公开(公告)号：EP0989662A1

公开(公告)日：2000-03-29

申请号：EP98830554.6

申请日：1998-09-23

Applicant: STMicroelectronics S.r.l.

Inventor： Spampinato, Sergio Tommaso ,  Tagliavia, Donato ,  Torres, Antonino

IPC: H02M3/338

CPC classification number: H02M3/33523 ,  Y02B70/1433

Abstract: A flyback DC-DC converter, autooscillating in a quasi resonant manner (QRC) during steady state operation, employing a flyback transformer for storing and transferring energy to a load having an auxiliary winding (AUS) whose voltage is compared by a comparator (COMP1) with a threshold (VREF1) to detect its crossing and as a consequence switch on through a control flip-flop (FF) a power transistor (POWER) driving the primary winding of said transformer for a new phase of conduction and accumulation of energy, whose duration is established by a secondary control loop of the output voltage (ERROR AMP, CONTROL) producing the switching off of the power transistor for a successive energy transfer phase toward the load of the energy stored in the transformer during the preceding conduction phase, has a wholly integrated control circuit that comprises a second comparator (HVCOMP) of the voltage existing on the current terminal of said power transistor (POWER) connected to the primary winding of the transformer in respect to the ground potential of the circuit; a logic gate (OR) having a first input connected to the output of said second comparator (HVCOMP) and an output coupled to the set terminal of said control flip-flop (FF); a delay network (ON DELAY) coupled in cascade to the output of said first comparator (COMP1) and having an output coupled to a second input of said logic gate (OR), so that under steady state functioning conditions of the converter, the setting of the flip-flop (FF) is done by said second comparator (HVCOMP) rather than by said first comparator (COMP1).

Abstract translation: 反激式DC-DC转换器在稳态运行期间以准谐振方式（QRC）自动振荡，采用回扫变压器，用于存储和传递能量到具有通过比较器（COMP1）比较电压的辅助绕组（AUS）的负载， 具有阈值（VREF1）以检测其交叉，并且因此通过控制触发器（FF）导通驱动所述变压器的初级绕组的功率晶体管（POWER），以实现新的能量传导和积聚阶段 持续时间由输出电压（ERROR AMP，CONTROL）的二级控制回路建立，以产生功率晶体管的关断，用于连续的能量传输阶段朝向在先前传导阶段期间存储在变压器中的能量的负载，具有 全集成控制电路，其包括存在于连接到初级绕组o的所述功率晶体管（POWER）的电流端子上的电压的第二比较器（HVCOMP） f变压器相对于电路的地电位; 具有连接到所述第二比较器（HVCOMP）的输出的第一输入和耦合到所述控制触发器（FF）的所述设置端的输出的逻辑门（OR）; 延迟网络（ON DELAY）级联耦合到所述第一比较器（COMP1）的输出，并具有耦合到所述逻辑门（OR）的第二输入的输出，使得在转换器的稳态运行条件下，设置 的触发器（FF）由所述第二比较器（HVCOMP）而不是由所述第一比较器（COMP1）完成。

公开(公告)号：EP0989662B1

公开(公告)日：2003-05-02

申请号：EP98830554.6

申请日：1998-09-23

Applicant: STMicroelectronics S.r.l.

Inventor： Spampinato, Sergio Tommaso ,  Tagliavia, Donato ,  Torres, Antonino

IPC: H02M3/338

CPC classification number: H02M3/33523 ,  Y02B70/1433

公开(公告)号：EP0991170A1

公开(公告)日：2000-04-05

申请号：EP98830568.6

申请日：1998-09-28

Applicant: STMicroelectronics S.r.l.

