Other Parts Discussed in Thread: CSD18504Q5A, TPS92641
Hi team,
Could you please let know how to modify the EVM to operate it with 24V input?
What component should be modified to extend VIN range lower?
Regards,
Itoh
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Hi team,
Could you please let know how to modify the EVM to operate it with 24V input?
What component should be modified to extend VIN range lower?
Regards,
Itoh
Hi Frank-san,
OK, I understand.
My customer is trying to use below parameters for the modification. Could you please review it?
Vin 24.0V±1.2V
Vout 16V (Vf=3.2V ×5 series)
Rvout1 54kΩ
Rvout2 10kΩ
Con 1μF
fsw 1MHz
Ron 6.4kΩ
RIADJ1 10kΩ
RIADJ1 20kΩ
L 20μH
(⊿iL-PP - 296.3mA)
rD 3.2Ω
Cout 0.01uF×4 parallel
(Cout = 38.6nF)
ILED 1A
RUDIM1 100kΩ
RUDIM2 3.0kΩ
RUDIM3 18.0kΩ
Also, please help to address below questions.
Can TPS9241 drive >1A if right FET is selected? My customer should use CSD18504Q5A.
Do you think it can drive up to 15A?
Also, the FET is required for shunt dimming as well. Is CSD18504Q5A good for the shunt dimming?
Is there any component required between SDRV and Qsdim?
When using shunt FET dimming with SDIM, how should the UDIM pin terminated?
Is it recommended to input same signal as SDIM pin?
Regards,
Itoh
Hi Itoh,
Please send the schematic to me.
Yes, TPS92641 could support >1A output. When shunt dimming, the UDIM should be pull-up.
Robin
Hi Robin-san,
My customer is trying to modify the EVM, so please check the EVM schematic.
The above parameters are what my customer want to use on the EVM.
You can find them from the datasheet.
Best regards,
Itoh
Hi Robin,
Thank you for your kind review.
Do you think they should use a gate resistor at SDRV?
Regards,
Itoh
Hi Robin,
My customer is modifying the design (EVM modification) as below:
Vin 24.0V±1.2V
Vout 17V (Vf=3.0V ×5-series + 12Ω balance resistance) (modified from 16V )
Rvout1 56kΩ (modified from 58kΩ)
Rvout2 10kΩ
Con 1μF
fsw 280kHz (modified from 1MHz)
Ron 24kΩ (modified from 6.4kΩ)
RIADJ1 10kΩ
RIADJ1 20kΩ
L 68μH (modified from 20μH)
(⊿iL-PP - 306.4mA)
rD 3.2Ω
Cout 0.1uF+0.47uF (modified from 0.01uF×4)
(Cout = 142nF)
ILED 1A
RUDIM1 100kΩ
RUDIM2 3.0kΩ
RUDIM3 18.0kΩ
By the above modification, my customer cares if 5LEDs should work with 280kHz switching frequency.
Could you please help to check it?
Best regards,
Itoh
Hi Itoh,
280kHz should work normally. BTW, TPS92641 is used for what application? And why switching frequency is change to 280kHz from 1MHz?
Robin