A problem in using low-drop 5V regulator with an audio circuit
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Hi stampers
I have an application using a low-drop regulator LT1300 for a battery
operated device with an audio circuit and BS2.
A LT1300 is a nice device to play with because it allows 4x 1.5VV AA
batteries to be used with a 5V application like BS II. For fresh batteries,
it buck 6.4V to 5V, when the batteries go near the end of their life, this
IC just boost 3.2V (say) up to 5V.
However, I have found the ripple voltage is too much for an audio circuit,
which is a pre-amplifier in the audio range. That seems to be coming from
the inductor and capacitor combination.
No matter what capacitor do I use, I cannot get rid of the noise.
Could anyone suggest if I should use this kind of boost-buck voltage supply
for a portable audio circuit?
Should I consider other way to do it?
Note: 78L05 is not chosen because no 9V battery is allowed in my design.
John
I have an application using a low-drop regulator LT1300 for a battery
operated device with an audio circuit and BS2.
A LT1300 is a nice device to play with because it allows 4x 1.5VV AA
batteries to be used with a 5V application like BS II. For fresh batteries,
it buck 6.4V to 5V, when the batteries go near the end of their life, this
IC just boost 3.2V (say) up to 5V.
However, I have found the ripple voltage is too much for an audio circuit,
which is a pre-amplifier in the audio range. That seems to be coming from
the inductor and capacitor combination.
No matter what capacitor do I use, I cannot get rid of the noise.
Could anyone suggest if I should use this kind of boost-buck voltage supply
for a portable audio circuit?
Should I consider other way to do it?
Note: 78L05 is not chosen because no 9V battery is allowed in my design.
John