JPH0640740B2 - Multi-output DC stabilized power supply - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a multiple output DC stabilized power supply device, and more particularly to an improvement suitable for use in increasing the capacity of a type having a transformer.

[Prior art]

FIG. 3 shows, for example, JP-A-60-106363 proposed by the present applicant.
FIG. 2 is a block diagram showing the configuration in the case where an on-on converter known in Japanese Patent Application No. 58-214511 (Japanese Patent Application No. 58-214511) is used as a multi-output power supply. In the figure, switching elements Q1 and Q2 are composed of transistors, FETs, etc., and an emitter, a collector terminal or a drain, a source terminal are used as input / output terminals, and a base terminal or a gate terminal is used as a control terminal. ON-ON type, so switching elements Q1, Q
2 is turned on and off synchronously. The input DC voltage Vin is applied to the input terminal of the switching element Q1, and the anode side of the primary winding n1 and the diode D2 are connected to the output terminal. The input voltage Vin is connected to the input terminal of the switching element Q2 via the diode D1, the cathode side of the primary winding n1 is connected, and the output terminal is connected to the input side common. The main output circuit # 1 includes diodes D3 and D4 for rectifying the switching signal appearing on the secondary winding n2, a choke coil L1 for removing high frequency components, and a smoothing capacitor C1. Supply to the load. The output stabilizing circuit for the main output voltage Vout1 is
An error amplifier 10 for obtaining an error signal by comparing t1 with a predetermined reference voltage Vref, a PWM (pulse width modulation) circuit 20 for outputting a control signal such that the error signal becomes zero, and an amplifier for amplifying this control signal. It consists of an amplifier 30 and an insulating transformer 40 that insulates this control signal between the primary side and the secondary side of the transformer, and this control signal is sent to the control terminals of the switching elements Q1, Q2. The secondary output circuit # 2 transmits the switching signal appearing in the secondary winding n3 to the diodes D5, D via the saturable reactor SR.
The high frequency component is removed by the choke coil L2, smoothed by the capacitor C1, and the secondary output voltage Vout2 is supplied to the load. Mag amplifier control unit 50
Supplies a control signal to the saturable reactor SR via a diode D7 so that the secondary output voltage Vout2 is always equal to a predetermined reference voltage Vref.

[Problems to be Solved by the Invention]

However, the conventional device has the following problems because the transformer becomes larger in size as the capacity increases. It becomes a restriction on mounting on the printed circuit board. The larger size increases the amount of heat generated, so cooling is necessary, but in order to radiate heat, the distance increases and loss increases,
As a result, there is a vicious circle in which the transformer becomes even larger. Increased leakage inductance slows switching and reduces efficiency. Therefore, for example, as disclosed in Japanese Utility Model Laid-Open No. 61-185290, a large-capacity multi-output stabilized DC power supply device is provided by connecting a plurality of transformers in parallel. In this case, it is desirable to use a common switching element for the two transformers so that they can be regarded as substantially equivalent to a single transformer. However, if both transformers are simply connected, interference will occur, so it is necessary to install a diode for separation.
This diode has a problem that the power conversion efficiency is lowered. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a multi-output stabilized DC power supply device that prevents interference between transformers and can easily increase the capacity by paralleling when a plurality of transformers are connected in parallel. And

[Means for Solving the Problems]

The present invention that achieves such an object includes a first switching element Q1 to which a DC input voltage is applied to an input terminal, a second switching element Q2 whose output terminal is connected to a primary side common, and a second switching element Q2. The first diode D1 mounted between the input terminal of the switching element and the DC input voltage, and the output terminal of the first switching element is the second
It is connected to the anode side through the diode D41 of
An output terminal of the second switching element is connected to the anode side through a third diode D42, and a primary winding n4 of the first transformer T1 whose input terminal is connected to the cathode side,
The output terminal of the first switching element is connected to the anode side via the fourth diode D11, and the second terminal
The output terminal of the switching element of the fifth diode D12
And a primary winding n1 of a second transformer T2 connected to the anode side of the second transformer T2, the input terminal of which is connected to the cathode side. Then, a main output circuit that rectifies and smoothes the switching signal induced in the first secondary winding that forms a pair with the primary winding of the first transformer, and outputs the main output circuit and a predetermined reference voltage. The main output stabilizing circuit which compares the voltage with the voltage and determines the difference, changes the control signal in the direction in which the error becomes zero, and sends the main output stabilizing circuit to the first and second switching elements, and the primary winding of the second transformer are paired. Of the secondary output circuit that rectifies and smoothes the switching signal induced in the second secondary winding and outputs the switching signal, the output voltage of the secondary output circuit is compared with a predetermined reference voltage to determine the difference. It is characterized by having a slave output stabilizing circuit for feeding back the control signal to the primary winding side or the secondary winding side in the direction in which this error becomes zero.

