CN206533572U - Light modulation compensation circuit - Google Patents
Light modulation compensation circuit Download PDFInfo
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- CN206533572U CN206533572U CN201621359853.5U CN201621359853U CN206533572U CN 206533572 U CN206533572 U CN 206533572U CN 201621359853 U CN201621359853 U CN 201621359853U CN 206533572 U CN206533572 U CN 206533572U
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Abstract
A dimming compensation circuit comprises a signal input end, a signal output end, a filter circuit, a comparator and a signal compensation circuit, wherein a first input end and a second input end of the comparator respectively receive a reference signal and an input signal of the signal input end; the first output end and the second output end of the signal compensation circuit are respectively connected with the signal output end and the first input end of the comparator, and when the comparator outputs a first electric signal, the signal compensation circuit clamps a signal of the signal output end to a preset minimum analog dimming signal. The utility model discloses can the accurate minimum simulation light modulation voltage of setting for, make the stable minimum simulation light modulation signal of signal output part output through signal compensation.
Description
Technical field
The utility model is related to analog light-adjusting circuit technical field, more particularly to a kind of light modulation compensation circuit.
Background technology
LED is adjusted due to being widely used the features such as its luminous efficiency is high and service life is long
The application of light can play the characteristic of its energy-conservation and increase LED service life.
Simulation light modulation is one of LED main dimming mode.At present in LED analog light-adjusting circuits, the signal of input reaches
During to minimum simulation dim signal, dim signal is easily disturbed by other outside load changes, and such as TV boards are in supper bass
Under, it is impossible to stable voltage, dim signal can produce disturbance because of regulation problem, cause backlight to occur dodging frequency.
Utility model content
In view of above-mentioned condition, it is necessary to provide a kind of light modulation compensation circuit of output dim signal that can be stable.
The utility model provides a kind of light modulation compensation circuit, including signal input part, signal output part and is connected to institute
The filter circuit between signal input part and the signal output part is stated, in addition to, the ratio being connected in parallel with the filter circuit
Compared with device and signal compensation circuit, wherein,
The first input end of the comparator and the second input receive reference signal and the signal input part respectively
Input signal, when the input signal is less than the reference signal, the comparator exports the first electric signal, otherwise output the
Two electric signals, the output end of the comparator is connected with the input of the signal compensation circuit;
The first output end and the second output end of the signal compensation circuit respectively with the signal output part and the ratio
First input end compared with device is connected, and when the comparator exports the first electric signal, the signal compensation circuit is defeated by the signal
The signal for going out end is clamped to default minimum simulation dim signal.
Above-mentioned light modulation compensation circuit, wherein, the signal compensation circuit includes:
First bleeder circuit, includes the first divider resistance of multiple series connection, the input connection of first bleeder circuit
Power supply, output end connects the second input of the signal output part and comparator;
Second bleeder circuit, includes the section between the second divider resistance of two series connection, described two second divider resistances
The first input end of point connection second comparator, the input and output end of second bleeder circuit connect described respectively
Power supply and ground wire;
Switch module, the first end of the switch module connects the output end of the comparator, the second end and the 3rd end point
The power supply and first bleeder circuit are not connected to, when the first electric signal that the comparator is exported, the switch module
The first bleeder circuit conducting and the connection of the power supply are controlled, it is described to open when the second electric signal that the comparator is exported
Closing module controls first bleeder circuit to disconnect the connection with the power supply.
Above-mentioned light modulation compensation circuit, wherein, first bleeder circuit includes the first divider resistance of two series connection, two
Node connection reference circuit between first divider resistance, the reference circuit is used to produce the reference signal.
Above-mentioned light modulation compensation circuit, wherein, the filter circuit includes grounding resistance and the ground capacity being connected in parallel.
Above-mentioned light modulation compensation circuit, wherein, the light modulation compensation circuit meets relationship below:
Wherein, VREF1 is default minimum simulation dim signal, and VREF2 is default threshold signal, and R1 is the filtering
Grounding resistance in circuit, R2 and R3 are two the first divider resistances in first bleeder circuit, and R4 and R5 are described the
Two the second divider resistances in two bleeder circuits, VCC is the voltage of the power supply.
