LM2623: LM2623 for 4.2V , 2A

Hi Mandar,

This device cannot support 4.2V@2A. When input voltage is 0.8V, the input current will be more than 10A since the load power is neary 8.4W. What does the input voltage come from? A battery? I'm afraid this will be too big for a battery.

Hi Zack,

Thanks for your prompt reply. Input voltage is from 50F super capacitor.Input voltage range will be 0.8V to 3v. 

Application :- We want to send data wirelessly after power fail. We want to use LM2623 to boost super cap voltage from 3V to 4.2V. During this peak current of 3G/4G module will be 2A. This will take 10Sec to transmitt data wirelessly. 

If you have any low cost solution please suggest.

Thanks,

Dattatray

Hi Dattatray,

LM2623 is not suitable for this application because of the current limit. I think a boost controller+mosfet will be needed. I'll let you know if i find a suitable controller.
Do you have other power rails on the board. 0.8V is too low as the power supply of IC.

Hi Zack,

We have low current capacity 3.3V.

Regards,

Dattatray

Hi Dattatray,

Using external 3.3V rail + boost controller is one way. However, you need a very high current rating MOSFET. As the Vgs of mosfet will be not high<4V. The Rdson of mosfet will be high. When input voltage is low as below 1V, the efficiency will be low and the heat problem will be found.
Do you really need to boost circuit to work at Vin<1V.