"60V Synchronous 4-Switch Buck-Boost Controller" output voltage range

I am using LT8390 as a voltage controller in my design. In my application, the DC/DC output maybe used to charge12V,24V or 48V battery. It works fine under 12V and 24V conditions, but often damaged at 48V condition. The working conditions are as below:

The output voltage I set for 8390 is around 54V. Input voltage is around 20V~30V. "Damaged" means the chip damaged and the output side 4 MOSFETs damaged. On the 48V battery there's load(another DC/DC converter, the converter converts the 48v voltage to 24v and there is a "noisy" load under this 24V, an AC air pump with max current around 1A )

What will cause the chip damaged? The output voltage too close to 60V limit? Or the load on the 48V rail make some voltage variation which cause the chip burnt?

In the datasheet it shows maximum output voltage can be up to 60V. I looked through several datasheet of "60V Synchronous 4-Switch Buck-Boost Controller" like LT8390 and LT3790, there are no 48V application example in both chips' datasheet(there's a 36V battery charger application example in LT3790's datasheet ). 

Is it proper to use LT8390 in >48V output application. What's the recommended output range?

If LT8390 is used in bigger than 48V battery charger application, what should be noted?

Could someone give me some advice? Thank you very much!



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[edited by: zkf19 at 1:33 AM (GMT -4) on 6 May 2021]
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    •  Analog Employees 
    on May 10, 2021 3:52 AM

    Hi zkf19,

    Hope you are doing well.

    What will cause the chip damaged? The output voltage too close to 60V limit? Or the load on the 48V rail make some voltage variation which cause the chip burnt?

    Can you try to do a transient test but at lower output voltage( just to prevent the chip from being damaged) and check the response of your Vout? Also, can you monitor the behavior of the switching waveform? If jittering is present on the switching waveform, this tells us that there may be instability in your control loop. 

    Is it proper to use LT8390 in >48V output application. What's the recommended output range?

    I think it's okay to use the LT8390 at output Voltage greater than 48V and 54V since it has been tested to operate to 60V. However, transients  may cause overshoots to ramp your Output voltage >60V.

    If LT8390 is used in bigger than 48V battery charger application, what should be noted?

    I think you should always check for the layout consideration for the IC (seen on page 26), proper loop compensation,  and the voltage and current rating of the components you are using if they are capable of operating within your specification. 

    Regards,

    Siglo

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  • 0
    •  Analog Employees 
    on May 10, 2021 3:52 AM

    Hi zkf19,

    Hope you are doing well.

    What will cause the chip damaged? The output voltage too close to 60V limit? Or the load on the 48V rail make some voltage variation which cause the chip burnt?

    Can you try to do a transient test but at lower output voltage( just to prevent the chip from being damaged) and check the response of your Vout? Also, can you monitor the behavior of the switching waveform? If jittering is present on the switching waveform, this tells us that there may be instability in your control loop. 

    Is it proper to use LT8390 in >48V output application. What's the recommended output range?

    I think it's okay to use the LT8390 at output Voltage greater than 48V and 54V since it has been tested to operate to 60V. However, transients  may cause overshoots to ramp your Output voltage >60V.

    If LT8390 is used in bigger than 48V battery charger application, what should be noted?

    I think you should always check for the layout consideration for the IC (seen on page 26), proper loop compensation,  and the voltage and current rating of the components you are using if they are capable of operating within your specification. 

    Regards,

    Siglo

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