Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.
With reference to Fig. 3, show a kind of composition structural drawing that can suppress terminal first embodiment of LCDs interface electromagnetic interference (EMI) of the present invention.Described terminal comprises: printed circuit board (PCB) 110, LCDs chip for driving 120, LCDs 130, source end capacitance-resistance match circuit 140 and do not hold filtering circuit 150.
Described source end capacitance-resistance match circuit 140 is used for the reflecting background signal is suppressed, limit the common mode current of described LCDs chip for driving 120 output noises, and the switching noise that conduction produces in the contactor process of the described LCDs chip for driving of filtering 120 inside.
The described filtering circuit 150 of not holding is used to suppress the noise that LCDs 130 winding displacements are introduced, and isolates the interference that described LCDs chip for driving 120 sides produce.
Described source end capacitance-resistance match circuit 140 is arranged on described LCDs chip for driving 120 ends, near the output pin of described LCDs chip for driving 120.
Described source end capacitance-resistance match circuit 140 comprises first resistance R 1 and first capacitor C 1.
The described filtering circuit 150 of not holding is arranged on described LCDs 130 ends, near the interface of described LCDs 130.
The described filtering circuit 150 of not holding comprises the magnetic bead LB and second capacitor C 2.
The concrete value of described first resistance R 1, first capacitor C 1, magnetic bead LB, second capacitor C 2 need be taken all factors into consideration factors such as signal quality, clock frequency, resonance frequency and adjusts, to guarantee the optimal design of signal integrity and EMC.
In embodiments of the present invention, the resistance span of described first resistance can can be 0 to 100 pico farad for the electric capacity span of 0 to 100 pico farad, described second electric capacity for 0 to 100 ohm, the electric capacity span of described first electric capacity.
Described printed circuit board (PCB) 110, LCDs chip for driving 120 and LCDs 130 all belong to existing parts in terminal, for length considers that its principle of work and the course of work embodiment of the invention no longer are described in detail.
The described technical scheme of the embodiment of the invention can suppress the aerial radiation effect of LCD winding displacement effectively by source end capacitance-resistance match circuit being set and not holding filtering circuit under the prerequisite that ensures signal quality, guarantee that the EMC standard-required is satisfied in the RE test of terminal; And circuit is simple, can effectively reduce cost.
With reference to Fig. 4, show a kind of circuit diagram that can suppress terminal first embodiment of LCDs interface electromagnetic interference (EMI) of the present invention.
Described source end capacitance-resistance match circuit 140 is arranged on described LCDs chip for driving 120 ends, near the output pin of described LCDs chip for driving 120.
Described source end capacitance-resistance match circuit 140 comprises first resistance R 1 and first capacitor C 1.
One end of described first resistance R 1 is connected with described LCDs chip for driving 120 pins, the other end of described first resistance R 1 and described first capacitor C 1 and be connected described LCDs chip for driving 120 and the transmission line of described LCDs 130 is connected.
The described filtering circuit 150 of not holding is arranged on described LCDs 130 ends, near the interface of described LCDs 130.
The described filtering circuit 150 of not holding comprises the magnetic bead LB and second capacitor C 2.
The end of described magnetic bead LB is connected with the interface of described LCDs 130 and described second capacitor C 2, and the other end of described magnetic bead LB is connected with the transmission line that is connected described LCDs chip for driving 120 and described LCDs 130.
The concrete value of described first resistance R 1, first capacitor C 1, magnetic bead LB, second capacitor C 2 need be taken all factors into consideration factors such as signal quality, clock frequency, resonance frequency and adjusts, to guarantee the optimal design of signal integrity and EMC.
In embodiments of the present invention, the resistance span of described first resistance can can be 0 to 100 pico farad for the electric capacity span of 0 to 100 pico farad, described second electric capacity for 0 to 100 ohm, the electric capacity span of described first electric capacity.
In second embodiment of a kind of terminal that can suppress LCDs interface electromagnetic interference (EMI) of the present invention, described terminal comprises: printed circuit board (PCB) 110, LCDs chip for driving 120, LCDs 130, source end capacitance-resistance match circuit 140 and do not hold filtering circuit 150.
Described source end capacitance-resistance match circuit 140 is used for the reflecting background signal is suppressed, limit the common mode current of described LCDs chip for driving 120 output noises, and the switching noise that conduction produces in the contactor process of the described LCDs chip for driving of filtering 120 inside.
The described filtering circuit 150 of not holding is used to suppress the noise that LCDs 130 winding displacements are introduced, and isolates the interference that described LCDs chip for driving 120 sides produce.
Described source end capacitance-resistance match circuit 140 is arranged on described LCDs chip for driving 120 ends, near the output pin of described LCDs chip for driving 120.
Described source end capacitance-resistance match circuit 140 comprises first resistance R 1 and first capacitor C 1.
One end of described first resistance R 1 is connected with described LCDs chip for driving 120 pins, the other end of described first resistance R 1 and described first capacitor C 1 and be connected described LCDs chip for driving 120 and the transmission line of described LCDs 130 is connected.
The described filtering circuit 150 of not holding is arranged on described LCDs 130 ends, near the interface of described LCDs 130.
