CN111445843B - Display driving module and driving method - Google Patents
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3648—Control of matrices with row and column drivers using an active matrix
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Abstract
The invention relates to a display driving module and a driving method, wherein the display driving module comprises a pulse width control unit and a driver, the driver is electrically connected with the pulse width control unit to receive a pulse width control signal and a signal slope information and generates a driving signal according to the signal slope information, and the driver controls the signal rising rate of the driving signal in the on-time according to the signal slope information and controls the on-time of the driving signal according to the pulse width control signal and the signal slope information; when the driving signal does not reach the output target value in the on-time and the rising and falling curves are approximately linear, the total output of the driving signal in the working period is in direct proportion to the square of the on-time, and the resolution and the regulation range of the total output at low brightness are increased.
Description
Technical Field
The present invention relates to a driving module and a driving method, and more particularly, to a driving module of a display and a driving method thereof.
Background
In a conventional display, a Pulse Width Modulation (PWM) is generally used to control a brightness level for human eyes to recognize, and the human eyes cannot feel flicker of a light source when a brightness frequency of the light source is greater than a threshold value due to a visual persistence characteristic of the human eyes, so that the total output of the light source of the display is changed by modulating a percentage of an on-time in each duty cycle in a duty cycle greater than the threshold frequency to provide different brightness for human eyes to feel. The percentage of on-time is determined by dividing the duty cycle into a plurality of minimum on-time units by a digital on-control signal to produce a total on-time that is a specified percentage of the duty cycle, thereby providing on-time control of different levels. For example, according to a 4-bit on-control signal, the duty cycle can be divided into 16 minimum on-unit times, and a 16-level on-time control is provided. That is, under the condition of the same duty cycle, the more the number of bits of the on-control signal, the more the number of the minimum on-unit time of the duty cycle is, and the less the minimum on-unit time is, the more the number of the steps of on-time control can be performed in the duty cycle, so as to provide finer brightness control of the display. For example, assume that the on signal is a 4-bit signal, and when the on control signal is 0000, it represents the state with the on time percentage of 0%, and when the on control signal is 0001, it represents the state with the on time percentage of 6.25%, the adjustable amplitude is 6.25% each time. For example, assuming that the on signal is a 5-bit signal, when the on control signal is 00000, the on time percentage represents a state of 0%, and when the on control signal is 00001, the on time percentage represents a state of 3.125%, and the adjustable amplitude is 3.125% each time.
However, the human eye does not have a linear perception of brightness, and at high brightness, the human eye is less sensitive to brightness changes, and at low brightness, the human eye is able to distinguish between subtle brightness changes. Therefore, the degree of brightness of the display requires higher resolution brightness control at low luminance. When the number of bits of the on-control signal is larger, the unit pulse width of each amplitude adjustment is smaller, wherein the on-time corresponding to the minimum percentage of the on-time is shorter, which also means that the required frequency is larger, resulting in technical difficulties.
In addition to Pulse width Modulation, Pulse Amplitude Modulation (PAM) is another display control method. Compared with the pulse width modulation mechanism, the pulse height modulation mechanism adjusts the brightness seen by human eyes by controlling the percentage of the conduction time, and the pulse height modulation mechanism controls the intensity of the driving signal in the same conduction period, for example, adjusts the magnitude of the current value of the driving signal in the conduction time so as to control the total output quantity generated in each working period and adjust the brightness felt by human eyes. At high light and dark resolution, the pwm scheme requires very small control signal pulse height units to achieve control of each intensity level, which makes it difficult to achieve ideal control effect due to different signal rise and fall times required by different pulse heights.
