faizanbrohi Posted September 7, 2006 Report Share Posted September 7, 2006 Hello Everyone , this is faizanbrohi again to discuss yet another project design . actually it is related to building a Power supply for car audio using a IC UC2577-ADJ and fits the need Perfectly for a 12V battery step up psu. Main Page : http://focus.ti.com/docs/prod/folders/print/uc2577-adj.htmlDatasheet : http://www-s.ti.com/sc/ds/uc2577-adj.pdfApplication Note : http://www-s.ti.com/sc/psheets/slua181/slua181.pdfThe application note discusses a supply for a automotive application but has less voltage specification and less current specification . The absoulute maximum rating is good for my design as i require +55V and -55V @3A or @6A so since this is a single mode supply , We can make two identical units and then joing them serialy like two voltage sources producing +55 and -55V . Sounds Really Good , But SOme Calculation is needed . The Datasheet is very comprehensive in providing the adequate information for each and every thing. THere is only theoratical Calculations THat need to be done . The Pictures For the Block Diagram are included and the Absoulte Ratings along the Note . Quote Link to comment Share on other sites More sharing options...
ante Posted September 7, 2006 Report Share Posted September 7, 2006 I would call this unnecessary littering! Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 7, 2006 Report Share Posted September 7, 2006 Hi Faizan,This is a positive stepup converter. It has the same ground as another one. So it cannot be used serially to get a negative voltage unless the two circuits are completely separate.In two different cars?? One car would have a positive supply and the other car would have a negative supply. Hee, hee. ;DThat is why high power car amplifiers have a stepup inverter that uses a transformer so its output can be rectified to give positive and negative voltages. Quote Link to comment Share on other sites More sharing options...
faizanbrohi Posted September 8, 2006 Author Report Share Posted September 8, 2006 I think you are right but the problem is that is there any converter capable of Positve to negative voltage conversion having high amperage . or any other distinct method to convert positive to negative Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 8, 2006 Report Share Posted September 8, 2006 I think you are right but the problem is that is there any converter capable of Positve to negative voltage conversion having high amperage . or any other distinct method to convert positive to negativeYou don't want a converter. You want the power supply circuit to be a high frequency inverter with a transformer, not just a coil. Then a full-wave rectifier at its output provides positive and negative high voltages. Quote Link to comment Share on other sites More sharing options...
faizanbrohi Posted September 8, 2006 Author Report Share Posted September 8, 2006 Well THere can be another way why not invert the voltages using TI OPA548 configured as an inverting amplifier with gain 1 , ie configured as a voltage regulatorit is capable of 60V @ 3A (3000mA) , since it has inverting negative ouptut it will work . Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 8, 2006 Report Share Posted September 8, 2006 I said that you should use a DC to AC inverter, not an inverting amplifier. An inverting amplifier with a negative output needs a negative supply that you don't have! Quote Link to comment Share on other sites More sharing options...
faizanbrohi Posted September 8, 2006 Author Report Share Posted September 8, 2006 actually it is you can operate it on a single supply see this application note of OPA548 http://www-s.ti.com/sc/psheets/sboa059/sboa059.pdf Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 8, 2006 Report Share Posted September 8, 2006 actually it is you can operate it on a single supply You can properly bias and capacitor-couple the load on any opamp or power amplifier.For a high power amplifier, the single supply voltage must be very high. Quote Link to comment Share on other sites More sharing options...
faizanbrohi Posted September 9, 2006 Author Report Share Posted September 9, 2006 so you are saying we can invert it but the voltage will be less , i mean if we give the OPA548 60v and give it input 60v also and use inverting configration will it not produce -60 at the output Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 9, 2006 Report Share Posted September 9, 2006 The OPA548 is a power opamp. If it has a +60V and 0V supply then its output will be from +2V to +58V, it won't be negative. Even if it is connected as an inverting opamp with a gain of one, then with a +2V input its output will be +58V and with a +58V input its output will be +2V.An opamp doesn't make a supply voltage. It uses a supply voltage that is frequently positive and negative.To make a high voltage positive and negative supply for your car's high power amplifier, you need a DC to AC inverter circuit (a high power oscillator) with a stepup transformer in it, then it feeds a rectifier to make a positive high voltage and a negative high voltage. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.