JPS5932220Y2 - Ringing choke converter - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a ringing choke converter.

A ringing choke converter, as illustrated in FIG. 1, connects windings N1 . By applying positive feedback from the collector side to the base side of the transistor Q1 using N3, and thereby causing blocking oscillation operation,
The configuration is such that a rectified DC input provided by a full-wave rectifier diode D1 and a capacitor C1 is switched, and the switched output is taken out via a winding N2 of a transformer T1 and a diode D2.

R1, R2, R3 are resistors, C3, C4 are Zener diodes, D.

D is a diode, C3 and C4 are capacitors, transistor Q1, transformer winding N1. Together with N3, it constitutes a floraking generation circuit.

When starting up the ringing choke converter described above, when AC power is turned on from terminals a and b, a large surge current flows, partly because the input impedance seen from the power supply side is low.

This surge current causes burn-out of switches connected to the AC power input circuit and adversely affects other devices connected to the same power line.

Therefore, conventionally, a surge current limiting resistor R4 is inserted and connected in series with the power supply line to increase the input impedance and reduce the surge current to an appropriate value when the AC power is turned on, while at the same time keeping the surge current attenuated. After a certain period of time, the thyristor SCR connected in parallel to the resistor R4 is turned on to form a short circuit that bypasses the resistor R4, thereby preventing burnout of the resistor R4 and wasting power, etc., which occur during normal operation.

However, since a surge current flows even when the thyristor SCR is turned on, further countermeasures are required.

In this case, the surge current is generated by the AC line, input filter,
Although limited by the impedance of the rectifier diode D1, capacitor C1, and thyristor SCR, the rectified peak voltage of the full-wave rectifier diode D1 and the capacitor C1
The greater the difference between the voltages Vc1 across the , the larger the peak value.

Therefore, in the past, as a circuit for triggering the thyristor SCR, a dedicated winding N4 was provided in the transformer T1 as shown in FIG. , diode D
7. Rectified and smoothed by capacitor C3, and further by resistor R
5. After the voltage difference between the rectified peak voltage and the voltage Vc1 across the capacitor C1 becomes sufficiently small by integrating the signal through the integrating circuit constituted by the capacitor C6 and supplying this signal to the gate of the thyristor SCR. , to trigger the thyristor SCR.

However, since the range of the trigger level of the thyristor SCR is wide, the time from when the power is turned on until the thyristor SCR is triggered is not constant, making it very difficult to obtain the desired surge current reduction effect.

For example, in the starting characteristic diagram shown in FIG. 2 a1, time t.

When the AC power is turned on, and the capacitor C1 is charged with the rectified voltage VD1, the ringing choke converter will start at time t1 when the voltage Vc1 across the capacitor C1 reaches the starting voltage vB. Since the range of the trigger level of the thyristor SCR is wide, the thyristor SCR may be triggered at 11 at startup or at a slightly delayed time.

In this case, the peak value vDp of the rectified voltage vD1 when the thyristor SCR is turned on and the voltage across the capacitor v
The voltage difference with c1 is equal to the difference (VD, -VB) between the peak value VDp of the rectified voltage VD1 and the starting voltage vB, but since it is necessary to start the converter even at the lowest allowable input voltage, the previous voltage difference (VDp-VB) is set to a fairly large value at the maximum allowable input voltage.

Therefore, when the thyristor SCR is turned on, a very large surge current P occurs as shown in Figure 2 a2.
2 flows, making it impossible to obtain the desired surge current reduction effect.

Among them, P in Figure 2 a2 is the resistor R4 when the AC power is turned on.
It shows the surge current limited by.

Furthermore, when configuring a power supply having multiple ringing choke converters and attempting to sequence control the output of each ringing choke converter, conventionally, a sequence control circuit was provided separately, and the sequence control created here Each ringing choke converter is controlled in sequence by the signal, which results in a complicated circuit configuration and an increase in the number of parts, resulting in a disadvantage in terms of cost.