In addition, referring to the taiwan patent publication of TWI430710B, another display control method combines the pulse width and pulse height modulation mechanisms, i.e. the pulse width or signal strength can be controlled to adjust the total output in an active period. For example, assume that when the minimum on-time unit is 1 duty cycle and the pulse height is 1 output unit, the total output is 1 output unit. Then a total output of 0.01 output units can be achieved when the minimum on-time unit is 0.1 duty cycle and the minimum pulse height unit is 0.1 output units. Under the same assumption, the PWM modulation scheme should adjust the pulse width to 0.01 duty cycle, or the PAM modulation scheme should adjust the pulse height to 0.01 output unit, so as to achieve 0.01 total output. Therefore, the combination of the pulse width and pulse height modulation mechanism can increase the resolution of the brightness change without increasing the minimum unit of the pulse width or pulse height. However, the non-idealities of the driving circuit lead to difficulties in implementation, such as the time required for switching different output currents, and in the switching time, the output value is different from the ideal value; for example, because the rise time and fall time of signals with different target pulse heights are different, the increase/decrease width and the target pulse height are not necessarily in a linear proportional relationship, so that the total output quantity of the pulse width increased by 2 times is different from the total output quantity of the pulse height increased by 2 times, and the modulation result is not consistent with the target value of the total output quantity. In summary, the conventional monitor control module needs to be further improved.
Disclosure of Invention
In view of the difficulty of achieving ideal high-resolution brightness change control in the case of low brightness of the conventional display control module, the present invention provides a display driving module, which comprises a pulse width control unit and a driver, wherein the driver is electrically connected to the pulse width control unit to receive the pulse width control signal, receive signal slope information, and generate a driving signal according to the pulse width control signal and the signal slope information. Further, the driver controls a signal rising rate of the driving signal in an on-time according to the signal slope information, and controls the on-time of the driving signal according to a pulse width control signal and the signal slope information.
The signal slope information may be a digital control signal, a voltage signal or a current signal.
The present invention further provides a display driving method, comprising the following steps:
receiving a pulse width information and generating a pulse width control signal;
receiving a signal slope information;
generating a driving signal according to the pulse width control signal and the signal slope information, controlling the signal rising rate of the driving signal in a turn-on time according to the signal slope information, and controlling the turn-on time of the driving signal according to the pulse width control signal and the signal slope information.
The signal slope information may be a digital control signal, or may be a reference voltage signal or a reference current signal. In some embodiments, the falling rate of the driving signal can be controlled according to the signal slope information, but the effect of the present invention can be achieved no matter whether the falling rate of the driving signal is controlled or not.
The display driving module controls the on-time of the driving signal and the signal rising rate and the signal falling rate in the on-time respectively, and the generated driving signal output waveform is usually a non-linear curve, and here for convenience of explanation, it is simplified that the signal intensity of the driving signal rises at a constant rate and falls at a constant rate in the on-time, and when the rising of the driving signal in the on-time does not reach a stable target value, the driving signal starts to fall, and the driving signal forms a triangular waveform in each working period. Further, the bottom of the triangular waveform signal is the on-time, and when the on-time is a fixed value, the height of the triangular waveform is proportional to the rising rate and the rising time of the signal; when the signal rising rate and the signal falling rate are fixed values respectively, the 'high' of the triangular waveform signal is in direct proportion to the conduction time, namely when the conduction time is modulated, the triangular waveform is changed by an equal ratio triangular waveform; according to a triangular area formula: the "area is equal to bottom and is high/2", and when the signal rising rate and the signal falling rate are fixed values, the total output of the driving signal in each working period is proportional to the square of the on-time, and when the on-time is fixed values, the total output of the driving signal in each working period is proportional to the signal rising rate and the signal falling rate.
For example, assuming that the signal rising rate and the signal falling rate are respectively a fixed value, when the on-time is 1 time unit, the total output of the driving signal in the duty cycle is 1 output unit. Then when the on-time is reduced from 0.2 time units to 0.1 time units, the total output is reduced from 0.04 output units to 0.01 output units.
