A light-emitting diode assembly comprising: a pulse width modulator configured to generate a plurality of pulse width modulation signals; and a pixel array comprising a plurality of LED pixel assemblies (235a, 235b; 310a, 310b; 410a, 410b; 510a, 510b; 610a, 610b), each LED pixel assembly comprising an LED (320a, 320b, 420a, 420b; 520a, 520b; 620a, 620b); a switching circuit (340a, 340b; 440a, 440b; 540a, 540b; 640a, 640b) configured to receive a PWM signal (380a, 380b) of the plurality of PWM signals, and to alternately turn on and off the LED according to the received PWM signal, the switching circuit comprising a PWM switch (442a, 442b; 542a, 542b) and a switching circuit transistor (444a, 444b: 544a, 544b); and a close loop circuit (330a, 330b; 430a, 430b; 530a, 530b; 630, 630b) configured to regulate an input current provided by the switching circuit to the LED based on a feedback signal (355a, 355b); characterized in that the close loop circuit further comprises: a reference current transistor (432a, 432b; 532a, 532b; 632a, 632b) arranged to output a reference current based on a current control signal; an op-amp (434a, 434b; 534a, 534b; 634a, 634b) coupled to the switching circuit transistor; a first resistor (436a, 436b; 536a, 536b; 636a, 636b) coupled to the non-inverting input of the op-amp and arranged to sense the reference current; a second resistor (438a, 438b; 538a, 538b; 638a, 636b) coupled to the inverting input of the op-amp and arranged to sense the LED current; and wherein the difference between the voltage drop across the first resistor and the voltage drop across the second resistor is amplified by the op-amp to adjust the gate voltage of the switching circuit transistor. a pulse width modulator configured to generate a plurality of pulse width modulation signals; and a pixel array comprising a plurality of LED pixel assemblies (235a, 235b; 310a, 310b; 410a, 410b; 510a, 510b; 610a, 610b), each LED pixel assembly comprising an LED (320a, 320b, 420a, 420b; 520a, 520b; 620a, 620b); a switching circuit (340a, 340b; 440a, 440b; 540a, 540b; 640a, 640b) configured to receive a PWM signal (380a, 380b) of the plurality of PWM signals, and to alternately turn on and off the LED according to the received PWM signal, the switching circuit comprising a PWM switch (442a, 442b; 542a, 542b) and a switching circuit transistor (444a, 444b: 544a, 544b); and a close loop circuit (330a, 330b; 430a, 430b; 530a, 530b; 630, 630b) configured to regulate an input current provided by the switching circuit to the LED based on a feedback signal (355a, 355b); an LED (320a, 320b, 420a, 420b; 520a, 520b; 620a, 620b); a switching circuit (340a, 340b; 440a, 440b; 540a, 540b; 640a, 640b) configured to receive a PWM signal (380a, 380b) of the plurality of PWM signals, and to alternately turn on and off the LED according to the received PWM signal, the switching circuit comprising a PWM switch (442a, 442b; 542a, 542b) and a switching circuit transistor (444a, 444b: 544a, 544b); and a close loop circuit (330a, 330b; 430a, 430b; 530a, 530b; 630, 630b) configured to regulate an input current provided by the switching circuit to the LED based on a feedback signal (355a, 355b); a reference current transistor (432a, 432b; 532a, 532b; 632a, 632b) arranged to output a reference current based on a current control signal; an op-amp (434a, 434b; 534a, 534b; 634a, 634b) coupled to the switching circuit transistor; a first resistor (436a, 436b; 536a, 536b; 636a, 636b) coupled to the non-inverting input of the op-amp and arranged to sense the reference current; a second resistor (438a, 438b; 538a, 538b; 638a, 636b) coupled to the inverting input of the op-amp and arranged to sense the LED current; and wherein the difference between the voltage drop across the first resistor and the voltage drop across the second resistor is amplified by the op-amp to adjust the gate voltage of the switching circuit transistor.