6/26/2023 0 Comments Schematic dimmer for led lights![]() Zero resistance at the potentiometer’s W1 terminal corresponds to minimum LED current, resulting to minimum brightness. Moreover, it multiplies that voltage by a gain to set the maximum output current. To control the LED brightness, operational amplifier U2 monitors the difference between the high-side voltage and the wiper voltage of digital potentiometer U1. ![]() Internal circuitry maintains the SET terminal at 0.6V. The driver is a charge pump that mirrors the current ISET (sourced from U3's SET terminal), to produce a current of (215ISET ☓%) through each LED. It is designed for portable-power applications that require white LEDs with adjustable, logarithmic dimming levels. With the use of DS1808, a dual audio taper potentiometer with logarithmic resistive characteristics and MAX1573, a fractional charge pump with regulated constant current for uniform intensity, the device can effectively adjust the total LED current from 1mA to 106mA, in 64 steps of 1dB each. This circuit is an LED dimmer that uses DS1808 and MAX1573 components which drive the four LEDs to light logarithmically.
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