TW201640955A - Control device capable and method capable of improving panel dimming performance - Google Patents

Abstract

This invention relates to a control device and method capable of improving panel dimming performance comprising a dimming controller, a booster circuit, a comparing circuit and a light-emitting array module. A signal output end of the dimming controller is coupled to the booster circuit and the comparing circuit respectively. The booster circuit is further coupled, respectively, to the signal input and output ends of the comparing circuit and the light-emitting array module. The dimming controller drives, through the booster circuit, the light-emitting array module to emit light. When the comparing circuit executes an optimized comparing mechanism according to a reference signal and an output voltage of the booster circuit, the output voltage generated by the booster circuit is adjusted to become a stable turn-on voltage, and noises generated byr unstable voltages are eliminated to achieve the purpose of improving the working performance of the control device.

Description

Control device and method capable of improving panel dimming performance

The invention relates to a control device, in particular to a control device and method for improving the dimming performance of a panel.

A commercially available thin film transistor liquid crystal display (TFT-LCD) is commonly used in televisions, flat panel displays, and projectors, and the display generally has a dimming control device for adjusting brightness. The dimming control device adjusts the brightness of the panel through various dimming control technologies, such as a pulse width modulation (PWM) mode or a phase shift mode, and adjusts the panel according to switching conditions of the switch ON/OFF. brightness.

Please refer to FIG. 4 , which is a known dimming control device, which includes a dimming controller 91 , a driving circuit and an LED array module 92 . The driving circuit includes a current source controller 93 and a voltage. The converter 94 is connected to the current source controller 93. The input end and the output end of the LED array module 92 are respectively connected to the voltage converter 94 and the current source controller 93 to form a converter. An LED current source is fed back; wherein the PWM operation signal is received by the dimming controller 91, and the voltage converter 94 generates an output voltage to control the LED array module 92 to emit light, as shown in FIG. a horizontal axis representing time, a vertical axis representing a voltage value, and a waveform S of the output voltage, when a duty ratio obtained by dividing the operating time t of the output voltage by the cycle time T is low, The switching time of the voltage converter 94 is also relatively small. Especially when the output voltage is between switching and non-switching, the AC ripple of the output voltage is too large, so the output voltage is In a regulated battery Problems occur abnormal noise (acoustic noise) or when a charging inductor.

The output voltage of the voltage converter 94 is fed back by a voltage division and the output voltage is increased. Although the problem of abnormal sound can be reduced, the above solution causes the dimming control device to generate a low dimming duty ratio. (low dimming duty), the voltage converter 94 is boosted to generate an excessively high voltage, and the problem of inefficiency is indeed generated. Therefore, the PWM operation signal received by the dimming control device in the prior art. When the duty ratio is low, the output voltage and the input current have large ripples and abnormal noise, and it is necessary to propose a better solution.

In view of the above-mentioned deficiencies of the prior art, the main object of the present invention is to provide a control device and method for improving the dimming performance of a panel, which can detect an electrical state of a lighting module and design an adaptive power conversion architecture. To provide sufficient output voltage for the operation of the light-emitting module, and to maintain a stable and energy-saving output voltage to eliminate the noise generated by voltage instability and improve work efficiency.

The technical means adopted to achieve the above object is to control the dimming performance of the panel by a dimming controller connected to a boosting circuit and a comparing circuit, and the boosting circuit is connected to the comparing circuit. The method includes the following steps: receiving, by the dimming controller, a PWM working signal, and providing an output voltage by the boosting circuit; when the PWM working signal meets a predetermined condition, and the comparing circuit obtains a reference signal, The comparison circuit performs an optimized comparison mechanism according to the reference signal and the output voltage; and outputs a turn-on voltage having stability to adjust the brightness of an illumination array module.

Through the above method, when the dimming controller receives the PWM working signal, and the output voltage is provided by the boosting circuit, when determining whether the PWM working signal meets the preset condition, the preset condition is associated with a PWM The air ratio is related, especially when the PWM duty cycle is low, the noise is generated due to the voltage instability. Therefore, when the preset condition is that the PWM duty ratio is lower than a preset threshold, the comparison circuit detects The comparison circuit performs the optimized comparison mechanism according to the reference signal and the output voltage, and outputs the turn-on voltage having stability to the light-emitting array module to eliminate voltage instability. The noise is achieved for the purpose of improving work efficiency.

