JPS60216768A - Switching power source - Google Patents

Abstract

PURPOSE:To early drop the partial output voltage from the other output voltages by applying the rising waveform of the pulse generated in a rectified voltage of a flyback converter system to a controller of a stabilized power source. CONSTITUTION:Feed-forward converter type rectifiers 8, 8', a flyback converter type rectifier 12, loads 9, 9', 9'' and bleeder resistors 13, 13', 13'' are connected to the secondary side of a switching transformer 3. A transient voltage is generated to a flyback rectifier 12 when the primary AC power source is turned OFF. A transient voltage is detected by a detector 21 and applied to a time constant circuit 25. The output of the circuit 25 operates the controller 23 of a stabilized power source through a switching circuit 22 to abruptly drop the feed-forward rectified voltage VB.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is applicable to power supply voltage OFF, such as a three-power supply CPLI (Central Processing Unit).
The present invention relates to a switching power supply device used in a power supply circuit such as a logic circuit that sometimes requires a sequence.

The configuration of the conventional example and its problems Before going into the explanation of the conventional sequence circuit, let us explain the feed forward converter 75N- in the switching regulator.
Differences in structure and characteristics between the evening type and the flyhack combination type will be explained with reference to FIGS. 1, 2, and 3. In FIG. 1, 1 is a switching transistor, 2 is a power supply line smoothing capacitor, 3 is a switching transformer, 8 is a feedforward converter type rectifier circuit, and diodes 4, 5. Choke coil 6, capacitor 7
12 is a fly-hack converter type rectifier circuit, which is composed of a diode 10 and a capacitor 11. 9.9' is the load. vl is the collector voltage waveform of switching transistor 1, vl is the primary rectified voltage, v2 is the feedforward converter output voltage waveform before rectification, v2 is the feedforward converter output voltage after rectification, and v3 is the flywheel voltage before rectification. 3 represents the buck converter output voltage waveform, and 3 represents the fly bank converter output voltage after rectification.

The feedforward converter is called the ON10N method, and is a converter method that transmits power to the secondary side during the ON period of the switching transistor 1, as shown in Fig. 2 (A
> collector voltage waveform V of switching transistor 1
1, and FIG. 2(B) shows the feedforward converter output voltage waveform v2 before rectification, and also shows the phase relationship between the two types of pressure. In addition, the flybank converter
It is called the 0N10FF method and is a converter method that transmits power to the secondary side during the OFF period of the switching transistor 1. Fig. 2(C) shows the flybank converter output voltage waveform v3 before rectification. The phase relationship between vl and v3 is shown together with (A).

Here, the falling characteristics of the feedforward rectified voltage and the flybank rectified voltage when the primary AC voltage is OFF are expressed as
This will be explained using figures. In Figure 3, (A) is the primary AC
(B) shows the falling characteristic of the feedforward rectified voltage V2 when the primary AC voltage is OFF, and (C) shows the falling characteristic of the primary rectified voltage V2 when the primary AC voltage is OFF. This shows the falling characteristics of rectified voltage ■3. Further, Via is the primary rectified voltage value when the flyback rectified voltage V3 starts to rise transiently after the primary AC voltage is turned off. The primary AC voltage is now OFF
Then, the primary rectified voltage (■1) also turns off, but at the feedforward rectified voltage (■2), the primary rectified voltage V
The value of (2) before the primary AC voltage is turned off is held until it reaches a certain value (the lower limit value of the stabilized input voltage), and then it decreases. On the other hand, the flyback rectification voltage V3
When the primary rectified voltage V falls to a certain value Via, the voltage shows a transient increase characteristic, and then falls (Switching Regulator Design Method and Power (See page 70 of How to use the device J)
.

Now, a conventional example of a sequence circuit of a switching power supply device will be explained with reference to FIGS. 4 and 5, and FIGS. 6 and 7. Figures 4 and 5 show the trigger voltage for rapidly lowering one feedforward rectification voltage;
That is, they are a configuration diagram and a sequence diagram of a conventional example in which the input voltage of the control circuit of the stabilized power supply circuit is detected and shaped from the falling voltage of the other feedforward rectified voltage. In addition, Figures 6 and 7 show that the trigger voltage for rapidly decreasing the feedforward rectification voltage is set to 1.
Detected from the falling voltage of the next rectified voltage ■1.