In contrast to the conventional PWM scheme, the total output is only proportional to the on-time. For example, also assuming that the on-time is 1 time unit and the total output of the driving signal in the duty cycle is 1 output unit, when the pulse width control signal decreases the on-time from 0.2 time unit to 0.1 time unit, the total output is only decreased from 0.2 output unit to 0.1 output unit. As can be seen from the above description, the display driving module of the present invention generates a modulation amount of 0.03 output unit under the condition that the on-time of the driving signal is reduced from 0.2 time unit to 0.1 time unit, and compared with the pulse width modulation mechanism which can only reach the modulation amount of 0.1 output unit, the modulation resolution is increased, i.e. the minimum adjustable unit.
That is, under the condition that the unit of the regulation pulse width is also 0.1 work period, the display driving module of the invention increases the regulation range of the total output quantity at the low brightness. When the signal rising rate and the signal falling rate are further modulated at the same time, a higher modulation resolution is further achieved.
The present invention generates a triangular waveform by controlling the driving signal to decrease before the driving signal reaches an output target value in the conducting time, so as to achieve a finer modulation resolution than the general PWM, i.e. the minimum adjustable unit; the control signal rising rate and falling rate can control the total output quantity, and can also control the total output quantity to enter the nonlinear variation interval when the signal rising time is less than the quantity.
Although the actual driving signal output waveform is usually a non-linear curve, it still has the characteristics similar to the simplified triangle.
Therefore, compared with the prior art, the invention has the characteristics that: the rising and falling speed of the output waveform is adjustable, so that the condition that the output driving signal does not rise to the original target value in time becomes controllable, and a smaller controllable unit is generated by utilizing the characteristic.
In addition, the display driving module of the invention enables the driving signal to rise or fall in each working period in a controlled manner and not to switch between conduction and non-conduction instantly in a binary manner, thereby avoiding the problem of uncontrollable conduction or closing delay.
Drawings
FIG. 1 is a block diagram of a display driving module according to the present invention.
Fig. 2A and 2B are schematic diagrams of driving signal waveforms of the display driving module according to the present invention.
FIG. 3 is a schematic diagram of driving signal waveforms of the display driving module according to the present invention.
FIG. 4 is a graph of total output versus on-time of the display driver module according to the present invention.
FIG. 5A is a schematic diagram of driving signal waveforms of the display driving module according to the present invention.
FIG. 5B is a schematic diagram of a pulse width control signal waveform of the display driving module according to the present invention.
FIG. 6A is a schematic diagram of driving signal waveforms of the display driving module according to the present invention.
FIG. 6B is a schematic diagram of a pulse width control signal waveform of the display driving module according to the present invention.
FIG. 7 is a block diagram of a display driving module according to a first preferred embodiment of the present invention.
FIG. 8 is a circuit diagram of a display driving module according to a second preferred embodiment of the present invention.
FIG. 9 is a flow chart of a display driving method according to the present invention.
FIG. 10 is a flowchart illustrating a display driving method according to a first preferred embodiment of the present invention.
FIG. 11 is a flowchart illustrating a display driving method according to a second preferred embodiment of the present invention.
Description of the main component symbols:
11 pulse width control unit
12 driver
121 output unit
122 control unit
Detailed Description
The technical means adopted by the invention to achieve the predetermined object of the invention are further described below with reference to the drawings and the preferred embodiments of the invention.
Referring to fig. 1, the present invention provides a display driving module, which includes a pulse width control unit 11 and a driver 12, wherein the driver 12 is electrically connected to the pulse width control unit 11, the pulse width control unit 11 receives a pulse width signal and generates a pulse width control signal according to the pulse width signal, the driver 12 receives the pulse width control signal and receives a signal slope information, and the driver 12 generates a driving signal according to the pulse width control signal and the signal slope information.
The driver 12 controls the on-time of the driving signal according to the pulse width control signal and the signal slope information, and controls the signal rising rate of the driving signal in the on-time according to the signal slope information.
The pulse width information and the signal slope information are generated by a display processing module, for example, and the display processing module generates corresponding pulse width information and signal slope information after operation according to display brightness information. The driver 12 is electrically connected to a Display unit, such as a Light-emitting Diode (LED), an Organic Light-emitting Diode (OLED), or a Liquid Crystal Display (LCD), and the driving signal is used to drive the Display unit, and may be a voltage signal or a current signal according to the specification requirement of the Display unit to be controlled. When the voltage value or the current value of the driving signal is higher, the instant brightness of the display unit is higher; when the voltage value or the current value of the driving signal in the working period is larger than the time integral value, the total output quantity of the driving signal in the working period is larger.
