Driving circuit of AMOLED and method for driving the AMOLED

• US 9,343,012 B2
• Filed: 01/23/2014
• Issued: 05/17/2016
• Est. Priority Date: 12/31/2013
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Original Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Inventors: Wen, Yi-chien, Chu, Li-wei
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): McLoone, Peter D
• Application Number:
  US14/241,080
• Publication Number:
  US 20150187255A1
• Time in Patent Office: 845 Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2320/0266 Reduction of sub-frame artefacts
• CPC Class Codes: G09G 3/2025 the sub-frames having all the same time duration
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A driving circuit of an active matrix/organic light emitting diode (AMOLED) includes a first semiconductor controllable switch, a second semiconductor controllable switch, an energy-storage capacitor, an organic light emitting diode, and a sequential control unit that divides a driving time of one frame of the organic light emitting diode into driving times of N subframes. An output end of the second semiconductor controllable switch is coupled to an anode of the organic light emitting diode, a source electrode of the first semiconductor controllable switch receives a data driving signal of the AMOLED, a gate electrode of the first semiconductor controllable switch receives a scan driving signal of the AMOLED, a drain electrode of the AMOLED is connected with a gate electrode of the second semiconductor controllable switch, and the energy-storage capacitor is connected in series between a source electrode and the gate electrode of the second semiconductor controllable switch. The data driving signal is divided into an active signal that drives display of the organic light emitting diode and a blanking signal that turns off display of the organic light emitting diode in the driving time of each of the subframes.

Claims

1. A driving circuit of an active matrix/organic light emitting diode (AMOLED) display, comprising:

a first semiconductor controllable switch;

a second semiconductor controllable switch;

an energy-storage capacitor;

an organic light emitting diode;

a sequential control unit that divides a driving time of one frame of the organic light emitting diode into driving times of N subframes; and

an over-voltage driving unit that increases current of the organic light emitting diode when the organic light emitting diode displays;

the over-voltage driving unit comprises a data driving unit that provides the data driving signal and a gamma correction unit coupled to the data driving unit;

wherein an output end of the second semiconductor controllable switch is coupled to an anode of the organic light emitting diode, a source electrode of the first semiconductor controllable switch receives a data driving signal of the AMOLED, a gate electrode of the first semiconductor controllable switch receives a scan driving signal of the organic light emitting diode, a drain electrode of the first semiconductor controllable switch is connected with a gate electrode of the second semiconductor controllable switch, and the energy-storage capacitor is connected in series between a source electrode and the gate electrode of the second semiconductor controllable switch;

wherein the data driving signal is divided into an active signal that chives display of the organic light emitting diode, and a blanking signal that turns off display of the organic light emitting diode in tire driving time of each of the subframes;

wherein N is a natural number and is greater than or equal to 2;

in a time of outputting any one or more blanking signals, the over-voltage driving unit increases current of the organic light emitting diode through increasing a voltage of an output end of the second semiconductor controllable switch, reducing a voltage of the cathode of the organic light emitting diode, and increasing an output voltage of the gamma correction unit.

2. The driving circuit of the organic light emitting diode display of claim 1, further comprising a third semiconductor controllable switch, the third semiconductor controllable switch is connected in series with the gate electrode of the second semiconductor controllable switch, and a low level signal is input to the third semiconductor controllable switch.

3. The driving circuit of the organic light emitting diode display of claim 1, wherein the over-voltage driving unit comprises a first multiplexer, a second multiplexer, and a third multiplexer;

an input end of the first multiplexer receives X reference voltages that are different, an output end of the first multiplexer is coupled to an input end of the second semiconductor controllable switch, and the sequential control unit is coupled to a control end of the first multiplexer;

in the driving time from a first subframe to a (N−

X)th subframe, a time of outputting the active signal of the driving time of each of the subframes successively increases;

from the driving time of a (N−

X+1)th subframe on, the first multiplexer outputs one reference voltage in the time of outputting the blanking signal of the driving time of each of the subframes, and the reference voltage successively increases;

the time of outputting the active signal of the driving time of the each of the subframes is equal to the time of outputting the active signal of the driving time of a (N−

X)th subframe;

wherein an input end of the second multiplexer receives Y reference voltages that are different, an output end of the second multiplexer is coupled to a cathode of the organic light emitting diode, and the sequential control unit is coupled to a control end of the second multiplexer;

from the driving time of a (N−

Y)th subframe on, the second multiplexer outputs one reference voltage in the time of outputting the blanking signal of the driving time of each of the subframes, and the reference voltage successively reduces;

wherein an input end of the third multiplexer receives Z reference voltages that are different, an output end of the third multiplexer is coupled to the gamma correction unit, and the sequential control unit is coupled to a control end of the third multiplexer;

from the driving time of a (N−

Z)th subframe on, the third multiplexer outputs one reference voltage in the time of outputting the blanking signal of the driving time of each of the subframes, and the reference voltage successively increases;

wherein X, Y, and Z are natural numbers, and are less than N.