CN100397443C - Gamma adjusting method and device for multi-channel driver of display - Google Patents

Abstract

The invention relates to a GAMMA adjusting method and device of multi-channel driver applied to display, first converting m-bit input signal corresponding to GAMMA curve simulated by m-bit into n-bit input signal, then inputting the n-bit input signal and another n-bit input signal into a driving element, comparing the two signals by the driving element, outputting a PWM driving signal to a specific information channel; since the two sets of input signals of the driving device are n bits, the driver can select a low-bit n-bit digital driving device, so as to reduce the layout area and further reduce the manufacturing cost.

Description

Gamma adjustment method and device for multi-channel driver applied to display

technical field

The invention relates to a gamma (GAMMA) adjustment method and a device thereof applied to a multi-channel driver of a display, in particular to a gamma (GAMMA) adjustment method and a device thereof capable of effectively reducing the actual layout area of a driver.

Background technique

One of the multi-channel driving circuits currently used in digital displays is a GAMMA calibration method or circuit device. Since the displays have different channel numbers, the driving circuits have different layout areas.

Please refer to Fig. 5, which is an existing information channel driver 60 circuit, which includes:

Several m-bit digital comparators 61, each digital comparator 61 has two m-bit input terminals and a PWM output terminal, wherein the two m-bit input terminals are respectively connected to an m-bit register (D[m]);

An m-bit counter 62 is connected to the register (D[m]) of one input terminal of each digital comparator 61;

One look-up table 63 has built-in mapping information of n-bit to m-bit conversion, and its output terminal is respectively connected to the register (D[m]) of the other input terminal of each m-bit digital comparator 62; when the driver 60 After the n-bit input signal is input, the n-bit input signal is converted into the corresponding m-bit signal through the upper look-up table 63, and then output to the input terminals of each m-bit digital comparator 62 through the buffer (D[m]).

The driver 60 uses the main function of the digital comparator 61 to compare the output signal of the counter with the input signal of the driver, so as to output a driving signal to the corresponding information channel 51 of the display 50 . Since the m-digit number of the counting signal is greater than the n-digit number of the input signal, the digital comparator 61 needs to use a high-digit m-digit digital comparator to perform signal comparison. In this way, the n-bit input signal needs to be converted into an m-bit input signal through the upper look-up table 63 before it can be input to the digital comparator 61 for comparison with the m-bit input signal and output a driving signal smoothly.

Since the number of digital comparators 61 used by the driver 60 corresponds to the number of information channels of the display, and the two input ends of each digital comparator are respectively connected to a register (D[m]) for holding the input signal. It can be seen that, if the driver 60 is applied to a multi-information channel driver of a display, the number of digital comparators 61 and registers (D[m]) used will be multiplied. In addition, current display products have higher requirements for high resolution and pixels, so the number of driver components used in the control circuit of the entire display will naturally increase accordingly. In this way, the layout of the driver circuit will be complicated and the cost will be increased. In order to prevent the driving circuit from becoming an obstacle to the development of future displays, it is quite necessary and important to design driving circuits with small circuit layout and low cost in the development of future displays.

Contents of the invention

The main purpose of the present invention is to overcome the deficiencies and defects of the prior art, to provide a gamma (GAMMA) adjustment method applied to a multi-channel driver display, mainly through the adjustment of the GAMMA signal, so that more digits of m The 1-bit input signal can be converted into a low-digit n-bit signal (m>n), so that when the driver is applied to a display with multiple information channels, it can use digital drive components with fewer steps, thereby reducing the layout area of the overall display driver.

The main technical means used to achieve the above purpose is to apply the GAMMA adjustment method to a multi-information channel driver of a display, and the driver mainly includes a GAMMA correction unit for simulating a GAMMA curve and several PWM driving components. The GAMMA correction unit is used to convert the high-order m-bit counting signal output by the counter into a low-order n-bit counting signal, and then input it to an input terminal of the n-bit PWM driving element. Since the other input terminal of the n-bit driving element is input by an n-bit input signal, the PWM driving element will output a PWM driving signal to a specific information channel after comparing the input signal and the counting signal.

It can be seen from the above that the two sets of input signals of the PWM driving element are both n-bit, therefore, the driver can choose a low-digit n-bit PWM driving element, compared with the existing driver using more (m-bit) driving elements , can indeed reduce a lot of layout area, especially for displays with more information channels.