In the preferred embodiment, it is assumed that the rising rate of the driving signal in each duty cycle is equal to the falling rate of the driving signal, and the rising and falling of the driving signal are simple linear for the convenience of description. The invention is not limited in this regard.
Referring to fig. 2A and 2B, fig. 2A and 2B are schematic waveforms of the driving signal. In this embodiment, the driving signal forms a triangular waveform when the driving signal rises and falls at a constant rate according to the signal slope information during the on-time and the signal rises and falls before reaching an output target value. Since the total output of the driving signal in the duty cycle is proportional to the integral of the signal value of the driving signal in the duty cycle, i.e. proportional to the area of the signal waveform of the driving signal in the duty cycle. As shown in FIG. 2A, when the driving signal is in a first duty cycle T1In a second duty cycle T2The signal rising rate and the signal falling rate in the second working period T are equal2On-time t in2Is less than the first working period T1On-time t in1The second duty cycle T2Is less than the first duty cycle T1The total output quantity of (1); as shown in fig. 2B, when the driving signal is in the first duty cycle T1In the second working period T2On-time t in (1)1Is equal in the second working period T2The signal rising rate and the signal falling rate s in2、-s2Greater than during the first duty cycle T1The signal rising rate and the signal falling rate s in1、-s1The second duty cycle T2Is greater than the first duty cycle T1Total output of (2).
More specifically, referring to fig. 3, the total output a of the driving signals is expressed as follows:
A＝t*H/2
H＝t/2*s
A＝st2/4
where A is the total output of the driving signal (i.e., the area of the triangle), t is the on-time (i.e., the bottom of the triangle), H is the highest output intensity achieved (i.e., the height of the triangle), and s is the rise and fall rate (i.e., the slope).
Therefore, pleaseContinuing to refer to FIG. 2A, during the first duty cycle T1The on-time in (1) is t ═ t1The signal rising rate and the signal falling rate of the driving signal in the working period are s-s respectively1And s ═ s1The driving signal is in the first duty cycle T1The total output of the signal in (1) is st according to the above formula2/4＝s1t1 2/4. That is, the total output of the driving signal in a duty cycle is proportional to the square of the on-time thereof, and proportional to the rising rate and falling rate of the driving signal. For example, when the pulse width control signal decreases the on-time of the driving signal to 0.5 times, the total output of the driving signal is decreased to 0.25 times, compared to the conventional pulse width modulation scheme or pulse height modulation scheme, which decreases the total output to 0.5 times when the pulse width or pulse height is decreased to 0.5 times. Whether the falling rate of the driving signal is controlled or not or whether the driving signal is symmetrical to the rising rate or not can make the waveform of the driving signal resemble a triangular wave, so the effect of the invention can be achieved.
In short, the total output in the duty cycle is proportional to the square of the on-time and proportional to the rising and falling rates of the signal, and the modulation of the two factors can obtain the multiplied total output modulation result, so that the minimum controllable unit of the on-time or the signal value is not required to be increased, and the display driving module of the invention can achieve the multi-level total output modulation result compared with a pulse width modulation mechanism and a pulse height modulation mechanism. In addition, the display driving module of the invention enables the driving signal to be controlled to rise or fall in each working period and not to be switched between conduction and non-conduction instantly, and compared with a modulation method combining a pulse width and pulse height modulation mechanism, the display driving module is easy to generate different voltage or current target values, and the switching time between conduction and non-conduction is different, so that modulation errors are caused, and an ideal modulation result closer to the modulation target value is achieved.
