TWI662528B - Display driving apparatus - Google Patents

Abstract

A display driving device, each channel of which includes a first temporary storage unit, a second temporary storage unit, a first level conversion unit, a second level conversion unit, a first digital analog conversion unit, a second digital analog conversion unit, An operational amplifier unit, a pre-charging capacitor, a first switch unit and a second switch unit. The first temporary storage unit, the second temporary storage unit, the first level conversion unit and the first digital analog conversion unit are connected in series to the second input terminal of the operational amplifier unit. The second level conversion unit, the second digital analog conversion unit, the second switch unit and the first switch unit are connected in series between the first temporary storage unit and the second temporary storage unit and the second input terminal of the operational amplifier unit. The pre-charging capacitor is coupled between the first switching unit, the second switching unit and the ground terminal.

Description

Display driving device

The present invention relates to a display, and more particularly to a display driving device applied to a display.

The traditional display driving integrated circuit has relatively few internal channels, so its internal routing is relatively simple. However, as shown in Figure 1, the number of channels commonly used in display drive integrated circuit 1 is increasing day by day, and its internal wiring has become more complicated and affected by the size of the integrated circuit and the shrinking of the manufacturing process. IR-drop) is getting bigger and bigger. In addition, when the data signal is switched, because the digital analog converter selected is different, the analog voltage signal output by the digital analog converter also causes short-term low-frequency transient interference (Glitch). As shown in FIG. 2, the voltage VAN decreases instantaneously at time T2.

Due to the above factors, it takes a long time for the input signal of the operational amplifier unit of each channel to be charged (or discharged) to the target voltage level. As shown in FIG. 2, the input signal SIN1 of the operational amplifier unit OPA of the first channel CH1 starts to rise from time T2. Due to its slow rising speed, the target voltage level VCH cannot be reached until time T3.

All of the above phenomena will have an adverse effect on the normal operation of the display driver integrated circuit and the display, and need to be overcome urgently.

In view of this, the present invention proposes a display driving device to effectively solve the aforementioned problems encountered in the prior art.

A specific embodiment of the invention is a display driving device. In this embodiment, the display driving device includes a plurality of channels. Each of the plurality of channels includes a first temporary storage unit, a second temporary storage unit, a first level conversion unit, a second level conversion unit, a first digital analog conversion unit, a second digital analog conversion unit, An operational amplifier unit, a pre-charging capacitor, a first switch unit and a second switch unit. The first temporary storage unit is used for receiving and temporarily storing input data signals. The second temporary storage unit is coupled to the output end of the first temporary storage unit, and is used for receiving and temporarily storing the input data signal from the first temporary storage unit. The first quasi-conversion unit is coupled to the output of the second temporary storage unit. The second level conversion unit is coupled to the output terminal of the first temporary storage unit. The first digital analog conversion unit is coupled to the output terminal of the first level conversion unit. The second digital analog conversion unit is coupled to the output terminal of the second level conversion unit. The operational amplifier unit has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the operational amplifier unit is coupled to the output terminal and the second input terminal is coupled to the output terminal of the first digital analog conversion unit. The pre-charging capacitor is coupled between the second input terminal and the ground terminal of the operational amplifier unit. The first switching unit is coupled between the second input terminal of the operational amplifier unit and the pre-charging capacitor. The second switching unit is coupled between the output terminal of the second digital analog conversion unit, the first switching unit and the pre-charging capacitor.

In an embodiment, when the first temporary storage unit outputs an input data signal according to the first control signal, the first switch unit is not turned on and the second switch unit is turned on. To precharge or discharge the precharge capacity to the first voltage; when the second temporary storage unit outputs the input data signal according to the second control signal, the first switch unit is turned on and the second switch unit is not turned on, causing The pre-charging capacitor having the first voltage charges or discharges the input signal received by the second input terminal of the operational amplifier unit through the turned-on first switching unit.

In an embodiment, the second digital analog conversion unit is coupled to the first voltage. When the first temporary storage unit outputs an input data signal according to the first control signal, the first voltage is used to charge the pre-charge capacity through the turned-on second switch unit. Pre-charge or pre-discharge.

In one embodiment, the first voltage is selected according to different input data signals.

In an embodiment, the first digital analog conversion unit is further coupled to the second voltage. When the second temporary storage unit outputs an input data signal according to the second control signal, in addition to the second input terminal of the operational amplifier unit with the second voltage In addition to charging or discharging the received input signal, there is a precharge capacity with a first voltage to charge or discharge the input signal received by the second input terminal of the operational amplifier unit through the turned on first switching unit, thereby shortening Charging or discharging time.

In an embodiment, the first switch unit and the second switch unit are controlled by the first switching signal and the second switching signal which are opposite to each other and operate.