FIG. 2 is a configuration diagram and a sequence diagram of a conventional example obtained by shaping and transmitting.

First, in Fig. 4, 2 is a power line smoothing capacitor, 3 is a switching transformer, 8 and 8' are feedforward converter type rectifier circuits, 9 and 9
' is a load, and 13 is a bleeder resistance. 19 is a stabilized power supply circuit, which includes series control transistors 14. Stabilized power supply circuit detection amplifier section 15° Output voltage detection resistor 16, 17.18
It consists of 20 is a smoothing capacitor, 21 is a detection circuit, 22 is a switching circuit, and 23 is a control circuit for a stabilized power supply circuit. Further, VA represents one of the feedforward rectified voltages, vB represents the other of the feedforward rectified voltages, and Vta represents the trigger voltage obtained by detecting and shaping the falling voltage of the feedforward rectification voltages. Note that the circuit configurations from 13' to 20' are the same as those from 13 to 20.

Next, the operation of the conventional example shown in FIG. 4 will be explained using a sequence diagram shown in FIG. Figure 5 (A) shows the primary AC voltage OFF.
3 shows the falling characteristics of the primary rectified voltage V1 at the time of the change. FIG. 5(B) shows the falling characteristic of one of the feedforward rectified voltages A when the primary AC voltage is OFF. Figure 5 (C
) detects the falling voltage of one feedforward rectified voltage VA.

The trigger voltage Vta obtained by shaping is shown. Figure 5 (D
) shows the falling characteristic of the other feedforward rectified voltage (3) which rapidly falls due to the trigger voltage Vta. Now, 1
When the next AC voltage is turned off, the primary rectified voltage (1) decreases as shown in FIG. 5(A). 5 At this time,
As already explained, the feedforward rectified voltages V^ and VB maintain the output values before the primary AC voltage was turned off until the value of the primary rectified voltage ■1 reaches the lower limit value of the input voltage to be stabilized. and then descends. Here, the detection circuit 21 detects a falling voltage of one feedforward rectified voltage VA.
The switching circuit 22 further obtains a trigger voltage Vta. When the trigger voltage Vta rises, the switching element in the control circuit 23 of the stabilized power supply circuit turns on, and the output voltage of the control circuit 23 drops to about O■. As a result, the base voltage of the series control transistor 14 in the stabilized power supply circuit 19 of the other feedforward rectification circuit 8 becomes approximately 0, and the emitter voltage of the series control transistor 14, that is, the other feedforward rectification voltage vB rapidly increases. It will go down. Here, the falling time of the other feedforward rectified voltage vB can be made earlier than that of the one feedforward rectified voltage ■4, and a certain degree of sequence can be obtained, but the starting time of both vA and vB voltage fall Since they are the same, it is impossible to obtain the desired sequence, that is, a sequence in which the falling start time of vB is earlier than that of (4).

Next, in Fig. 6, 2 is a smoothing capacitor for the power line, 3 is a switching transformer, 8°8' is a feedforward converter rectifier circuit, 9.9' is a load, and 13.13' is a bleeder resistor. , 19 and 19' are stabilized power supply circuits each including a stabilized power supply circuit detection amplification unit 15 and 15'. 20.20' is a smoothing capacitor, 21 is a detection circuit, 22 is a switching circuit, 23 is a control circuit for the stabilized power supply circuit, 24 is a photocoupler, and vtb detects the falling voltage of the primary rectified voltage V1. , represents the trigger voltage obtained by shaping. Next, the operation of the conventional example shown in FIG. 6 will be explained using a sequence diagram shown in FIG.

FIG. 7(A) shows the falling characteristic of the primary rectified voltage V1 when the primary AC voltage is OFF.