[Action]

Each component of the present invention has the following action. The main output stabilizing circuit controls the switching elements by the PWM method. Since stabilization of the secondary output cannot control the switching element by the PWM method, other output stabilization is performed by a mag amplifier or the like. Since the transformers for the main output and the sub-outputs are provided separately, the size of the transformer is small, the heat dissipation is good, and the efficiency is improved. Here, in order to electrically separate the first and second transformers from the DC input power source, a second diode D41 and a fourth diode D11 are provided. Further, the third diode D42 and the fifth diode D12 are individually attached to each transformer to facilitate parallel operation of the transformers. Further, a first diode D1 is mounted in common with each transformer to prevent interference between the transformers.

【Example】

The present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a first embodiment of the present invention. Incidentally, in FIG. 1, those having the same functions as those in FIG. In the figure, as a circuit on the primary side, a first switching element Q1 having a DC input voltage Vin applied to an input terminal, a second switching element Q2 having an output terminal connected to a primary side common, and a second switching element The input terminal of the element Q2 and the DC input voltage V
and a first diode D1 mounted between in and. The primary winding is the primary winding n1 of the first transformer T1.
Is connected to the anode side of the first switching element Q1 via the second diode D11, and the output terminal of the second switching element Q2 is the third diode D1.
It is connected to the anode side via 12 and this input terminal is connected to the cathode side. The primary winding n4 of the second transformer T2 connected in parallel with the primary winding n1 of the first transformer T1 is
The output terminal of the first switching element Q1 is connected to the anode side via the fourth diode D41, and the output terminal of the second switching element Q2 is the fifth diode D42.
To the anode side, and this input terminal is connected to the cathode side. The diodes D11, D12, D41, D42 and the primary windings n1, n4 are connected such that the cathode side is on the anode side. The main output # 1 compares the output voltage of this main output circuit and a predetermined reference voltage with a main output circuit that rectifies and smoothes the switching signal induced in the secondary winding n2 of the first transformer T1 and outputs it. The difference is obtained by changing the control signal so that this error becomes zero, and the first and second switching elements Q1, Q
It is composed of a main output stabilizing circuit that is sent to
It is the same as the figure. The secondary outputs # 2,3 are the secondary windings n5, n6 of the second transformer T2.
The output voltage of this slave output circuit is compared with a predetermined reference voltage to obtain the difference, and the error becomes zero. And a secondary output stabilizing circuit for feeding back a control signal to the primary winding side or the secondary winding side.
The sub output # 2 uses the same mag-amplifier as the sub output # 2 in FIG. 3, and the sub output # 3 transmits the switching signal appearing in the secondary winding n6 to the diodes D8, D9 and the capacitor C.
3 is used for rectification and smoothing, and the voltage stored in the capacitor C3 is level-shifted to a lower voltage and output. Amplifier 60 used for secondary output # 3
The output voltage may be stabilized by using, for example, the one known in Japanese Patent Publication No. 58-42885 “Power Supply Circuit” proposed by the present applicant. The operation of the apparatus thus configured will be described below. The case will be described separately. (1) When switching elements Q1 and Q2 are on. In this case, the diodes D11, D41 are rendered conductive, and the diodes D1, D12, D42 are rendered non-conductive. Therefore,
Currents corresponding to the respective loads flow through the primary windings n1 and n4, and the total current flows through the switching elements Q1 and Q2. (2) Switching element Q1, Q2 is off, diode D
1, D12, D42 are conductive. Since the switching element Q1 is off, the diode D11,
D41 becomes non-conductive. Therefore, each transformer T1, T2
Is reset by the current flowing through the next path. T1; D12 → n1D1 T2; D42 → n4D1 (3) Switching elements Q1 and Q2 are off, and diode D
1, D12, D42 are in non-conducting state. No current flows in the primary windings n1, n4 of each transformer T1, T2, but only in the secondary windings n2, n5, n6. As described above, the diodes D11, D12, D41, D42
By the function of, the transformer here operates exactly like the state of one transformer. Here, the first and second
A second diode D41 and a fourth diode D11 are provided to electrically separate the transformer from the DC input power source. Further, the third diode D42 and the fifth diode D12 are individually attached to each transformer to secure a path through which the reset current flows, thereby facilitating parallel operation of the transformers. Further, the first diode D1 is commonly used with each transformer.
Is installed to prevent interference between transformers. The stabilization of the main output # 1 is performed using the PWM control circuit 20. The secondary outputs # 2 and # 3 are stabilized by the mag-amplifier and the amplifier 60, respectively. Since the primary windings n1 and n4 are provided for each of the transformers T1 and T2, even if the number of secondary outputs increases, the number of secondary windings of the transformer for the main output does not increase, and the number of transformers increases. It can be dealt with by increasing. As a result, the dispersion of the transformer is promoted, and the characteristics are improved as compared with the case where the secondary windings are collectively mounted. FIG. 2 is a circuit diagram showing a second embodiment of the present invention. Compared with FIG. 1, the connection position of the diode is changed to the cathode side of the primary winding. In the figure, as a primary side circuit, a first switching element Q1 having a DC input voltage Vin applied to its input terminal, a second switching element Q2 having an output terminal connected to a primary side common, and this first switching element Q1. It has a first diode D2 mounted between the output terminal of the element Q1 and the primary side common. In the primary winding n1 of the first transformer T1, the input terminal of the first switching element Q1 is connected to the cathode side via the second diode D43), and this output terminal is connected to the anode side and The input terminal of the switching element Q2 is connected to the cathode side via the third diode D44. In the primary winding n4 of the second transformer T2 connected in parallel with the primary winding n1 of the first transformer T1, the input terminal of the first switching element Q1 is connected to the cathode side through the fourth diode D13. This output terminal is connected to the anode side, and the input terminal of the second switching element Q2 is connected to the cathode side via the fifth diode D14. The diodes D13, D14, D43, D44 and the secondary windings n1, n
Explaining the connection state of 3, the anode side is connected to the cathode side. The main output circuit, the main output stabilizing circuit, the sub output circuit, and the sub output stabilizing circuit similar to those in FIG. 1 are provided.
The operation is similar to that of the device of FIG.
Diodes D44 and D14 are provided to electrically separate the transformer from the DC input power source. Further, the diodes D43 and D13 are individually attached to each transformer to secure a path through which the reset current flows, which facilitates parallel operation of the transformers. Furthermore, the diode D2 common to each transformer
Is installed to prevent interference between transformers. It should be noted that, in the above embodiment, the description has been made with respect to the case where one sub-output transformer is provided, but the present invention is not limited to this, and the same diode is used as a switching element by dispersing two or more pieces. It may be installed between.

