TPS61021A: Boost converter with fixed output of 3.3V and min current of 300mA

Hi Jasper Li,

I have made PCB using TPS61021A, when I am giving input of 1.2V the output of 1.8V is coming. But according to webench application it should be 3.3V.

I am inserting webench schemtic, schematic in PCB designer software and PCB images.

Regards,

Fig.1 Webench schematic

Fig.2 Schematic in PCB designer software

Fig.3 Final PCB 

Hi,

I had placed capacitor instead of a resistor, I have changed it, now I am getting proper 3.3V.

Regards,

Hi Jasper Li,

I have question about efficiency of DC to DC converter.

Input voltage is 1.2V

Output Voltage is 3.3V

However the efficiency over various current output is shown below. Why efficiency is below 25 percent. Why boost converter is taking so much current. In the BOM, TI WEBENCH software recommends using 10UF 10V capacitor, but I am using 10uF 6.3V.  

Regards,

Load Current	Load Resistance	Boost converter Input current	Efficiency %
105 mA	30 ohm	570 mA	18.42
27 mA	120 ohm	116 mA	23.27
3.40 mA	1 K ohm	13.40 mA	25.37

i'm afraid the device is damaged, you can confirm that by measuring the impedance between the SW pin to GND pin.
the layout of your PCB is not good. you should following the suggestion in datasheet and EVM user guide to optimize the layout.
bad layout could lead to unexpected problem or damage of the IC.

Hi Jasper Li,

I am using standard layout as described in TI TPS61021A datasheet. Please find screen shot of the layout (below)

Regards,

Hi Helen,

Can you explain what do you mean by relief connect to direct connect.

Regards,

Thanks Helen, I got it. Will it not cause the issue of reflow of solder paste. As there will not be any thermal relief left.

Regards,