BD2802GU データシートの表示（PDF） - ROHM Semiconductor
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BD2802GU Datasheet PDF : 28 Pages
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BD2802GU
Technical Note
●RGB Waveform Setting
Various kinds of RGB control can be implemented by designating waveform cycles, waveform patterns, current settings 1, 2
and rising/falling slope times.
To activate a RGB waveform, a continuous operation via RGB*EN or a single-shot operation via RGB*OS can be selected.
In addition, when control via the external terminal RGB*CNT is enabled via RGB*MEL, the corresponding LED can be lit in
synchronization with the external signal.
1. Waveform cycle
A single cycle time is set for a waveform pattern.
This setting can be made independently for RGB1 and RGB2.
2. Waveform pattern
A pattern in a waveform cycle is set.
Sixteen types of waveform patterns can be set in units of waveform patterns.
For concrete waveform patterns, refer to the timing diagram shown on the next page.
3. Current settings 1 and 2 (I1, I2)
Two currents in a waveform pattern are set.
When the maximum current value is 25.4mA, it is possible to set the current ranging from 0 to 25.4mA with an
increment of 0.2mA (128 steps).
The polarity of a waveform is determined by the greater-than/ less-than relationship in the current setting.
This setting can be made in units of terminals.
4. Rising/falling slope time
A current change time during switching between current settings 1 and 2 is set.
A time per step (0.2mA) is calculated based on a difference between the currents selected in current settings 1, 2
and a setting slope time.
For this reason, a time per step (0.2mA) is short when a difference between setting currents I1 and I2 is large. In
contrast, it is long when a difference between setting currents I1 and I2 is small.
Regardless of current settings 1 and 2, a rising slope time applies at current increase and a falling slope time applies
at current decrease. For concrete waveform images, refer to the timing diagram shown on the next page.
5. External terminal synchronization control
When control via the external terminal RGB*CNT is enabled via RGB*MEL, lighting is enabled if the input external signal
goes “H.” In contrast, it is disabled if the external input signal goes “L.” In this way, synchronization with the external
signal is enabled so that LED can be blinked in conjunction with a ringing tone (a melody signaling a ringtone).
Waveform cycle
A RGB thin line indicates an image where
external terminal control does not take
place.
R*LED
G*LED
B*LED
RGB*CNT
RGB*MEL
External terminal control
is enabled.
Remains “Enabled” with
RGB*MEL=1 and
RGB*CNT=H
External terminal
control is disabled.
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© 2011 ROHM Co., Ltd. All rights reserved.
18/27
2011.04 - Rev.A
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