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# I am trying to design SMPS using ICE1HS01G-1 need help in feedback circuit design.

Hello,

I am designing a 325V nominal DC to 72V DC convertor using ICE1HS01G-1. But don't get any solution from the datasheet or demo board documentation.  So what is the way for feedback circuit design?

Mark

1 Solution
Moderator
Moderator

# Re: I am trying to design SMPS using ICE1HS01G-1 need help in feedback circuit design.

Hi,

Thanks for posting at the Infineon community.

Regarding TL431 feedback circuit design, we recommend you follow the below steps to estimate the feedback circuit parameters.

1. For RB1 (Refer Part Datasheet ICE1HS01G-1) where RB1 = RLED, MAX

VZ = VO

Rpull-up value Refer to the datasheet.

2. RB2 Refer to TL431 datasheet and follow the selection guide (Preferred value 1k to allow min required bias current)

3. ROS1 and ROS2 are feedback divider values choose to set the TL431 Reference value from the output voltage

4. CC1 is DNP in the application design guide

5. For RC1 = R2

In above formula R1=ROS1

FC = Cross over frequency
FZ = Zero Frequency
FP = High Frequency Pole

5. For CC2 = C1

However, after the estimation of feedback design values, better to sweep the response for different load conditions.

Thanks,

SPCH

7 Replies
Level 1
Level 1

# Re: I am trying to design SMPS using ICE1HS01G-1 need help in feedback circuit design.

I am asking is any explanation on this circuit. I appreciate any help.

Thank you

Moderator
Moderator

# Re: I am trying to design SMPS using ICE1HS01G-1 need help in feedback circuit design.

Hi,

Thanks for posting at the Infineon community.

Regarding TL431 feedback circuit design, we recommend you follow the below steps to estimate the feedback circuit parameters.

1. For RB1 (Refer Part Datasheet ICE1HS01G-1) where RB1 = RLED, MAX

VZ = VO

Rpull-up value Refer to the datasheet.

2. RB2 Refer to TL431 datasheet and follow the selection guide (Preferred value 1k to allow min required bias current)

3. ROS1 and ROS2 are feedback divider values choose to set the TL431 Reference value from the output voltage

4. CC1 is DNP in the application design guide

5. For RC1 = R2

In above formula R1=ROS1

FC = Cross over frequency
FZ = Zero Frequency
FP = High Frequency Pole

5. For CC2 = C1

However, after the estimation of feedback design values, better to sweep the response for different load conditions.

Thanks,

SPCH

Level 1
Level 1

# Re: I am trying to design SMPS using ICE1HS01G-1 need help in feedback circuit design.

1- Here RB1 written as RLED,max so it is some type of LED or it's simple resistor ? why it's name is RLED?
2- In datasheet I am not able to find Rf value will you highlight something.
3- VZ=VO=72V it is ok or I am getting wrong ?

Moderator
Moderator

# Re: I am trying to design SMPS using ICE1HS01G-1 need help in feedback circuit design.

Hi,

1- Here RB1 is written as RLED, max so it is some type of LED, or is it a simple resistor? why its name is RLED?

It is a simple Resistor. For your information, a light-emitting diode (LED) is an integral part of an Optocoupler at the input side which is the reason we named as RLED.

2- In the datasheet I am not able to find the Rf value will you highlight something.

I did not understand Rf Ref. where it is mentioned.

If you are looking for a pull-up resistance value, it was mentioned in datasheet page No. 15, Section 4.3.6 (Typical value 20kΩ)

3- VZ=VO=72V it is ok or I am getting wrong?

Yes, you are correct VZ = VO=72V.

The simulation tool as shown in the below link may help to tune the feedback circuit accordingly.

https://www.infineon.com/cms/en/product/power/ac-dc-power-conversion/ac-dc-pwm-pfc-controller/llc-re...

Thanks,

SPCH

Level 1
Level 1

# Re: I am trying to design SMPS using ICE1HS01G-1 need help in feedback circuit design.

1 - FZ = Resonant frequency?
And I don't know what is the cross over or high-frequency pole is.
They are minimum or maximum frequency or something else?

Moderator
Moderator

# Re: I am trying to design SMPS using ICE1HS01G-1 need help in feedback circuit design.

Hi,

Thanks for posting at the Infineon community.

FC, FZ, and FP are not related to the Power section. These are parameters that will be used while estimating the feedback loop compensation values.

We recommend you to refer to the below link to get a better understanding of these parameters with an example design, this reference is just for your understanding of these parameters only.

https://www.infineon.com/dgdl/an-1162.pdf?fileId=5546d462533600a40153559a8e17111a

Note: The above-mentioned formulas in the previous post will be helpful to arrive at the initial operating point for compensation design. The simulation is recommended with these values and fine-tuning is necessary before finalizing the compensation values since the converter is working on frequency modulation. CFB capacitor functions as FB signal noise filtering and also sets the extended blanking time during over load protection.

Thanks,
SPCH

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