CN106211495A - Control device and method capable of improving panel dimming efficiency - Google Patents

Abstract

The invention relates to a control device and method that can improve panel dimming performance, which includes a dimming controller, a boost circuit, a comparison circuit and a light-emitting array module; wherein, the signal output end of the dimming controller The boost circuit is connected to the signal input and output terminals of the comparison circuit and the light-emitting array module respectively, and is driven by the dimming controller through the boost circuit. The light-emitting array module emits light. When the comparison circuit executes an optimized comparison mechanism based on a reference signal and an output voltage of the boost circuit, the output voltage generated by the boost circuit is adjusted to be stable. The starting voltage is increased, and the noise generated when the voltage is unstable is eliminated, thereby improving the working efficiency of the control device.

Description

Control device and method capable of improving panel dimming performance

technical field

The present invention relates to a control device, in particular to a control device and method capable of improving panel dimming efficiency.

Background technique

The general thin film transistor liquid crystal display (TFT-LCD) on the market is often used in TVs, flat panel displays and projectors. The above-mentioned displays usually have a dimming control device for adjusting brightness. The dimming The control device adjusts the brightness of the panel through various dimming control technologies, such as: pulse width modulation (PWM) mode or phase shift (phase shift) mode, which adjusts the brightness of the panel according to the switching condition of the switch ON/OFF.

Please refer to Fig. 4, it is a known dimming control device, which includes a dimming controller 91, a driving circuit and an LED array module 92, and the driving circuit includes a current source controller 93 and a voltage Converter 94, the dimming controller 91 is connected to the current source controller 93, the input end and 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 LED current source feedback; wherein, the dimming controller 91 receives a PWM working signal, so that the voltage converter 94 generates an output voltage to control the LED array module 92 to emit light, as shown in FIG. 5 , wherein there is a representative time The horizontal axis, a vertical axis representing the voltage value and the waveform S of the output voltage, when the duty ratio (dutyratio) obtained by dividing the working time t of the output voltage by the cycle time T is low, the voltage converter The switch switching time of 94 is also relatively small, especially when the output voltage is between switching and non-switching, it is easy to cause the AC ripple R (ACripple) of the output voltage to be too large, so the output voltage is in a stable voltage Acoustic noise occurs when capacitor or a charging inductor is used.

The output voltage of the voltage converter 94 is fed back through a divided voltage to increase the output voltage. Although the problem of abnormal sound can be reduced, the above-mentioned solution will allow the dimming control device to generate a low dimming duty cycle ( low dimming duty), the voltage converter 94 is boosted to generate an excessively high voltage, which does cause a problem of poor efficiency. Therefore, in the prior art, when the PWM working signal received by the dimming control device When the duty cycle is low, the output voltage and input current have large ripples and abnormal sound. It is indeed necessary to propose a better solution.

Contents of the invention

The object of the present invention is to provide a control device and method that can improve panel dimming performance. It detects the power consumption status of a light emitting module and designs an adaptive power conversion structure to provide enough power for the light emitting module to work. output voltage, and keep the generated output voltage in a stable and energy-saving state, so as to eliminate the noise caused by voltage instability and improve work efficiency.

The technical solution of the present invention is to provide a control method that can improve the dimming performance of the panel. The control method that can improve the dimming performance of the panel is to connect a boost circuit and a comparison circuit with a dimming controller. The boost circuit Also connected with the comparison circuit, the method includes the following steps:

The dimming controller receives a PWM working signal, and the boost circuit provides an output voltage;

When the PWM working signal meets a preset condition and the comparison circuit obtains a reference signal, the comparison circuit executes an optimized comparison mechanism according to the reference signal and the output voltage;

A stable turn-on voltage is output to adjust the brightness of a light-emitting array module.

Through the above method, when the dimming controller receives the PWM working signal and the boost circuit provides an output voltage, when judging whether the PWM working signal meets the preset condition, the preset condition is consistent with a PWM Duty cycle is related, especially when the PWM duty cycle is low, noise is generated due to voltage instability, so when the preset condition is that the PWM duty cycle is lower than a preset threshold value, it is detected by the comparison circuit The reference signal, the comparison circuit executes the optimized comparison mechanism according to the reference signal and the output voltage, and outputs the stable turn-on voltage to the light-emitting array module to eliminate voltage instability. Noise, to achieve the purpose of improving work efficiency.