For example, assume that the driving signal has a signal rising rate s-s1The signal falling rate is s-s1When the on-time is 1 time unit, the driving signalThe number output just reaches the output target value, and the total output quantity in the working period is 1 output unit. That is, when the on-time is less than 1 time unit, the driving signal forms the triangular waveform. According to the above-mentioned calculation method of the total output, when the rising and falling rates of the driving signal are not changed, and the driving signal takes 0.1 time unit as a modulation unit in a working period, the total output generated by different on-times is as shown in table 1 below, and please refer to fig. 4, in which fig. 4 is an output curve graph of the driving signal of the present embodiment, the horizontal axis is on-time, and the vertical axis is total output. As can be seen from table 1 and fig. 4, the minimum total output of the driver 12 of the present invention is 0.01 output unit under the condition that the minimum unit of the on-time is 0.1, and the output curve of the gamma curve (gamma curve) close to the ideal output curve of the driving signal of the display is reached, i.e. an exponential output curve, so that the display can achieve better resolution at low total output, i.e. low brightness.
On the other hand, when the on-time is greater than 1 time unit, the driving signal reaches the output target value and maintains the output target value during the on-time, thereby forming a trapezoidal waveform. Under the condition, the amplification of the total output quantity of the driving signal and the modulation amplification of the conduction time form a direct proportion relation.
TABLE 1
Further, as shown in FIG. 2B, when the slope of the driving signal is further changed, the total output of more steps can be obtained. For example, when the on-time is 0.1 time unit, the rising and falling slopes of the driving signal are s2＝2s1、s2＝3s1、s2＝4s1、…、s2＝10s1The total output of the driving signals is 0.02, 0.03, 0.04, …, 0.10 output unit respectively; when turned on, is 0.2 time unit, and the rising and falling slopes of the driving signal are s2＝2s1、s2＝3s1、s2＝4s1、…、s2＝10s1The total output of the driving signals is 0.08, 0.12, 0.16, …, 0.40 output units, and so on. As can be seen from the above description, this achieves more multi-level total output modulation compared to the PWM scheme or the pulse-height modulation scheme, and more flexible and higher resolution output control of the driving signal at low brightness, i.e., low output.
In summary, the display driving module of the present invention controls a turn-on time and a signal rising rate of the driving signal, so as to increase the resolution of the output driving signal at low luminance without increasing the resolution of the control signal, i.e. without changing the minimum unit pulse width or the minimum unit pulse height. Furthermore, the display control module of the invention avoids the delay error of switching between conduction and non-conduction or avoids the problem that the switching speed is different at different pulse heights so as to cause the failure of accurate control compared with a pulse height modulation mechanism by accurately controlling the signal rising rate of the signal.
Referring to fig. 5A and 5B, fig. 5A is a waveform diagram of the driving signal, and fig. 5B is a waveform diagram of the pulse width control signal. In a preferred embodiment, the driving signal has a signal rising interval tr and a signal falling interval tf in each duty cycle, and the driver 12 controls the starting time of the signal rising interval tr and the signal falling interval tf according to the pulse width control signal, and controls the signal rising rate of the driving signal in the signal rising interval tr and the signal falling rate in the signal falling interval tf according to the signal slope information.
As shown in fig. 5B, the pwm signal is a pwm signal, and the driver 12 controls the on-time of the driving signal in each duty cycle according to the pwm signal. For example, as shown in fig. 5A, in an operating cycle, the driver 12 makes the driving signal enter the signal rising interval tr when the pulse width control signal switches to a high level signal, and makes the driving signal enter the signal falling interval tf when the pulse width control signal switches to a low level signal.
In practice, there is usually a time delay (t) from the switching of the pulse width control signal to the start of the rising or falling of the driving signalplh/tphl). For convenience of explanation, the time delay is omitted in this example, and the circuit characteristics are well known to those skilled in the art, and do not affect the implementation of the present invention, and therefore, for convenience of explanation, they are not described in detail herein. The invention is not limited in this regard.
