Driving scheme for emissive displays providing compensation for driving transistor variations

A method of compensating for deviations by a measured device current from a reference current in a display having a plurality of pixel circuits each including a storage device, a drive transistor, and a light emitting device, the method comprising:

• performing a first reset operation on an integration circuit, the reset operation restoring the integration circuit to a first known state;
• performing a first current integration operation at the integration circuit, the integration operation operative to integrate a first input current corresponding to a difference between a reference current and a measured first device current flowing through the drive transistor or the light emitting device of a selected one of the pixel circuits;
• storing a first voltage corresponding to the first current integration operation on a first storage capacitor;
• performing a second reset operation on the integration circuit, the reset operation restoring the integration circuit to a second known state;
• performing a second current integration operation at the integration circuit, the integration operation operative to integrate a second input current corresponding to the leakage current on a reference line;
• storing a second voltage corresponding to the second current integration operation on a second storage capacitor;
• generating an amplified output voltage corresponding to the difference between the first voltage and the second voltage using one or more amplifiers;
• and
• quantizing the amplified output voltage.

A method of compensating for deviations by a measured device current from a reference current in a display having a plurality of pixel circuits each including a storage device, a drive transistor, and a light emitting device, the method comprising:

• performing a first reset operation on an integration circuit, the reset operation restoring the integration circuit to a first known state;
• performing a first current integration operation at the integration circuit, the integration operation operative to integrate a first input current corresponding to a difference between a reference current and a measured first device current flowing through the drive transistor or the light emitting device of a selected one of the pixel circuits;
• storing a first voltage corresponding to the first current integration operation on a first storage capacitor;
• performing a second reset operation on the integration circuit, the reset operation restoring the integration circuit to a second known state;
• performing a second current integration operation at the integration circuit, the integration operation operative to integrate a second input current corresponding to the leakage current on a reference line;
• storing a second voltage corresponding to the second current integration operation on a second storage capacitor;
• and
• performing a multibit quantization operation based on the first stored voltage and the second stored voltage.

A system for compensating for deviations by a measured device current from a reference current in a display having a plurality of pixel circuits each including a storage device, a drive transistor, and a light emitting device, the system comprising:

• a readout system configured to:
• a) process a voltage corresponding to a difference between a reference current and a measured first device current flowing through the drive transistor or the light emitting device of a selected one of the pixel circuits and b) convert the voltage into a corresponding quantized output signal indicative of the difference between the reference current and the measured first device current;
• and
• a controller configured to adjust a programming value for the selected pixel circuit by an amount based on the quantized output signal such that the storage device of the selected pixel circuit is subsequently programmed with a current or voltage related to the adjusted programming value.