Abstract: Various embodiments relate to a method for driving a light emitting diode (LED) flash including: measuring a junction temperature of the LED by applying a test current to the LED and measuring the LED forward voltage; determining the drive current based upon the measured junction temperature and measured data characteristics of the LED; and applying the drive current to the LED for a specified length of time.

Abstract: Various embodiments relate to a method of producing a high precision current using N current mirrors, a feedback control amplifier, and a reference current regulator to drive a light emitting diode, including: selecting one of the N current mirrors as a first current mirror; driving the first current mirror using a reference current produced by the reference current regulator; measuring a first sense voltage at the first current mirror; measuring a second sense voltage at a second current mirror that is one of the remaining N?1 current mirrors; integrating a difference of the first sense voltage and the second sense voltage to produce a feedback signal; and driving the remaining N?1 current mirrors using the feedback signal.

Abstract: Various embodiments relate to a method of producing a high precision current using N current mirrors, a feedback control amplifier, and a reference current regulator to drive a light emitting diode, including: selecting one of the N current mirrors as a first current mirror; driving the first current mirror using a reference current produced by the reference current regulator; measuring a first sense voltage at the first current mirror; measuring a second sense voltage at a second current mirror that is one of the remaining N?1 current mirrors; integrating a difference of the first sense voltage and the second sense voltage to produce a feedback signal; and driving the remaining N?1 current mirrors using the feedback signal.

Abstract: Various embodiments relate to a method for driving a light emitting diode (LED) flash including: measuring a junction temperature of the LED by applying a test current to the LED and measuring the LED forward voltage; determining the drive current based upon the measured junction temperature and measured data characteristics of the LED; and applying the drive current to the LED for a specified length of time.

Abstract: A power source provides an output voltage to drive a plurality of light emitting diode (LED) strings. A feedback controller monitors the tail voltages of the LED strings to identify the minimum tail voltage and adjusts the output voltage based on a relationship between the minimum tail voltage and a reference voltage. The feedback controller implements precharging of the output voltage, including one or both of short-term precharging or long-term precharging. Further, the feedback controller incorporates a track/hold circuit that tracks the minimum tail voltage while the LED strings are active and holds the minimum tail voltage at the last tracked minimum tail voltage while the LED strings are inactive and uses the held minimum tail voltage for controlling the output voltage while the LED strings are inactive so as to permit the power source to supply an appropriate output voltage when the LED strings are subsequently activated again.