Above-mentioned light modulation compensation circuit, wherein, the switch module is triode, and the base stage of the triode connects the ratio
Compared with the output end of device, colelctor electrode connects the power supply, and emitter stage connects the input of first bleeder circuit.
Above-mentioned light modulation compensation circuit, wherein, the second input of the comparator connects a ground capacity.
Above-mentioned light modulation compensation circuit, wherein, the switch module is metal-oxide-semiconductor, and the grid of the metal-oxide-semiconductor connects the comparison
The input of the output end of device, the drain electrode connection power supply and the second bleeder circuit, source electrode connects first bleeder circuit
Input.
The utility model can accurately set minimum simulation dimmer voltage, when the signal that signal input part is inputted is less than setting
Minimum simulation dim signal when, the signal compensation that the output signal of signal input part is produced by the first bleeder circuit to setting
Minimum simulation dim signal, make the minimum simulation dim signal that signal output part output is stable.Inputted when signal input part
Signal is more than the simulation dim signal for not influenceing signal output part to export during the minimum simulation dim signal of setting value.
Brief description of the drawings
Fig. 1 be the utility model first embodiment in light modulation compensation circuit schematic diagram;
Fig. 2 be the utility model second embodiment in light modulation compensation circuit structured flowchart;
Fig. 3 be the utility model second embodiment in light modulation compensation circuit schematic diagram;
Fig. 4 is the equivalent circuit diagram in Fig. 3 during triode ON;
Fig. 5 be the utility model 3rd embodiment in light modulation compensation circuit schematic diagram.
Embodiment
For the ease of understanding the utility model, the utility model is more fully retouched below with reference to relevant drawings
State.The utility model embodiment is given in accompanying drawing.But, the utility model can be realized in many different forms, and
It is not limited to embodiment described herein.On the contrary, the purpose for providing the embodiment is made to disclosure of the present utility model
It is more thorough comprehensive.
It should be noted that when element is referred to as " being fixedly arranged on " another element, it can be directly on another element
Or can also have element placed in the middle.When an element is considered as " connection " another element, it can be directly connected to
To another element or it may be simultaneously present centering elements.Term as used herein " vertical ", " level ", " left side ",
" right side " and similar statement are for illustrative purposes only.
Unless otherwise defined, all of technologies and scientific terms used here by the article is led with belonging to technology of the present utility model
The implication that the technical staff in domain is generally understood that is identical.It is herein to be in term used in the description of the present utility model
The purpose of description specific embodiment, it is not intended that in limitation the utility model.Term as used herein " and/or " include
The arbitrary and all combination of one or more related Listed Items.
Referring to Fig. 1, be the light modulation compensation control circuit in the utility model first embodiment, including signal input part
40th, signal output part 50, the filter circuit U3 being connected between the signal input part 40 and the signal output part 50, and
With the filter circuit U3 comparator U1 being connected in parallel and signal compensation circuit U2.The input letter of the signal input part 40
Number, that is, dim signal is simulated, the brightness for controlling to adjust the LED for being connected to signal output part 50.
The first input end and the second input of the comparator U1 is respectively input in the same direction and reverse input end, difference
Reference signal and the input signal of the signal input part are received, it is described when the input signal is less than the reference signal
It is high level signal that comparator U1, which exports the first electric signal, otherwise the second electric signal of output is low level signal.The benchmark letter
Number REF is equal to minimum simulation dim signal VREF1.
The output end of the comparator U1 is connected with the input of the signal compensation circuit U2.The signal compensation circuit
First input end of U2 the first output end and the second output end respectively with the signal output part and the comparator U1 is connected.
When the comparator U1 exports the first electric signal, the signal compensation circuit U2 arrives the signal clamper of the signal output part
Default minimum simulation dim signal, realizes light modulation.
When simulating dim signal input, signal output part is directly output to after on the one hand being filtered by filter circuit, separately
On the one hand it is input to comparator with REF signal to be compared, comparator exports corresponding logic level, this logic level is input to signal
The control end of compensation circuit, determines whether signal compensation circuit works.When signal compensation circuit does not work, signal output part it is defeated
Go out signal is not influenceed by signal compensation circuit, and when signal compensation circuit works, the output signal of signal output part is clamped to
The minimum simulation dim signal VREF1 of setting.
