Split driver backlight systems and methods

An electronic device having a display, the display comprising:

• a backlight unit, comprising:
• a light-emitting diode;
• direct current control circuitry, wherein the direct current control circuitry comprises:
• a current control transistor coupled in series between the light-emitting diode and a ground voltage;
• and
• a digital-to-analog converter coupled to a gate terminal of the current control transistor;
• and
• pulse-width-modulation current control circuitry to modulate a first peak current provided by the direct current control circuitry through the light-emitting diode and to modulate a second peak current provided by the direct current control circuitry through the light-emitting diode, wherein the first peak current is larger than the second peak current.

A method of operating an electronic device, comprising:

• operating at least one light-emitting diode using a first pulse-width-modulation duty cycle and a first peak current;
• and
• operating the at least one light-emitting diode using a second pulse-width-modulation duty cycle and a second peak current, wherein the first and second peak currents are different,
• wherein operating at least one light-emitting diode using the first pulse-width-modulation duty cycle and the first peak current comprises providing the first peak current using a digital-to-analog converter and providing the first pulse-width-modulation duty cycle with a pulse-width-modulation controller.

A method of operating an electronic device, comprising:

• operating at least one light-emitting diode using a first driver circuit that provides a constant current to the at least one light-emitting diode;
• and
• operating the at least one light-emitting diode using a second driver circuit that provides a modulated current to the at least one light-emitting diode,
• wherein the first driver circuit comprises a first digital-to-analog converter coupled to a first current control transistor for the at least one light-emitting diode,
• wherein the second driver circuit comprises a second digital-to-analog converter coupled to a second current control transistor for the at least one light-emitting diode, and
• wherein the first digital-to-analog converter is an N-bit digital-to-analog converter, wherein the second digital-to-analog converter is an M-bit digital-to-analog converter, and wherein N is greater than M.