CN107248815B - 低emi非对称中心抽头整流电路 - Google Patents

低emi非对称中心抽头整流电路 Download PDF

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CN107248815B
CN107248815B CN201710422004.2A CN201710422004A CN107248815B CN 107248815 B CN107248815 B CN 107248815B CN 201710422004 A CN201710422004 A CN 201710422004A CN 107248815 B CN107248815 B CN 107248815B
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diode
rectifying diode
power transformer
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CN107248815A (zh
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吴新科
蓝桂星
张思亮
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Zhejiang University ZJU
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00Details of apparatus for conversion
    • H02M1/44Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/22Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/22Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • H02M3/33592Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00Details of apparatus for conversion
    • H02M1/12Arrangements for reducing harmonics from ac input or output
    • H02M1/123Suppression of common mode voltage or current
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Dc-Dc Converters (AREA)
  • Rectifiers (AREA)

Abstract

本发明涉及直流/直流变换领域,旨在提供一种低EMI非对称中心抽头整流电路。其原边为半桥LLC拓扑,后级为中心抽头整流电路,功率变压器原副边绕组采用交错绕的绕组结构,且定义变压器绕组的同名端标识为正端另一为负端;第一整流二极管的阴极与第二副边绕组的负端连接至输出滤波电容的正端;第二整流二极管的阳极与第一副边绕组的负端连接至输出滤波电容的负端;且第一整流二极管的阳极与第一副边绕组的正端相接,第二整流二极管的阴极与第二副边绕组的正端相接。本发明减小了共模电流及其造成的干扰,消除或缓解了变压器原副边之间共模电流对励磁电感电流的抽流效应,减小桥壁开关管的死区时间,提高变换器转换效率。