In one embodiment, when the first switching unit is controlled by the first switching signal and turned on, the second switching unit is controlled by the second switching signal and is not turned on; when the first switching unit is controlled by the first switching signal and When not conducting, the second switch unit is controlled It is turned on at the second switching signal.

In an embodiment, when the first temporary storage unit outputs an input data signal according to the first control signal, the first control signal is at a first level and the second control signal and the first switching signal are at a second level. The voltage value of the pre-charge capacity is changed to a first voltage.

In an embodiment, when the second temporary storage unit outputs an input data signal according to the second control signal, the second control signal and the first switching signal are both at the first level and the first control signal is at the second level. The pre-charge capacity of the second voltage charges or discharges the input signal received by the second input terminal of the operational amplifier unit through the turned-on first switch unit.

Compared with the prior art, the display driving device of the present invention uses a dynamic switching control and a precharge (or discharge) mechanism to first charge (or discharge) the capacitor with a first voltage VSE for different data signals. When the digital analog converter is used, When the corresponding second voltage VAN is selected, the input voltage of the amplifier is quickly charged (or discharged) with the stored charge of the capacitor for a period of time, and then the conduction between the capacitor and the input terminal of the amplifier is cut off, thereby effectively shortening the charging. (Or discharge) time to be able to charge (or discharge) to the target voltage level within the existing time, and the pre-charged (or discharged) capacitor will also cut off the input to the amplifier immediately after the fast charge (or discharge) is completed. The terminals are conductive, so the pre-charged (or discharged) capacitor will not become an additional load.

The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the accompanying drawings.

1. 3‧‧‧ display driving device

CH1 ~ CHN‧‧‧First channel ~ Nth channel

DAT1 ~ DATN‧‧‧First input data signal ~ Nth input data signal

LA1‧‧‧The first temporary storage unit

LA2‧‧‧Second temporary storage unit

LS‧‧‧level conversion unit

LS1‧‧‧First Level Conversion Unit

LS2‧‧‧Second level conversion unit

DAC‧‧‧Digital Analog Conversion Unit

DAC1‧‧‧The first digital analog conversion unit

DAC2‧‧‧Second Digital Analog Conversion Unit

OPA‧‧‧ Operational Amplification Unit

-‧‧‧First input

+ ‧‧‧Second input

K‧‧‧ output

Cpc‧‧‧ pre-charged capacity

VCpc‧‧‧ pre-charge capacitor voltage

SW1‧‧‧The first switch unit

SW2‧‧‧Second Switch Unit

SCLK‧‧‧The first control signal

SLAT‧‧‧Second Control Signal

SIN1 ~ SINN‧‧‧First input signal ~ Nth input signal

VSE‧‧‧First Voltage

VAN‧‧‧second voltage

CTRL1‧‧‧The first switching signal

CTRL2‧‧‧Second switch signal

T1 ~ T3, T3’‧‧‧‧time

FIG. 1 is a schematic diagram illustrating a display driving device of the prior art.

FIG. 2 is a timing diagram of each signal corresponding to the first channel in FIG. 1.

FIG. 3 is a schematic diagram of a display driving device according to a specific embodiment of the present invention.

FIG. 4 is a timing diagram of each signal corresponding to the first channel in FIG. 3.

A specific embodiment of the invention is a display driving device. In this embodiment, the display driving device is applied to a display and includes a plurality of channels.

Please refer to FIG. 3, which is a schematic diagram illustrating a display driving device in this embodiment. As shown in FIG. 3, the display driving device 3 includes N channels CH1 to CHN, where N is a positive integer greater than 1. The N channels CH1 to CHN include a first channel CH1,... (N-1) th channel CH (N-1), and an Nth channel CHN.

Taking the first channel CH1 as an example, the first channel CH1 includes a first temporary storage unit LA1, a second temporary storage unit LA2, a first level conversion unit LS1, a second level conversion unit LS2, and a first digital analog conversion unit. DAC1, a second digital analog conversion unit DAC2, an operational amplifier unit OPA, a precharge capacity Cpc, a first switch unit SW1, and a second switch unit SW2.

The first temporary storage unit LA1 is used to receive and temporarily store the first input data signal DAT1. The second temporary storage unit LA2 is coupled to the output terminal of the first temporary storage unit LA1, and is used for The first input data signal DAT1 is received and temporarily stored from the first temporary storage unit LA1.

The first quasi conversion unit LS1 is coupled to the output terminal of the second temporary storage unit LA2. The second level conversion unit LS2 is coupled to the output terminal of the first temporary storage unit LA1. The first digital analog conversion unit DAC1 is coupled to the output terminal of the first level conversion unit LS1. The second digital analog conversion unit DAC2 is coupled to the output terminal of the second level conversion unit LS2. The first digital analog conversion unit DAC1 is coupled to the second voltage VAN, and the second digital analog conversion unit DAC2 is coupled to the first voltage VSE. In practical applications, the first voltage VSE and the second voltage VAN are multiple sets of analog voltages, but not limited thereto.