When applied signal voltage is more than the minimum simulation dim signal VREF1 of setting, i.e., compare when more than reference signal
Device will export logic low, and signal compensation circuit is stopped, and the output end directly exports filtered signal.If now
Input signal is reduced, until when being less than reference signal, comparator output high level, signal compensation circuit work, signal output part
The minimum simulation dim signal VREF1 of output.
When applied signal voltage is less than the minimum simulation dim signal VREF1 of setting, i.e., when less than reference signal, comparator
High level signal, signal compensation circuit U2 work, by the signal clamper of output end to VREF1, synchronous signal compensation electricity will be exported
Road U2 raises the input signal of the input in the same direction of comparator for VREF2, especially, and (VREF2-VREF1) is default time
Potential difference, VREF2 is more than VREF1, and this hysteresis voltage may insure to be increased above VREF2 from less than VREF1 in input signal
Comparator U1 exports lasting high level signal before, so that signal compensation circuit works always, the output letter of signal output part
VREF1 number is always remained as, minimum dim signal compensation is realized, without because comparator U1 the second input terminal voltage is lifted
It is high to after VREF1, two input terminal voltages of comparator are identical and cause misoperation.If now continuing to increase input signal until big
In VREF2, comparator U1 output low level signals, signal compensation circuit U2 no longer works, and signal output part 50 directly exports filter
Signal after ripple.
The utility model can accurately set minimum simulation dimmer voltage, when the signal that signal input part is inputted is less than setting
Minimum simulation dim signal when, the signal compensation that the output signal of signal input part is produced by the first bleeder circuit to setting
Minimum simulation dim signal, make the minimum simulation dim signal that signal output part output is stable.Inputted when signal input part
Signal is more than the simulation dim signal for not influenceing signal output part to export during the minimum simulation dim signal of setting value.
Fig. 2 and Fig. 3 are referred to, is the light modulation compensation circuit in the utility model second embodiment.Including signal input part
40th, signal output part 50, reference circuit 60, the filtering being connected between the signal input part 40 and the signal output part 50
Circuit U 3, and with the filter circuit U3 comparator U1 being connected in parallel and compensation circuit U2.The reference circuit 60 is used for
Reference signal REF is produced, the reference signal is minimum simulation dim signal.The signal compensation circuit U2 includes comparator
U1, the first bleeder circuit 10, the second bleeder circuit 20 and switch module 30.
The input in the same direction and reverse input end of the comparator U1 is respectively connected to the reference signal of the output of reference circuit 60
With the input signal of signal input part 40.When input signal is less than reference signal, comparator U1 output high level signals are on the contrary
Export low level signal.
The input connection power supply VCC of first bleeder circuit 10, the output end connection of first bleeder circuit 10
The reverse input end of the signal output part 50 and comparator 10.First bleeder circuit 10 includes first point of two series connection
Node between piezoresistance R2, R3, two the first divider resistance R2, R3 connects the reference circuit 60.
Second bleeder circuit 20 includes the second divider resistance R4, R5 of two series connection, described two second partial pressure electricity
The first input end that the node between R4, R5 connects the second comparator U1 is hindered, the input of second bleeder circuit connects
Connect the power supply, output head grounding.
The first end of the switch module 30 connects the output end of the comparator U1, and the second end and the 3rd end are connected respectively
In the power supply VCC and first bleeder circuit 10.Specifically, the switch module 30 is a triode, the three-level
The base stage of pipe connects the output end of the comparator U1, and colelctor electrode connects the power supply VCC, and is connected by the second divider resistance R4
The input in the same direction of the comparator U1 is connect, its emitter stage connects the input of first bleeder circuit 10.
The filter circuit 70 is connected between the signal input part 40 and signal output part 50.The filter circuit 70
Including grounding resistance R1 and ground capacity C1 in parallel.
Further, the reverse input end of the comparator U1 connects a ground capacity C2.