Description

低EMI非对称中心抽头整流电路
技术领域
本发明属于直流/直流变换领域,涉及一种能够减小变换器共模电流的整流电路结构。更具体的说,本发明涉及一种针对有两个副边绕组的功率变压器实现低共模干扰电流的非对称结构中心抽头整流电路。
背景技术
电磁干扰(Electromagnetic Interference简称EMI),指电磁波与电子元件作用而产生的干扰现象,有传导干扰和辐射干扰两种。
电容性输出中心抽头整流电路(如图1)因其结构简单、无输出电感,容易实现整流管的软开关等众多优势,被广泛地应用于DC-DC谐振变换器的整流结构中。但高频功率变压器漏感及引线电感等,与副边整流管的寄生输出结电容在换流时极易产生电压寄生振荡,增加整流管的电压应力。因此,在实际应用中仍需采用辅助的电压缓冲吸收电路或者选用相对耐压高的输出整流管。从而增加了辅助损耗或导通损耗,降低了变换器整体转换效率。
在高频DC-DC变换器中,变压器原副边绕组一般采用交错绕的方法来减小涡流损耗。如图2所示,将原边绕组分为第一绕组P1和第二绕组P2,然后将副边绕组置于原边第一绕组和第二绕组之间。但也会因此带来较大的原副边寄生电容(如图3)。开关管动作时产生的dv/dt,导致较大的共模电流通过寄生电容,和空气与大地之间的寄生电容形成回路。带来比较严重的电磁干扰问题,而且使原边开关管ZVS的实现需要更长的时间。
发明内容
本发明要解决的技术问题是,克服现有技术中的不足,提供了一种低EMI非对称中心抽头整流电路。该整流电路能够减小变换器共模电流,实现整流管电压箝位降低整流管电压应力。
为实现发明目的,本发明的解决方案是:
提供一种低EMI非对称中心抽头整流电路,其原边为半桥LLC拓扑,后级为中心抽头整流电路,包括一组桥臂、谐振电感(Lr)、谐振电容(Cr)、两个整流二极管(D1,D2),以及一个功率变压器(T1);功率变压器(T1)包括原边绕组(P)、第一副边绕组(Sa)和第二副边绕组(Sb),功率变压器(T1)原副边绕组采用交错绕的绕组结构,且定义变压器绕组的同名端标识为正端另一为负端;
两个整流二极管(D1,D2)中,第一整流二极管(D1)的阴极与第二副边绕组(Sb)的负端连接至输出滤波电容(C0)的正端;第二整流二极管(D2)的阳极与第一副边绕组(Sa)的负端连接至输出滤波电容(C0)的负端;且第一整流二极管(D1)的阳极与第一副边绕组(Sa)的正端相接,第二整流二极管(D2)的阴极与第二副边绕组(Sb)的正端相接。
本发明中,该电路还包括一个辅助箝位电容(Cs),且第一整流二极管(D1)的阳极与辅助箝位电容(Cs)的正端相连;第二整流二极管(D2)的阴极与辅助箝位电容(Cs)的负端相连。
本发明中,第一整流二极管(D1)和第二整流二极管(D2)是普通二极管、快恢复二极管、肖特基二极管、N沟道的MOSFET同步整流管或P沟道的MOSFET同步整流管中的任意一种。
本发明中,功率变压器(T1)的绕组结构是:原-副1-副2-原绕组方式或副1-副2-原-原-副1-副2绕组方式,或者是以该两种绕组方式为基础进行推广的交错方式。
本发明中,所述的谐振电感(Lr)是独立的电感或者是功率电压器的漏感。
与现有技术相比,本发明的有益效果在于:
(1)通过副边第一绕组Sa与第一整流二极管D1的交换位置,减小了共模电流及其造成的干扰。
(2)消除或缓解了变压器原副边之间共模电流对励磁电感电流的抽流效应,减小桥壁开关管的死区时间,提高变换器转换效率。
(3)借助辅助电容Cs,有效抑制整流管上的电压寄生振荡,电压应力被箝位于2倍输出电压的值。
(4)输出电流纹波因辅助电容的旁路作用而下降,变压器副边绕组内的电流有效值下降,而且可以采用较小的输出滤波电容减小体积。
(5)本发明无需增加任何有源辅助器件,仅借助无损的电容储能元件,有效的抑制整流管上的电压寄生振荡。
附图说明
图1传统的半桥LLC中心抽头电容性输出整流电路。
图2原副边交错变压器结构图。
图3变压器原副边寄生电容简化等效图。
图4变压器原副边寄生电容简化后中心抽头整流电路图。
图5是图4中原副边绕组电位变化图。
图6是图4中共模回路等效电路图。
图7是本发明中副边第一绕组Sa与D1交换位置后的整流电路图。
图8是图6中原副边绕组电位变化图。
图9是图6中共模回路等效电路图。
图10是一种低EMI非对称中心抽头整流电路。
图11是另一种低EMI非对称中心抽头整流电路。
图12是一种箝位低EMI非对称中心抽头整流电路。
图13是另一种箝位低EMI非对称中心抽头整流电路。
具体实施方式
本发明中的低EMI非对称中心抽头整流电路,其原边为半桥LLC拓扑,后级为中心抽头整流电路,包括一组桥臂、谐振电感Lr、谐振电容Cr、两个整流二极管D1、D2,以及一个功率变压器T1;功率变压器T1包括原边绕组P、第一副边绕组Sa和第二副边绕组Sb,功率变压器T1原副边绕组采用交错绕的绕组结构,且定义变压器绕组的同名端标识为正端另一为负端;其特征在于:
两个整流二极管D1、D2中,第一整流二极管D1的阴极与第二副边绕组Sb的负端连接至输出滤波电容C0的正端;第二整流二极管D2的阳极与第一副边绕组Sa的负端连接至输出滤波电容C0的负端;且第一整流二极管D1的阳极与第一副边绕组Sa的正端相接,第二整流二极管D2的阴极与第二副边绕组Sb的正端相接。
该电路还包括一个辅助箝位电容Cs,且第一整流二极管D1的阳极与辅助箝位电容Cs的正端相连;第二整流二极管D2的阴极与辅助箝位电容Cs的负端相连。
第一整流二极管D1和第二整流二极管D2可选择普通二极管、快恢复二极管、肖特基二极管、N沟道的MOSFET同步整流管或P沟道的MOSFET同步整流管中的任意一种。功率变压器(T1)的绕组结构可选择原-副1-副2-原绕组方式或副1-副2-原-原-副1-副2绕组方式,或者是以该两种绕组方式为基础进行推广的交错方式。
下面结合附图,对本发明进行详细描述。
本发明中,功率变压器T1结构如图2所示,变压器原副边相邻绕组之间的距离小,因此寄生电容比较大:原边绕组P与副边绕组Sa的Cps1及原边绕组P与副边绕组Sb的Cps2(如图3)。图4为现有技术中变压器原副边寄生电容简化后中心抽头整流电路图及等效电路图,CY为Y电容,其值为nF级别,远大于变压器寄生电容,因此在开关过程中,由于该Y电容的存在,原边的地与副边的地电位变化可以近似为零。在副边二极管换流过程中,原边绕组的正端对地会有电位变化,假设换流过程为D1导通、D2截止,转换到D2导通而D1截止,如图5中所示:原边绕组的正端对地的电位变化为从nVo到-nVo,所以整个原边绕组对地的电位变化为负;与此同时,Sa绕组的同名端与输出电容相连,对地电位不变,异名端电位从0上升到2Vo,因此Sa绕组对地的电位变化为正;Sb绕组的异名端与输出电容相连,对地电位不变,同名端电位从2Vo下降到0,因此Sb绕组对地的电位变化为负,其等效模型如图6所示。从等效电路图6中可以看出,Sa绕组与原边绕组的电位变化是反方向的,因此此时寄生电容Cps1上的电位变化为(nVo+2Vo),而Sb绕组与原边绕组的电位变化是同方向的,因此此时寄生电容Cps2上的电位变化为(nVo-2Vo),所以流过Cps1的电流远大于流过Cps2的电流。
而在本发明中,通过将第一副边绕组Sa与第一整流二极管D1交换位置(如图7),得到如图8所示的等效电路:假设换流过程为D1导通,D2截止到D2导通,D1截止,那么原边绕组的正端对地的电位变化为从nVo到-nVo,所以整个原边绕组对地的电位变化是为负的;与此同时,Sa绕组的异名端与输出电容相连,对地电位不变,同名端电位从2Vo下降到0,因此Sa绕组对地的电位变化为负;Sb绕组的异名端与输出电容相连,对地电位不变,同名端电位从2Vo下降到0,因此Sa绕组对地的电位变化为负,其等效原理图如图9。从图9的等效电路可以看出,Sa绕组与Sb绕组都与原边绕组电位变化同方向,此时寄生电容Cps2与Cps1的电位变化同为原副边电位之差(nVo-2Vo),所以能相互抵消,从而有效的减小共模电流。又因为此共模电流是从给原边开关管实现ZVS的励磁电感电流中来的,所以共模电流越小,原边开关管越容易实现ZVS,从而可以减小变压器的励磁电流,进而提高效率。
在图7中整流电路的基础上,本发明在D1的阳极与D2的阴极之间加入一个辅助箝位电容Cs(如图12、13所示),由于辅助箝位电容Cs的存在,使整流二极管D1和D2的两端的电压箝位在(Vo+VCs),其中VCs是辅助箝位电容Cs两端的电压,VCs的纹波很小,可以忽略,而其平均值为Vo。由于辅助箝位电容Cs的容值较大,因此,其两端电压在一个开关周期内可以看作稳定的直流。另外,由于辅助箝位电容可以起到吸收部分变压器中的交流电流纹波,因此流入输出滤波电容Co的开关交流纹波减少,从而可以减少输出滤波器的体积和成本。
本发明中,所述的谐振电感Lr可以是独立的电感,也可以是功率电压器的漏感。
参照图10,原边为半桥LLC拓扑,后级为中心抽头整流电路,包括一组桥臂、谐振电感Lr、谐振电容Cr、励磁电感Lm、功率变压器T1及两个整流二极管D1、D2。其中,谐振电感Lr、谐振电容Cr、励磁电感Lm串联,功率变压器T1并联在励磁电感Lm两端。
参照图11,为图10半桥LLC的另一种原边连接方式。
参照图12,在图10的基础上,该电路还包括一个辅助电容Cs,且第一整流二极管D1的阳极与辅助电容Cs的正端相连;第二整流二极管D2的阴极与辅助电容Cs的负端相连。谐振电感Lr是独立的电感。

