Method and apparatus for sensing current and voltage in circuits with voltage across an LED

摘要

Methods and apparatuses to sense current and voltage in circuits with voltage drop. In one aspect of the invention, a circuit includes a transistor coupled to a voltage reference. A light emitting diode (LED) is coupled to be driven by the transistor in response to a voltage across an output of the circuit. A first diode is coupled to the LED. A first resistor coupled to the first diode and the LED. The LED is coupled to be driven in response to a voltage drop across the first diode and the first resistor to sense a first current directed through the first diode and the first resistor.