{"id":382,"date":"2015-08-08T14:53:00","date_gmt":"2015-08-08T14:53:00","guid":{"rendered":"http:\/\/machineryequipmentonline.com\/video-equipment\/uncategorized\/power-supply-systemsstep-up-switch-mode-psu\/"},"modified":"2015-08-08T14:53:00","modified_gmt":"2015-08-08T14:53:00","slug":"power-supply-systemsstep-up-switch-mode-psu","status":"publish","type":"post","link":"http:\/\/machineryequipmentonline.com\/video-equipment\/power-supply-systemsstep-up-switch-mode-psu\/","title":{"rendered":"POWER SUPPLY SYSTEMS:STEP-UP SWITCH-MODE PSU."},"content":{"rendered":"<div class=\"klwmp6a0dc91b591ec\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '61e5902552e2353963d8d2f1bd1f4a8f',\n\t\t'format' : 'iframe',\n\t\t'height' : 250,\n\t\t'width' : 300,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/61e5902552e2353963d8d2f1bd1f4a8f\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.klwmp6a0dc91b591ec {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.klwmp6a0dc91b591ec {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.klwmp6a0dc91b591ec {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.klwmp6a0dc91b591ec {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.klwmp6a0dc91b591ec {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<h4 align=\"justify\">STEP-UP SWITCH-MODE PSU<\/h4>\n<p align=\"justify\">Except where they drive very small picture-tubes, TV chassis need a main supply line voltage around 110\u2013170 V to satisfy the requirements of the line output stage. Where operation from a mobile power source such as 12 V and 24 V vehicle and marine batteries is required a step-up converter is used. Fig. 11.8 shows the circuit of a switch- mode d.c.\u2013d.c. converter designed by Ferguson for this purpose. This circuit (shown in simpli\ufb01ed form) uses a T9005 V transistor TR407 in a blocking oscillator con\ufb01guration. The oscillator\/output transformer T401 has a preset switching arrangement in its primary winding to cater for 12 V or 24 V inputs. The voltage induced across secondary winding 2\u20134 is recti\ufb01ed and smoothed to form the 115 V stabilised output. Secondary winding 3\u20135 supplies positive feedback to the transistor\u2019s base, whose operating voltage sits on a pedestal of 0.5 V set up by diodes D408 and D409 to ensure correct start-up conditions via resistors R410 and R413. R427 and C413 protect TR407 from voltage surges. <\/p>\n<p align=\"justify\">The regulating action is based on the collector-current sampling transformer T402 and a two-transistor regenerative switch TR405\/ TR406. TR406 base is biased from the junction of R419 and R422 (via <\/p>\n<p align=\"justify\"><a href=\"http:\/\/lh3.googleusercontent.com\/-xW5_F_On0s8\/VcYXyQPLkII\/AAAAAAAB1BE\/KJauhzo_ndw\/s1600-h\/POWER%252520SUPPLY%252520SYSTEMS-0147%25255B2%25255D.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"POWER SUPPLY SYSTEMS-0147\" border=\"0\" alt=\"POWER SUPPLY SYSTEMS-0147\" src=\"http:\/\/lh3.googleusercontent.com\/-FiWQzCGbCzQ\/VcYX3h5kMGI\/AAAAAAAB1BM\/iuTWtleiGVE\/POWER%252520SUPPLY%252520SYSTEMS-0147_thumb.jpg?imgmax=800\" width=\"244\" height=\"220\" \/><\/a> <\/p><div class=\"otrps6a0dc91b593f1\" ><script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-0778475562755157\"\n     crossorigin=\"anonymous\"><\/script>\n<!-- 300x600 television-and-video -->\n<ins class=\"adsbygoogle\"\n     style=\"display:inline-block;width:300px;height:600px\"\n     data-ad-client=\"ca-pub-0778475562755157\"\n     data-ad-slot=\"6549443290\"><\/ins>\n<script>\n     (adsbygoogle = window.adsbygoogle || []).push({});\n<\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.otrps6a0dc91b593f1 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.otrps6a0dc91b593f1 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.otrps6a0dc91b593f1 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.otrps6a0dc91b593f1 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.otrps6a0dc91b593f1 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<div class=\"gpuqk6a0dc91b592c6\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '0c1eb4c533eaedb7b996f49a5a4983a9',\n\t\t'format' : 'iframe',\n\t\t'height' : 300,\n\t\t'width' : 160,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/0c1eb4c533eaedb7b996f49a5a4983a9\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.gpuqk6a0dc91b592c6 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.gpuqk6a0dc91b592c6 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.gpuqk6a0dc91b592c6 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.gpuqk6a0dc91b592c6 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.gpuqk6a0dc91b592c6 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n\n<p align=\"justify\">T402 secondary) such that when the voltage across R425 (corresponding to TR407 collector current) reaches a predetermined level TR406 conducts, turning on TR405 and rapidly latching the pair into hard conduction. A grounding path for the positive plate of C407 is thus established. This point previously carried about 6 V, so the negative plate of C407 tries to move 6 V negative likewise. The effect is to divert TR407 base current into C407, as a result of which TR407 turns off; its base is now driven into reverse bias by T401\u2019s feedback winding. <\/p>\n<p align=\"justify\">A further circuit (not shown) compares a sample voltage derived from secondary winding 2\u20137 with a zener reference potential; an error volt- age is developed for application to the junction of R419 and R422 where it in\ufb02uences TR407 base bias to complete a voltage stabilisation loop. Further circuit sections cater for low supply voltage and overcurrent trip functions; the latter operates on any load current exceeding 650 mA. The low supply voltage protection device shuts down the converter if the battery voltage falls below 10.9 V (21.8 V in 24 V mode). Other speci\ufb01cations are: Input voltage 11 V\u201314.4 V and 23\u201328 V; input cur- rent 4\u20135 A (depending on beam current) in 12 V mode, 2\u20132.5 A in 24 V mode; reverse-input voltage protection by diode and fuse.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>STEP-UP SWITCH-MODE PSU Except where they drive very small picture-tubes, TV chassis need a main supply line voltage around 110\u2013170 V to satisfy the requirements of the line output stage. Where operation from a mobile power source such as 12 V and 24 V vehicle and marine batteries is required a step-up converter is used. [&hellip;]<br \/><a href=\"http:\/\/machineryequipmentonline.com\/video-equipment\/power-supply-systemsstep-up-switch-mode-psu\/\" class=\"more-link\" >Continue reading&#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"aioseo_notices":[],"views":593,"_links":{"self":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/382"}],"collection":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/comments?post=382"}],"version-history":[{"count":0,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/382\/revisions"}],"wp:attachment":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/media?parent=382"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/categories?post=382"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/tags?post=382"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}