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</o:shapelayout></xml><![endif]--></head><body lang=FR-CA link=blue vlink=purple style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Keep us informed.. Thanks !<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Until I find something that cures this problem better, I’ll stick with the PIC/NPN transistors power up.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=FR>De :</span></b><span lang=FR> Nathan Christopher <fashionproofer@gmail.com> <br><b>Envoyé :</b> 16 février 2024 16:22<br><b>À :</b> Jean-Pierre Desrochers <jpdesroc@oricom.ca><br><b>Cc :</b> The SynthiMuse <synthimuse@gmail.com>; Synth DIY <synth-diy@synth-diy.org><br><b>Objet :</b> Re: [sdiy] BUCK stepup converter module... output goes way too high on startup !!!<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>I've used these same boards many times and have never seen something like that happen, and it definitely would have destroyed a few devices I've powered with them... I have a bunch and am happy to check any behavior you're seeing against the ones I've got. I'll be at my shop tonight and will check out some things that have been mentioned in this thread..<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Nathan. <o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Fri, Feb 16, 2024 at 12:25 PM Jean-Pierre Desrochers <<a href="mailto:jpdesroc@oricom.ca">jpdesroc@oricom.ca</a>> wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><div><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Tests made on the +15vdc BUCK output :<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>100 ohms resistor to the GND.. no startup.. inrush current.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Even with a 1k ohms resistor to the GND the BUCK won’t settle up.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>When the BUCK starts to work correctly it’s when the >30vdc output riseup starts to occurs..<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><span lang=FR>De :</span></b><span lang=FR> The SynthiMuse <<a href="mailto:synthimuse@gmail.com" target="_blank">synthimuse@gmail.com</a>> <br><b>Envoyé :</b> 16 février 2024 12:05<br><b>À :</b> Jean-Pierre Desrochers <<a href="mailto:jpdesroc@oricom.ca" target="_blank">jpdesroc@oricom.ca</a>><br><b>Cc :</b> Synth DIY <<a href="mailto:synth-diy@synth-diy.org" target="_blank">synth-diy@synth-diy.org</a>><br><b>Objet :</b> Re: [sdiy] BUCK stepup converter module... output goes way too high on startup !!!</span><o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Hi Jean-Pierre <o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>It might be a load issue. Most buck regulators need a minimum load of about 5% to 10% of their max rating. <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>It could be that you're not loading it appropriately and it's struggling to establish on startup.<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Not a solution, but if you give it an appropriate resistive load, it might give you an insight in to the problem.<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Best wishes <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Gerry<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>On Fri, 16 Feb 2024, 16:50 Jean-Pierre Desrochers, <<a href="mailto:jpdesroc@oricom.ca" target="_blank">jpdesroc@oricom.ca</a>> wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt'><div><div><p class=m5799772145258663727m6699767645608166082msoplaintext>Hi all,<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext> <o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>I’m using this type of stepup voltage regulator to generate +15vdc and +30vdc<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>From an incoming single +9vdc power adapter.<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>These BUCK’S converters generate very good regulated voltage outputs but I noticed<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>that on power up they ‘need’ to rise up to around +48vdc<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>Before settling down to their trimmed voltages.<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>Well these 2 voltages will supply a DSP module @ +15vdc (not more !!!)<br>and a dual opamp TL072 that has a maximum allowed supply voltage of +/- 18vdc (36vdc overall).<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>I tried putting a 16v zener diode in parallel with the trimmed +15vdc<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>But the BUCK goes wild (input current rise up to around 2.5 amp and stays there !!)<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>I also tried to put an RC circuit at the input (33ohms + 100uf) of one of these BUCKs<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>But again the modules rise its input current to ‘try’ stabilize the regulation..<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>Even with 100ohms resistors and 16v zeners.. the BUCKs won’t start<br>and finalise their outputs (inrush current installs).<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext> <o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>So.. I’m stuck with this problem..<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext>Any possible solutions ???<o:p></o:p></p><p class=m5799772145258663727m6699767645608166082msoplaintext><o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>________________________________________________________<br>This is the Synth-diy mailing list<br>Submit email to: <a href="mailto:Synth-diy@synth-diy.org" target="_blank">Synth-diy@synth-diy.org</a><br>View archive at: <a href="https://synth-diy.org/pipermail/synth-diy/" target="_blank">https://synth-diy.org/pipermail/synth-diy/</a><br>Check your settings at: <a href="https://synth-diy.org/mailman/listinfo/synth-diy" target="_blank">https://synth-diy.org/mailman/listinfo/synth-diy</a><br>Selling or trading? Use <a href="mailto:marketplace@synth-diy.org" target="_blank">marketplace@synth-diy.org</a><o:p></o:p></p></blockquote></div></div></div></div><p class=MsoNormal>________________________________________________________<br>This is the Synth-diy mailing list<br>Submit email to: <a href="mailto:Synth-diy@synth-diy.org" target="_blank">Synth-diy@synth-diy.org</a><br>View archive at: <a href="https://synth-diy.org/pipermail/synth-diy/" target="_blank">https://synth-diy.org/pipermail/synth-diy/</a><br>Check your settings at: <a href="https://synth-diy.org/mailman/listinfo/synth-diy" target="_blank">https://synth-diy.org/mailman/listinfo/synth-diy</a><br>Selling or trading? Use <a href="mailto:marketplace@synth-diy.org" target="_blank">marketplace@synth-diy.org</a><o:p></o:p></p></div></blockquote></div></div></div></body></html>