TLV61220 boost circuit doesnt work

Aneesh Nair100769

Other Parts Discussed in Thread: TLV61220

Hi,

I am using TLV61220 to boost my voltage from 3.7V to 5V ... I followed the datasheet for the value of resistors ..

I works fine with no load on it as soon i connect the load the volatge drops to 3V.. My load consumes less than 150mA but still it does nt work..

over 11 years ago

0 Chris Glaser over 11 years ago

TI__Guru**** 150650 points

Board layout and component selection can cause this type of symptom. You can compare the waveforms on your PCB to that on the EVM and/or order the EVM with its known good design and test it.

0 Bibith Paul over 9 years ago in reply to Chris Glaser

Prodigy 45 points

I am also facing the same issue...

TLV61220 gives 3.3v at no load , but as soon as the load is connected it drops to 3v.

Looking forward to your help.

0 Jasper Li over 9 years ago in reply to Bibith Paul

TI__Mastermind 46905 points

Paul
please share your schematic and layout.
what is the load current?
please also measure the VIN, SW and VOUT pin waveform.

0 Bibith Paul over 9 years ago in reply to Jasper Li

Prodigy 45 points

Hi Jasper,

Since i was just prototyping , i haven't made any PCB.
Schematic is exactly same as Datasheet with 4.7uH inductor, 10uF input and output capacitor R1 =1Mohm , R2= 180Kohm.
Load current : 20mA
Vin = CR2032(3V)

0 Jasper Li over 9 years ago in reply to Bibith Paul

TI__Mastermind 46905 points

two possible reason
please measure the VIN voltage to make sure the input voltage doesn't drop down.
prototyping? no sure your meaning. how do you connect the external component? could you take a picture?

0 Bharati Aravatagi over 9 years ago in reply to Chris Glaser

Prodigy 145 points

Hi ,
I am also facing the same problem.
I have given 1V as input and taking out 3V at output. Everythig is fine when I check without load but as soon as I connect load, voltage drops down to 1V and Vfb comes down to 200mV which is 500mV when load is not connected.

I have connected load of hardly 50mA, which is fine as per graphs in the TI datasheet. And also using recommended components.

But the strange thing is that, voltage doesn't drop when I connect load of just 10mA. Does that mean TLV61220 boost converter, not supporting as much of current mentioned in datasheet???

Please help me on this.

0 Jasper Li over 9 years ago in reply to Bharati Aravatagi

TI__Mastermind 46905 points

could you measure the VIN and VOUT waveform when the load is connected? maybe the VIN drop down to UVLO.
please share your schematic and layout.

0 Bharati Aravatagi over 9 years ago in reply to Jasper Li

Prodigy 145 points

YES I can check the Vin and Vout waveforms after connecting load. And I have confirmed that Vin remains same even after connecting load. Input waveform is same at all time (When load is connected and when load is not connected).

Here is the schematics of DC-DC converter I used. I need to connect load of 200mA in my application but its not working even with 50mA load. Please let me know what's going wrong.

0 Bharati Aravatagi over 9 years ago in reply to Bharati Aravatagi

Prodigy 145 points

In my previous post , I have copied schematics. In that I have shorted EN pin(Pin 3) to VBAT (Pin 6) as recomended in datasheet as I am not using that pin now.

0 Jasper Li over 9 years ago in reply to Bharati Aravatagi

TI__Mastermind 46905 points

the schematic is good.
1. what is part number of the inductor and output capacitor
2. please share the image of the layout

0 Bharati Aravatagi over 9 years ago in reply to Jasper Li

Prodigy 145 points

Inductor P/N: 1269AS-H-4R7M=P2

Input and Output capacitor P/N: TMK316F106ZL-T

Here is the screenshot of layout,

Where,

U7: TLV61220DBVR

L2: 4.7uH

C9 & C8: 10uF

R21: 1M

R24: 200K

R32: 0R

0 Jasper Li over 9 years ago in reply to Bharati Aravatagi

TI__Mastermind 46905 points

the component is good, but the layout is bad.
the trace between the IC and the output capacitor should be short and wide. please try to placed a 1uF capacitor right above the IC , and connect the capacitor to the IC directly with solder. this could help to check if the problem is caused by the layout.

please also measure the waveform of VIN and VOUT.

0 Bharati Aravatagi over 9 years ago in reply to Jasper Li

Prodigy 145 points

THUMBS UP......It works....Just removed output capacitir and placed it above IC (TLV61220) directly.

But output has lot of ripple at the beginning. Around 260mV and then its reducing to 50mV automatically.

THANK YOU for guidence.

0 Bharati Aravatagi over 9 years ago in reply to Jasper Li

Prodigy 145 points

Any suggetion on ripple issue? I added 10uF in parallal with input capacitor. But this did not solve the problem. Anything related to inductor at input??

0 Jasper Li over 9 years ago in reply to Bharati Aravatagi

TI__Mastermind 46905 points

could you share the waveform of input voltage and output ripple? please try to increase the output capacitor.(add another capacitor at the original location)

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TLV61220 boost circuit doesnt work