The next object of the present invention is to be applicable to digital displays such as planes and circles. Because the driver of the present invention uses low-level drive components, it can be applied to any display with multiple information channels, except that it will not take up a large layout area. It can also reduce the cost relatively.

Description of drawings

Fig. 1 is the circuit block diagram that the driver of the present invention is used to cooperate with a display with multiple information channels;

Fig. 2 is the flowchart of the GAMMA correction unit of the present invention;

Fig. 3 is the GAMMA curve diagram corresponding to the m-bit signal of the present invention-specific voltage range;

Fig. 4 is a partial graph of Fig. 3;

FIG. 5 is a circuit block diagram of a conventional driver for a display with multiple information channels.

Description of symbols in the figure

10 Display 11 Information channel

20 driver 21 drive element

22 m bit counter 23 GAMMA correction unit

50 Display 51 Information channel

60 driver 61 drive element

62 m-bit counter 63 look-up table

Detailed ways

The present invention is a gamma (GAMMA) adjustment method and device of a display, which can be applied to any driver with multiple information channel displays, and can reduce the area of the driving elements of each information channel (using a few-bit driving element), Avoid occupying an excessively large circuit layout area, thereby reducing the production cost.

First please refer to shown in Fig. 1, be the circuit schematic diagram that the present invention is applied to a display with multiple information channels, this circuit schematic diagram is made up of a display 10 and a channel driver 20 part circuits, and the information channel 11 of this display 10 Corresponding to the output terminals of the channel driver 20 respectively; wherein the channel driver 20 at least includes:

An m-bit counter 22 is used to count out m-bit output signals (m_Bits DI);

A GAMMA correction unit 23, set on the output end of the m-bit counter, is used to map the m-bit output signal (m_Bits DI) to a specific range of the GAMMA curve, and then output the n-bit signal corresponding to the fixed range (n_Bits DI), and then output the n-bit signal (n_BitsDI);

Several PWM driving elements 21, each PWM driving element 21 includes two input ends and an output end, wherein one input end is connected to the output end of the GAMMA correction unit 23 through a register (D[n]), and the other The input terminal also supplies the n-bit input signal (DI[n:1]) of the driver 20 through a buffer (D[n]), and then compares the two n-bit input signals to output a PWM driving signal to the display 10 The corresponding information channel 11; wherein the driving element 21 is an n-bit digital comparator.

The number of digits of the count signal output by the m-bit counter 22 is higher than that of the n-bit input signal (m>n). The above-mentioned GAMMA correction unit 23 provides a GAMMA analog curve with an m-bit converted to n-bit. When the m-bit counter 22 outputs an m-bit count signal, it will first convert an n-bit count signal through the GAMMA correction unit 23, and then compare it with the n-bit input signal (DI[n:1]) are input to the driving element 21 together, and the driving element 21 outputs a PWM driving signal to the corresponding information channel 11 after comparison.

Please refer to Fig. 2, Fig. 3 and shown in Fig. 4, it is the adjustment method flow process of aforementioned GAMMA correction unit 23, and it comprises:

The curve range 231 for judging the position of the input signal includes an approximate GAMMA curve (C1') of an m-bit input signal to an n-bit voltage range (V _min ~ V _max ), and the approximate GAMMA curve (C1') is represented by a number Line segments (L1, L2, L3) with different slopes and lengths are described, so it can be judged which line segment (L1, L2, L3) the m-bit input signal falls on, and the minimum voltage value corresponding to the line segment (n-bit Indicated offset value) output;

即可求对应该线段的n位的电压数值；One calculates the n-bit voltage value (G') 232 corresponding to the m-bit input signal, subtracts the m-bit signal from the minimum value (X _a-1 ) of the line segment corresponding to the m-bit input signal, and then divides it by the slope of the line segment

That is, the voltage value of n bits corresponding to the line segment can be calculated;

Adding the correction value 233, the relative voltage value (G') of the segment line corresponding to the m-bit signal was calculated in the previous step, so the offset value needs to be added for correction to obtain the actual voltage value corresponding to the m-bit signal, that is, The result of the second step is added to the offset value output by the first step, and after adjustment, the actual corresponding n-bit voltage value is obtained.

