data/text/DLP1/899642

LM3646: LM3646

Part Number: LM3646 Hi Sir, My customer looking for IR LED driver, control by Flash. Could you pls advise if LM3646 is suitable one? Thanks. Vendor OSRAM OSRAM P/N SFH 4725AS A01 SFH 4180S Forward voltage(V) 2.65(@1A), 3.65max 2.95(@1A), 3.3max Usage amount 3PCS 4~6PCS Thanks, Ian.

Hi Ian, For IR LED driver application with a fast response time requirement, I strongly recommend our LM3643/LM3644(two-channel) or LM36010/LM36011(single channel). Because those device has integrated the IR mode which can respond with the "STROBE" pin very quickly. It means that you put the trigger signal to the "STROBE" pin and it can respond very quickly. BR Sean

Hi Sean, Some questions as following, IR mode which can respond with the "STROBE" pin very quickly Q. What is the raising and falling time? 2. For SFH 4725AS 3PCS use a LM3644, and a LM36011 is OK. Q. customer will need to use 2 LM3644, and 2 LM36011, if there are two I2C address for each part? 3. There are three mode in IR Mode: Boost, Pass Only, Timeout Q. Timeout mode is not suitable for customer . What is the difference between Boost and Pass Only mode? Thanks, Ian.

Hi Ian, Here is a great AN that can answer your most questions. <secret URL>/lit/an/snva773/snva773.pdf For LM3644, you can use LM3644+LM3644TT they have different addresses, but for LM36010, there is only one I2C address. Boost mode means it will switch and Vin is not enough to driver output LED under a special current. Pass mode is like LDO mode which means the Vin is higher than Vout and internal switched will not switch. BR Sean

Hi Sean, We can find the i2c slave address of LM3644(0x63),but cannot find address of LM3644TT. What is the address of LM3644TT? 2. 3PCS SFH 4725AS is OK for driven by LM3644+ LM36011 But SFH 4180S just only can drive 5PCS by LM3644+ LM3644TT +LM36011, do you have any countermeasure? Vendor OSRAM OSRAM P/N SFH 4725AS SFH 4180S Forward voltage(V) 2.9(@1A), 3.4max 2.95(@1A), 3.3max Usage amount 3PCS 6PCS Thanks,Ian.

Hi Ian, 1. I'm sorry that LM3644TT has the same I2C address with LM3644, But you can try with LM3643 and LM3643A which has the different I2C address wit LM3643; 2. LM3643+LM3643A+LM36011 may be a good solution for 5 pcs LEDs. BR Sean

Hi Sean, Thanks. Do you have solution for 6PCS IR LED SFH 4180S? Vendor OSRAM P/N SFH 4180S Forward voltage(V) 2.95(@1A), 3.3max Usage amount 6PCScompany solutions ? Thanks, Ian.

Hi Ian, What's the supply voltage? And how about the LED configuration? All serially connected or can be connected parallelly? I would recommend TPS54201 first. BR Sean

Hi Sean, Serially is better, but can also consider others. supply voltage is 3.2~5CV. TPS54201 is still the better solution? Thanks, Ian.

Hi Ian, No, TPS54201 is a buck topology LED driver, for this kind of high current application, usually, it will use buck topology. If you are considering the boost LED driver, it may need a LED controller, from our team, you can try with TPS61500. BR Sean

Hi Sean, Thanks for information You means use TPS61500 be a solution for 6PCS IR LED SFH 4180S? Thanks, Ian.