The cap connected between GND and Vout

Posted by: suk chan song on 05/05/2024

I'm looking some family note of INN327x series

There are some technique reduce out put ripple

This picture put Cap between Gnd and Vout

In my opinion this cap reduce signal noise for Vout pin, so it can help reduce output voltage ripple

This cap is relative for Foward pin regulator or primary resiver signal

Files

KakaoTalk_20240430_201402253.png (20.91 KB)

Comments

Hi Suk Chan Song,
To add on the image you shared, this capacitor serves as a decoupling capacitor for the Vout pin. This is to reduce the noise on the output voltage signal to the IC.

The main purpose of the VOUT pin is to provide supply to the secondary controller of the InnoSwitch3-CP IC. Another purpose of this pin is to provide output overvoltage protection. The regulation of the output does not happen on this pin.

The actual regulation of the output will depend on the FB pin. Modifying this circuit can change the output voltage and will also have an effect on its ripple.

I hope to have answered your question. Thank you for using PI Forum.

A capacitor connected between GND (ground) and VOUT (output) serves various purposes in electronic circuits. DirecTV satellite tv It can stabilize voltage levels, filter out noise and ripple, and improve transient response. This configuration is commonly used in voltage regulator circuits to enhance performance and reduce output voltage fluctuations. By effectively coupling the output to ground, the capacitor helps maintain stable and reliable power delivery in electronic systems.

Hi Riyanasam,

Thanks for your response. Indeed, a capacitor between Vout to Gnd can help with the items you mentioned.

You can also add a post filter if you require a small output ripple. Please refer to page 22 of our Innoswitch family design guide: an-72_innoswitch3_family_design_guide.pdf (power.com)

Output Post Filter Components (LPF, CPF)

If necessary a post filter (LPF and CPF) can be added to reduce high frequency switching noise and ripple. Inductor LPF should be in the range of 1 µH – 3.3 µH with a current rating above the peak output current. Capacitor CPF should be in the range of 100 µF to 330 µF with a voltage rating ≥ 1.25 × VOUT.

Thank you and have a great day.

-Gavin