The operational amplifier unit OPA has a first input terminal +, a second input terminal-and an output terminal K. The second input terminal of the operational amplifier unit OPA-is coupled to the output terminal K and the first input terminal + is coupled to the first digital analog conversion. Output of the unit DAC1. The pre-charging capacitor Cpc is coupled between the first input terminal + of the operational amplifier unit OPA and the ground terminal.

The first switch unit SW1 is coupled between the first input terminal + of the operational amplifier unit OPA and the pre-charge capacity Cpc. The second switching unit SW2 is coupled between the output terminal of the second digital analog conversion unit DAC2, the first switching unit SW1 and the pre-charging capacity Cpc.

In one embodiment, when the first temporary storage unit LA1 outputs the first input data signal DAT1 according to the first control signal SCLK, the first switch unit SW1 is not turned on and the second switch unit SW2 is turned on, so that the precharge capacity Cpc Pre-charge (or pre-discharge) to a target voltage level (ie, the first voltage VSE). In fact, the first voltage VSE can pre-charge (or pre-discharge) the pre-charging capacity Cpc through the turned-on second switching unit SW2, and the first voltage VSE can be selected according to different input data signals.

When the second temporary storage unit LA2 outputs the first input data signal DAT1 according to the second control signal SLAT, the first switching unit SW1 is turned on and the second switching unit SW2 is not turned on, so that the precharge capacity Cpc with the first voltage VSE is turned on through The first switch unit SW1 charges (or discharges) the second input terminal + the first input signal SIN1 received by the operational amplifier unit OPA.

When the second temporary storage unit LA2 outputs the first input data signal DAT1 according to the second control signal SLAT, the second input terminal + received first input signal SIN1 of the operational amplifier unit OPA is charged in addition to the second voltage VAN ( In addition, there is a precharge capacitor Cpc having a first voltage VSE to charge (or discharge) the second input terminal + received first input signal SIN1 of the operational amplifier unit OPA through the first switch unit SW1 that is turned on. ) To shorten the charging time (or discharging time).

In practical applications, the first switching unit SW1 and the second switching unit SW2 are controlled by the first switching signal CTRL1 and the second switching signal CTRL2 which are opposite to each other and operate. For example, when the first switching unit SW1 is controlled by the first switching signal CTRL1 and turned on, the second switching unit SW2 is controlled by the second switching signal CTRL2 and is not turned on. When the first switching unit SW1 is controlled by the first switching signal CTRL1 and is not turned on, the second switching unit SW2 is controlled by the second switching signal CTRL2 and is turned on.

Please refer to FIG. 4. FIG. 4 is a timing diagram of signals corresponding to the first channel CH1 in FIG. 3. As shown in FIG. 4, when the first temporary storage unit LA1 outputs the first input data signal DAT1 according to the first control signal SCLK, that is, the time T1 in FIG. 4, the first control signal SCLK is at a high level and the second control The signal SLAT and the first switching signal CTRL1 are both at a low level, and the voltage VCpc of the pre-charge capacity Cpc will change To the target voltage level (ie, the first voltage VSE).

When the second temporary storage unit LA2 outputs the first input data signal DAT1 according to the second control signal SLAT, that is, the time T2 in FIG. 4, the second control signal SLAT and the first switching signal CTRL1 are both at a high level and the first control The signal SCLK is at a low level. At this time, the pre-charge capacity Cpc with the first voltage VSE charges the second input terminal + of the operational amplifier unit OPA + the first input signal SIN1 received through the first switch unit SW1 that is turned on (or Discharge).

It should be noted that the two first input signal SIN1 curves shown in FIG. 4, the solid line represents the first input signal SIN1 of the present invention, and the dashed line represents the first input signal SIN1 of the prior art as shown in FIG. 2. Input signal SIN1. Comparing the two first input signals SIN1, it can be known that the first input signal SIN1 of the prior art with a dashed line and the first input signal SIN1 of the present invention with a solid line both rise from time T2, but the first input signal of the present invention with a solid line The rise speed of SIN1 is significantly faster, and the target voltage level (that is, the second voltage VAN) has been reached at time T3 ', while the first input signal SIN1 of the dashed prior art does not reach the target voltage level until time T3 ( That is, the second voltage VAN). Therefore, the present invention can indeed effectively accelerate the charging (or discharging) speed and shorten the charging (or discharging) time.

Although the above embodiment is described by taking the first channel CH1 of the display driving device 3 as an example, the second channel CH2, ..., (N-1) channel CH (N-1), and the Nth channel of the display driving device 3 are actually described. The operation of the channel CHN is similar to that of the first channel CH1 and can be inferred from the first channel CH1, so it will not be repeated here.