When the signal that signal input part 40 is inputted is higher than minimum simulation dim signal VREF1, i.e. the comparator U1's set
During the voltage for the input in the same direction that the voltage of reverse input end input is less than the comparator U1, comparator U1 output low level letters
Number, triode cut-off, the connection of deenergization VCC and the second bleeder circuit 10, the output signal of signal output part 50 is not by shadow
Ring, as the filtered input signal of filtered circuit 70.
When reverse input end input of the input signal less than minimum simulation dim signal VREF1, i.e. the comparator U1 of setting
The voltage input in the same direction that is more than the comparator U1 voltage when, the comparator U1 exports high level signal, described three
Pole pipe is turned on, and power supply VCC sequentially passes through second divider resistance R2, R3 and grounding resistance R1 and flows to ground, signal output part 50
The offset voltage that voltage is produced by the first bleeder circuit 10, is elevated as VREF1, the minimum simulation dim signal output of realization.
Power supply VCC sequentially passes through two second divider resistance R4 and R5 ground connection simultaneously, comparator U1 input in the same direction
Input voltage is elevated as VREF2.Especially, the purpose for raising the voltage of the input of comparator U1 input in the same direction is,
When the output voltage of signal output part 50 is compensated, when voltage is increased to VREF1, if comparator U1 input in the same direction is defeated
The voltage entered is not elevated accordingly, then the now input voltage phase of comparator U1 input in the same direction and reverse input end
Together, the electric signal for causing comparator U1 to export can not remain high level, so that stable output signal compensation can not be realized.And
After the voltage for the input for raising comparator U1 input in the same direction, it is ensured that comparator U1 exports permanent High level, so that real
Compensation return difference is showed, it is ensured that the reliability of signal compensation circuit.When the input voltage of signal input part is raised, VREF2 is reached
Afterwards, comparator just exports low level, and triode 30 ends, and the circuit of the second partial pressure 10 disconnects the connection with power supply CVV, signal compensation
Stop.
As minimum simulation dim signal VREF1 of the input signal higher than setting, triode cut-off.Wherein minimum simulation is adjusted
Optical signal VREF1 and the second divider resistance R4 and resistance R5 meet formula one:
The second divider resistance R4 and R5 resistance can be calculated according to above-mentioned formula.
As minimum simulation dim signal VREF1 of the input signal less than setting, triode 30 is turned on, corresponding equivalent electric
Road figure is as shown in Figure 4.
During circuit compensation, the output signal of signal output part, i.e. output voltage are VREF1, comparator input in the same direction
Input voltage is VREF2, then the first divider resistance, the second divider resistance, resistance and grounding resistance meet following formula two and public affairs
Formula three.
Formula two:
Formula three:
Resistance R1, R2, R3, R4, R5 of corresponding resistance are chosen according to formula one, two and three so that circuit meets minimum
Light modulation compensation is required.
When simulation dim signal is inputted from signal input part 40, on the one hand exported from signal output part 50, on the other hand
It is input in comparator U1 and is compared with reference signal REF, comparator U1 exports corresponding logic level according to comparative result, and this is patrolled
Collect level and be input to switch module 30, the connection that the first bleeder circuit 10 of control is turned on or off with power supply VCC.When the first partial pressure
During circuit 10 and power supply VCC disconnection, the output signal of signal output part 50 is not influenceed by the first bleeder circuit 10;When first
When bleeder circuit 10 is connected with power supply VCC, the compensation that the signal that output signal is produced by the first bleeder circuit 10 is carried out is clamped
Light modulation is realized to the minimum simulation dim signal VREF1 of setting in position.
Referring to Fig. 5, being the light modulation compensation circuit in the utility model 3rd embodiment, it is real with the utility model first
The light modulation compensation circuit applied in example is essentially identical, and difference is, the switch module 30 is metal-oxide-semiconductor.The grid of the metal-oxide-semiconductor
Pole connects the input of the output end of the comparator U1, the drain electrode connection power supply VCC and the second bleeder circuit, source electrode connection
The input of first bleeder circuit 10.Its principle is identical with first embodiment, i.e. the electric signal control exported according to comparator
MOS processed disconnection and conducting, so as to control the connection of the second bleeder circuit and power supply VCC, realizes that input signal is less than minimum modulus
Intend compensating output signal during dim signal VREF1.Specific operation principle can refer to first embodiment, and the present embodiment is not
Repeat again.
