TRICOLOR_LED_PEAK_INDICATOR_CIRCUIT

Published:2009/7/13 4:44:00 Author:May | From:SeekIC

This is a tricolor LED circuit. With a low input level, LED2 is off. As the input voltage increases, LED2 turns on and glows first green, then yellow, and finally red. Resistor R10 and 2.5-V precision voltage reference IC4 provide a precision voltage reference that is further subdivided by resistors R11, R12, R13, and R14, This chain of resistors creates three different reference voltages that set the voltage thresholds for the three LEDs, which are fed to the three comparators along with the input signal. The output of these comparators is then connected to LED2. If the output of all of the comparators is floating, the red and green dies in the tricolor LED are biased ON by R15 and R16, causing LED2 to glow yellow. However, if the output of a comparator is internally grounded, the connected color element will be pulled below 2 V, and the element will turn off. To set the gain level of the amplifier, apply a maximum-level signal to the input of the averager and reduce the level to allow for headroom.



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