FIG. 7(B) shows the trigger voltage vtb obtained by detecting and shaping the falling voltage of the primary rectified voltage (1). Figure 7 (C)
indicates a drop characteristic to one feedforward rectified voltage V when the primary AC voltage is OFF. FIG. 7(D) shows the falling characteristic of the other feedforward rectified voltage vB, which rapidly falls due to the trigger voltage vtb. Now, primary AC
When the voltage is turned off, the primary rectified voltage V1 drops accordingly, so the detection circuit 21 detects this falling voltage of the primary rectified voltage 1, and the switching circuit 22 obtains the trigger voltage vtb. Here, this trigger voltage vtb
is transmitted from the primary side to the secondary side by the photocoupler 24, which is an insulated transmission element, and is applied to the control circuit 23 of the stabilized power supply circuit. Here, the trigger voltage vtb
The photocoupler 24 and the control circuit 23 of the stabilized power supply circuit are operated by the pulse signal, and as already explained, the other feedforward rectified voltage VB rapidly falls, so that the other feedforward rectified voltage VB
The fall start time of is earlier than that of feedforward rectified voltage ■6 when one trigger is not applied, and the desired sequence can be obtained, but in this case, the trigger voltage vtb is transmitted from the primary side to the secondary side. A photocoupler 24, which is an insulated transmission element, is required, which results in a complicated circuit and an increase in cost.

OBJECT OF THE INVENTION The object of the invention will be explained with reference to FIG. Figure 8 (A)
shows the falling characteristic of one feedforward rectified voltage ■A when the primary AC voltage is OFF. Figure 8 (B) is 1
The falling characteristic of the other feedforward rectified voltage VB when the next AC voltage is OFF is shown. This invention is shown in FIG.
), (B), when the primary AC voltage is turned off, the output voltage VB of one or more of the multiple rectifier circuits of the feedforward converter type decreases, causing the output voltage of the other rectifier circuits to decrease. It is an object of the present invention to provide a switching power supply device that can control the sequence time faster than the drop in voltage VA using a simple and low-cost circuit.

Structure of the Invention The switching power supply device of the present invention has a primary AC voltage OF
The detection circuit detects the pulse-like rising waveform that occurs in the rectified voltage of the flyback converter method at F time,
The output of the detection circuit is connected to the time constant circuit, the output of the time constant circuit is connected to the switching circuit, and the output of the switching circuit is connected to the control circuit of the stabilized power supply circuit. The output voltage of one or more of the rectifier circuits is made to fall faster than the output voltage of the other rectifier circuits, and the sequence time is controlled by the discharge time constant of the time constant circuit. It is characterized by.

Description of examples Examples of the present invention are shown in FIGS. 9 and 10 below.

This will be explained with reference to FIGS. 11 and 12. FIGS. 9 and 10 are a block diagram and a waveform diagram, respectively, of an embodiment of the present invention, and FIGS. 11 and 12 are specific circuit diagrams of an embodiment of the invention, respectively. In Figure 9, 2 is a power line smoothing condenser, 3 is a switching transformer, 8 and 8' are feedforward converter type rectifier circuits, 9.9' and 9'' are loads, and 12 is a flyback converter type rectifier circuit. , 13.13', 13'' are bleeder resistances. 19.19' is a stabilized power supply circuit including a stabilized power supply circuit detection amplification section 15.15'. 20.20
' is a capacitor for flat water, 21 is a detection circuit, 22 is a switching circuit, 23 is a control circuit of the stabilized power supply circuit, 25 is a time constant circuit, c is a fly hack rectified voltage, and Vt is a detection circuit 21 The output voltage of Vt2
represents the output voltage of the time constant circuit 25, and Vt3 represents the output voltage of the switching circuit 22, respectively.

Next, the operation of the embodiment shown in FIG. 9 will be explained using the waveform diagram shown in FIG. In FIG. 10, (A) shows the primary AC voltage VAC when it is OFF. (B) is the primary AC voltage OF
The falling characteristic of the primary rectified voltage V at F is shown. (C) is 1
The falling characteristic of the flyhack rectified voltage Vc when the next AC voltage is turned off is shown.

(D) shows the output voltage Vt of the detection circuit 21 obtained by detecting the rising waveform generated in the flybank rectified voltage (c) when the primary AC voltage is turned off.