Claims (3)

1.一种低EMI非对称中心抽头整流电路,其原边为半桥LLC拓扑,后级为中心抽头整流电路,包括一组桥臂、谐振电感(Lr)、谐振电容(Cr)、两个整流二极管(D1,D2),以及一个功率变压器(T1);功率变压器(T1)包括原边绕组(P)、第一副边绕组(Sa)和第二副边绕组(Sb),功率变压器(T1)原副边绕组采用交错绕的绕组结构,且定义变压器绕组的同名端标识为正端另一为负端;其特征在于:
功率变压器(T1)的绕组结构是:原-副1-副2-原绕组方式或副1-副2-原-原-副1-副2绕组方式;
两个整流二极管(D1,D2)中,第一整流二极管(D1)的阴极与第二副边绕组(Sb)的负端连接至输出滤波电容(C0)的正端;第二整流二极管(D2)的阳极与第一副边绕组(Sa)的负端连接至输出滤波电容(C0)的负端;且第一整流二极管(D1)的阳极与第一副边绕组(Sa)的正端相接,第二整流二极管(D2)的阴极与第二副边绕组(Sb)的正端相接;
该电路还包括一个辅助箝位电容(Cs),且第一整流二极管(D1)的阳极与辅助箝位电容(Cs)的正端相连;第二整流二极管(D2)的阴极与辅助箝位电容(Cs)的负端相连。
2.根据权利要求1所述的电路,其特征在于,第一整流二极管(D1)和第二整流二极管(D2)是普通二极管、快恢复二极管、肖特基二极管、N沟道的MOSFET同步整流管或P沟道的MOSFET同步整流管中的任意一种。
3.根据权利要求1所述的电路,其特征在于,所述的谐振电感(Lr)是独立的电感或者是功率变压器的漏感。
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101697456A (zh) * 2009-10-29 2010-04-21 浙江大学 以双功率变压器实现整流管电压箝位的整流电路
CN104302063A (zh) * 2014-10-29 2015-01-21 东莞勤上光电股份有限公司 一种led电路

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US6490181B1 (en) * 2001-08-24 2002-12-03 The University Of Hong Kong Apparatus for reducing common mode noise current in power converters

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101697456A (zh) * 2009-10-29 2010-04-21 浙江大学 以双功率变压器实现整流管电压箝位的整流电路
CN104302063A (zh) * 2014-10-29 2015-01-21 东莞勤上光电股份有限公司 一种led电路

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