JPS6349112Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a ringing chcke converter, and in particular provides a converter that can suppress the rush current of the input capacitor and easily adjust the rise time of the converter output. . The present invention will be explained in detail below using the drawings. Figure 1 is a circuit diagram of one embodiment of this invention. In the figure, AC is an alternating current power supply, and SW
is a power on/off switch, RF is a full-wave rectifier, R1 and S are resistors and thyristors connected in parallel, and are a DC power supply (between the rectified outputs) and an input capacitor C ₁
The inrush current of the capacitor _C1 is prevented. Next, _T1 is an output transformer, the primary winding _N1 of which is connected in series with the switching transistor _Q1 , and connected to both ends (DC output ends) of the capacitor _C1 . NS is an auxiliary winding of the transformer _T1 , one end of which is connected to one terminal of the primary winding _N1 , and the other end connected to the gate G of the thyristor S via the diode _D1 and resistor _R2 . , forming the gate circuit of the thyristor S. NB is a base winding connected between the base and emitter of transistor _Q1 via current limiting resistor _R3 . _N2 is a secondary (output) winding _D2 , _C2 is an output rectifier diode and a capacitor, and _R4 and _R5 are resistors forming a voltage divider circuit for starting the transistor _Q1, and are connected to the capacitor.
Connected between one end of C ₁ and the base of transistor Q ₁ . _C3 is an auxiliary capacitor connected between the voltage dividing point of the resistors _R4 and _R5 and the other end of the capacitor _C1 ,
A time constant circuit is formed together with the resistor _R4 . In addition,
R ₆ is a supplementary resistor. The circuit of the present invention is configured as described above. In the above configuration, when the switch SW is turned on, the capacitor _C1 is prevented from inrush current by the resistor _R1 , and starts charging while being limited by the resistor _R1 . Therefore, before the charging of the capacitor C ₁ is completed, a starting current flows through the starting voltage divider circuit and the transistor Q ₁ starts operating, and the power switch SW - resistor R ₁ - primary winding N ₁ - transistor Q ₁ Current flows through the path of the resistor R1, and a voltage with the same polarity as the primary winding _N1 is generated in the auxiliary winding NS, giving a gate signal to the thyristor S and making it conductive.As a result, both ends of the resistor _R1 Thyristor S causes a short circuit. Therefore, when the transistor _Q1 switches, an inrush current flows through the capacitor _C1 , and if the power switch SW is turned on and off frequently, the inrush current causes deterioration of the power switch and the capacitor _C1 , shortening its life. This may cause problems such as For this reason, conventional methods have been adopted such as introducing a delay signal from the outside to delay the firing of the thyristor S or providing another delay circuit, but this method has the disadvantage of making the device complicated and expensive. There is. However, according to the present invention, the above-mentioned drawbacks are solved at once by adding a simple circuit. In other words, by connecting the auxiliary capacitor C ₃ to one end of the starting voltage dividing resistors R ₄ and R ₅ , the starting current flowing through the resistors R ₄ and R ₅ of the transistor Q ₁ is reduced by the resistance.
The charging time constant (in time) of R ₄ and capacitor C ₃ is bypassed by capacitor C ₃ during which activation of transistor Q ₁ is delayed. Therefore, the charging time constant of resistor R ₄ and capacitor C ₃ , i.e. the transistor
If the operation delay time of Q ₁ is set in advance around the time when the capacitor C ₁ is fully charged, the capacitor ₁ will be fully charged when the switching operation starts, so inrush current of the capacitor C ₁ can be prevented. Since the charging voltage is almost constant, the switching operation at startup is stable, and at the same time, it is possible to prevent deterioration of capacitor _C1 due to inrush current.Also, by setting this charging time constant arbitrarily, the rise timing of the converter output can be easily adjusted. Can be adjusted. After starting the transistor Q ₁ , the base current is supplied through the base winding NB due to the action of the transformer T ₁ , and the collector current of the transistor Q ₁ increases linearly, but the base current is limited to a predetermined value. After the transistor Q ₁ reaches saturation, it becomes non-conducting (CFF) and performs the well-known operation of transferring the energy previously stored in the transformer T ₁ through the diode D ₂ and the capacitor C ₂ to generate an output VO ₁ . . Note that the charge in the capacitor C ₃ is discharged through the resistor R ₅ when the transistor Q ₁ is turned off to prepare for the next startup operation.
Figures 2a and 2b are circuit diagrams and explanatory diagrams of other embodiments of the present invention. This embodiment shows an example in which the present invention is applied to a multi-output converter.
Another converter unit CNV having a common rush current prevention circuit consisting of a resistor _R1 and a resistor R1 is added, and its output _VO2 is set to the output voltage of the first converter unit.
VO is set to a value higher than ₁ . and resistance
Charging time constant of R41 and auxiliary capacitor C31 (t=
C31・R41) is the time constant of the first converter (t=
C3/R4) is set longer. Therefore, when the switch SW is turned on, as shown in Figure 2b, after a delay of time _t1 , the output voltage of the first converter is
There is an advantage that an output rise sequence in a so-called multi-output power supply in which VO ₁ rises and, after a delay of time t ₂ , the output voltage VO ₂ of the second converter CNV rises can be easily achieved. In the above embodiments, an example of a two-output converter has been explained, but the output may be even more multi-output. It is also possible to run the converters in parallel by matching their capacities. As is clear from the above explanation, the present invention has a simple structure and can prevent inrush current in the capacitor, thereby stabilizing the operation and protecting the capacitor or other components.Furthermore, it can be applied to multi-output power supplies, etc. This has great practical effects, such as the ability to easily achieve the rising sequence of each output stage.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams of one embodiment of the present invention. In the figure, AC is an alternating current power supply, SW is a power switch, RF ₁ is a full-wave rectifier, S is a thyristor, R ₁ ,
R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₃₁ , R ₄₁ , R ₅₁ , R ₆₁ are resistors, T ₁ , T ₂ are output transformers, N ₁ , N ₂ , NB,
NS is the primary winding, secondary winding base winding and auxiliary winding, Q ₁ , Q ₁₁ are switching transistors, D ₁ ,
D ₂ , D ₂₁ are rectifier diodes, C ₁ , C ₁₁ , C ₂ , C ₃ ,
C ₃₁ is the capacitor, VO ₁ and VO ₂ are the output voltage, CNV
is a converter unit.

Claims (1)

[Scope of utility model registration request] In a ringing chain converter, in which a capacitor is connected between DC power sources through a parallel circuit of a resistor and a thyristor, and a primary winding of an output transformer and a conversion transistor are connected in series between terminals of the capacitor, one end of the capacitor A resistor voltage divider circuit for starting the transistor is connected between the base of the voltage divider circuit and the base of the transistor, and a second capacitor is connected between the voltage divider point of the voltage divider circuit and the other end of the capacitor to form a time constant circuit together with the resistor. A ringing-choke converter, characterized in that the start-up current of the transistor is bypassed through the time constant circuit to delay the start-up of the transistor by the time constant period, thereby controlling the rise of the converter output.