Compared with the prior art, the display driving device of the present invention is The state switching control and precharge (or discharge) mechanism first charge (or discharge) the capacitor with the first voltage VSE for different data signals. When the digital analog converter selects the corresponding second voltage VAN, the capacitor The stored charge quickly charges (or discharges) the amplifier's input voltage for a period of time to cut off the conduction between the capacitor and the amplifier's input terminal, thereby effectively reducing the charging (or discharging) time and being able to charge within the existing time. (Or discharge) to the target voltage level, and the pre-charged (or discharged) capacitor is also cut off from the conduction with the amplifier's input terminal after the fast charge (or discharge) is completed, so the pre-charged (or discharged) The capacitor does not become an additional load.

From the detailed description of the above preferred embodiments, it is hoped that the features and spirit of the present invention can be described more clearly, and the scope of the present invention is not limited by the preferred embodiments disclosed above. On the contrary, the intention is to cover various changes and equivalent arrangements within the scope of the patents to be applied for in the present invention. With the above detailed description of the preferred embodiments, it is hoped that the features and spirit of the present invention can be more clearly described, and the scope of the present invention is not limited by the preferred embodiments disclosed above. On the contrary, the intention is to cover various changes and equivalent arrangements within the scope of the patents to be applied for in the present invention.

Claims (8)

A display driving device includes a plurality of channels. Each of the plurality of channels includes: a first temporary storage unit for receiving and temporarily storing an input data signal; and a second temporary storage unit coupled to the first storage unit. An output terminal of a temporary storage unit is used to receive and temporarily store the input data signal from the first temporary storage unit; a first level conversion unit is coupled to the output terminal of the second temporary storage unit; a second position A quasi conversion unit coupled to the output of the first temporary storage unit; a first digital analog conversion unit coupled to the output of the first level conversion unit; a second digital analog conversion unit coupled to the second An output terminal of the level conversion unit; an operational amplifier unit having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal of the operational amplifier unit is coupled to the output terminal and the second The input terminal is coupled to the output terminal of the first digital analog conversion unit; a pre-charging capacitor is coupled between the second input terminal of the operational amplifier unit and a ground terminal; a first switching unit is coupled to the The first part of the operational amplifier unit Input terminal and the pre-charge capacitance between; and a second switching unit coupled to the output terminal of the second digital-analog converting unit, the switching between the first unit and the pre-charging capacitor. The display driving device according to item 1 of the scope of patent application, wherein when the first temporary storage unit outputs the input data signal according to a first control signal, the first switch unit is not turned on and the second switch unit is turned on. Pre-charge or pre-discharge the pre-charge capacity to a first voltage; when the second temporary storage unit outputs the input data signal according to a second control signal, the first switch unit is turned on and the second switch unit Non-conducting, so that the pre-charging capacitor with the first voltage charges or discharges the input signal received by the second input terminal of the operational amplifier unit through the first switching unit that is conducting, the second digital analog conversion unit Coupled to the first voltage, when the first temporary storage unit outputs the input data signal according to the first control signal, the first voltage precharges or precharges the precharge capacity through the second switch unit that is turned on Discharge. The display driving device according to item 2 of the scope of patent application, wherein the first voltage is selected according to different input data signals. According to the display driving device described in item 2 of the patent application scope, wherein the first digital analog conversion unit is further coupled to a second voltage, and when the second temporary storage unit outputs the input data signal according to the second control signal, In addition to the second voltage charging or discharging the input signal received by the second input terminal of the operational amplifier unit, there is also the first switch unit with the precharge capacity having the first voltage being turned on. The input signal received by the second input terminal of the operational amplifier unit is charged or discharged, thereby shortening the charging or discharging time. The display driving device according to item 2 of the scope of patent application, wherein the first switch unit and the second switch unit are controlled by a first switching signal and a second switching signal which are opposite to each other. The display driving device according to item 5 of the scope of patent application, wherein when the first switching unit is controlled by the first switching signal and turned on, the second switching unit is controlled by the second switching signal and is not turned on; When the first switching unit is controlled by the first switching signal and is not turned on, the second switching unit is controlled by the second switching signal and is turned on. The display driving device according to item 5 of the scope of patent application, wherein when the first temporary storage unit outputs the input data signal according to the first control signal, the first control signal is at the first level and the second The control signal and the first switching signal are both at the second level, and the voltage value of the pre-charge capacity is changed to the first voltage. The display driving device according to item 7 of the scope of patent application, wherein when the second temporary storage unit outputs the input data signal according to the second control signal, the second control signal and the first switching signal are both in the first position. Level and the first control signal is at the second level, the pre-charging capacitor with the first voltage performs the input signal received by the second input terminal of the operational amplifier unit through the first switch unit that is turned on. Charge or discharge.