This invention eliminates the above-mentioned drawbacks, has a high surge current reduction effect, and has a ringing choke.

An object of the present invention is to provide a ringing choke converter that facilitates sequence control when turning on a power supply having a plurality of converters.

In order to achieve the above object, the ringing choke converter according to the present invention includes a rectifier circuit that rectifies an AC input, a smoothing circuit that smoothes the rectified output of the rectifier circuit, a transformer, and a ringing choke converter that is connected to the transformer. a ringing choke converter comprising a blocking oscillator that switches a DC input provided from the smoothing circuit, including a switching element, and a circuit that converts the switching output taken out through the transformer into DC and outputs the DC input; A surge current limiting circuit consisting of a parallel circuit of a resistor and a switching element is inserted and connected to the input line before the smoothing circuit, and a resistor forming the starting circuit is connected to a starting circuit of the switching element forming the blocking oscillation section. A time constant charging circuit serving as a charging resistor is connected, and a winding is further provided in the transformer to conductively connect a trigger circuit of the switching element to the surge current limiting circuit, and the time constant depends on the time constant of the charging circuit. After starting the blocking oscillator with a delay time of , the voltage signal generated in the winding of the transformer is supplied to the switching element of the surge current limiting circuit through the trigger circuit to make it conductive.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The content of the present invention will be specifically explained in detail below with reference to the accompanying drawings, which are examples.

FIG. 3 is an electrical circuit connection diagram of the ringing choke converter according to the present invention.

In the figure, the same reference numerals as in FIG. 1 indicate components having the same functions.

In this example, transistor Q1, transformer T1, resistors R1-R3, capacitor C3sC4b and diode D
A time constant charging circuit consisting of a resistor R1 and a capacitor C7 is connected to the input side of the blocking oscillation section consisting of blocks 3 to D6, and a trigger consisting of a diode D8 and resistors R6 and R7 is connected to the winding N4 of the transformer T1. The circuit is connected so that the trigger circuit drives the gate of the thyristor SCR.

Next, Figure 4 a1. The starting operation of the above-mentioned ringing choke converter according to the present invention will be explained in detail with reference to the starting characteristic diagram shown in a2.

4 a1, time t.

If AC power is turned on at this moment, resistor R4
A primary peak P1 of the surge current is generated, which is limited by .

At the same time as the AC power is turned on, rectified voltage VDI is applied to capacitor C1, and the voltage across capacitor C1 increases according to curve Vc1.

On the other hand, the capacitor C7 that constitutes the time constant charging circuit is charged via the resistor R1, but since the charging time constant of this time constant charging circuit is thicker than that of the capacitor C1, the capacitor C7 The voltage across the capacitor C1 is as shown by the curve VC7, and the rising curve of the voltage across the capacitor C1 is vC.
It will be slower than 1.

When the voltage Vc7 across the capacitor C7 reaches the starting voltage vB after time t1, the button is pressed at time t1 and the blocking oscillation section starts oscillating.

Simultaneously with the activation of the blocking oscillator, a voltage is induced in the winding N4 of the transformer T1, and the diode D8, resistor R6,
A trigger circuit consisting of R7 turns on thyristor SCR, which short-circuits resistor R4.

On the other hand, the voltage Vc7 across the capacitor C7 is the starting voltage vB
At the moment (time 11), the voltage Vc1 across the capacitor C1 rises to near the peak value VDp of the rectified voltage VD1, and the voltage difference between the two terminals (Vnp - Vc1) increases.
'J): Very small.

Therefore, since the thyristor SOR turns on at the time when the difference between the peak value VDp of the rectified voltage VD1 and the voltage VclO across the capacitor C1 becomes small, the surge current peak value when the thyristor SCR turns on is as shown in FIG. It is limited to a very small value, such as P2 of a2.

Since the starting time t1 is determined by the time constants R1 and C7, by appropriately selecting these, the starting time t1 can be set arbitrarily.

