System control unit, led driver including the system control unit, and method of controlling static current of the led driver

A system control unit included in a light-emitting diode (LED) driver, the LED driver also comprising a switching unit, a transformer, and a zero current detection unit, wherein the switching unit comprises a power transistor configured to operate in response to a gate control signal, and a switching resistor placed between the power transistor and a ground voltage, wherein the transformer is configured to transfer an input voltage to a secondary coil of the transformer at a specific ratio in response to a switching operation of the switching unit connected to a primary coil of the transformer, and wherein the zero current detection unit is placed on a primary side of the transformer and is configured to generate a resonant voltage into which voltage that drops to an LED array connected to the secondary coil and voltage that drops to a diode connected to the secondary coil are incorporated,

• wherein the system control unit is configured to:
• estimate a second peak value that is a highest value of currents flowing through the diode using current flowing through the power transistor;
• calculate a mean value of currents supplied to the LED array for a specific time interval using a point of time at which the power transistor is turned off, a point of time at which the diode is turned off, and the second peak value;
• and
• update the gate control signal using the mean value,
• wherein the system control unit is configured to determine the point of time at which the power transistor is turned off by using the gate control signal.