Another technical means for achieving the above object is that the control device for improving the dimming performance of the panel includes: a dimming controller having at least one signal input terminal and a plurality of signal output terminals, the dimming controller The signal input terminal is configured to receive a PWM operation signal; a booster circuit includes a boost converter connected to the dimming controller; and an illumination array module is coupled to the boost circuit a comparator circuit, comprising: a voltage selector and a voltage comparator, wherein the voltage selector is respectively connected to the dimming controller, the boost converter of the boost circuit, and the voltage comparator, a voltage comparator is connected to the boost converter; wherein the PWM operation signal is received by the dimming controller, and an output voltage is supplied from the boost converter of the boost circuit to the light emitting array module. The PWM working signal received by the dimming controller meets a predetermined condition, and the voltage selector of the comparing circuit obtains a reference signal, and then the voltage comparator of the comparing circuit is based on the reference signal Output voltage, performing a comparison of the best mechanism for adjusting the output voltage having a stable threshold voltage, and the turn-on voltage is output to the light emitting array module to adjust its brightness.

According to the above configuration, the control device for improving the dimming performance of the panel is mainly connected to the boosting circuit and the comparing circuit by the dimming controller, and the boosting circuit is respectively connected to the comparing circuit and the light emitting array module. The dimming controller continuously receives the PWM working signal, and the boost converter of the boosting circuit provides an output voltage to the light emitting array module to drive the light emitting array module to emit light, when the dimming control The PWM working signal received by the device conforms to a preset condition, and the preset condition is related to a PWM duty ratio, especially when the PWM duty ratio is low, noise is generated due to voltage instability, so when The preset condition is that when the PWM duty ratio is lower than a preset threshold, the voltage selector of the comparison circuit detects a reference signal, and then the voltage comparator of the comparison circuit is based on the reference signal and the output. Voltage, the comparison mechanism for performing the optimization adjusts the output voltage to a stable turn-on voltage, thereby adjusting the brightness of the light-emitting array module and eliminating the noise generated when the voltage is unstable, thereby achieving an increase Operation control means of the object of the invention is performance.

A preferred embodiment of the control device for improving the dimming performance of the panel of the present invention, as shown in FIG. 1 , includes a dimming controller 10 , a boosting circuit 20 , a comparing circuit 30 , and a light emitting array module . The dimming controller 10 is connected to the boosting circuit 20 and the comparing circuit 30. The boosting circuit 20 is further connected to the comparing circuit 30 and the light emitting array module 40, respectively, by the dimming control. The device 10 continuously receives a PWM operation signal, and the boost circuit 20 provides an output voltage Vo to the light emitting array module 40 to drive the light emitting array module 40 to emit light.

The dimming controller 10 has at least one signal input end and a plurality of signal output ends, and receives the PWM working signal through the signal input end of the dimming controller 10; the boosting circuit 20 is mainly controlled by a current source. The controller 21 is composed of a boost converter 22 and a voltage protection circuit 23, and the current source controller 21 is connected to the dimming controller 10 and the boost converter 22, respectively. The voltage protection circuit 23 is connected; the comparison circuit 30 is mainly composed of a voltage selector 31 and a voltage comparator 32, and the voltage selector 31 is respectively connected to the dimming controller 10 and the boosting circuit 20 for boost conversion. The voltage converter 32 is connected to the voltage comparator 32, and the voltage comparator 32 is connected to the voltage protection circuit 23 and the boost converter 22 of the booster circuit 20, respectively.

The above-mentioned light-emitting array module 40 is respectively connected to the boost converter 22 of the booster circuit 20, the voltage protection circuit 23 of the booster circuit 20, and the current source controller 21, and when the dimming controller 10 continues The PWM operation signal is received, and the output voltage Vo is supplied from the boost converter 22 to the light emitting array module 40. If the PWM working signal received by the dimming controller 10 meets a predetermined condition, in the embodiment, the preset condition is a PWM duty cycle (eg, a percentage), especially in the received PWM duty. When the ratio is low, noise will be generated due to voltage instability. Therefore, when the preset condition is that the PWM duty ratio is lower than a preset threshold (unit can be a percentage), the voltage of the comparison circuit 30 The selector 31 detects a reference voltage REF outputted by the boost converter 22, and converts the reference voltage REF into a reference signal, and the voltage comparator 32 of the comparison circuit 30 according to the reference signal The output voltage Vo is subjected to an optimized comparison mechanism to adjust the output voltage Vo to a stable turn-on voltage, and output the turn-on voltage to the light-emitting array module 40 to adjust its brightness.

