LTM4625 comp FB管脚增加电容导致输出电压过大

LTM4625电源芯片在COMP和FB管脚同时增加10nF电容,会导致FB电压升高到0.7V左右,导致输出电压增大,COMP和FB管脚,单独加电容电压正常,这是什么原因

  • +1
    •  Analog Employees 
    on May 29, 2020 8:46 AM
    Hi rookiebird,

    I have the question translated below, hopefully it is accurate :

    'The LTM4625 power chip adds 10nF capacitors at the COMP and FB pins at the same time,
    which will cause the FB voltage to rise to about 0.7V, resulting in an increase in the output voltage.
    COMP and FB pins, adding capacitors separately, the voltage is normal, what is the reason?'

    Adding excessive COMP pin and/or FB pin capacitance to ground can make the loop become unstable, where the output
    voltage may begin to oscillate and so the measured dc output voltage read may be higher than the set regulation point. The oscillation may typically be more sensitive to the FB to gnd capacitance.

    Thanks