The present invention also provides a control device that can improve the dimming performance of the panel, and the control device that can improve the dimming performance of the panel includes:

A dimming controller has at least one signal input terminal and a plurality of signal output terminals, and the signal input terminal of the dimming controller is used to receive a PWM working signal;

A boost circuit, including a boost converter, is connected to the dimming controller;

A light emitting array module is connected with the boost converter of the boost circuit;

A comparison circuit, which includes a voltage selector and a voltage comparator, the voltage selector is respectively connected to the dimming controller, the boost converter of the boost circuit and the voltage comparator, the voltage comparator is connected to the boost converter;

Wherein, the dimming controller receives the PWM working signal, and the boost converter of the boost circuit provides an output voltage to the light-emitting array module, when the PWM working signal received by the dimming controller meets a preset Conditions are set, and the voltage selector of the comparison circuit obtains a reference signal, and then the voltage comparator of the comparison circuit performs an optimized comparison mechanism according to the reference signal and the output voltage, so as to adjust the output voltage to A stable turn-on voltage is provided, and the turn-on voltage is output to the light-emitting array module to adjust its brightness.

It can be seen from the above structure that the control device of the present invention that can improve panel dimming performance is mainly connected by the dimming controller to the boost circuit and the comparison circuit, and the boost circuit is respectively connected to the comparison circuit and the light-emitting array module, The dimming controller continuously receives the PWM working signal, and the boost converter of the boost circuit provides an output voltage to the light-emitting array module to drive the light-emitting array module to emit light. When the dimming controller receives The PWM working signal meets a preset condition, and the preset condition is related to a PWM duty cycle, especially when the PWM duty cycle is low, noise will be generated due to voltage instability, so when the preset The condition is that when the duty cycle of the PWM is lower than a preset threshold value, the voltage selector of the comparison circuit detects a reference signal, and then the voltage comparator of the comparison circuit performs the operation according to the reference signal and the output voltage. The optimized comparison mechanism adjusts the output voltage to a stable turn-on voltage, which can adjust the brightness of the light-emitting array module and eliminate the noise generated when the voltage is unstable, so as to achieve the purpose of improving the working performance of the control device of the present invention .

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

Description of drawings

Fig. 1 is the architectural block diagram of a preferred embodiment of the present invention;

Fig. 2 is a circuit diagram of a preferred embodiment of the present invention;

Fig. 3 is a control method flowchart of a preferred embodiment of the present invention;

Fig. 4 is a known dimming control device;

FIG. 5 is a waveform diagram of an AC ripple output by a known dimming control device.

detailed description

In the following, the technical means adopted by the present invention to achieve the intended purpose of the invention will be further described in conjunction with the accompanying drawings and preferred embodiments of the present invention.

Please refer to FIG. 1 for a preferred embodiment of the control device capable of improving panel dimming performance according to the present invention, which includes a dimming controller 10, a boost circuit 20, a comparison circuit 30 and a light-emitting array module. 40, the dimming controller 10 is connected to the boost circuit 20 and the comparison circuit 30, and the boost circuit 20 is connected to the comparison circuit 30 and the light-emitting array module 40 respectively, through the dimming controller 10 Continuously receiving a PWM working signal, and providing an output voltage Vo to the light emitting array module 40 from the booster circuit 20 to drive the light emitting array module 40 to emit light.

The dimming controller 10 has at least one signal input terminal and a plurality of signal output terminals, and receives the PWM working signal through the signal input terminal of the dimming controller 10; the boost circuit 20 is mainly composed of a current source The controller 21, a boost converter 22 and a voltage protection circuit 23 are composed, the current source controller 21 is respectively connected with the dimming controller 10 and the boost converter 22, and the boost converter 22 is connected with the The voltage protection circuit 23 is connected; the comparison circuit 30 is mainly composed of a voltage selector 31 and a voltage comparator 32. The converter 22 is connected to the voltage comparator 32 , and the voltage comparator 32 is respectively connected to the voltage protection circuit 23 of the boost circuit 20 and the boost converter 22 .

The above-mentioned light emitting array module 40 is respectively connected with the boost converter 22 of the boost circuit 20, the voltage protection circuit 23 of the boost circuit 20 and the current source controller 21, and when the dimming controller 10 continues to receive The PWM working signal, and the boost converter 22 provides the output voltage Vo to the light emitting array module 40 . If the PWM working signal received by the dimming controller 10 meets a preset condition, in this embodiment, the preset condition is a PWM duty cycle (for example: a percentage), especially when the received PWM duty cycle When the ratio is low, noise will be generated due to voltage instability. Therefore, when the preset condition is that the PWM duty cycle is lower than a preset threshold value (unit is a percentage), the voltage selection of the comparison circuit 30 The device 31 detects a reference voltage REF output by the boost converter 22, and converts the reference voltage REF into a reference signal, and then the voltage comparator 32 of the comparison circuit 30 according to the reference signal and the output voltage Vo, implement 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.

