Soft-start enhances LED driver
To emulate the natural soft start of an incandescent bulb, this circuit makes use of the thermal-foldback protection built into an LED-driver IC (MAX16832). It thereby avoids the annoying and almost instantaneous startup otherwise exhibited by LEDs. Fortunately, you can use the thermal-foldback protection built into an LED-driver IC (MAX16832) to emulate the natural soft start of an incandescent bulb. Figure 1 shows the typical application circuit for this IC.
Using the thermal-foldback circuitry to implement a soft-start for LEDs does not interfere with its protection function. The big capacitor slows that function, but its operation remains satisfactory because thermal effects are inherently slow. Nor is the PWM dimming feature affected. Only the reference voltage is influenced; the rest of the driver behaves normally.
Using the thermal-foldback circuitry to implement a soft-start for LEDs does not interfere with its protection function. The big capacitor slows that function, but its operation remains satisfactory because thermal effects are inherently slow. Nor is the PWM dimming feature affected. Only the reference voltage is influenced; the rest of the driver behaves normally.
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