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BD1206GUL
Datasheet
TSZ02201-0G3G0C200020-1-2
02.Oct.2012 Rev.001
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© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
b) LED current level
The interface records rising edges of the EN pin and decodes them into 16 different indicated in following table.
(2) Charge pump
a) Description of operations
Pin voltage comparison takes place at Vout control section, and then Vout generation takes place so that the LED
cathode voltage with the highest Vf is set to 0.15V. A boost rate is changed automatically to a proper one at the
Charge Pump Mode Control section so that operation can take place at possible low boost rate. In addition, when the
VOUT output is short-circuited to GND, the leak current is suppressed via the over current protection function.
b) Soft start function
BD1206GUL have a soft start function that prevents the rush current.
Soft Start Ordinal mode
EN/LED*
VOUT
I
LED
T
OFF
* EN/LED is an internal enable
Figure 6. Soft Start
c) Automatic boost rate change
The boost rate automatically switches to the best mode.
* (×1 mode ×1.5 mode) or (×1.5 mode ×2 mode)
If a battery voltage drop occurs BD1206GUL cannot maintain the LED constant current,
and then mode transition begins.
* (×1.5 mode ×1 mode) or (×2 mode ×1.5 mode)
If a battery voltage rise occurs, VOUT and VBAT detection are activated, and then mode transition begins.
(3) UVLO (Under Voltage Lock Out)
If the input voltage falls below 2.2V(Typ.), BD1206GUL is shut down to prevent malfunction due to ultra-low voltage.
(4) OVP (Over Voltage Protection)
This circuit protects this IC against damage when the C/P output voltage (VOUT) rises extremely for some external
factors.
(5) Thermal shutdown (TSD)
To protect this IC against thermal damage or heat-driven uncontrolled operations, this circuit turns off the output if the
chip temperature rises over 175ºC. In addition, it turns on the output if the temperature returns to the normal
temperature. Because the built-in thermal protection circuit is intended to protect the IC itself, the thermal shutdown
detection temperature must be set to below 175ºC in thermal design.
Data Output current [mA] Data Output current [mA]
1 20.0 9 5.0
2 17.0 10 4.0
3 14.0 11 3.0
4 12.0 12 2.0
5 10.0 13 1.0
6 8.5 14 0.5
7 7.0 15 0.25
8 6.0 16 0.125