To illustrate the specific application of the preferred embodiment of the present invention, please refer to FIG. 2, wherein the current source controller 21 of the boost circuit 20 has multiple current sources, and the light emitting array module 40 has multiple groups of light emitting Unit strings 41, these light emitting unit strings 41 are composed of a plurality of light emitting diodes (LEDs) connected in series, one input end of these light emitting unit strings 41 is connected to the output voltage Vo, and the other input end of the light emitting unit strings 41 terminal is connected to the current source. When the boost converter 22 operates in the boost mode, multiple groups of light-emitting unit strings 41 and multiple current sources form feedback, and select the lowest voltage signal among the light-emitting unit strings 41 for comparison, so as to allow The output voltage Vo of the boost converter 22 reaches 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 is used to set the LED current of the light-emitting array module 40 and the PWM duty cycle of LED turning on. (such as PWM duty cycle), and generate sufficient output voltage Vo by the boost converter 22 to meet the current setting required by the light emitting array module 40, further, the voltage protection circuit of the boost circuit 20 23 has an over-voltage protection (Over Voltage Protection, OVP) mechanism, the main purpose is to protect the circuit components from being damaged by excessive voltage. If the PWM duty cycle of the LED is on the low side, the rise Due to the short turn-on time and long turn-off time of the voltage converter 22, the ripples of the input current and the output voltage Vo become larger and cause abnormal sound, but the overvoltage protection mechanism of the voltage protection circuit 23 mentioned above makes this The boost converter 22 generates the output voltage Vo to avoid the ripple of the input current and the output voltage Vo becoming larger. Although the generated output voltage Vo is quite different from the voltage required to turn on the LED, the power consumption will increase. In a preferred embodiment of the present invention, before the boost circuit 20 switches to the overvoltage protection mechanism, an optimized reference voltage will be detected by the voltage selector 31 of the comparison circuit 30, and the The reference voltage REF is converted into a reference signal. When the PWM duty cycle is low, the output voltage Vo is compared with the reference signal, and a stable and sufficient voltage to turn on the LED is output, because the boost circuit 20 is stable at this time. Periodic switching action can be generated without the above-mentioned unstable switching situation, so it can eliminate abnormal noise and improve efficiency.

From the specific application and description of the above-mentioned preferred embodiments of the present invention, a control method that can improve the dimming performance of the panel can be summarized. connected, the booster circuit 20 is connected with the comparator circuit 30 again, as shown in Figure 3, the method comprises the following steps:

receiving a PWM working signal from the dimming controller 10, and providing an output voltage from the boost circuit 20 (S31);

When the PWM working signal meets a preset condition, and the comparison circuit 30 obtains a reference signal through detection, the comparison circuit 30 executes an optimized comparison mechanism according to the reference signal and the output voltage (S32); In this embodiment, the comparison mechanism is to further obtain an output voltage output by the booster circuit 20 and an overvoltage protection (OVP) voltage of the voltage protection circuit 23, and compare the output voltage (such as 15V) with The overvoltage protection voltage (such as 10V) is divided into M equal parts, and according to the current LED voltage is greater than N minus 1 equal part and less than N equal parts, then the output voltage is adjusted to another value suitable for N equal parts a regulated output voltage;

Outputting a stable turn-on voltage according to the adjusted output voltage to adjust the brightness of the light emitting array module 40 ( S33 ).

To sum up, the present invention is mainly aimed at a low dimming duty, the switching mode is switched from multiple groups of light-emitting unit strings 41 to a stable overvoltage protection mechanism and an optimized comparison is made. After the mechanism, it is locked at a voltage 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. In addition to solving the problem of abnormal sound, it can also reduce power consumption and achieve the goal of improving efficiency. Purpose.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art , within the scope of not departing from the technical solution of the present invention, when the technical content disclosed above can be used to make some changes or modifications to equivalent embodiments with equivalent changes, but any content that does not depart from the technical solution of the present invention, according to the technical content of the present invention Technical Essence Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

Claims (10)