【The invention's effect】

As described above, according to the present invention, when the main output transformer and the sub output transformer are separated, the separating diode D41,
Since D11, individual transformer diodes D42 and D12, and transformer common diode D1 are mounted, interference between the transformers is prevented and the two transformers can be regarded as a substantially single transformer, which facilitates parallel operation. There is an effect that the capacity can be increased. Further, for the main output of large current, since it becomes a single output transformer, there is an effect that the structure is simplified and the leakage inductance is reduced, which is preferable as a power supply.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention, and FIG. 2 is a circuit diagram showing a second embodiment of the present invention. Figure 3 shows
It is an explanatory view of a conventional device. Q: switching element, D: diode, T ... transformer, n ... primary or secondary winding.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 63-3650 (JP, A) JP 62-166768 (JP, A) JP 62-260560 (JP, A) JP 62- 210862 (JP, A) JP 62-163568 (JP, A) JP 62-118770 (JP, A) JP 61-199464 (JP, A) Actual development JP 61-185290 (JP, U) Actual Open Sho 56-171586 (JP, U) Special Public Sho 63-21425 (JP, B2) Actual Sho 62-27027 (JP, Y2)

Claims (2)

[Claims] 1. A first input terminal to which a DC input voltage is applied
Switching element (Q1), a second switching element (Q2) whose output terminal is connected to the primary side common, and a second switching element mounted between the input terminal of the second switching element and the DC input voltage. The first diode (D1) and the output terminal of the first switching element are connected to the anode side via the second diode (D41), and the output terminal of the second switching element is the third diode. The primary winding (n) of the first transformer (T1), which is connected to the anode side through (D42) and whose input terminal is connected to the cathode side,
4), the output terminal of the first switching element is connected to the anode side through the fourth diode (D11), and the output terminal of the second switching element is connected to the fifth diode (D12). A primary winding (n1) of a second transformer (T2) which is connected to the anode side via an input terminal of which is connected to the cathode side, and a first secondary winding which forms a pair with the primary winding of the first transformer. The main output circuit, which rectifies and smoothes the switching signal induced in the next winding, and outputs it, compares the output voltage of this main output circuit with a predetermined reference voltage to obtain the difference, and in the direction where this error becomes zero. A main output stabilizing circuit that changes a control signal and sends it to the first and second switching elements, and rectifies a switching signal induced in a second secondary winding paired with the primary winding of the second transformer. One or more secondary outputs that are smoothed and output Path and the output voltage of the slave output circuit and a predetermined reference voltage are compared to obtain a difference, and a control signal is fed back to the primary winding side or the secondary winding side in a direction in which the error becomes zero. A multi-output stabilized DC power supply device, comprising: a secondary output stabilization circuit. 2. A first input terminal to which a DC input voltage is applied
Switching element (Q1), a second switching element (Q2) whose output terminal is connected to the primary side common, and a first switching element which is mounted between the output terminal of this first switching element and the primary side common. Diode (D2) and the input terminal of the first switching element are connected to the cathode side through the second diode (D13), the output terminal is connected to the anode side, and the second switching element is connected. The primary winding (n1) of the first transformer whose input terminal is connected to the cathode side through the third diode (D14), and the input terminal of the first switching element are the fourth diode (D43). A second transistor connected to the cathode side via the output terminal connected to the anode side and the input terminal of the second switching element connected to the cathode side via the fifth diode (D44). Scan of the primary winding and (n4), primary output circuit according to claim 1, the main output stabilizing circuit, a multi-output DC stabilized power supply apparatus characterized by comprising a secondary output circuit and secondary output stabilizing circuit.