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LTC4071 - VCC drooping to 0V after disconnecting Solar Panel

Question asked by nahit on Jun 15, 2018
Latest reply on Jun 29, 2018 by nahit

Hello,

 

I am using LTC4071 to charge LiPo (3.7 1200ma) from Solar Panel. I have a custom made PCB for this. The connection on PCB is as follows:

NTCBAIS - Floating

NTC - connected to VCC

ADJ - Floating

LBSEL - connected to VCC

BAT - connected to LiPO

 

Everything works good if the Solar Panel is connected and is supplying the necessary power to charge the LiPO. I can see VCC to reach the programmed float voltage of 4.1V (ADJ pin float). But in order to simulate the absence of sun light I removed the solar panel from the board. As per datasheet it should supply voltage from LiPo (at least 3.7V of LiPo). But as soon as I remove the solar panel the VCC is drooping to 0V.

 

My question is why VCC is drooping to 0V?, it should supply system load either from Solar Panel or LiPo.

I hope my understanding is correct. 

 

Let me know if you need additional information.

 

Regards,

Nahit

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