A method of providing two-step linear spectral tunability in a light emitting diode device, the method comprising: providing a first output current (Iww) to a first LED array at approximately an end of a desired tunable spectral range, a second output current (I CW) to a second LED array at approximately an opposite end of the desired tunable spectral range, and a third output current (I NW) to a third LED array at approximately a middle of the desired tunable spectral range, characterized by the steps of: receiving a first input current from a first channel of a two channel LED driver; receiving a second input current from a second channel of the two channel LED driver; comparing the first input current to the second input current to determine a ratio, comprising detecting that the first input current is greater than or approximately equal to the second input current or that the second input current is greater than or approximately equal to the first input current; and converting the first input current and the second input current to the first output current (Iww), the second output current (I CW), and the third output current (I NW) based on the ratio, wherein the first output current (Iww) is a difference between the first input current and the second input current, the second output current (I CW) is approximately zero, and the third output current (I NW) is approximately twice the second input current when the first input current is greater than or approximately equal to the second input current, and wherein the first output current (Iww) is approximately zero, the second output current (I CW) is the difference between the second input current and the first input current, and the third output current (I NW) is approximately twice the first input current (Iww) when the second input current is greater than or approximately equal to the first input current. providing a first output current (Iww) to a first LED array at approximately an end of a desired tunable spectral range, a second output current (I CW) to a second LED array at approximately an opposite end of the desired tunable spectral range, and a third output current (I NW) to a third LED array at approximately a middle of the desired tunable spectral range, characterized by the steps of: receiving a first input current from a first channel of a two channel LED driver; receiving a second input current from a second channel of the two channel LED driver; comparing the first input current to the second input current to determine a ratio, comprising detecting that the first input current is greater than or approximately equal to the second input current or that the second input current is greater than or approximately equal to the first input current; and converting the first input current and the second input current to the first output current (Iww), the second output current (I CW), and the third output current (I NW) based on the ratio, wherein the first output current (Iww) is a difference between the first input current and the second input current, the second output current (I CW) is approximately zero, and the third output current (I NW) is approximately twice the second input current when the first input current is greater than or approximately equal to the second input current, and wherein the first output current (Iww) is approximately zero, the second output current (I CW) is the difference between the second input current and the first input current, and the third output current (I NW) is approximately twice the first input current (Iww) when the second input current is greater than or approximately equal to the first input current. receiving a first input current from a first channel of a two channel LED driver; receiving a second input current from a second channel of the two channel LED driver; comparing the first input current to the second input current to determine a ratio, comprising detecting that the first input current is greater than or approximately equal to the second input current or that the second input current is greater than or approximately equal to the first input current; and converting the first input current and the second input current to the first output current (Iww), the second output current (I CW), and the third output current (I NW) based on the ratio, wherein the first output current (Iww) is a difference between the first input current and the second input current, the second output current (I CW) is approximately zero, and the third output current (I NW) is approximately twice the second input current when the first input current is greater than or approximately equal to the second input current, and wherein the first output current (Iww) is approximately zero, the second output current (I CW) is the difference between the second input current and the first input current, and the third output current (I NW) is approximately twice the first input current (Iww) when the second input current is greater than or approximately equal to the first input current.