(E) shows the output voltage Vt of the time constant circuit 25 obtained by adding ■tl to the time constant circuit 25.

(F) shows the output voltage ■t3 of the switching circuit 22 obtained by applying Vt2 to the switching circuit 22. (G) shows the falling characteristic of one feedforward rectified voltage (6) when the primary AC voltage is OFF. (H)
shows the falling characteristic of the other feedforward rectified voltage vB, which rapidly falls due to the trigger voltage Vt3. Also, V
a is the output voltage value of the time constant circuit 25 when the output voltage Vt3 of the switching circuit 22 rises, and vb is the output voltage value of the time constant circuit 25 when the output voltage Vt3 of the switching circuit 22 rises. .

Now, when the primary AC voltage VAC is turned OFF, the primary rectified voltage V is also turned OFF, but at this time, as explained in FIG.
As shown in FIG. 0 (C), a transient rising waveform occurs, which is detected by the detection circuit 21 to obtain Vt1. By inverting this Vtl and applying it to the time constant circuit 25, ■tl is inverted and due to the time required for charging and discharging the capacitor in the time constant circuit, a charging/discharging voltage waveform vt2 exists, and the next stage switching circuit It is further inverted and shaped at 22 to obtain the trigger voltage Vt3. This trigger voltage Vt3 operates the control circuit 23 of the stabilized power supply circuit to rapidly lower the other feedforward rectified voltage VB. In this way, the falling start time of the other feedforward rectified voltage VB is set to the feedforward rectified voltage ■ when one trigger is not applied.

The parenthesis sequence time can be controlled at the time t determined by the discharge time constant in the time constant circuit 25.

11 and 12 show specific circuit diagrams of the above embodiment, in which the detection circuit 212, time constant circuit 25. switching circuit 2
2 and the control circuit 23 of the stabilized power supply circuit will be specifically explained. The detection circuit 21 is a capacitor 26
．． A differentiation circuit composed of resistors 27 and 29, and a switching transformer 30 for preventing reverse voltage. Resistance 31, 3.2
, 33° 36, a diode 343 and a capacitor 35. The switching circuit 22 includes a resistor 37. Zena, -
Diode 38. It is composed of 39 switching transistors. The control circuit 23 of the stabilized power supply circuit includes a resistor 40. Transistor 41. It is composed of a capacitor 42.

Here, a rising waveform generated in the flyback rectified voltage Vc when the primary AC voltage is turned off is detected by the differentiating circuit (constituent circuits 26, 27, and 29), and generates a pulse voltage Vt. Next, when this Vt1 rises, the switching transistor 30 is turned on, so that the charge stored in the capacitor 35 through the resistor 32 during the OFF period of the switching transistor 30 is transferred to the diode 34. It is discharged by the switching transistor 30 through the resistor 33, and the potential of Vt2 gradually decreases according to a time constant determined by the output impedance of the transistor 3o, the resistance value of the resistor 33, and the capacitance value of the capacitor 35. Thereafter, when Vt1 disappears, the switching transistor 3o is turned off, the capacitor 35 is charged from the power supply line through the resistor 32, and the potential of Vt2 gradually rises. Therefore, Vt2 has a charging/discharging voltage waveform as shown in FIG. 10(E) depending on the time required for charging and discharging the capacitor 35. This Vt2 is the switching circuit 2
2, Vt3 becomes a voltage waveform obtained by inverting and shaping Vt2, but at the rising edge, the voltage value Va when the output voltage vt2 of the switching circuit 22 decreases due to discharge of the capacitor 35 is the Zener voltage of the Zener diode 38. This occurs when the voltage becomes less than the sum of the voltage between the gate and the emitter, which turns on the switching transistor 39. In addition, the rising edge of the switching circuit 2
When the output voltage vt2 of 2 increases due to charging of the capacitor 35, the voltage value vb becomes equal to or higher than the voltage value obtained by adding the Zener voltage and the voltage between the circuit and the switch at which the switching transistor 39 turns on, and the switching transistor 39 turns on. It is activated when it is turned on. Here, in Figure 10 (D
).

