Abstract:
A power convertor includes a transformer, a filtering unit, an isolating unit, a starting unit, a rectifier, an accelerating capacitor, a controlling module and an auxiliary capacitor. The filtering unit is electrically connected to the transformer and the isolating unit. The accelerating capacitor is electrically connected to the rectifier and the isolating unit. The starting unit is electrically connected to the rectifier, the isolating unit, the accelerating capacitor, the controlling module and the auxiliary capacitor. The power convertor is shut down when the controlling module enters a latch mode. The isolating unit is configured to prevent an electric power stored in the filtering unit from entering the starting unit when the controlling module leaves the latch mode. The accelerating capacitor obtains a voltage level and rapidly charges to the auxiliary capacitor to make the power convertor restart when the controlling module leaves the latch mode and resets.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Field of the Invention 
         [0002]    The present invention relates to a power apparatus, and especially relates to a power convertor. 
         [0003]    Description of the Related Art 
         [0004]    As technology grows, electronic products are very important for our daily life. The power sources of the electronic products are mainly the direct current power. However, the wall socket mainly provides the alternating current power. Therefore, the power convertor is usually arranged inside the electronic product to convert the alternating current power into the direct current power to supply power to other components inside the electronic product. 
         [0005]    Generally speaking, the power convertor has a latch circuit which can stop the power convertor outputting power when the user operates the electronic product incorrectly. Therefore, the electronic product is protected when the electronic product is operated incorrectly or abnormally. 
         [0006]    When the latch circuit of the power convertor is started (namely, when the power convertor enters a latch mode), the electronic product cannot be operated by the input commands from the user. At this time, most of the users will remove the plug of the electronic product from the wall socket, and then will re-plug the plug of the electronic product into the wall socket, so that the latch function provided by the latch circuit is terminated. However, even if the re-plug action mentioned above is executed, the latch circuit cannot terminate the latch function in a short time. This will result that the user thinks that the electronic product having the power convertor is faulted, so that the user may return the electronic product or raise customer complaints. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a power convertor comprising a transformer, a filtering unit, an isolating unit, a starting unit, a rectifier, an accelerating capacitor, a controlling module and an auxiliary capacitor. The filtering unit is electrically connected to the transformer. The isolating unit is electrically connected to the filtering unit. The starting unit is electrically connected to the isolating unit. The rectifier is electrically connected to the starting unit and the isolating unit. The accelerating capacitor is connected to the rectifier in parallel. The controlling module is electrically connected to the transformer and the starting unit. A power switch of the power convertor is electrically connected to the transformer and the controlling module. The auxiliary capacitor is electrically connected to the starting unit and the controlling module. The power convertor is shut down (namely, the power convertor stops outputting a power) when the controlling module enters a latch mode. The isolating unit is configured to prevent an electric power stored in the filtering unit from entering the starting unit when the controlling module leaves (namely, terminates or stops) the latch mode. The accelerating capacitor obtains (namely, establishes) a voltage level and rapidly charges to the auxiliary capacitor to make the power convertor restart (namely, to re-output the power) when the controlling module leaves the latch mode and resets. 
         [0008]    The starting unit mentioned above can comprise a first starting resistor and a second starting resistor. The first starting resistor is connected to the second starting resistor in series. Moreover, the first starting resistor is electrically connected to the rectifier, the isolating unit and the accelerating capacitor. The second starting resistor is electrically connected to the auxiliary capacitor and the controlling module. 
         [0009]    Moreover, the filtering unit mentioned above can comprise two filtering capacitors and a filtering inductor. The filtering inductor can be a common mode inductor. The two filtering capacitors are connected to two sides of the filtering inductor respectively. 
         [0010]    Moreover, the transformer mentioned above can comprise a primary winding and an auxiliary winding. The primary winding and the auxiliary winding are coupled to each other. The primary winding is electrically connected to the filtering unit. The auxiliary winding is electrically connected to an auxiliary rectifying component. 
