Patent ID: 7808497

Claim:
An AMOLED driving circuit controlling one light-emitting device in one pixel and connecting to a scan line providing scanning voltage, a data line providing an image data signal, a controllable voltage terminal, a constant low voltage source providing a constant low voltage and the light-emitting device, the AMOLED driving circuit comprising: a storage capacitor having two ends; a first switching transistor having a source terminal connected to the data line, a drain terminal connected to one end of the storage capacitor, and a gate terminal connected to the scan line; a driving transistor having a drain terminal connected to the controllable voltage terminal, a source terminal connected to the other end of the storage capacitor, and the a gate terminal connected to the drain terminal of the first switching transistor; a second switching transistor having a drain terminal directly connected to the controllable voltage terminal, a source terminal connected to the source terminal of the driving transistor, and a gate terminal connected to the scan line; and a controllable voltage source producing a pulse width modulation signal with high and low voltage levels in a frame time of the scanning voltage, wherein a modulating cycle of the pulse width modulation signal is corresponding to a time of one frame; wherein an anode of the light-emitting device is connected to the source terminal of the driving transistor, and a cathode of the light-emitting device is connected to the constant low voltage source.