Ucd_400 ad 關機有吱吱聲

請問 UCD400 的J4 直 short 落地，
關機時，是否會有吱吱聲 ?

Thanks !!   :?:

YES, so, you need to add fast turn off to enable pin.

Apply a additional DC voltage (without Cap), only 2 diode + TR, when power is off, the DC voltage of EN pin fast pull to GND, it let the AMP enter to Disable mode, will solve the problem

This problem happen on all UCD series, it is not the bug, impossible to do this function from main DC voltage, because due to the dis-charging time of the large bulk cap.



KK.Ho


[quote:95c77b8927="Old Boy"]請問 UCD400 的J4 直 short 落地，
關機時，是否會有吱吱聲 ?

Thanks !!   :?:[/quote]

Thanks ! K.K.

Merry X'mas and Happy New Year !

Dear K.K.
Do you mean to apply a DC voltage to "J4 & Ground" ?
My transformer has an additional "12 X2 " (AC)
Please show me how !!

Thanks !

can also put a relay between the power rails which will cut off when the power is off

Try this simple method

Save alot of money, simple circuit and more reliable.

KK.Ho @ Taiwan




[quote:7ca682f97b="ackcheng"]can also put a relay between the power rails which will cut off when the power is off[/quote]

Thanks !
Already done !

Old boy,

Please let me know you are solving the problem or not ?

Thanks
KK.HO

It works now !
Thanks !