wuchy143
Member
Hi all,
I'm driving a bank of 100 LED's using a 1k resistor with PWM @ 60Hz. The device is a keyboard and has other circuitry on it but I don't think those are worth mentioning at least for this conversation.
I have a speaker in my circuit which has the 60 Hz hum on it and I cannot get rid of it without a 1000uF cap. Even with the 1000uF cap the noise is very much attenuated but looking at +5v on my scope the 5V is still disrupted with a nasty looking periodic signal which is @ 60 hz. Althugh you cannot hear it on the speaker.
Does anyone have any ideas on how to get my 5V rail to stay @ 5V without having that hum on it? I cannot use such a big cap in my design so I"m forced to think of other ways. (they don't like electrolytics)
Basically I'm asking if anyone has some tricks up their sleeve?
Thanks guys!!
I'm driving a bank of 100 LED's using a 1k resistor with PWM @ 60Hz. The device is a keyboard and has other circuitry on it but I don't think those are worth mentioning at least for this conversation.
I have a speaker in my circuit which has the 60 Hz hum on it and I cannot get rid of it without a 1000uF cap. Even with the 1000uF cap the noise is very much attenuated but looking at +5v on my scope the 5V is still disrupted with a nasty looking periodic signal which is @ 60 hz. Althugh you cannot hear it on the speaker.
Does anyone have any ideas on how to get my 5V rail to stay @ 5V without having that hum on it? I cannot use such a big cap in my design so I"m forced to think of other ways. (they don't like electrolytics)
Basically I'm asking if anyone has some tricks up their sleeve?
Thanks guys!!