For the specific application mode of the preferred embodiment of the present invention, please refer to FIG. 2, wherein the current source controller 21 of the booster circuit 20 has a plurality of current sources, and the light-emitting array module 40 has multiple groups. The light-emitting unit string 41 is composed of a plurality of LEDs connected in series. One input end of the light-emitting unit string 41 is connected to the output voltage Vo, and the other input end of the light-emitting unit string 41 is connected. This current source is connected. When the boost converter 22 is operated in the boost mode, the plurality of sets of the light-emitting unit strings 41 and the plurality of current sources are configured to be feedback, and the lowest voltage signals in the light-emitting unit strings 41 are selected for comparison. The output voltage Vo of the boost converter 22 is allowed to reach the turn-on voltage required by the light emitting array module 40.

In addition, in order to be able to adapt to various applications, it is necessary to adjust various brightness through the dimming controller 10. The dimming controller 10 can be used to set the LED current of the LED array 40 and the PWM duty cycle (such as PWM). The duty cycle is generated by the boost converter 22 to generate a sufficient output voltage Vo to meet the current setting required by the light emitting array module 40. Further, the voltage protection circuit 23 of the boosting circuit 20 has a Over Voltage Protection (OVP) mechanism, the main purpose is to protect circuit components from being damaged by excessive voltage. If the PWM duty cycle of LED turn-on is in a low duty cycle, the boost converter 22 will cause the input current and the chopping of the output voltage Vo to become large due to the short opening time and long closing time, and cause abnormal noise, but the boosting mechanism can be made by the overvoltage protection mechanism of the voltage protection circuit 23. The converter 22 generates an output voltage Vo to prevent the input current and the output voltage Vo from becoming larger, and although the generated output voltage Vo is significantly different from the voltage required to turn on the LED, In the preferred embodiment of the present invention, the voltage selector 31 of the comparison circuit 30 is first detected by the voltage selector 31 of the comparison circuit 30 before the boost circuit 20 switches to the overvoltage protection mechanism. Optimizing the reference voltage, and converting the reference voltage REF into a reference signal, comparing the output voltage Vo with the reference signal when the PWM duty cycle is low, and outputting a voltage that is stable and sufficient to turn on the LED due to At this time, the booster circuit 20 stably generates the periodic switching operation without the unstable switch described above, so that the abnormal sound can be eliminated and the efficiency can be improved.

A specific control method and description of the preferred embodiment of the present invention described above can be summarized as a control method for improving the dimming performance of the panel, mainly by the aforementioned dimming controller 10, the boosting circuit 20 and the comparing circuit 30. Connected, the booster circuit 20 is further coupled to the comparison circuit 30. As shown in FIG. 3, the method includes the following steps: receiving a PWM operation signal from the dimming controller 10, and providing an output from the boost circuit 20. Voltage (S31); when the PWM operation signal meets a predetermined condition, and the comparison circuit 30 obtains a reference signal by detecting, the comparison circuit 30 performs an optimized comparison according to the reference signal and the output voltage. Mechanism (S32); in this embodiment, the comparison mechanism further obtains an output voltage output by the booster circuit 20 and an overvoltage protection (OVP) voltage of the voltage protection circuit 23, and the output voltage is (such as 15V) and the overvoltage protection voltage (such as 10V) is divided into M equal parts, and according to the current open LED voltage is greater than N minus 1 equal division and less than N equal parts, then adjust the output voltage to apply Further adjusting the output voltage of the N aliquots; output voltage according to the adjusted threshold voltage having a stability, to adjust the brightness of the light emitting array module 40 (S33).

In summary, the present invention is mainly directed to a switching mode from a plurality of sets of light-emitting unit strings 41 to a stable over-voltage protection mechanism and an optimization when a low dimming duty is performed. After the comparison mechanism, the voltage is locked slightly higher than the normal light-emitting unit string 41, so that the problem of excessive AC ripple of the output voltage can be solved, and in addition to solving the abnormal sound problem, the power consumption can be reduced, and the efficiency can be improved. purpose.

10‧‧‧ dimming controller
20‧‧‧Boost circuit
21‧‧‧ Current source controller
22‧‧‧Boost Converter
23‧‧‧Voltage protection circuit
30‧‧‧Comparative circuit
31‧‧‧Voltage selector
32‧‧‧Voltage comparator
40‧‧‧Lighting array module
41‧‧‧Lighting unit string
91‧‧‧ dimming controller
92‧‧‧LED array module
93‧‧‧current source controller
94‧‧‧Voltage Converter

1 is a block diagram of an architecture of a preferred embodiment of the present invention. 2 is a circuit diagram of a preferred embodiment of the present invention. 3 is a flow chart of a control method in accordance with a preferred embodiment of the present invention. Figure 4 is a known dimming control device. Fig. 5 is a waveform diagram of a known dimming control device outputting an AC chopping wave.

