ncp5890 ON Semiconductor, ncp5890 Datasheet - Page 16

• Manufacturer Part Number: ncp5890
• Description: Light Management Ic Dedicated For Lcd Backlighting And Multi-led Fun Light Applications
• Manufacturer: ON Semiconductor

PWM Sequence
possible sequence depicted in Figure 16. In all cases, the
Main Display is powered first.
share the same timings, the rise and fall time being
identical. At this point, the feedback voltage will rapidly
swap from a low 400 mV (normal operation) to the large Vf
span coming from the three LED added in series.
time, the sequence being synchronized but delayed until
The three PWM can be controlled according to one of the
Strategy #1: the three PWM are fully synchronized and
Strategy #2: the three PWM share the same rise and fall
Strategy #1
Strategy #2
Strategy #3
Strategy #4
Main Display
PWM1
PWM2
PWM3
PWM1
PWM2
PWM3
PWM1
PWM2
PWM3
PWM1
PWM2
PWM3
Figure 16. Basic PWM Sequences
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the previous LED is at full power (PWM = 100%). This is
the most stable sequence, from a human eye stand point,
since we have a minimum blinking (one Vf variation only).
time but they can be activated independently.
NCP5890 is capable of operating under such conditions,
but care must be observed since such random PWM (as
depicted by the circles) might be a stress from a human eye
stand point.
Strategy #3: the three PWM share the same rise and fall
Startegy#4: the three PWM operate randomly: the