A Pixel Circuit With Leakage Current Compensation Using PWM-Based Data Cycling for AMLED Displays

This brief presents a leakage current compensation scheme by using a data cycling function to a pixel driver circuitry of the active-matrix light emitting diode (AMLED) displays. The proposed function cycles the stored dimming data to repeat pulse width modulation (PWM) multiple times at a given frame time. It compensates for a decay of the LED driving current due to leakage by repeatedly charging the target dimming data across a storage capacitor in the current driver. The proposed circuit has been fabricated using a 0.18- $\boldsymbol{\mu }\text{m}$ CMOS process. The test chip includes a $2\,\,\mathbf {\times }\,\,16$ pixel circuit array with a control system. The functional operation has been verified at a prototype using an $8\,\,\mathbf {\times }\,\,16$ LED array system.