TPS63070: TPS63070

Ram Sai

Part Number: TPS63070

Hi Team,

As I am performing load transient analysis for TPS63070 using the circuit attached, I observed a unwanted voltage dip in input voltage. I want to avoid or minimize the voltage dip in input voltage. To achieve this please suggest me a way.

The test conditions are Vin = 3.2V, Vout = 5.3V, initial load current = 10mA, final load current = 1A. I used time dependent switches to perform the load change at 2ms after the input and output voltages are stabilized at 3.2V.

Due to load transient at 2ms of time, the input voltage dipped from 3.2V to 1.85V which is not acceptable for my application, because the same Vin is a AA battery source to different circuit which needs at least 3V supply.

I need to address this issue at priority. So, please respond ASAP with the suggestion or if you need any more details about circuit below.

Thanks and Regards,

Ram Sai.

over 5 years ago

0 Moritz. over 5 years ago

TI__Intellectual 1700 points

Hi Ram,

thank you for using our device and the detailed information.

What power supply are you using and is a current clamp set?

regards,

Moritz

0 Ram Sai over 5 years ago in reply to Moritz.

Prodigy 60 points

Hi Moritz,

Thanks for the quick response.

I am using 4 x AA alkaline batteries in series connection from Duracell.

Datasheet reference: www.batterijenhuis.nl/.../Datasheet-Duracell-Ultra-Power-AA.pdf.

I am verifying the circuit in low battery condition, which is 3.2V.

Any how for simulations I used ideal voltage source. I have added the forward (R3) and backward (R5) path resistances which ever present in the path from battery to the converter circuit in series with voltage source according to my schematic.

While calculating the resistances present in path, I have included the batteries internal resistance as well.

Regards,

Ram Sai.

0 Moritz. over 5 years ago in reply to Ram Sai

TI__Intellectual 1700 points

Hi Ram,

my question is, can you verify that the setup works with a regular power supply that can deliver the needed current during that 1A load?

I assume that the battery voltage just drops due to the load. According to the spec of a Duracell Industrial AA, the max current is 1A and at that you'll see a voltage drop of around 0.7V.

During you load you see VIN=1.85V, VOUT=3.5V. In boost mode the input current has to be higher than the output current.

In your waveform picture you can see the Imax of 1A of the battery and you see a reduced Iload.

regards,

Moritz

0 Ram Sai over 5 years ago in reply to Moritz.

Prodigy 60 points

Hi Moritz,

As you asked me to verify the circuit with the power supply which can deliver the needed current, I simulated by removing resistances present in the path which makes the source ideal enabling it to deliver the current needed.

Screenshot for circuit and waveforms are available below.

In this case due to load transient i.e., after 2ms,
I observed Vin dipped to 2.86V and then stabilized at 3.01V. Vout = 5.3V, input current is around 2A when the load is 1A.

Is there any chance to reduce the voltage dip in Vin?