BCR420UW6 Datasheet, PDF (10/13 Pages) Diodes Incorporated – LINEAR LED CONSTANT CURRENT REGULATOR IN SOT26

BCR420UW6 / BCR421UW6
Application Information (Cont.)
PWM dimming can be achieved by driving the EN pin. Dimming is achieved by turning the LEDs ON and OFF for a portion of a single cycle. The
PWM signal can be provided by a micro-controller or analog circuitry; typical circuit is shown in Figure 3. Figure 4 is a typical response of LED
current vs. PWM duty cycle on the EN pin. PWM up to 25kHz with duty cycle of 0.5% (dimming range 200:1). This is above the audio band
minimizing audible power supply noise.
REXT
(Optional)
Figure 3 Application Circuits for LED Driver with PWM Dimming Functionality
Figure 4 Typical LED Current Response vs. PWM Duty Cycle for
25kHz PWM Frequency (Dimming Range 200:1)
BCR420UW6 / BCR421UW6
Document number: DS37667 Rev. 4 - 2
10 of 13
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June 2016
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