Power offloading for linear current source

A controller circuit for a set of light emitting diodes (LEDs), the controller circuit comprising:

• a first linear current source configured to regulate a first current from a supply along a first series path to the set of LEDs;
• channel circuitry configured to control a second current from the supply along a second series path to the set of LEDs, the second series path being in parallel with the first series path and the second series path comprising a drop element coupled in series with the supply and the set of LEDs, wherein the channel circuitry comprises a second linear current source configured to regulate the second current;
• and
• supervisor circuitry configured to regulate a total current supplied to the set of LEDs using the linear current source and the channel circuitry, the total current comprising the first current and the second current, wherein, to regulate the total current, the supervisor circuitry is configured to:
• determine a voltage drop using one or more of a voltage across the first linear current source and a voltage across the second linear current source;
• in response to the voltage drop being not greater than an operating zone threshold, operate in a first state, wherein when operating in the first state the supervisor circuit is configured to drive the first linear current source such that the first current corresponds to a target total current and drive the second linear current source such that the second current corresponds to zero;
• and
• in response to the voltage drop being greater than the operating zone threshold, operate in a second state, wherein when operating in the second state the supervisor circuit is configured to drive the second linear current source such that the second current corresponds to the target total current and drive the first linear current source such that the first current corresponds to zero.

A method for controlling a set of light emitting diodes (LEDs), the method comprising:

• regulating, by a controller circuit, a first current from a supply along a first series path to the set of LEDs;
• controlling, by the controller circuit, a second current from the supply along a second series path to the set of LEDs, the second series path being in parallel with the first series path and the second series path comprising a drop element coupled in series with the supply and the set of LEDs, wherein the controller circuit comprises a switching element coupled in series with the supply, the drop element, and the set of LEDs along the second series path and configured to operate in an open state or a closed state, wherein during the open state the switching element sets the second current to correspond to zero and wherein during the closed state the switching element refrains from setting the second current to correspond to zero and wherein controlling the second current comprises operating the switching element in the open state or the closed state;
• determining, by the controller circuit, a measurement of the second current;
• and
• regulating, by the controller circuit, a total current supplied to the set of LEDs using the regulation of the first current and the controlling of the second current, the total current comprising the first current and the second current, wherein regulating the total current comprises:
• driving a linear current source to regulate the first current using the measured second current and operating the switching element in the closed state in response to a voltage across the linear current source being greater than an operating zone threshold and operating the switching element in the open state in response to the voltage across the linear current source being not greater than the operating zone threshold.