You can the following simple equations: I =3D V / ( T/C + R) when capacitor only got connected. I =3D V / ( L/T + R) when inductor only got connected. I =3D V / ( L/T + T/C + R) when capacitor and inductor both connected. Plot I Current Vs time T, you'll get approximate inrush current or do = spice simulation. Regards, Padmanaban -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of caydin@xxxxxxxxxxxxxxxxx Sent: Thursday, October 19, 2006 5:27 PM To: santhosh.etavalath@xxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: inrush current Santhosh, You can determine the value of max current peak using spice simulation. = The main effect comes from the startup circuitry of the dc-dc converter. If your's has a soft-start function, the duty cycle of the output = transistor switching time until soft-start threshold reach determines the amount of current peak. Regards, Cengiz Aydin On 19 Oct 2006 03:13 EEST you wrote: > Hi, > How do we generally calculate the inrush current in a dc-dc converter, formula? We will have inductor and bulk capacitors at the input side of = the regulator. > regards > santhosh >=20 >=20 >=20 >=20 > The information contained in this electronic message and any = attachments to this message are intended for the exclusive use of the addressee(s) = and may contain proprietary, confidential or privileged information. If you = are not the intended recipient, you should not disseminate, distribute or = copy this e-mail. Please notify the sender immediately and destroy all copies = of this message and any attachments. >=20 > WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. = The company accepts no liability for any damage caused by any virus = transmitted by this email. >=20 > www.wipro.com > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field >=20 > or to administer your membership from a web page, go to: > //www.freelists.org/webpage/si-list >=20 > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field >=20 > List FAQ wiki page is located at: > http://si-list.org/wiki/wiki.pl?Si-List_FAQ >=20 > List technical documents are available at: > http://www.si-list.org >=20 > List archives are viewable at: =20 > //www.freelists.org/archives/si-list > or at our remote archives: > http://groups.yahoo.com/group/si-list/messages > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > =20 >=20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 DISCLAIMER=20 The contents of this e-mail and any attachment(s) are confidential and = intended for the=20 named recipient(s) only. It shall not attach any liability on the = originator or HCL or its=20 affiliates. Any views or opinions presented in this email are solely = those of the author and=20 may not necessarily reflect the opinions of HCL or its affiliates. Any = form of reproduction,=20 dissemination, copying, disclosure, modification, distribution and / or = publication of this=20 message without the prior written consent of the author of this e-mail = is strictly=20 prohibited. If you have received this email in error please delete it = and notify the sender=20 immediately. Before opening any mail and attachments please check them = for viruses and=20 defect. ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu