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megamicro
Joined: 23 Jan 2003
Posts: 14
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 24 Jan 2003 15:51 How to control this circuit using a micro? |
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I'd like to use this circuit in my new project to get different voltages from
+5V (for example from +5 to +24V). I know that this can work but I
cannot control it.
All comments and suggestions are wellcome!
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aNdreiBuuu
Joined: 30 Apr 2001
Posts: 399
Helped: 11
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| 24 Jan 2003 16:04 ... |
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my advice is to use a clasic switching upconverter...
MAX1771 work great!
best,
//a
PS: make a search on www.m(at)xim-ic.com
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bunalmis
Joined: 03 Jan 2003
Posts: 251
Helped: 4
Location: Turkey
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| 24 Jan 2003 16:31 Re: How to control this circuit using a micro? |
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Apply the Pwm signal for the GVP input
You can produce different voltages
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zorro
Joined: 06 Sep 2001
Posts: 324
Helped: 36
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| 24 Jan 2003 16:50 |
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Hi megamicro,
this is a two stage power supply: the first is step-up switching, the second is linear.
The linear regulator can provide accuracy and fast response. The switching source, acting as a preregulator, gives the necessary voltage to the linear regulator for working fine without bad efficiency.
You can control the duty cycle of the PWM signal injected at GVP taking the sample of output voltage of the first stage at A.
The linear regulator must be controlled taking the output voltage (VPP), comparing against a reference and controlling VPPE.
Regards
Z
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bunalmis
Joined: 03 Jan 2003
Posts: 251
Helped: 4
Location: Turkey
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| 24 Jan 2003 17:18 |
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| Ok, But i think VPPE. on off control pin. (VPPenable)
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nebisman
Joined: 13 Apr 2002
Posts: 285
Helped: 1
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| 24 Jan 2003 18:27 |
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i'ts too complex to control the PMW signal and the VPPE signal. I agree with the use of simple STEP UP converter. The common lm3524 from National serves for this purpose and has built in automatic control of the output. only you shoul provide the reference input that can be one analog output of microcontroller (or the same , a filtered pwm output)
if you want to control the output voltaje with a micro only you need to implement the transistor, diode, and inductance in the STEP UP converter mode, feedback the output and realize a simple PI controller into the micro.
Nebisman
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megamicro
Joined: 23 Jan 2003
Posts: 14
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| 26 Jan 2003 0:40 |
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Thanks to all
I found a good article about boost regulators wich is enough for
me to realize this controller.
If someone is interested:
http://www.ee.uts.edu.au/~venkat/pe_html/pe07_nc8.htm
megamicro
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