LED Driver ICs Forum Discussions

Hello,

I'm writing code for communicating with a TLD7002 for a development tool, and would like to ask a few questions concerning the calculation of the CRC sums. As the driver library is not yet available to me, I'm implementing basic access to the HSLI in the programming language I'm using.

The datasheet of the TLD7002-16ES specifies two types of CRC algorithms, a 3-bit CRC, and an 8-bit CRC.

1. Regarding the 3-bit CRC, in the software design training video there appears a step where the crc value is reflected (mirrored) after processing the first 5 bits:

/* get reflected CRC3 value */
crc = TLD7002_MIRROR_MID_CRC3[crc];

I cannot find this step in the datasheet on page 67, though — an extra step reflecting the crc value after the first 5 bits and the tail 8 bits is not mentioned there; is the datasheet correct regarding the calculation of the 3-bit CRC?

2. The CRC-8 is defined as using the generator polynomial "0x8e = x^8 +x^4 +x^3 +x^2 +1" from CRC-8-AUTOSAR and SAE J1850.
But, from my understanding, 0x8E — binary: (1)-1000-1110 — actually is not the same as x⁸ + x⁴ + x³ + x² + 1;
0x8E is the reversed — LSB-first — form of 0x71  (1)-0111-0001, which corresponds to the polynomial x⁸ + x⁶ + x⁵ + x⁴ + 1, and is the reciprocal form, or Koopman representation, of the CRC-8-SAE polynomial 0x1D, but with similar properties:

(Source: Wikipedia)

So if the polynomial actually is 0x8E, then for calculating the CRC-8 of the safety byte the reversed, LSB first, algorithm would have to be used. Is this correct?
If yes, then this possibly also applies to the CRC-3, because two CRC sums used in the same HSLI frame are likely implemented in the same fashion. This could mean that the polynomial to be used when calculating the CRC-3 would be 0x6 ("reversed"), or 0x5 ("reversed reciprocal"), but not 0x3. Which one is actually used by the TLD7002-16ES?

The CRC-8 of SAEJ1850, by the way, also defines a final XOR step, where 0xFF is XOR'ed into the crc value. I suppose, since the datasheet of the TLD7002-16ES does not mention this, this final step of the original SAEJ1850 definition does not need to be performed in case of HSLI?

It could probably be helpful, if a table of example CRC results for various input values would be included in the datasheet, similarly as it is done in the Autosar document Specification of CRC Routines; this way users could perform a test for plausibility of their crc implementations, before sending actual requests to the TLD7002. 

Regards,
Michael

Good day~

Datasheet show extended supply voltage range form 4.5-45V, and parameter deviations possible.

Could you detail explain what is parameter deviations possible and if work voltage 4.5V-8V?

Best Regards
Ade

Device: ICL5102HV（PFC回路で使用）

Question:
1. IEC61000-3-2 Class-Cへ準拠可能ですか？
2. 最大電力は300Wで使用可能ですか？
3. 出力25W以上(最大は300W)で、IEC61000-3-2 Class-Cへの準拠は可能ですか？

Condition:
- AC100-240(±10%)

Two Questions for the Litix TLD5045EJ that I could not find in the datasheet:

a) how do I select the inductor value (the 220uH mentioned in some sections seems quite high especially for the higher frequencies)

b) what is the min dropout voltage, or the max LED voltage at say 12V input and 700mA LED current?

Thanks

KPN

We are developing a LED driver based on Infineon IC ICL5102. We are facing a problem with the burst Mode (BM) operation of the IC. 

We want to introduce a BM feature at reduced load condition when we dim the output current by using 1-10V analog Dimming signal. What we have found is that at dimming ( at say 3V dim signal), the unit starts flickering, and the unit operation becomes unstable if we try to use BM operation.

We want to understand how to introduce dimming at lower output current setting, and Is the BM possible under low load condition or not.

Dears:

  When  I installed DC-DC Designer,Design tool for DC-DC control ICs, an error is always showing when start running the software,and same  for other computers,would you please help and advise? Thank you.