Apparatuses of various forms and each having at least one LED string controlled by a current controller biased by voltage tap nodes in the LED string, and circuitry for implementing the same. In some implementations, circuitry made in accordance with the present disclosure includes a current controller and current-control circuitry. The current controller is biased by a voltage drop across one or more LEDs in an LED string and controls the current-control circuitry in a manner that controls the electrical current in the LED string. In some implementations, one or more additional LED strings and/or one or more other devices may be controlled directly or indirectly by operation of the current controller.