LED Display Driving Circuit Eliminates Cross-Channel Coupling

The patent applies preliminary action by pre-charging the parasitic capacitances during a reset period before the active display period. The reset period is arranged before each line scan, during which current sources are enabled to charge the parasitic capacitances of LEDs that will be in the dark state during the upcoming active period. This preliminary charging action ensures that when the active period begins, the parasitic capacitances are already charged, preventing coupling currents from affecting the brightness of dark pixels, thereby eliminating cross-channel coupling without requiring continuous charging operations that would increase power consumption.

The patent implements periodic action by structuring the operation into distinct periodic phases: a reset period followed by an active display period. During the reset period, current sources are enabled to charge parasitic capacitances; during the active display period, these capacitances remain charged and are not actively discharged. This periodic charging pattern, synchronized with the line scan timing, maintains brightness consistency while minimizing energy loss by avoiding continuous or repeated charging-discharging cycles.

The patent resolves this contradiction by performing preliminary charging of parasitic capacitances during the reset period before the active display period begins. This preliminary action ensures that when current sources are sequentially enabled during the active period (with bright pixel current sources enabled before dark pixel current sources), the already-charged parasitic capacitances cannot accept additional charging current, thereby preventing coupling currents from flowing and eliminating brightness errors in dark pixels while maintaining the required line scan operation speed.