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x0x:powersupply [2010/09/06 15:07]
ihatetoregister
x0x:powersupply [2016/01/28 18:05] (current)
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 See the [[jumpers]] page for a list of which jumpers go where. ​ See the [[jumpers]] page for a list of which jumpers go where. ​
 ==== Block Diagram ==== ==== Block Diagram ====
-{{:​x0x:​power-supply-overview-2.png|}}+{{:​x0x:​power-supply-overview-3.png|}} 
 <draw name=psblock namespace=x0x>​ <draw name=psblock namespace=x0x>​
  
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 The power also goes through another RC network (1K Ohm and 100uf), before sent to the voltage reference circuit. This is taken from the LM336Z datasheet. TM6 allows to adjust the "​breakdown voltage"​ of the voltage reference. D45-47 are used to "​obtain a lower temperature coefficient"​. This is then sent to an op-amp set up to be a [[voltagefollower|voltage follower]], to eliminate any loading effects. (This makes sure that 5.333 V is available throughout the entire circuit?​). ​ The power also goes through another RC network (1K Ohm and 100uf), before sent to the voltage reference circuit. This is taken from the LM336Z datasheet. TM6 allows to adjust the "​breakdown voltage"​ of the voltage reference. D45-47 are used to "​obtain a lower temperature coefficient"​. This is then sent to an op-amp set up to be a [[voltagefollower|voltage follower]], to eliminate any loading effects. (This makes sure that 5.333 V is available throughout the entire circuit?​). ​
  
-The 5.333 V is generated first with the voltage reference and buffer because it is the ac ground (virtual ground) for the whole circuit. It needs to be stable so is generated with this reference from ground rather than from a potentially unstable positive supply. It is buffered so it can supply current under load. As for why they chose 5.333 V maybe it was related to the VCO circuit. Ideally you would pick a bias voltage that is half the suppy rail, maybe they chose 5.333 as compromise related the generation of the saw wave+The 5.333 V is generated first with the voltage reference and buffer because it is the ac ground (virtual ground) for the whole circuit. It needs to be stable so is generated with this reference from ground rather than from a potentially unstable positive supply. It is buffered so it can supply current under load. The reason ​they chose 5.333 V is because ​it is evenly divisible by 0.08333 (i.e. 1/12 volt or one note in 1V/octave CV system).
   ​   ​
 The 5.333 V is sent to a [[noninvertingamplifier|non-inverting amplifier]],​ with the 2.2 k and 1.8 k resistors. This provides a 2.222 V gain to the 5.333 V, equaling a voltage of 11.851 V, giving us the 12 V power supply. Capacitors C60 and C61 seem to be [[bypasscapacitors|bypass capacitors]]. ​ The 5.333 V is sent to a [[noninvertingamplifier|non-inverting amplifier]],​ with the 2.2 k and 1.8 k resistors. This provides a 2.222 V gain to the 5.333 V, equaling a voltage of 11.851 V, giving us the 12 V power supply. Capacitors C60 and C61 seem to be [[bypasscapacitors|bypass capacitors]]. ​
/home/ladyada/public_html/wiki/data/attic/x0x/powersupply.1283785659.txt.gz · Last modified: 2016/01/28 18:05 (external edit)