As shown in (F), from the rising time of Vt, Vt3
The delay time t until reaching the rising time of is determined by the discharge time constant of the time constant circuit 25.

Furthermore, when the trigger voltage vt3 rises, the transistor 41 that constitutes the control circuit 23 of the stabilized power supply circuit turns on, so its collector voltage becomes approximately OV, and the Since the voltage at the gate of the series control transistor 14 in the forward rectified voltage stabilizing power supply circuit 19 also becomes approximately 0, the feedforward rectified voltage VB rapidly decreases.

FIG. 12 shows an example in which the control circuit 23 of the stabilized power supply circuit is configured using Cyrisk.

43 is a silicon risk, 44.45 is a resistor, and 46 is a capacitor. Now, the output voltage Vt3 of the switching circuit 22
When the voltage rises, the thyristor 43 turns on, so the heath voltage of the series control transistor 14 in the stabilized power supply circuit 19 connected through the resistor 44 becomes approximately OV, and the feedforward rectified voltage vB rapidly drops. At the same time, the current flowing through the thyristor 43 decreases and becomes less than the holding current value that kept the thyristor 43 in the ON state, so the thyristor 43 is turned OFF.

In this way, like the embodiment in which the transistor is used in the control circuit 23 of the stabilized power supply circuit,
The sequences shown in Figures (G) and (H) can be obtained. In addition, in the above embodiment, the power supply voltage falls quickly and slowly, but the falling timing is 3 times.
There may be more than one type.

Effects of the Invention As described above, according to the switching power supply device of the present invention, the drop in the output voltage of one or more of the plurality of rectifier circuits of the feedforward converter type after the primary AC voltage is turned off is lower than that of the other circuits. It is possible to obtain a faster sequence of the output voltage of the rectifier circuit than that of the rectifier circuit, and it is possible to easily realize a circuit that can control this sequence time at a low cost, so it is excellent in economy and functionality, and is extremely useful in practice. It is something.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram explaining the difference in configuration between a feedforward converter and a flybank converter as converter systems for Swiss regulation to evening, Fig. 2 is a waveform diagram of each part, and Fig. 3 is a sequence diagram. , Fig. 4 is a block diagram of the first conventional example, Fig. 5 is a sequence diagram thereof, Fig. 6 is a block diagram of the second conventional example, Fig. 7 is a sequence diagram thereof, and Fig. 8 is the purpose. 9 is a block diagram of an embodiment of the present invention, FIG. 10 is a sequence diagram thereof, and FIGS. 11 and 12 are specific circuit diagrams of FIG. 9. 3...Switching transformer, 8,8'...Feed forward converter type rectifier circuit, 12...Flyback converter type rectifier circuit, 14゜14'.
...Series control transistor, 19.19'...Stabilized power supply circuit, 21...Detection circuit, 22...Switching circuit, 23...Control circuit, 25...Time constant circuit Fig. 1 Figure 2 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 12

Claims (3)

[Claims] (1) A switching transformer, a plurality of feedforward converter rectifier circuits provided on the secondary side of the switching transformer, and a plurality of series control type rectifier circuits that each stabilize the output of the plurality of feedforward converter rectifier circuits. a stabilized power supply circuit, a flybank converter type rectifier circuit provided on the secondary side of the switching transformer, and a pulse shape of the rectified output of the flyhack converter type rectifier circuit when input to the switching transformer is cut off. a rise detection circuit that detects the rise of the rising edge of a control circuit for forcibly cutting off a control input to at least one series control element of the plurality of stabilized power supply circuits, and an output of at least one of the stabilized power supply circuits; A switching power supply device that lowers voltage faster than the remaining ones of the plurality of stabilized power supplies. (2) The rise detection circuit is configured with a differentiating circuit, the time constant circuit is normally in a charging state and is configured to discharge in response to the output of the differentiating circuit, and when the time constant circuit is discharged, 12. The switching power supply device according to claim 11, wherein the output generation timing of the switching circuit is changed by adjusting a constant. (3) The switching device according to claim (1), wherein the control circuit is constituted by a switching element such as a transistor or a thyrisk that is connected to the control pole of the series control element and turned on and off by the output of the switching circuit. power supply.