         [0011]    In one of the embodiments of the present invention, the power convertor further comprises a breaker, an absorbing circuit and the auxiliary rectifying component. The breaker is electrically connected to the rectifier. The absorbing circuit is connected between the filtering unit and the transformer. The absorbing circuit comprises an absorbing resistor, an absorbing capacitor and an absorbing diode. The absorbing resistor and the absorbing capacitor are connected in parallel. A cathode of the absorbing diode is electrically connected to the absorbing resistor and the absorbing capacitor. An anode of the absorbing diode is electrically connected to the power switch and the transformer. The auxiliary rectifying component is electrically connected to the transformer and the controlling module. The auxiliary rectifying component and the auxiliary capacitor form an auxiliary rectifying unit. 
     
    
     
       BRIEF DESCRIPTION OF DRAWING 
         [0012]      FIG. 1  shows a block diagram of the power convertor of the present invention. 
           [0013]      FIG. 2  shows a circuit diagram of the power convertor of the present invention. 
           [0014]      FIG. 3  shows a voltage waveform diagram of the controlling module of the power convertor when resetting. 
           [0015]      FIG. 4  shows a voltage waveform diagram of the VB. 
           [0016]      FIG. 5  shows a voltage waveform diagram of the Vcc. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]      FIG. 1  shows a block diagram of the power convertor of the present invention.  FIG. 2  shows a circuit diagram of the power convertor of the present invention. A power convertor is connected between an input power AC and an electronic apparatus (not shown in  FIG. 1  or  FIG. 2 ). The power convertor converts an alternating current power provided by the input power AC into a direct current power suitable for the electronic apparatus. The electronic apparatus is connected to an output side Vout of the power convertor. Moreover, the power convertor and the electronic apparatus can be combined as an electronic product (not shown in  FIG. 1  or  FIG. 2 ). The electronic product is connected to the input power AC and receives the alternating current power provided by the input power AC. Moreover, the alternating current power received by the electronic product is converted into the direct current power by the power convertor, and then the direct current power is transmitted to the electronic apparatus to execute user input commands. 
         [0018]    The power convertor comprises a transformer TR, a breaker  110 , a rectifier  120 , a filtering unit  130 , a power switch  140 , a controlling module  150 , an auxiliary rectifying unit  160 , an absorbing circuit  170 , a starting unit  180 , an accelerating capacitor  192  and an isolating unit  194 . 
         [0019]    The transformer TR comprises a primary winding Wp, a secondary winding Ws and an auxiliary winding Wa which are coupled to each other. The output side Vout of the power convertor is electrically connected to the secondary winding Ws through the rectifying diode  200  and the output filter  210 . Moreover, an anode of the rectifying diode  200  is connected to the secondary winding Ws. A cathode of the rectifying diode  200  is connected to the output filter  210  and the output side Vout. 
         [0020]    The breaker  110  is connected between the input power AC and the rectifier  120 . In a normal usage condition, the breaker  110  conducts the input power AC to the rectifier  120 , and maintains normal operations of the input power AC and the rectifier  120 . If the input power AC generates a surge, the breaker  110  is turned off (namely, not conducted) so that the rectifier  120  is isolated from the input power AC. The breaker  110  can be a fuse or a fused switch. In  FIG. 2 , the breaker  110  is a fuse. 
         [0021]    The rectifier  120  is, for example, a bridge rectifier which is connected between the breaker  110  and the primary winding Wp to rectify the alternating current power provided by the input power AC to generate a pulse direct current power to output. 
         [0022]    The filtering unit  130  is connected between the rectifier  120  and the primary winding Wp to restrain an electromagnetic interference and to filter the pulse direct current power. The filtering unit  130  comprises a filtering capacitor  132 , a filtering capacitor  134  and a filtering inductor  136 . The filtering capacitor  132  and the filtering capacitor  134  are connected to two reverse sides of the filtering inductor  136  respectively. In  FIG. 2 , the filtering inductor  136  is a common mode inductor. The filtering capacitor  132  is connected between the rectifier  120  and the filtering inductor  136 . The filtering capacitor  134  is connected between the filtering inductor  136  and the primary winding Wp. 