Further, please refer to fig. 6A and 6B, wherein fig. 6A is a waveform diagram of the driving signal, and fig. 6B is a waveform diagram of the pulse width control signal. In the second working period T2When the pulse width control signal makes the driving signal rise to the output target value H1, the driving signal is stably maintained at the output target value H1 until the pulse width control signal switches to low level and makes the driving signal enter the signal falling interval tf. Thus, the driving signal forms the trapezoidal waveform. That is, when the pulse width control signal has a high-level pulse width time longer than the signal rising interval tr required for the driving signal to reach the output target value, the driving signal forms the trapezoidal waveform, and the total output in the duty cycle is proportional to the high-level time of the pulse width control signal.
Further, the signal slope information may be a digital control signal, a voltage signal or a current signal. When the driver 12 receives the signal slope information, the driver 12 sets the signal rising rate and the signal falling rate of the driving signal in the signal rising interval and the signal falling interval according to the signal slope information. A preferred embodiment of the driver 12 is further described below. Referring to fig. 7, in a first preferred embodiment of the present invention, the driver 12 includes an output unit 121 and a control unit 122. The output unit 121 has an input end, an output end and a control end, and the output end of the output unit 121 is used for outputting the driving signal. The control unit 122 is electrically connected to the pulse width control unit 11 for receiving the pulse width control signal, and is electrically connected to the input terminal of the output unit 121 for providing an input voltage or current to the input terminal of the output unit 121, generating a conduction control signal according to the pulse width control signal and the signal slope information, and outputting the conduction control signal to the control terminal of the output unit 121 for controlling the conduction degree of the output unit 121.
That is, the on control signal of the control unit 122 controls the on degree of the output unit 121 to control the output current of the output unit 121.
Preferably, the output unit 121 is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) having a source, a gate and a drain, wherein the source is the input terminal, the gate is the control terminal, and the drain is the output terminal. When the signal value of the conduction control signal received by the control end of the output unit 121 is low, the conduction degree of the output unit 121 is low and the equivalent resistance value is large, and the output end of the output unit 121 outputs a low current; when the signal value of the on control signal received by the control terminal of the output unit 121 increases, the on degree of the output unit 121 increases and the equivalent resistance value decreases, and the output terminal current of the output unit 121 increases. In short, the output current of the output unit 121 is positively correlated to the signal value of the on-control signal.
Preferably, the control unit 122 controls the rising time and the falling time of the conducting control signal according to the pulse width control signal of the pulse width control unit 11, for example, when the pulse width control signal is switched to a high-level signal, the conducting control signal starts to rise, and when the pulse width control signal is switched to a low-level signal, the conducting control signal starts to fall, and the signal rising rate and the signal falling rate of the conducting control signal are determined according to the signal slope information, so as to achieve the purpose of controlling the output current of the output unit 121, that is, the signal value of the driving signal.
Referring to fig. 8, in a second preferred embodiment of the present invention, the control unit 122 includes an operational amplifier 1221 and a current regulating unit 1222, the operational amplifier 1221 has an on-off control terminal EN, a slope information input terminal S, a positive input terminal P, a negative input terminal N, and a conduction control signal output terminal OP, the on-off control terminal is electrically connected to the pulse width control unit for receiving the pulse width control signal, the slope information input terminal is for receiving the signal slope information, the positive input terminal is for receiving a set voltage Vd, the negative input terminal is electrically connected to the input terminal of the output unit 121, and the conduction control signal output terminal is electrically connected to the control terminal of the output unit 121 for outputting the conduction control signal.
The current regulating unit 1222 is preferably a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) having a source, a gate and a drain, the drain is electrically connected to the input terminal of the output unit 121, and the gate is for receiving a reference voltage Vg.
The negative input terminal of the operational amplifier 1221 is electrically connected to the input terminal of the output unit 121 and receives the input voltage, and outputs the turn-on control signal to the control terminal of the output unit 121 to control the turn-on degree of the output control unit 121, so that the operational amplifier 1221 and the output unit 121 form a negative feedback, when the negative feedback reaches a steady state, that is, when the input voltage received by the negative input terminal N is similar to the set voltage Vd of the positive input terminal P, the gate voltage and the source voltage of the output unit 121 are both stable, and thus the driving signal output by the output terminal of the output unit 121 is the stable output target value current. That is, the output target current value is set by inputting the setting voltage Vd and the reference voltage Vg.