Therefore, a power supply device equipped with multiple ringing choke converters is equipped with a ringing choke converter.
When sequentially controlling the output of a choke converter, by appropriately selecting the values of time constants R1, C7 and diode D3 for each ringing choke converter, the output sequence can be controlled without providing a separate sequence control circuit. Control becomes possible.

Among them, the thyristor SCR can also be replaced by another switching element.

Furthermore, it goes without saying that the blocking oscillation section is not limited to the circuit configuration shown in the embodiment, and may have other circuit configurations.

As described above, the ringing choke converter according to the present invention includes a rectifier circuit that rectifies an AC input, a smoothing circuit that smoothes the rectified output of the rectifier circuit, a transformer, and a switching circuit connected to the transformer. A ringing choke converter includes a blocking oscillator that switches the DC input provided from the smoothing circuit, and a circuit that converts the switching output taken out through the transformer into DC and outputs the DC input. A surge current limiting circuit consisting of a parallel circuit of a resistor and a switching element is inserted and connected to the input line before the circuit, and the resistor forming the starting circuit is charged to the starting circuit of the switching element forming the blocking oscillation section. A time constant charging circuit, which is a resistor, is connected to the transformer, and a winding is provided to conductively connect the trigger circuit of the switching element applied to the surge current limiting circuit to the transformer, and a delay depending on the time constant of the time constant charging circuit is provided. After activating the blocking oscillator in time, the voltage signal generated in the winding of the transformer is supplied to the switching element of the surge current limiting circuit through the trigger circuit to turn it on.
The peak value of the surge current that occurs when the AC power source is turned on and when the switching element is turned on can be significantly reduced.

In addition, when a power supply device equipped with multiple ringing choke converters is turned on, sequence control at power-on can be easily performed by adjusting the time constant of the time constant charging circuit without the need for a sequence control circuit. There are excellent effects such as being able to be realized.

Furthermore, the circuit configuration uses the voltage generated in the transformer winding after the blocking oscillator starts up as a trigger signal, which simplifies the trigger circuit and improves reliability, while also simplifying the overall circuit configuration. , miniaturization and cost reduction can be achieved.

In addition, the voltage generated in the transformer winding is usually stabilized by the action of a voltage stabilization circuit, etc., so a stable trigger signal can be obtained and the switching element of the surge current limiter can be stably triggered. becomes possible.

[Brief explanation of drawings]

Fig. 1 is an electric circuit connection diagram of a conventional ringing choke converter, and Fig. 2 a1. Similarly, a2 is its starting characteristic diagram, FIG. 3 is an electric circuit connection diagram of the ringing choke converter according to the present invention, and FIG. 4 is 81. Similarly, a2 is the starting characteristic diagram. DI'D2 = D5-D8...Diode, D3
．． D4...Zener diode, R1-R8...Resistor, C1-C6...Capacitor %Q1...Transistor, T1...Transformation amount, N1-N4...Winding, S
CR...Switching element.

Claims (1)

[Scope of utility model registration request] A blocking oscillation circuit that includes a rectifier circuit that rectifies an AC input, a smoothing circuit that smoothes the rectified output of the rectifier circuit, a transformer, and a switching element connected to the transformer that switches the DC input provided from the smoothing circuit. and a circuit for converting the switching output taken out through the transformer into DC and outputting the same, the ringing choke converter has a parallel circuit of a resistor and a switching element on the input line before the smoothing circuit. A surge current limiting circuit is inserted and connected, a time constant charging circuit whose charging resistor is a resistor forming the starting circuit is connected to the starting circuit of the switching element forming the blocking oscillation section, and a time constant charging circuit is connected to the starting circuit of the switching element forming the blocking oscillator. After providing a winding that conductively connects the trigger circuit of the switching element to the surge current limiting circuit and starting the blocking oscillator with a delay time that depends on the time constant of the time constant charging circuit,
A through-ringing, choke converter characterized in that a voltage signal generated in the winding of the transformer is supplied to a switching element of the surge current limiting circuit through the trigger circuit to make it conductive.