LTC3890 & LTC4000 ITH pin connection

What's connected to J13, J14 (BAT, GND) on DC1830A-B? Why do not use a formal stand-alone battery charger controller?

What is the relation between Vith of the LTC3890 en it's output voltage? 

the blue letter is what i measured on the board.

Hi Ayham, 

The DC2236A-B is designed as a polyphase synchronous step down converter. It has two step down converter paralleled together to obtain a higher output power. The schematic that you have simulated is not an exact equivalent with what you are doing with the actual evaluation board. From what I can see in your schematic, the first channel is disabled while the other channel is supplying power to the battery. In DC2236A-B, the converter is operating in a dual phase configuration and both channels are active. You should modify the board first according to your schematic and start doing an actual test from there. 

Regards,

Hi Gonzales,

Thank you for your respond. You'r wright, I have already did adjust the board. I have removed the next components from DC2236A-B: R10, R14, R27, C15, C25, D2, R19, R22 and R24 to insure that channel one is suppurated from channel two. I connected EXTVCC with the ground. The pins RUN2 and ITH are left open. The test results are after the adjustment. 

Kind regards,

Hi, 

Can you tell us the result after adjusting the demo board according to your simulated schematic in LTSpice? 

Regards,

Hi, 

The measured values are the blue letter. I have discharged the battery so its lower than 15,1V (the maximal voltage of the converter that i measure) and then i see that the battery is charging to 15,1V. I am noticing that the value of the ITH is maximal 0.2V the whole test. All the pins seems working expect ITH pin.  

Regards,

I have to say i just measured a resistance of 1.7 kOhm between ITH pin and the ground (pin GND) in LTC4000. I thought that ITH is a high impedance pin. 

this pic is from the datasheet of the LTC4000

Hi it looks like the Ith pin is sinking current. Have you tried to check if any of the parameter mentioned above is hitting its limit? Also make sure the connection between ith pin as close as possible to avoid any interference with the compensation. 

Regards

Hi, thank you for your reaction. Your right!! Ith was not functioning correctly by sinking the current. I have replaced the LTC4000 IC and finally its working completely. 

That's great to hear Ayham! 

Regards,

That's great to hear Ayham! 

Regards,