As can be seen from the foregoing, the GAMMA correction unit 23 stores an approximate GAMMA curve (C1'). The number of line segments of the approximate GAMMA curve (C1') depends on the fineness of the user's simulated GAMMA curve (C1). The voltage range corresponding to the curve (C1') is represented by an n-bit value, so when an m-bit counter inputs an m-bit signal, the corresponding n-bit signal can be calculated.

Please refer to shown in Fig. 4, for implementing the actual circuit block diagram of aforementioned method, make this GAMMA correction unit be made of a divider, the expression of this divider is:

$G^{\′}=\frac{\mathrm{CNT}-x_{a-1}}{\frac{x_a-x_{a-1}}{2^{\mathrm{no}}/(a+1)}};$ in:

G': Convert m-bit counting signal to n-bit signal;

CNT: m bit signal;

X _a : the maximum value of the line segment;

X _a-1 : the minimum value of the line segment; and

a+1: the number of line segments.

In addition, you can look up the table (Look Up Table) to store the value obtained from the above expression. If there is an m-bit count signal input, you can directly look up the table to convert an n-bit voltage signal.

Because the present invention converts the high-level input signal into a corresponding low-level signal through the GAMMA correction unit, and inputs the low-level input signal to the driving element together with the low-level input signal input by the driver, since both input terminals are low-level signals, the driving element is more capable than the existing driver. Using low-order digital comparators and registers, because each information channel is connected to a digital comparator, so as far as the overall circuit components of the driver are concerned, the area of the circuit layout can be reduced due to the use of low-order digital comparators, thereby reducing the driver. the cost of.

Claims (7)

1. A multi-channel driver applied to a display, characterized in that it comprises: An m-bit counter is used to output an m-bit counting signal; A GAMMA correction unit, connected to the m-bit counter, maps the m-bit count signal to a specific range of the GAMMA curve, so as to output the n-bit signal corresponding to the m-bit count signal; Several PWM driving elements, each PWM driving element includes two input ends and an output end, one of the input ends is connected to the output end of the GAMMA correction unit through an n-bit register, and the other input end is also passed through an n-bit register It is connected with the n-bit input signal, and compares the two n-bit input signals to output a PWM driving signal to the corresponding information channel of the display; where m>n. 2. The multi-channel driver applied to a display as claimed in claim 1, wherein the PWM driving element is an n-bit digital comparator. 3. The multi-channel driver applied to a display according to claim 1 or 2, wherein the GAMMA correction unit is a divider. 4. The multi-channel driver applied to a display according to claim 1 or 2, wherein the GAMMA correction unit is an upper look-up table. 5. A GAMMA adjustment method applied to a multi-channel driver of a display, characterized in that, comprising steps: Judging the curve range of the input signal location, including an approximate GAMMA curve of an m-bit input signal to the voltage range represented by n-bit, the approximate GAMMA curve is composed of several line segments with different slopes and lengths, so the m-bit input can be judged The signal falls on that line segment, and the minimum voltage value corresponding to the line segment is expressed in n bits and output; To calculate the voltage value represented by n bits corresponding to the m-bit input signal, subtract the minimum value (X _a-1 ) of the line segment corresponding to the m-bit input signal from the m-bit signal, and then divide it by the slope of the line segment to obtain the corresponding voltage value the voltage value of n bits of the line segment; and Add the correction value, the relative voltage value of the line segment corresponding to the m-bit signal is calculated in the previous step, so the actual voltage value corresponding to the m-bit signal needs to be added, that is, add the result of the second step to the first The voltage value output by the step is adjusted to be the actual corresponding n-bit voltage value. 6. the GAMMA adjustment method that is applied to the multi-channel driver of display as claimed in claim 5, wherein, this GAMMA correction unit is made of a divider, and the expression of this divider is: $G^{\′}=\frac{\mathrm{GNT}-x_{a-1}}{\frac{x_a-x_{a-1}}{2^{\mathrm{no}}/(a+1)}};$ in: G': Convert m-bit signal to n-bit signal; CNT: m bit signal; X _a : the maximum value of the line segment; X _a-1 : the minimum value of the line segment; and a+1: the number of line segments. 7. The GAMMA calibration method applied to the multi-channel driver of the display as claimed in claim 5, wherein, a look-up table can be used, and the look-up table stores the built-in mapping information of n bits to m bits for View the value of the look-up table according to the m-bit input signal, and convert the n-bit voltage signal.

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