1. the control method that can promote panel light modulation usefulness, it is characterised in that described method is used for controlling One light adjusting controller, a booster circuit and a comparison circuit, this light adjusting controller connects this booster circuit and is somebody's turn to do Light adjusting controller connects a booster circuit and comparison circuit, comparison circuit, and this booster circuit compares again electric with this Road connects, and described method comprises the following steps:

Received a pulse width modulation working signal by this light adjusting controller, and provided one defeated by this booster circuit Go out voltage；

When this pulse width modulation working signal meets one pre-conditioned, and this comparison circuit obtains one with reference to letter Number, and by this comparison circuit according to this reference signal and this output voltage, perform an optimized comparison mechanism；

This booster circuit exports a unlatching electricity with stability according to the result of this optimized comparison mechanism Pressure, to adjust the brightness of a luminous array module.

The control method promoting panel light modulation usefulness the most according to claim 1, it is characterised in that This is pre-conditioned is that the dutycycle of this pulse width modulation working signal is less than the threshold value preset；This compares Mechanism is to obtain the output voltage of this booster circuit and an overvoltage protection voltage, and by this output voltage with M decile it is divided between this overvoltage protection voltage, and according to a current cut-in voltage more than the N decile that subtracts 1 And less than N decile, then this output voltage is adjusted to another output voltage being applicable to N decile.

3. the control device that can promote panel light modulation usefulness, it is characterised in that the described panel that promotes is adjusted The control device of light transmittance efficiency includes:

One light adjusting controller, has at least one signal input part and multiple signal output part, this light adjusting controller Signal input part in order to receive a pulse width modulation working signal；

One booster circuit, it includes a boost converter, is connected with this light adjusting controller；

One luminous array module, is connected with the boost converter of this booster circuit；

One comparison circuit, it includes a voltage selector and a voltage comparator, this voltage selector respectively with This light adjusting controller, the boost converter of this booster circuit and this voltage comparator connect, this voltage comparator It is connected with this boost converter；

Wherein, this light adjusting controller receive this pulse width modulation working signal, and by this booster circuit Boost converter provide an output voltage to this luminous array module, when the pulse width that this light adjusting controller receives Degree modulation working signal meets one pre-conditioned, and the voltage selector of this comparison circuit obtains one with reference to letter Number, then by the voltage comparator of this comparison circuit according to this reference signal and this output voltage, perform one optimal The comparison mechanism changed, to be adjusted to a cut-in voltage of tool stability, and by this unlatching electricity by this output voltage Pressure exports to this luminous array module to adjust its brightness.

The control device promoting panel light modulation usefulness the most according to claim 3, it is characterised in that This booster circuit farther includes a current source controller, this current source controller be respectively with this brightness adjustment control Device, this boost converter connect；This luminous array module is to be connected with this current source controller further.

The control device promoting panel light modulation usefulness the most according to claim 3, it is characterised in that This booster circuit farther includes a voltage protection circuit, and this voltage protection circuit is the liter with this booster circuit Pressure converter connects；The voltage comparator of this comparison circuit is electric with the voltage protection of this booster circuit further Road connects；This luminous array module is that the voltage protection circuit with this booster circuit is connected.

The control device promoting panel light modulation usefulness the most according to claim 4, it is characterised in that This booster circuit farther includes a voltage protection circuit, and this voltage protection circuit is the liter with this booster circuit Pressure converter connects；The voltage comparator of this comparison circuit is electric with the voltage protection of this booster circuit further Road connects；This luminous array module is that the voltage protection circuit with this booster circuit is connected.

7. dim the control device of usefulness according to the promoted panel described in claim 4 or 6, its feature exists In, the current source controller of this booster circuit is to have multiple current source, this luminous array module be have many The luminescence unit string of group, the input of this luminescence unit string is to be connected with this output voltage, this luminescence unit string Outfan be to be connected with this current source.

The control device promoting panel light modulation usefulness the most according to claim 7, it is characterised in that This luminescence unit string comprises the light emitting diode of multiple concatenation.

9. the control dress of usefulness is dimmed according to the promoted panel described in any one in claim 3 to 6 Put, it is characterised in that this luminous array module has the luminescence unit string of many groups, this luminescence unit string defeated Entering end is to be connected with this output voltage, and the outfan of this luminescence unit string is the boost conversion with this booster circuit Device connects.

The control device promoting panel light modulation usefulness the most according to claim 9, it is characterised in that This luminescence unit string comprises the light emitting diode of multiple concatenation.