10‧‧‧ dimming controller

20‧‧‧Boost circuit

21‧‧‧ Current source controller

22‧‧‧Boost Converter

23‧‧‧Voltage protection circuit

30‧‧‧Comparative circuit

31‧‧‧Voltage selector

32‧‧‧Voltage comparator

40‧‧‧Lighting array module

Claims (10)

A control method for improving panel dimming performance is mainly connected to a booster circuit and a comparison circuit by a dimming controller, and the booster circuit is further connected to the comparison circuit, the method comprising the following steps: The controller receives a PWM operation signal, and the boost circuit provides an output voltage; when the PWM operation signal meets a predetermined condition, and the comparison circuit obtains a reference signal, and the comparison circuit determines the reference signal according to the reference signal The output voltage is subjected to an optimized comparison mechanism; the boost circuit outputs a turn-on voltage having stability according to the result of the optimized comparison mechanism to adjust the brightness of an illuminating array module. The control method for improving the dimming performance of the panel according to claim 1, wherein the preset condition is that the duty ratio of the PWM working signal is lower than a preset threshold; the comparison mechanism is obtained by the boosting circuit. The output voltage and an overvoltage protection voltage are divided into M equal parts between the output voltage and the overvoltage protection voltage, and the output is greater than N minus 1 equal division and less than N equal division according to the current opening voltage, and then the output is The voltage is adjusted to another output voltage suitable for N aliquots. A control device capable of improving panel dimming performance, comprising: a dimming controller having at least one signal input end and a plurality of signal output ends, wherein the signal input end of the dimming controller is configured to receive a PWM operation a booster circuit comprising a boost converter coupled to the dimming controller; an illumination array module coupled to the boost converter of the boost circuit; a comparison circuit including a a voltage selector and a voltage comparator connected to the dimming controller, the boost converter of the boost circuit, and the voltage comparator, wherein the voltage comparator is connected to the boost converter The PWM operation signal is received by the dimming controller, and an output voltage is supplied to the illumination array module by the boost converter of the boost circuit, and the PWM operation signal received by the dimming controller is met. a predetermined condition, and the voltage selector of the comparison circuit obtains a reference signal, and the voltage comparator of the comparison circuit performs an optimized comparison mechanism according to the reference signal and the output voltage. The output voltage is adjusted to having a stable threshold voltage, and the turn-on voltage is output to the light emitting array module to adjust its brightness. The control device for improving the dimming performance of the panel according to claim 3, the boosting circuit further comprising a current source controller, wherein the current source controller is respectively connected to the dimming controller and the boost converter; The light emitting array module is further connected to the current source controller. The control device for improving the dimming performance of the panel according to claim 3, the boosting circuit further comprising a voltage protection circuit connected to the boost converter of the boost circuit; the voltage of the comparison circuit The comparator is further connected to the voltage protection circuit of the booster circuit; the light emitting array module is connected to the voltage protection circuit of the booster circuit. The control device for improving the dimming performance of the panel according to claim 4, the boosting circuit further comprising a voltage protection circuit connected to the boost converter of the boosting circuit; the voltage of the comparing circuit The comparator is further connected to the voltage protection circuit of the booster circuit; the light emitting array module is connected to the voltage protection circuit of the booster circuit. The control device for improving the dimming performance of the panel according to claim 4 or 6, wherein the current source controller of the boosting circuit has a plurality of current sources, and the light emitting array module has a plurality of groups of light emitting cells. An input end of the string of light emitting cells is coupled to the output voltage, and an output of the string of light emitting cells is coupled to the current source. The control device for improving the dimming performance of the panel according to claim 7, wherein the light emitting unit string is composed of a plurality of LEDs connected in series. The control device for improving the dimming performance of the panel according to any one of claims 3 to 6, wherein the illuminating array module has a plurality of groups of illuminating unit strings, and the input end of the illuminating unit string is connected to the output voltage. The output end of the light emitting unit string is connected to the boost converter of the booster circuit. The control device for improving the dimming performance of the panel according to claim 9, wherein the light emitting unit string is composed of a plurality of LEDs connected in series.