Further, the operational amplifier 1221 adjusts its output stage according to the signal slope information to regulate the rising and falling rates of the on-state control signal, so as to achieve the purpose of controlling the rising and falling rates of the driving signal output by the output unit 121.
In an embodiment of the present invention, by inputting a fixed signal slope information, the reference voltage Vg and the setting voltage Vd, the signal rising rate, the signal falling rate and the output target value of the driving signal output by the output unit 121 can be determined, i.e. how long the driving signal reaches the output target value after entering the signal rising interval. Therefore, as long as the pulse width control signal is modulated by inputting the pulse width control information, when the time of the pulse width control signal at the high level signal is shorter than the time required by the driving signal to reach the output target value, the waveform of the driving signal is a triangular waveform, and the effect of high resolution at the time of low output quantity is achieved; when the time of the pulse width control signal at the high level signal is higher than the time required by the driving signal to reach the output target value, the waveform of the driving signal is a trapezoidal waveform, and the normal output modulation resolution is reached at the time of high output.
Referring to fig. 9, the present invention further provides a display driving method executed by a display driving module, including the following steps:
receiving a pulse width information, generating a pulse width control signal, and receiving a signal slope information (S901);
a driving signal is generated according to the pulse width control signal and the signal slope information (S902), and the rising rate of the driving signal in the on-time is controlled according to the signal slope information, and the on-time of the driving signal is controlled according to the pulse width control signal and the signal slope information.
The display driving method of the present invention controls the conducting time of the driving signal in each working period and the signal rising rate in the conducting time according to a pulse width control signal and signal slope information, so that a driving signal of an approximate triangular waveform pulse is generated in each working period. When the on-time is modulated according to the pulse width control signal, the pulse height of the triangular pulse is also changed along with the on-time, and the pulse height is in direct proportion to the on-time, that is, when the signal slope information is not changed and the on-time is modulated, the total output quantity in the working period is in direct proportion to the square of the on-time, therefore, the resolution of the driving signal is better at low total output quantity or low on-time, and the display control requirement that the brightness change of human eyes is sensitive at low brightness is met. When the signal rising rate and the signal falling rate of the driving signal are further regulated according to the signal slope information, more flexible and more level driving signal control output quantity can be obtained.
Referring to fig. 10, in a first preferred embodiment of the display driving method according to the present invention, the step of generating a driving signal according to the pulse width control signal and the signal slope information (S902) further comprises the following steps:
controlling a signal rising rate of the driving signal in a signal rising interval of the on-time and a signal falling rate of the driving signal in a signal falling interval of the on-time according to the signal slope information (S1001).
Controlling the start time of the signal rising interval and the signal falling interval of the driving signal in the on-time according to the pulse width control signal (S1002).
For example, preferably, the signal slope information may be a binary code of a digital bit, when the signal slope information is received, the signal rising rate and the signal falling rate of the driving signal in the signal rising interval and the signal falling interval are set according to the signal slope information, and further in a working period, when the pulse width control signal is switched to a high level signal, the display driving module makes the driving signal in the signal rising interval, and when the pulse width control signal is switched to a low level signal, the driving signal enters the signal falling interval,
referring to fig. 11, in a second preferred embodiment of the display driving method according to the present invention, the display driving method further includes the following steps:
setting an output target value (S1101);
controlling the driving signal to enter the signal rising interval according to the pulse width control signal (S1102);
when the driving signal rises to the output target value at the signal rising rate in the signal rising interval (S1103), maintaining the driving signal at the output target value (S1104);
the driving signal is controlled to enter the signal falling interval according to the pulse width control signal (S1105).
