If you use "Full-Wave Bridge Rectifier" it is necessary voltage drop 0.7 volts for each diode is in series, ie 0.7 * 2 = 1.4 volts for a "Full-Wave Bridge Rectifier".
In time of need you can put 2 or 3 "Full-Wave Bridge Rectifier" after each other, ie 2 units = 2.8 volts or 3 units = 4.2 volts.
In other words, 36 volts AC * SQR (2) = 51 volts AC minus 1.4 volts per "you use and at 2" Full-Wave Bridge Rectifier "will be about 48.2 volts at 3" Full-Wave Bridge Rectifier "is the 46.8 volts.
But the best is to have the correct AC voltage transformer and 1 "Full-Wave Bridge Rectifier"
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/rectct.html
http://www.otherpower.com/rectifiers/image002.jpg
http://wiki.answers.com/Q/How_you_convert_from_AC_volt_to_DC_volt_by_equations
In time of need you can put 2 or 3 "Full-Wave Bridge Rectifier" after each other, ie 2 units = 2.8 volts or 3 units = 4.2 volts.
In other words, 36 volts AC * SQR (2) = 51 volts AC minus 1.4 volts per "you use and at 2" Full-Wave Bridge Rectifier "will be about 48.2 volts at 3" Full-Wave Bridge Rectifier "is the 46.8 volts.
But the best is to have the correct AC voltage transformer and 1 "Full-Wave Bridge Rectifier"
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/rectct.html
http://www.otherpower.com/rectifiers/image002.jpg
http://wiki.answers.com/Q/How_you_convert_from_AC_volt_to_DC_volt_by_equations
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Your transformer is ideal for an unregulated supply.
for a regulator , try PA100 DIY 2x LM3886 in parallel gainclone audio amplifier
for a regulator , try PA100 DIY 2x LM3886 in parallel gainclone audio amplifier
Hi,
I want to build a +-45v dc regulated power supply for my TDA7293 stereo amplifier. But the problem is i have a 36-0-36 v ac 1000va transformer and the max voltage for TDA7293 is +-50v dc. can someone give me schematics for +-45v dc regulated power supply?
Sorry for English.
how heavy is your traffo? what is the primary dc resistance? how high does your power line go?
if you know the answers to my question then we can say if you can use your traffo....as it stands, yours is on the brink....
36-0-36 v ac 1000va transformer looks huge for 7293 you can power half a dozen of such amps easy....
36-0-36 v ac will give you +-50volts dc unloaded, but loaded it will still drop....
i guess you thinking of regards to main voltage?
i can confirm that 2*36V transformer gives +/-50.5V unloaded with dual rectifier bridges and CRC with R at 0.11ohm, on 234V mains. this was with a 500VA transformer.
I have seen and measured +-50.5Vdc from a 4% regulation 0-35,0-35Vac transformer run on a 240Vac supply. My supply is specified as rising to 254Vac.
That +6% on supply voltage and the +5% due to regulation gives much higher voltages at the output of the PSU.
If a higher regulation transformer (EI or smaller toroid) were adopted the upper voltage would be even further outside the manufacturer's specification for voltage when zero signal is present.
That +6% on supply voltage and the +5% due to regulation gives much higher voltages at the output of the PSU.
If a higher regulation transformer (EI or smaller toroid) were adopted the upper voltage would be even further outside the manufacturer's specification for voltage when zero signal is present.
Here's +_50dc High speed regulated power supply. My friend has DIY this power supplies for sale in USA ($3000)Hi,
I want to build a +-45v dc regulated power supply for my TDA7293 stereo amplifier. But the problem is i have a 36-0-36 v ac 1000va transformer and the max voltage for TDA7293 is +-50v dc
Sorry for English.
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i will await Maroof to respond......
meanwhile please look at the 7293 datasheet and see that it is a 120-volt, 100-watt, DMOS audio amplifier with mute and standby part......http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00001887.pdf
so i do not know what the big deal is....
You need the 2X45VAC transformer right?Hi,
I want to build a +-45v dc regulated power supply for my TDA7293 stereo amplifier. But the problem is i have a 36-0-36 v ac 1000va transformer and the max voltage for TDA7293 is +-50v dc
Sorry for English.
Attachments
In my area mains voltage is 220v but it is always 5% to 10% less so as u said above i think there is no problem in using 35-0-35vac transformer.
you did not look closely enough at the datasheeet................ look at the 7293 datasheet and see that it is a 120-volt, 100-watt, DMOS audio amplifier with mute and standby part......http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00001887.pdf
so i do not know what the big deal is....
The 120Vs spec is for the no signal condition.
The Vs limit is +-50Vdc max.
In my area mains voltage is 220v but it is always 5% to 10% less so as u said above i think there is no problem in using 35-0-35vac transformer.
No problem as long as you have enough heatsinking. When the speaker impedance is way below 8 Ohm, you will need very big heatsink, may be with a fan. Bottom line, you will be able to find out if it is okay or not by observing the temperature with high volume condition (and known speaker).
Problem is, the distortion may be high in that situation, so with the transformer current capability, it is even preferable to drop some voltage with transistor (mosfet for easy drop). This is not only solution to your problem, but I will do it for the sake of sound quality even if the chip can handle +/-70V
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