Inventor： Spampinato, Sergio Tommaso ,  Tagliavia, Donato

IPC: H02M3/335 ,  H02M1/00

CPC classification number: H02M1/32 ,  H02M3/33523

Abstract: A method of protection from the effects of a persistent short circuit of the output of a DC-DC flyback converter self-oscillating either at a variable frequency or functioning at a fixed frequency in a discontinuous manner, using a transformer for storing and transferring energy to a load, having an auxiliary winding (AUS) for synchronizing the turning on of the power switch (POWER) that drives the winding (N1) of the transformer under a condition of null current in the primary winding when self-oscillating at a variable frequency, wherein the voltage induced back from the current flowing in a secondary winding (N2) of the transformer on said auxiliary winding (AUS) is rectified and filtered (D2, C2) to power, during a steady state of operation, the control circuitry (CONTROL) of the converter, the turning on of the power switch (POWER) being driven during a start-up or recovery phase by a primary control loop, when the supply voltage (VDD) of the control circuit reaches or is over a preestablished enabling threshold of the control circuit, a secondary control loop comprising a photocoupler of the output error voltage (ERROR AMP) to an input (COMP) of the control circuitry (CONTROL) to which it is connected a compensation capacitor (CCOMP), includes the steps of discriminating an output short circuit condition from a start-up or recovery condition by comparing (COMP1) the voltage (V AUS ) present on said auxiliary winding (AUS) with a preestablished threshold (Vref1) higher than the voltage (V AUS ) that is induced on the auxiliary winding (AUS) under a short circuit condition of the secondary winding (N2) of the flyback transformer and by comparing the voltage existing on said compensation capacitor (CCOMP) with a second threshold (Vref2) of value equal or close to the value of maximum charge of said compensation capacitor (CCOMP), within a time interval sufficiently delayed from the turn-off instant of the power switch (POWER); conditioning, by means of a (SET CC) signal resulting from the logic combination (AND) of the signal originating from said two comparisons (OUTZC, OUTCOMP), in said interval of definite time (MONO1), the enabling upon turning on (FF2, FF1, DRIVER) of the Power switch (POWER).

Abstract translation: 一种防止DC-DC反激转换器的输出的持续短路的影响的方法，其以可变频率自振荡或以不连续的方式以固定频率工作，使用用于存储和传送能量的变压器 具有辅助绕组（AUS），用于在以可变频率自振荡的情况下在初级绕组中的零电流条件下驱动变压器的绕组（N1）的电源开关（POWER）的导通同步 ，其中从在所述辅助绕组（AUS）上的变压器的次级绕组（N2）中流动的电流感应回来的电压被整流和滤波（D2，C2）以在稳定运行状态期间对所述控制电路 控制），当控制电路的电源电压（VDD）达到或超过ap时，电源开关（POWER）的启动在启动或恢复阶段由主控制回路驱动 重新建立控制电路的使能阈值，包括输出误差电压（ERROR AMP）的光电耦合到其连接有补偿电容器（CCOMP）的控制电路（CONTROL）的输入（COMP）的二次控制回路包括 通过将存在于所述辅助绕组（AUS）上的电压（VAUS）与高于所述电压（VAUS）的预定阈值（Vref1）进行比较（COMP1）（COMP1），将所述输出短路状况与所述启动或恢复条件区分开的步骤， 在回扫变压器的次级绕组（N2）的短路状态下在辅助绕组（AUS）上感应，并且将存在于所述补偿电容器（CCOMP）上的电压与值等于或等于的值的第二阈值（Vref2）进行比较 在从功率开关（POWER）的关断瞬间充分延迟的时间间隔内，与所述补偿电容器（CCOMP）的最大充电值相对应; 在所述定时时间间隔（MONO1）中，通过来自所述两个比较（OUTZC，OUTCOMP）的信号的逻辑组合（AND）产生的（SET CC）信号进行调理， ，FF1，DRIVER）。

公开(公告)号：EP0991170B1

公开(公告)日：2003-11-26

申请号：EP98830568.6

申请日：1998-09-28

Applicant: STMicroelectronics S.r.l.

Inventor： Spampinato, Sergio Tommaso ,  Tagliavia, Donato

IPC: H02M3/335 ,  H02M1/00

CPC classification number: H02M1/32 ,  H02M3/33523