         [0023]    The power switch  140  is electrically connected to the primary winding Wp. In  FIG. 2 , the power switch  140  is a metal oxide semiconductor field effect transistor. A drain of the power switch  140  is connected to the primary winding Wp and the absorbing circuit  170 . A gate of the power switch  140  is connected to controlling module  150 . A source of the power switch  140  is connected to ground. 
         [0024]    The controlling module  150  is electrically connected to the auxiliary rectifying unit  160  and the starting unit  180 . The controlling module  150  comprises a signal input side Sin and a pulse width modulator  152 . The signal input side Sin can be, for example, connected to a microprocessor (not shown in  FIG. 1  or  FIG. 2 ) or an abnormal detection circuit (not shown in  FIG. 1  or  FIG. 2 ) of the electronic product or the electronic apparatus. When the electronic product or the electronic apparatus is in an abnormal operation, the microprocessor or the abnormal detection circuit mentioned above will send an abnormal signal to the controlling module  150 , so that the controlling module  150  enters a latch mode. The pulse width modulator  152  outputs a pulse width modulation signal to the power switch  140 , so that the power switch  140  is switched between turned-on and turned-off. Moreover, a level of the power outputted from the output side Vout can be changed by controlling a duty cycle of the pulse width modulation signal. 
         [0025]    The auxiliary rectifying unit  160  is electrically connected to the auxiliary winding Wa. The auxiliary rectifying unit  160  comprises an auxiliary rectifying component  162  and an auxiliary capacitor  164 . In  FIG. 2 , the auxiliary rectifying component  162  can be, for example, a diode. An anode of the auxiliary rectifying component  162  is connected to the auxiliary winding Wa. A cathode of the auxiliary rectifying component  162  is connected to the auxiliary capacitor  164 , the controlling module  150  and the starting unit  180 . The auxiliary winding Wa and the auxiliary rectifying unit  160  provides a required power to the controlling module  150  when operating. A turn ratio of the auxiliary winding Wa can be adjusted according to the required power of the controlling module  150 , so that a level of the direct current power outputted by the auxiliary winding Wa is different from a level of the direct current power outputted by the secondary winding Ws. 
         [0026]    The starting unit  180  comprises a first starting resistor  182  and a second starting resistor  184 . The first starting resistor  182  is connected to the second starting resistor  184  in series. A side (which is not connected to the second starting resistor  184 ) of the first starting resistor  182  is connected between the rectifier  120  and the filtering unit  130 . A side (which is not connected to the first starting resistor  182 ) of the second starting resistor  184  is connected between the auxiliary rectifying component  162 , the auxiliary capacitor  164  and the controlling module  150 . 
         [0027]    The absorbing circuit  170  is connected between the filtering unit  130 , the primary winding Wp and the power switch  140 . The absorbing circuit  170  comprises an absorbing resistor  172 , an absorbing capacitor  174  and an absorbing diode  176 . The absorbing resistor  172  and the absorbing capacitor  174  are connected in parallel. One side of the absorbing resistor  172  and one side of the absorbing capacitor  174  are connected between one side of the filtering unit  130  and one side of the primary winding Wp. The other side of the absorbing resistor  172  and the other side of the absorbing capacitor  174  are connected to a cathode of the absorbing diode  176 . An anode of the absorbing diode  176  is connected to the drain of the power switch  140 . 
         [0028]    The accelerating capacitor  192  and the rectifier  120  are connected in parallel. The isolating unit  194  is electrically connected between the rectifier  120  and the filtering unit  130 . In  FIG. 2 , an anode of the isolating unit  194  is connected to the rectifier  120  and the starting unit  180 . A cathode of the isolating unit  194  is connected to the filtering unit  130 . 
