Saturday, July 17, 2004
This Web site has an article about dual tracking supplies that includes many of the key ideas...
As the article says, 7818 and 7918 regulators could be used to replace about 20 components in the published circuit.
http://members.tripod.com/michaelgellis/power3.html
A super low noise preamp needs a super low noise power supply.
And just in case you want a single chip to do the job... http://cds.linear.com/docs/Datasheet/3032fa.pdf
Dual low noise linear supply 150 ma.
The idea is to use chip amps as regulators to take advantage of their 65db of supply rejection.
The model for this circuit is in Horowitz and Hill and uses a voltage regulator with two power op amps. App notes for the LM548 and LM549 show similar circuits.
Candidate audio amps include ones from Philips and National.
Maxim has a low noise supply app note. The idea is to feed an ultra low noise voltage source as input to a pair of low noise amplifiers. Use the gain from the low noise amps to establish the working voltate (e.g. +/- 15 volts) and then use a MOSFET source follower to lower the impedence.
http://www.maxim-ic.com/appnotes.cfm/appnote_number/3657
This design only shows one side. Need some thinking and pspice work to figure out what a tracking supply would look like.
And just in case you want a single chip to do the job... http://cds.linear.com/docs/Datasheet/3032fa.pdf
Dual low noise linear supply 150 ma.
The idea is to use chip amps as regulators to take advantage of their 65db of supply rejection.
The model for this circuit is in Horowitz and Hill and uses a voltage regulator with two power op amps. App notes for the LM548 and LM549 show similar circuits.
Candidate audio amps include ones from Philips and National.
Maxim has a low noise supply app note. The idea is to feed an ultra low noise voltage source as input to a pair of low noise amplifiers. Use the gain from the low noise amps to establish the working voltate (e.g. +/- 15 volts) and then use a MOSFET source follower to lower the impedence.
http://www.maxim-ic.com/appnotes.cfm/appnote_number/3657
This design only shows one side. Need some thinking and pspice work to figure out what a tracking supply would look like.
