Please recommend a current sensing amplifier for 1Mhz switching buck converter

Shengnan Li

Other Parts Discussed in Thread: INA296A, INA281, INA296B, INA290, INA241B, INA241A, INA280, INA293

Hi, I am designing a 1MHz buck converter, can you please recommend an amplifier that is fast enough? high side is better, but low side is also acceptable.

Thanks,

Shengnan

over 3 years ago

+1 Javier Contreras4 over 3 years ago

TI__Mastermind 32680 points

Hello Shenganan,

You can use this filter in our product search.https://www.ti.com/amplifier-circuit/current-sense/analog-output/products.html#p314=800;1300&sort=p314;desc

Like you saw in our product search you have to dig into the details. I would recommend the INA296A, INA296B, INA241A, INA241B. The INA290, INA280, INA293 and INA281 have the same issue you saw in your other post as they have the same architecture.

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi Shengnan,

keep in mind, though, that when installing an OPAmp within the feedback loop of a converter the phase margins of OPAmp and converter can be eroded eventually resulting in instability. In this case you should perform a phase stability analysis of the circuit.

Kai

0 Shengnan Li over 3 years ago in reply to Javier Contreras4

Expert 1010 points

Hi, Javier, with INA241, it says support switching frequency up to 125kHz, what does that mean?

0 Javier Contreras4 over 3 years ago in reply to Shengnan Li

TI__Mastermind 32680 points

Hello Shengnan,

This is the VCM switching frequency for a PWM system. This is due to the Enhanced PWM rejection limitations.

0 kai klaas69 over 3 years ago in reply to Shengnan Li

Guru 140200 points

Hi Shengnan,

keep in mind that the datasheet of INA241 is incomplete so far. As being a new device the datasheet only contains advance information. Many specs and figures are still missing.

Kai

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Please recommend a current sensing amplifier for 1Mhz switching buck converter