         [0029]    When the electronic apparatus is operated normally (for example, the signal input side Sin of the controlling module  150  does not receive the abnormal signal), the power convertor receives the alternating current power outputted from the input power AC. The alternating current power is processed through the rectifier  120 , the filtering unit  130  and the primary winding Wp, and then is coupled to the secondary winding Ws. The rectifying diode  200  rectifies the power which is coupled to the secondary winding Ws to obtain the half-wave direct current power. The output filter  210  filters out the ripple component of the half-wave direct current power, so that the output side Vout outputs the direct current power which is smooth to the electronic apparatus. 
         [0030]    When the electronic apparatus is operated abnormally (for example, the signal input side Sin of the controlling module  150  receives the abnormal signal), the controlling module  150  enters the latch mode to stop the output side Vout of the power convertor outputting power to the electronic apparatus to protect the electronic apparatus. 
         [0031]    Then, when the controlling module  150  leaves the latch mode (for example, the user removes the plug of the electronic product from the wall socket), the isolating unit  194  is used to avoid the power stored in the filtering unit  130  reversely recharging to the starting unit  180 . Moreover, when the controlling module  150  leaves the latch mode and resets (for example, the user re-plugs the plug of the electronic product into the wall socket), the accelerating capacitor  192  obtains (namely, establishes) a voltage level (as shown in  FIG. 4  and would be described later) to rapidly charge to the auxiliary capacitor  164  to make the power convertor restart (namely, re-output power). 
         [0032]      FIG. 3  shows a voltage waveform diagram of the controlling module of the power convertor when resetting. In  FIG. 3 , the dash line indicates the power curve of the related art power convertor, the solid line indicates the power curve of the power convertor of the present invention, Vcc indicates the power transmitted to the controlling module  150 , Vreset indicates the reset power level of the controlling module  150 , and t indicates time. Moreover, after the electronic product is reset, the power of the controlling module  150  has to be lower than the reset power level (namely, the Vreset), so that the controlling module  150  can be reset. In  FIG. 3 , after the electronic product is reset, the time (t 2 ) that the controlling module  150  of the power convertor of the present invention draws down to the reset status is shorter than the time (t 1 ) that the related art power convertor draws down to the reset status. 
         [0033]      FIG. 4  shows a voltage waveform diagram of the VB. A power waveform A shown in  FIG. 4  indicates the waveform of the point VB of the power convertor with the accelerating capacitor  192 . A power waveform B shown in  FIG. 4  indicates the waveform of the point VB of the power convertor without the accelerating capacitor  192 . As the power waveform A and the power waveform B shown in  FIG. 4 , after the electronic product is reset, the voltage of the point VB of the power convertor with the accelerating capacitor  192  is higher than the voltage of the point VB of the power convertor without the accelerating capacitor  192 , so that the auxiliary capacitor  164  is rapidly charged. Moreover,  FIG. 5  shows a voltage waveform diagram of the Vcc. A power waveform C shown in  FIG. 5  indicates the waveform of the point VCC of the power convertor with the accelerating capacitor  192 . A power waveform D shown in  FIG. 5  indicates the waveform of the point VCC of the power convertor without the accelerating capacitor  192 . As shown in  FIG. 5 , the starting time (the power waveform C) of the controlling module  150  of the power convertor with the accelerating capacitor  192  is shorter than the starting time (the power waveform D) of the controlling module  150  of the power convertor without the accelerating capacitor  192 . 
         [0034]    After the electronic product is operated abnormally and then is reset, the time that the controlling module  150  draws down to the normal operation is shorter than the time that the related art power convertor draws down to the normal operation, to avoid the user thinking that the electronic product is faulted or the system is faulted, and to avoid the user returning the electronic product or raising customer complaints. 
         [0035]    Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.