i.MX ProcessorsのトピックRe: LVDS Display Interface with i.MX6Q

LVDS Display Interface with i.MX6Q

r2 — Tue, 10 Sep 2019 13:14:25 GMT

Hello,

I need to interface an OLED display with an i.MX6Q using both i.MX6Q LVDS channels. Parameters for the devices are shown below and the OLED LVDS pin equivalent circuit is attached. The receiver does not have internal termination so I will use a couple of 50R resistors on each LVDS pair. Does the interface also require voltage level converters? If so, is there a suitable IC to accomplish this?

Thank you.

i.MX6 LVDS DC parameters

Parameter	Symbol	Test Conditions	Min	Max	Unit
Output Differential Voltage	VOD	Rload=100 Ω between padP and padN	250	450	mV
Output High Voltage	VOH	IOH = 0 mA	1.25	1.6	V
Output Low Voltage	VOL	IOL = 0 mA	0.9	1.25
Offset Voltage	VOS	—	1.125	1.375

OLED Receiver LVDS parameters

Item	Symbol	Conditions	Min	Typ	Max	Unit
Power Supply Voltage	VDD1IF		1.62	1.8	1.98	V
Differential Voltage Range	VID	RL=100Ω	100		300	mV
Differential Voltage Deviation (Between Lanes)	⊿VID	RL=100Ω	-10		10	%
Input voltage range	VI	RL=100Ω	650		1500	mV
Common Voltage	VIC	RL=100Ω	800		1350	mV
Common Voltage Deviation (Between Lanes)	⊿VIC	RL=100Ω	-100		100	mV

Re: LVDS Display Interface with i.MX6Q

igorpadykov — Wed, 11 Sep 2019 00:40:53 GMT

Hi Rodney

for i.MX6Q LVDS parameters one can look at

sect.4.12.11 LVDS Display Bridge (LDB) Module Parameters

i.MX 6Dual/6Quad Applications Processors for Consumer Products - Data Sheet

If lcd complies with LVDS interface TIA/EIA 644-A standard no converters are needed.

For termination/layout one can check guidelines provided in

IMX6DQ6SDLHDG, Hardware Development Guide for i.MX 6Quad, 6Dual, 6DualLite, 6Solo Families of Applications Processors

Best regards
igor
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Re: LVDS Display Interface with i.MX6Q

r2 — Wed, 11 Sep 2019 14:48:49 GMT

Thanks, Igor,

The specification compliance is certainly the issue. I can use voltage dividers to keep the i.MX6 output within the OLED input specifications but I could use some advice on handling the differential voltage mismatch. The i.MX6 can have a differential of up to 450 mV and the OLED spec shows a maximum differential of 300 mV. If I keep voltages below the OLED VI_max (1.5V) is there any adverse impact with the 450 mV differential?

Respectfully

Rod