{"id":14013,"date":"2016-05-26T21:31:38","date_gmt":"2016-05-26T21:31:38","guid":{"rendered":"http:\/\/www.iacdrive.com\/2016\/05\/26\/switching-frequency-selection\/"},"modified":"2024-01-27T04:10:46","modified_gmt":"2024-01-27T04:10:46","slug":"switching-frequency-selection","status":"publish","type":"post","link":"http:\/\/abbdrivex.com\/?p=14013","title":{"rendered":"AQ: Switching frequency selection"},"content":{"rendered":"

Switching frequency selection is actually a tradeoff, and follows the below guidelines: <\/p>\n

    \n
  1. \n\t\tLower frequency (Eg 30kHz) means bulkier magnetics and capacitors; Higher frequency (Eg 1Mhz)) means smaller parts, hence more compact PSU.\n\t<\/li>\n
  2. \n\t\tStay away from exact 150kHz as this is the low end of any EMI compliance; So, if your frequency happens to be exactly 150kHz, then your PSU will be a strong emitter; For many commercial low cost PSUs, 100 KHz has been used for many years, which is why many inductors and capacitors are specified at 100kHz.\n\t<\/li>\n
  3. \n\t\tHigher frequency >\/= 1MHz converters provide for better transient response. Obviously, the control IC should be capable of supporting. There are plenty of resonant converters available.\n\t<\/li>\n
  4. \n\t\tHigher frequency results in higher switching losses; To control that, you will need faster switching FETs, Diodes, capacitors, magnetics and control ICs.\n\t<\/li>\n
  5. \n\t\tHigher frequency MAY result in more broadband noise; its not always true, since noise can be controlled by good PCB layout and good magnetics designs.\n\t<\/li>\n<\/ol>\n

    \nBoard power DC\/DC converters are commonly built using 1MHz switchers.
    \nChassis power Telecom\/Server PSUs seem to stay with 100-300KHz range. <\/p>\n

    Manufacturers are able to achieve exceptional density by virtue of High frequency resonant topologies, but they have to achieve high efficiencies too; Else, they will generate so much heat that they cannot meet UL\/IEC safety requirements.
    \nIn some cases, they will leave the thermal problem to the user.  Usually, the first few paragraphs of any reference design discusses the tradeoffs.<\/p>\n","protected":false},"excerpt":{"rendered":"

    Switching frequency selection is actually a tradeoff, and follows the below guidelines: <\/p>\n

      \n
    1. \n\t\tLower frequency (Eg 30kHz) means bulkier magnetics and capacitors; Higher frequency (Eg 1Mhz)) means smaller parts, hence more compact PSU.\n\t<\/li>\n
    2. \n\t\tStay away from exact 150kHz as this is the low end of any EMI compliance; So, if your frequency happens to be exactly 150kHz, then your PSU will be a strong emitter; For many commercial low cost PSUs, 100 KHz has been used for many years, which is why many inductors and capacitors are specified at 100kHz.\n\t<\/li>\n
    3. \n\t\tHigher frequency >\/= 1MHz converters provide for better transient response. Obviously, the control IC should be capable of supporting. There are plenty of resonant converters available.\n\t<\/li>\n
    4. \n\t\tHigher frequency results in higher switching losses; To control that, you will need faster switching FETs, Diodes, capacitors, magnetics and control ICs.\n\t<\/li>\n
    5. \n\t\tHigher frequency MAY result in more broadband noise; its not always true, since noise can be controlled by good PCB layout and good magnetics designs.\n\t<\/li>\n<\/ol>\n

      \nBoard power DC\/DC converters are commonly built using 1MHz switchers.
      \nChassis power Telecom\/Server PSUs seem to stay with 100-300KHz range. <\/p>\n

      Manufacturers are able to achieve exceptional density by virtue of High frequency resonant topologies, but they have to achieve high efficiencies too; Else, they will generate so much heat that they cannot meet UL\/IEC safety requirements.
      \nIn some cases, they will leave the thermal problem to the user.  Usually, the first few paragraphs of any reference design discusses the tradeoffs.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[67],"tags":[],"_links":{"self":[{"href":"http:\/\/abbdrivex.com\/index.php?rest_route=\/wp\/v2\/posts\/14013"}],"collection":[{"href":"http:\/\/abbdrivex.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/abbdrivex.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/abbdrivex.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/abbdrivex.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=14013"}],"version-history":[{"count":1,"href":"http:\/\/abbdrivex.com\/index.php?rest_route=\/wp\/v2\/posts\/14013\/revisions"}],"predecessor-version":[{"id":15232,"href":"http:\/\/abbdrivex.com\/index.php?rest_route=\/wp\/v2\/posts\/14013\/revisions\/15232"}],"wp:attachment":[{"href":"http:\/\/abbdrivex.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=14013"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/abbdrivex.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14013"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/abbdrivex.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14013"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}