therefore, when VOUT becomes 18.5V or higher, the
over voltage limit works, and turns off the output Tr, and prevents the SW terminal and the VOUT terminal from
exceeding the absolute maximum ratings.
At this moment, the IC changes from its action condition into its non action condition, and the output voltage goes down
slowly. And, when the output voltage becomes the hysteresis of the over voltage limit or below, the output voltage goes
on up to 18.5V once again.
This protection action is shown in Fig.66.
Fig.66 Block diagram of short-circuit protection and over voltage
VIN
SW
SW
driver
Fig.65 Isolation control
Vout
OVER VOLTAGE REF
UNDER VOLTAGE REF
21/29
Cout
OVER Detector
UNDER Detector
Vout
VFB
Control
White LED
2011.01 - Rev.C
Technical Note