That is, the signal value of the driving signal rises according to the signal rising rate in the signal rising interval and falls according to the signal falling rate in the signal falling interval. When the time of the signal rising interval is less than the time of the driving signal rising to the output target value, the driving signal enters the signal falling interval according to the pulse width control signal, and then the waveform of the driving signal forms the triangular waveform, thereby achieving the effect of high resolution at low output. On the other hand, when the time of the signal rising interval is longer than the time of the driving signal rising to the output target value, the driving signal is maintained at the output target value after rising to the output target value, and falls according to the signal falling rate after entering the signal falling interval according to the pulse width control signal, the waveform of the driving signal forms the trapezoidal waveform, and the modulation amount is proportional to the total on-time, that is, the normal output modulation resolution is achieved at the time of high output.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A display driving module, comprising:
a pulse width control unit for receiving a pulse width information and generating a pulse width control signal;
a driver electrically connected to the pulse width control unit for receiving the pulse width control signal and receiving a signal slope information; the driver generates a driving signal according to the pulse width control signal and the signal slope information; wherein,
the driver controls the signal rising rate of the driving signal in a conducting time according to the signal slope information;
the driver controls the conducting time of the driving signal according to the pulse width control signal and the signal slope information;
the driving signal comprises a signal rising interval and a signal falling interval in the conducting time;
the driver confirms an output target value according to a set current or voltage;
the length of the signal rising interval is less than the time required for the driving signal to rise to the output target value at the rising rate, and the driving signal does not reach the output target value.
2. The display driving module according to claim 1,
the driver controls the start time of the signal rising interval and the signal falling interval according to the pulse width control signal.
3. The display driving module according to claim 1,
the driver controls the signal rising rate of the driving signal in the signal rising interval according to the signal slope information.
4. The display driver module of claim 1, wherein the driver comprises:
an output unit having an input terminal, an output terminal and a control terminal;
a control unit electrically connected with the pulse width control unit to receive the pulse width control signal and electrically connected with the input end of the output unit; wherein,
the control unit provides an input voltage or current to the input end of the output unit, and the control unit generates a conduction control signal according to the pulse width control signal and the signal slope information and outputs the conduction control signal to the control end of the output unit so as to control the conduction degree of the output unit.
5. The display driving module according to claim 4,
the output unit is a metal oxide semiconductor field effect transistor having a source, a gate and a drain, wherein the source is the input terminal, the gate is the control terminal, and the drain is the output terminal.
6. A method for driving a display, comprising the steps of:
receiving a pulse width information and generating a pulse width control signal;
receiving a signal slope information;
generating a driving signal according to the pulse width control signal and the signal slope information, and controlling the signal rising rate of the driving signal in a conducting time according to the signal slope information, and controlling the conducting time of the driving signal according to the pulse width control signal and the signal slope information, wherein the driving signal comprises a signal rising interval and a signal falling interval in the conducting time;
setting an output target value;
modulating the pulse width control signal or the signal slope information to make the length of the signal rising interval smaller than the time required for the driving signal to rise to the output target value at the rising rate, and the driving signal does not reach the output target value.
7. The display driving method according to claim 6, comprising the steps of:
controlling the signal rising rate of the driving signal in the signal rising interval of the on-time according to the signal slope information.
8. The display driving method according to claim 7, comprising the steps of:
controlling the start time of the signal rising interval and the signal falling interval of the driving signal in the conducting time according to the pulse width control signal.
9. The method for driving a display according to claim 8, further comprising the steps of:
setting an output target value;
controlling the driving signal to enter the signal rising interval according to the pulse width control signal;
when the driving signal rises to reach the output target value at the signal rising rate in the signal rising interval, maintaining the driving signal at the output target value;
controlling the driving signal to enter the signal falling interval according to the pulse width control signal.
10. The display driving method according to claim 6 or 7,
the signal slope information is a binary code, or a voltage signal or a current signal.
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| CN114783353A (en) * | 2021-01-22 | 2022-07-22 | 中国科学院微电子研究所 | Mu LED unit light-emitting circuit, light-emitting control method thereof and display device |
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