VRM Output cap ESR

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • davmax
    Badcaps Veteran
    • Dec 2005
    • 899
    #1

    VRM Output cap ESR

    The output capacitor ESR is important in terms by bypassing the bulk of the output ripple and transients away from the CPU.

    I thought I would see what the ratio of ESR is to the CPU load (V/I) is used on motherboards. I calculated the ratio for two boards.

    1. A 1.5V 85W CPU = 26.7 milliohm the filter caps 6 x 3300u MBZ = 2 milliohm an ESR to Load ratio of 1: 13.35

    2. A 1.35V 65W CPU = 28 millohm the filter caps 9 x 820u 2.5V poly = 0.78 millohm (my current system)
    ESR to load ratio. 1:36

    Clearly the second board has a higher percentage of ripple flowing through the caps.
    Last edited by davmax; 03-12-2008, 12:57 AM.
    Gigabyte EP45-DS3L Ultra Reliable (Power saver)
    Intel E8400 (3000Mhz) Bios temps. 4096Mb 800Mhz DDR2 Corsair XMS2 4-4-4-12
    160Gb WD SATAII Server grade
    Nvidia 8500GT 256Mb
    160Gb WD eSATAII Server grade for backup.
    Samsung 18x DVD writer
    Pioneer 16x DVD writer + 6x Dual layer
    33 way card reader
    Windows XP Pro SP3
    Thermaltake Matrix case with 430W Silent Power
    17" Benq FP737s LCD monitor
    HP Officejet Pro K5300 with refillable tanks
    Tags: None
    Previous template Next

    Related Topics

    Collapse
    • FrancescoV
      Onkyo HT-R390 no sound output, video output ok
      by FrancescoV
      Good morning everyone,
      I'm trying to repair an onkyo ht-r390 that has no sound output, despite the volume being at maximum, the rest seems to work; the video output signal (coming from an hdmi input) is present, but the audio is absent. Similar situation if I send an audio signal from any input I have no output.

      The firmware reported is the following:
      M:1.00/11107BLP
      D:?.??/????????
      O:1.00/11107AL

      The DSP firmware given the question marks seems corrupt.

      On the BCHDM-0678 - 25140678 - QPWBCHDM0678A0 board the chip that usually seems...
      05-11-2025, 02:59 AM
    • bauto601
      KDM 480W PSU upgrade succes! (opinions?)
      by bauto601
      Back in 2020 i bought a (2nd hand) compact ATX psu to replace my current one. My PC case only fits very short ATX power supplies so i didn't really have the choice of buying a decent 80Plus unit. The current unit is a modded YoungYear unit that i made a thread about a while ago:
      A "nice" YoungYear unit? - Badcaps

      The "new" unit is a KDM-M6480 480W psu, the 480W number is a typical KDM bullshit claim of course, but the 24A rating on the 12V rail seemed reasonable and the "Active PFC" claim gave me a bit of hope that this was going to be decent-ish....
      12-26-2023, 03:05 PM
    • quickname
      Cyberpower 1500AVR UPS repair
      by quickname
      I'd like to start out by thanking this forum for providing the info to be able to repair my 15 year old CP1500AVRLCD UPS. Here is all the info I gathered during my trouble-shooting and re-capping.

      Like clockwork, I've had to replace the SLA batteries every 4 years. It was about that time and the UPS was acting like it needed new batteries... randomly shutting off with AC present, not being able to charge fully, and poor runtime when AC was removed. So, I replaced the batteries but noticed that it was not charging properly.

      I decided to verify that the batteries were...
      11-12-2023, 09:57 AM
    • Document Archive
      Texas Instruments TPS51427ARHBT TPS51427ARHBR Dual D-CAP Synchronous Step-Down Controller for Laptop Computers
      by Document Archive
      The TPS51427A TPS51427ARHBT TPS51427ARHBR are dual synchronous step-down controllers designed for laptop and mobile communications applications. This device is part of a low-cost suite of notebook power bus regulators that enables system designs with low external component counts.

      The TPS51427A includes two pulse-width-modulation (PWM) controllers, SMPS1 and SMPS2. The output of SMPS1 can be adjusted from 0.7V to 5.9V, while the output of SMPS2 can be adjusted from 0.5V to 2.5V. This device also features a low-dropout (LDO) regulator that provides a 5-V/3.3-V output, or adjustable...
      10-23-2024, 02:37 AM
    • AJ847.63e
      Testing ATX PSUs under load - Does loading the ATX 24 pin also load EPS & PCIE?
      by AJ847.63e
      Hi Folks,

      Just wanted to clear up a misunderstanding of mine (or what I expect is one). Isn't the 12V rail from the 24 pin, EPS and PCIE separated? IE if I put a power resistor on the ATX 12V pin that is not going to load, thus tell me if the EPS or PCIE rails are fine?

      I was recently watching ArIs from Hardware Busters video on how to properly test ATX PSUs without using 5 figure Croma substations.

      The PCB adapter he used breaks out the 12, 5 and 3.3V pins from the 24 pin and gives you banana plugs to connect to. That is a bit useless is it not? Aren't...
      https://www.youtube.com
      05-06-2025, 10:37 PM
    • Loading...
    • No more items.
    Working...