CN-119889240-B - Pixel compensation circuit, compensation method and display based on floating gate

CN119889240BCN 119889240 BCN119889240 BCN 119889240BCN-119889240-B

Abstract

The application discloses a pixel compensation circuit based on a floating gate, which comprises an input circuit, a driving transistor and a threshold reading circuit which are sequentially connected, wherein the input circuit is used for outputting a V in signal, the driving transistor is a floating gate transistor, a grid electrode of the driving transistor is connected to the input circuit through a Scan transistor, a substrate of the driving transistor is connected with VB voltage, and the threshold reading circuit is connected with a source electrode and a drain electrode of the driving transistor through a Sense transistor and is used for outputting V out to measure threshold voltage. The scheme utilizes the characteristics of the stability of the threshold value and the adjustable threshold value of the floating gate transistor, so that the floating gate transistor can be used in a pixel external compensation circuit to obtain stable current more easily and has better compensation effect.

Inventors

ZHANG YUTING
KAI YUAN
HE KE
YANG YA
ZHOU YUAN
KANG JIAHAO

Assignees

山西北大碳基薄膜电子研究院
北京大学

Dates

Publication Date: 20260512
Application Date: 20250307

Claims (3)

1. The pixel compensation circuit based on the floating gate is characterized by comprising an input circuit, a driving transistor and a threshold reading circuit which are connected in sequence, wherein: the input circuit is used for outputting The signal, the drive transistor is a floating gate transistor, the grid of the drive transistor is connected to the input circuit through a Scan transistor, and the substrate of the drive transistor is connected The threshold reading circuit is connected with the source and drain of the driving transistor through a Sense transistor and is used for outputting Measuring threshold voltage, wherein the Scan transistor and the Sense transistor are MOS transistors, and the source and drain of the drive transistor are respectively connected An anode of the OLED light emitting diode; the input circuit is an integrated operational amplifier circuit and inputs And Subtraction is performed to generate A signal of the input circuit The signal output end is connected with Signal, 0V signal, Signals and methods A signal for adjusting the driving timing of the pixel compensation circuit to output The signal is used as the gate voltage of the driving transistor; The threshold reading circuit is an integrated operational amplifier circuit, and the Sense transistor passes through the capacitor Charging the threshold reading circuit to integrate and output The following formula is satisfied: Wherein, the In order to drive the current on the transistor, Time is; The threshold voltage is calculated according to the following formula : Wherein, the Is the current on the drive transistor; Is the mobility of the charge carriers and, Is the capacitance of the gate oxide layer per unit area, And The width and length of the channel respectively, Is the source-drain voltage of the drive transistor, Is the gate-source voltage of the drive transistor by measuring To measure threshold voltage ; The specific working method of the pixel compensation circuit is as follows: Step 1, a scan transistor is turned on, writing V ref to V in , writing VDD to VD, floating a floating gate substrate potential, turning on a Sense transistor, obtaining current I ds of a drive transistor, starting a threshold reading circuit to work, starting charging after resetting a capacitor C int , and obtaining V out containing threshold information after charging is completed; Step 2, a Scan transistor is turned on, a Sense transistor is turned off, V in is written with 0V voltage, the substrate potential VB of a driving transistor is set to 20V, VD is set to float, and threshold erasure of a floating gate transistor is completed; Writing VD and VB into a 0V signal, performing programming operation on a driving transistor, writing V in into a V prgm voltage, applying the signal to the grid electrode of the driving transistor, and regulating the threshold voltage by controlling the charge on a floating gate; Step 4, writing VDD to VD by taking V data as the input of V in , and setting the substrate potential VB of the driving transistor to be floating for writing data information; and 5, when the Vanode point potential is larger than the starting voltage of the OLED, the OLED starts to emit light, and the floating gate transistor provides driving current for the OLED.
2. The floating gate based pixel compensation circuit of claim 1 wherein the capacitance An erase switch is connected in parallel and is used for resetting the capacitor 。
3. A display employing the floating gate based pixel compensation circuit of claim 1 or 2.

