OPA4354-Q1: OPA4354-Q1

Munesh Tripathi

Part Number: OPA4354-Q1
Other Parts Discussed in Thread: OPA4354

Hi TI team,

I am using OPA4354 IC to provide PWM to Mos-fet in step down converter. application is automotive. I usually preferred Schmitt trigger + integration + comparator/error type for my design to reduce other components and it should be closed loop to control my output voltage, so output feedback preferred.

My design parameter's are

1. Required Switching frequency - 650Khz/1.5uS

2. Duty cycle- 37%

3. Step down input & output voltage - 12V(input) & 5V(output)

4. Feedback voltage - 1V to 2.5V (can adjust as per requirement)

I am confused, how to provide 1st pulse to start circuit and to get feedback voltage for control/set output voltage.

I request you to kindly provide simulation model, component calculation with basic op-amp with simulation result to get clarity about other component calculation

Thanks in advance

over 2 years ago

0 Sima Jalaleddine over 2 years ago

TI__Mastermind 28865 points

Hello Munesh,

It will depend on your input signal if you are looking for the closed-loop route. What is your input signal characteristics to the OPA4354?

Thank you,

Sima

0 Munesh Tripathi over 2 years ago in reply to Sima Jalaleddine

Prodigy 140 points

Input signal s DC voltage and it can be set as per our op-amp VCC. I am using Mosfet based power supply (high input to low output, as per op-amp supply).

0 Sima Jalaleddine over 2 years ago in reply to Munesh Tripathi

TI__Mastermind 28865 points

Hello Munesh,

I wasn’t able to look into providing an example application today, but I should be by end of the week. I would think you would then need to operate the amplifier in its saturation region, which will be non-ideal.

Thank you,

Sima

0 Munesh Tripathi over 2 years ago in reply to Sima Jalaleddine

Prodigy 140 points

I didn't get your point regarding saturation region.

0 Munesh Tripathi over 1 year ago in reply to Sima Jalaleddine

Prodigy 140 points

Hello Sima,

I am waiting for your design support, as discussed. Kindly share it ASAP as we are getting delayed.

Regards

Munesh Tripathi

0 Munesh Tripathi over 1 year ago

Prodigy 140 points

Hi Team,

I shared my query around 15 days ago and still it is pending, Kindly share your team expertise to get it done fastly.

Regards

Munesh Tripathi

0 Sima Jalaleddine over 1 year ago in reply to Munesh Tripathi

TI__Mastermind 28865 points

Hello Munesh,

I apologize I missed your previous replies and the long delay. As in you to generate a pulse with just a DC signal and closed loop feedback, you would have to purposely generate a signal to clamp at VS+ or VS+ which would be in the amplifier's non-linear region.

Or would something like this work for you: PWM Reference Design. It would use two dual channel amplifiers/comparator which won't take as much space as your preferred method.

Thank you,
Sima

0 Munesh Tripathi over 1 year ago in reply to Sima Jalaleddine

Prodigy 140 points

Hi Sima,

1. It's very helpful for me to design fast if you provide any simulation circuit, where 5V feedback will used to vary PWM as closed loop buck converter works.

2. If I need to select OP-AMP to generate upto 1Mhz switching frequency, then what are the main parameter's of op-amp that I have to look on

Regards

Munesh Tripathi

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OPA4354-Q1: OPA4354-Q1