Embodiment described above only expresses embodiment of the present utility model, and it describes more specific and detailed, but simultaneously
Therefore the limitation to the utility model the scope of the claims can not be interpreted as.It should be pointed out that for the ordinary skill of this area
For personnel, without departing from the concept of the premise utility, various modifications and improvements can be made, these belong to this
The protection domain of utility model.Therefore, the protection domain of the utility model patent should be determined by the appended claims.
Claims (8)
1. one kind light modulation compensation circuit, including signal input part, signal output part and it is connected to the signal input part and described
Filter circuit between signal output part, it is characterised in that also include, the comparator and letter being connected in parallel with the filter circuit
Number compensation circuit, wherein,
The first input end of the comparator and the second input receive the input of reference signal and the signal input part respectively
Signal, when the input signal is less than the reference signal, the comparator exports the first electric signal, otherwise output second is electric
Signal, the output end of the comparator is connected with the input of the signal compensation circuit;
The first output end and the second output end of the signal compensation circuit respectively with the signal output part and the comparator
First input end connection, when the comparator exports the first electric signal, the signal compensation circuit is by the signal output part
Signal be clamped to default minimum simulation dim signal.
2. compensation circuit is dimmed as claimed in claim 1, it is characterised in that the signal compensation circuit includes:
First bleeder circuit, includes the first divider resistance of multiple series connection, and the input of first bleeder circuit connects power supply,
Output end connects the second input of the signal output part and comparator;
Second bleeder circuit, the node included between the second divider resistance of two series connection, described two second divider resistances connects
The first input end of the comparator is connect, the input and output end of second bleeder circuit connect the power supply and ground respectively
Line;
Switch module, the first end of the switch module connects the output end of the comparator, and the second end and the 3rd end connect respectively
The power supply and first bleeder circuit are connected on, when the first electric signal that the comparator is exported, the switch module control
The first bleeder circuit conducting and the connection of the power supply, when the second electric signal that the comparator is exported, the switching molding
Block controls first bleeder circuit to disconnect the connection with the power supply.
3. compensation circuit is dimmed as claimed in claim 2, it is characterised in that what first bleeder circuit was connected including two
Node connection reference circuit between first divider resistance, two first divider resistances, the reference circuit is used to produce
The reference signal.
4. compensation circuit is dimmed as claimed in claim 3, it is characterised in that the filter circuit includes the ground connection being connected in parallel
Resistance and ground capacity.
5. compensation circuit is dimmed as claimed in claim 4, it is characterised in that the light modulation compensation circuit meets following relation
Formula:
Wherein, VREF1 is default minimum simulation dim signal, and VREF2 is default threshold signal, and R1 is the filter circuit
In grounding resistance, R2 and R3 are two the first divider resistances in first bleeder circuit, and R4 and R5 are described second point
Two the second divider resistances in volt circuit, VCC is the voltage of the power supply.
6. compensation circuit is dimmed as claimed in claim 2, it is characterised in that the switch module is triode, three pole
The base stage of pipe connects the output end of the comparator, and colelctor electrode connects the power supply, and emitter stage connects first bleeder circuit
Input.
7. compensation circuit is dimmed as claimed in claim 1, it is characterised in that the second input of the comparator connects one
Ground capacity.
8. compensation circuit is dimmed as claimed in claim 2, it is characterised in that the switch module is metal-oxide-semiconductor, the metal-oxide-semiconductor
Grid connect the input of the output end of the comparator, the drain electrode connection power supply and the second bleeder circuit, source electrode connection
The input of first bleeder circuit.
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CN201621359853.5U CN206533572U (en) | 2016-12-12 | 2016-12-12 | Light modulation compensation circuit |
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CN201621359853.5U CN206533572U (en) | 2016-12-12 | 2016-12-12 | Light modulation compensation circuit |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN110944435A (en) * | 2019-12-31 | 2020-03-31 | 上海鸣涵电子科技有限公司 | Security protection LED backlight control circuit, control implementation method and chip |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN110944435A (en) * | 2019-12-31 | 2020-03-31 | 上海鸣涵电子科技有限公司 | Security protection LED backlight control circuit, control implementation method and chip |
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