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Question

What is LED dimming control? How can it be done?

Answer

DC/DC Switching RegulatorsFunction

LED dimming control

The brightness of an LED can be set by regulating the current flowing to it.
Our boost DC/DC converters for LEDs can control the current flowing to the sense resistors by changing the reference voltage of the feedback circuit inside the IC according to the duty cycle of PWM signals input to the CE pin.
These ICs adopt a method different from the PWM dimming control widely used.

The current through the LEDs can be calculated by the following formula with the Hduty of PWM signals represented as Hduty, the feedback voltage as VFB, and the sense resistor as R1.

ILED=Hduty × VFB / R1

The following products have a wide PWM signal range from 200 Hz to 300 kHz.
Using high-frequency PWM signals enables high-speed dimming control.
When controlling the LED brightness with a PWM signal of 20 kHz or less, the variations of the inductor current might cause audible sounds.
In that case, please use higher-frequency PWM signals to avoid the phenomenon.

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