Description

Pixel compensation circuit, compensation method and display based on floating gate Technical Field The application belongs to the field of display devices, and particularly relates to a floating gate-based pixel compensation circuit, a floating gate-based pixel compensation method and a display. Background The pixel internal compensation circuit is a key part in an AMOLED (active matrix organic light emitting diode) display screen and is mainly used for compensating parameter fluctuation of a driving transistor and an OLED device caused by manufacturing process, aging or environmental change, so that uniformity and stability of display brightness are ensured. The conventional in-pixel compensation circuit includes a driving transistor (T1) for controlling brightness of the pixel, a switching transistor (T2) for gating the pixel, a storage capacitor (Cst) for maintaining a gate voltage of the driving transistor, and a compensation circuit generally including additional transistors and capacitors for compensating for variations in threshold voltage and mobility. However, the conventional in-pixel compensation circuit requires reset, threshold acquisition, and data writing compensation every frame, and the threshold voltage of the conventional MOS transistor is shifted with time and stress, so that the compensation effect becomes poor or even fails after the compensation circuit exceeds a certain threshold voltage range. Therefore, a pixel compensation circuit is needed that can solve the above-described problems. Disclosure of Invention In order to solve the defects in the prior art, the application provides a floating gate-based pixel compensation circuit, a floating gate-based pixel compensation method and a display, and the floating gate transistor is used in a pixel external compensation circuit to obtain stable current and better compensation effect by utilizing the characteristic that the threshold stability and the threshold value of the floating gate transistor can be adjusted. The technical effects to be achieved by the application are realized by the following scheme: According to a first aspect of the present application, there is provided a floating gate based pixel compensation circuit comprising an input circuit, a drive transistor and a threshold reading circuit connected in sequence, wherein: the input circuit is used for outputting The signal, the drive transistor is a floating gate transistor, the grid of the drive transistor is connected to the input circuit through a Scan transistor, and the substrate of the drive transistor is connectedThe threshold reading circuit is connected with the source and drain of the driving transistor through a Sense transistor and is used for outputtingA measurement of the threshold voltage is performed. Preferably, the Scan transistor and the Sense transistor are both MOS transistors. Preferably, the source and drain electrodes of the driving transistor are respectively connected withAnd an anode of the OLED light emitting diode. Preferably, the input circuit is an integrated operational amplifier circuit, and inputsAndAfter subtraction, outputThe signal serves as the gate voltage of the drive transistor. Preferably, the input circuitThe signal output end is connected withSignal, 0V signal,Signals and methodsAnd a signal for adjusting the driving timing of the pixel compensation circuit. Preferably, the threshold reading circuit is an integrated operational amplifier circuit, and the Sense transistor passes through a capacitorCharging the threshold reading circuit to integrate and outputThe following formula is satisfied: Wherein, the The current on the Sense transistor, t is time. Preferably, the threshold voltage is calculated according to the formula: Wherein, the Is the current on the Sense transistor; Is the mobility of the charge carriers and, Is the capacitance of the gate oxide layer per unit area,AndThe width and length of the channel respectively,Is the source-drain voltage of the Sense transistor,Is the gate-source voltage of the Sense transistor. Preferably, the capacitorAn erase switch is connected in parallel and is used for resetting the capacitor。 According to a second aspect of the present application, there is provided a pixel compensation method using the above floating gate-based pixel compensation circuit, comprising the steps of: Step 1 Scan transistor is turned on, write To the point ofWrite(s)To the point ofThe Floating gate substrate potential is flowing, the Sense transistor is turned on, and current from the drive transistor is obtained. The threshold reading circuit starts to work and resets the capacitorThen charging is started, and after charging is completed, threshold information is obtained; Step 2: scan transistor on, sense transistor off,Writing 0V voltage, driving substrate potential of transistorThe set-up voltage was set to 20V,Setting the floating to finish the threshold value erasure of the floating gate transistor; St