Described second resistance R 2 and the 3rd capacitor C 3 of not holding filtering circuit 150 to comprise low resistance.
The described technical scheme of present embodiment is applied under the unconspicuous situation of noise characteristic, and the magnetic bead composition that the resistance of use low resistance substitutes among first embodiment is not held filtering circuit 150, thereby can reduce cost greatly.The Standard resistance range of described second resistance R 2 can be 0 to 10 ohm.Preferred in embodiments of the present invention 0 ohm resistance substitutes magnetic bead.
The concrete value of described first resistance R 1, first capacitor C 1, the 3rd capacitor C 3 need be taken all factors into consideration factors such as signal quality, clock frequency, resonance frequency and adjusts, to guarantee the optimal design of signal integrity and EMC.
In embodiments of the present invention, the resistance span of described first resistance can can be 0 to 100 pico farad for the electric capacity span of 0 to 100 pico farad, described the 3rd electric capacity for 0 to 100 ohm, the electric capacity span of described first electric capacity.
The described technical scheme of the embodiment of the invention can suppress the aerial radiation effect of LCD winding displacement effectively by source end capacitance-resistance match circuit being set and not holding filtering circuit under the prerequisite that ensures signal quality, guarantee that the EMC standard-required is satisfied in the RE test of terminal; And circuit is simple, can effectively reduce cost.
With reference to Fig. 5, show a kind of circuit diagram that can suppress terminal second embodiment of LCDs interface electromagnetic interference (EMI) of the present invention.
The described filtering circuit 150 of not holding is arranged on described LCDs 130 ends, near the interface of described LCDs 130.
Described second resistance R 2 and the 3rd capacitor C 3 of not holding filtering circuit 150 to comprise low resistance.
One end of described second resistance R 2 is connected with the interface of described LCDs 130 and described the 3rd capacitor C 3, and the other end of described second resistance R 2 is connected with the transmission line that is connected described LCDs chip for driving 120 and described LCDs 130.
The described technical scheme of present embodiment is applied under the unconspicuous situation of noise characteristic, and the magnetic bead composition that the resistance of use low resistance substitutes among first embodiment is not held filtering circuit 150, thereby can reduce cost greatly.The Standard resistance range of described second resistance R 2 can be 0 to 10 ohm.Preferred in embodiments of the present invention 0 ohm resistance substitutes magnetic bead.
The concrete value of described first resistance R 1, first capacitor C 1, the 3rd capacitor C 3 need be taken all factors into consideration factors such as signal quality, clock frequency, resonance frequency and adjusts, to guarantee the optimal design of signal integrity and EMC.
In embodiments of the present invention, the resistance span of described first resistance can can be 0 to 100 pico farad for the electric capacity span of 0 to 100 pico farad, described the 3rd electric capacity for 0 to 100 ohm, the electric capacity span of described first electric capacity.
With reference to Fig. 6, show a kind of circuit diagram that can suppress terminal the 3rd embodiment of LCDs interface electromagnetic interference (EMI) of the present invention.
Described source end capacitance-resistance match circuit 140 is arranged on described LCDs chip for driving 120 ends, near the output pin of described LCDs chip for driving 120.
Described source end capacitance-resistance match circuit 140 comprises first resistance R 1 and first capacitor C 1.
One end of described first resistance R 1 is connected with described LCDs chip for driving 120 pins, the other end of described first resistance R 1 and described first capacitor C 1 and be connected described LCDs chip for driving 120 and the transmission line of described LCDs 130 is connected.
The described filtering circuit 150 of not holding is arranged on described LCDs 130 ends, near the interface of described LCDs 130.
The described filtering circuit 150 of not holding comprises the magnetic bead LB and second capacitor C 2.
The end of described magnetic bead LB is connected with the interface of described LCDs 130 and described second capacitor C 2, and the other end of described magnetic bead LB is connected with the transmission line that is connected described LCDs chip for driving 120 and described LCDs 130.
The concrete value of described first resistance R 1, first capacitor C 1, magnetic bead LB, second capacitor C 2 need be taken all factors into consideration factors such as signal quality, clock frequency, resonance frequency and adjusts, to guarantee the optimal design of signal integrity and EMC.
In embodiments of the present invention, the resistance span of described first resistance can can be 0 to 100 pico farad for the electric capacity span of 0 to 100 pico farad, described second electric capacity for 0 to 100 ohm, the electric capacity span of described first electric capacity.
The difference of the present embodiment and first embodiment is: under complicated radiation event, FPC radiation-screening noise by shielding between described printed circuit board (PCB) and the described LCDs, the overlap joint of interface is designed to multipoint earthing, is connected on the LCDs interface of described printed circuit board (PCB).
Under complicated radiation event, can adopt the gentle band of the FPC line of shielding between PCB circuit board and the LCD screen, for the processing of FPC line, adopt shielding line radiation-screening noise, the overlap joint of interface is designed to multipoint earthing, is connected on the LCD interface of pcb board.
The part of clock line on the PCB circuit board among the LCD interface cable FPC should be done bag ground and handle; PCB is provided with a plurality of earth points near the LCD interface, can guarantee the multipoint earthing of screen layer when RE radiation event complexity needs the gentle band of FPC line to adopt shielding line.
The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.