Appliances such as toaster ovens, microwave ovens, refrigerators, cloth dryers, and more implement door lights for monitoring the status of the function. These door lights dim and brighten when the door closes and opens, respectively. Appliance manufacturers prefer to provide a smooth-dimming transition for a better user experience. However, a microcontroller is required for such an operation, and implementing a separate microcontroller and associated software is a big overhead. For this reason, only high-end appliances have such features. The DACx3701 provides a simpler way to control the slew of such lights without software. Figure 9-1 shows the simplified circuit diagram of light fade-in fade-out using MOSFET based control and Figure 9-2 shows the circuit with an external LED driver. For high-power LEDs, external LED drivers with headroom control are preferred over MOSFET-based LED control.

Figure 9-1 Appliance Light Fade-In Fade-Out

Figure 9-2 Fade-In Fade-Out with Switching LED Driver