JPH06335255A - Secondary dc power generator - Google Patents

Abstract

PURPOSE:To increase the efficiency of a power supply by making a smoother capacitor absorb counter-electromotive force generated in the primary winding of a transformer to prevent heat from being generated in a transformer-coupled type secondary direct-current generator. CONSTITUTION:In a counter-electromotive force absorption circuit 11 provided are synchronous switching element Q3, an inflow diode D2 and a feedback dide D3, and in the case where a switching element Q1 is turned off, the counter- electromotive force generated in the primary winding CL1 of a transformer 20 is stored in a smoother capacitor C1 for absorption by turning on the synchronous switching element Q3 in synchronism. In the case where the switching element Q1 is turned on, the synchronous switching element Q3 is turned off in synchronism for effective utilization. Thereby, the counter-electromotive force is smoothly absorbed for utilization, so that the efficiency of a power supply may be increased.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a primary DC power supply circuit and a secondary DC power supply circuit.
The present invention relates to a secondary DC power supply generation device that is connected to a secondary DC power supply circuit via a transformer and that is provided with a counter electromotive force absorption circuit on the primary side.

[0002]

2. Description of the Related Art In FIG. 2, a primary DC power supply circuit 10 and a secondary DC power supply circuit 30 are connected via a transformer 20. The primary DC power supply circuit 10 includes a commercial power supply (for example, 100V, 50HZ) 1, a filter 2, a rectifier circuit (for example, a diode bridge) DB1, and an electric circuit connecting a positive electrode side electric circuit LP and a negative electrode side electric circuit LM of the rectification circuit DB1. The control circuit 40 includes a smoothing capacitor C1, a switching element (for example, a transistor) Q1, and a switching element Q2 connected to L1, and is formed.

The switching element Q1 (collector C, emitter E) is a primary winding CL1 of the transformer 20.
Is connected in series, and the switching element Q2 is connected to its base B. The control power supply for the switching element Q1 is induced by the auxiliary winding CL2 and is driven by the diode D1.
Is oscillated and generated through and is supplied through the resistor R1.

The secondary DC power supply circuit 30 includes a diode connected to a secondary winding (not shown) of the transformer 20,
It includes a smoothing capacitor, etc., and supplies stabilized power to the load. The voltage of this secondary DC power supply is the switching element Q2 on the primary side.
It is fed back as the opening / closing control signal of.

Thus, in the secondary DC power supply generator (10, 20, 30), the switching element Q1 is turned on by the control power generated by the auxiliary winding CL2.
The control circuit 4 is closed (closed) and is provided with a feedback signal.
When the switching element Q2 of 0 is closed, it is turned off (open). That is, the switching element Q1 can be ON-OFF controlled to supply electric power energy from the primary winding CL1 to the secondary winding (30).

By the way, this switching element Q1 is O
When FF is applied, a counter electromotive force is generated in the primary winding CL1. Therefore, the counter electromotive force absorption circuit 11P is provided and absorbed.
As shown in FIG. 2, the conventional counter electromotive force absorption circuit 11P has one
A diode D11 and a capacitor C11 are connected in parallel to the next winding CL1, and a capacitor R11 has a discharging resistor R.
It is formed of a so-called snubber circuit (11P) in which 11 are connected in parallel. Therefore, the counter electromotive force is the diode D
Is absorbed by the capacitor C11 through the resistor 11 and the resistor R1
Consumed through 1.

[0007]

However, when the secondary DC power supply generator is used as a drive / control power supply for a small printer, for example, it has the following drawbacks.
That is, since the conventional counter electromotive force absorption circuit 11P is a power consumption type, it violates the power saving request. Also, the discharge resistor R11
Since the heat generation of (1) has a delicate effect on the printing accuracy, it not only hinders the further improvement of accuracy, but also the increase of the resistance R11 hinders the downsizing of the entire printer.

An object of the present invention is to provide a secondary DC power supply generator having a back electromotive force absorption circuit which can smoothly absorb and use back electromotive force while preventing heat generation and saving power.

[0009]

The present invention focuses on the fact that a relatively large-capacity smoothing capacitor is provided as an indispensable component, and smoothes the counter electromotive force generated from the primary winding. The above-mentioned object is achieved by making the capacitor absorb and effectively use it.

That is, in the secondary DC power supply generator according to the present invention, the smoothing capacitor, the primary winding and the switching element connected in series are connected in parallel between the positive electrode and the negative electrode of the rectifier circuit. A primary DC power supply circuit, a secondary DC power supply circuit connected to the primary DC power supply circuit via a transformer including the primary winding, and the primary winding is provided on the primary DC power supply circuit side. In a secondary DC power supply generator provided with a back electromotive force absorption circuit that absorbs back electromotive force of a line, the back electromotive force absorption circuit is opened / closed in synchronization with opening / closing of the switching element, and is connected to the smoothing capacitor. A synchronous switching element connected in series, and an inflow side connected to the electric path between the primary winding and the switching element and a cathode side connected to the electric path between the synchronous switching element and the smoothing capacitor. Die And over de, an anode side and a is connected to the negative electrode and the cathode side and the connection to the positive electrode has been feedback diode of the rectifier circuit, it is characterized.

[0011]

In the case of the present invention having the above configuration, when the switching element of the primary DC power supply circuit is turned off (open), the synchronous switching element is turned off (open) in synchronization with this, and the positive side of the smoothing capacitor is connected to the rectifier circuit. Separate from the positive electrode. Then 1
The secondary winding, the inflow diode, the smoothing capacitor, and the feedback diode open each electric path to establish a serial connection state.
Therefore, the counter electromotive force generated from the primary winding is absorbed by the smoothing capacitor, and then the synchronous switching element is turned on.
It is effectively used when it becomes (closed).

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the secondary DC power supply generation device has the same basic configuration (10, 20, 30) as the conventional example (FIG. 2), but the counter electromotive force absorption circuit 11 is an effective power utilization type. It has a new configuration. The same components as those in the conventional example (FIG. 2) are designated by the same reference numerals, and the description thereof will be simplified or omitted.

The counter electromotive force absorption circuit 11 is composed of a synchronous switching element Q3, a flow-in diode D2, a feedback diode D3, and electric lines L11 and L2. The synchronous switching element Q3 (terminals Y and X) is connected in series with the smoothing capacitor C1 via the electric path L1, and the terminal Z is a switching element Q1 (base B) in the control power source generated by induction from the auxiliary winding CL2. Is connected as well. And
In response to opening / closing of the switching element Q2 in the control circuit 40, the synchronous switching element Q3 opens / closes in synchronization with the switching element Q1 (O
N-OFF) is selected.

The inflow diode D2 is connected on the anode side to the electric path between the primary winding CL1 and the switching element Q1 via the electric path L11, and on the cathode side between the switching element Q3 and the smoothing capacitor C1. It is connected to L1.

The feedback diode D3 is connected to the electric line L1.
The anode side is connected to the negative electrode (negative electrode side electric line LM) of the rectifier circuit DB1 via the electric line L2 on the downstream side, and the cathode side is connected to the positive electrode (positive side electric line LP).

In the embodiment having such a structure, when the switching element Q1 is ON (closed), the synchronous switching element Q3 is provided.
Is also ON (closed), the smoothing capacitor C1 performs a smoothing action. However, when the switching element Q2 is turned on (closed) and the switching element Q1 is turned off, the synchronous switching element Q3 is also opened (OFF) in synchronization with this.

Therefore, the primary winding CL1 is connected to the electric line L1.
1, inflow diode D2, smoothing capacitor C1,
The feedback diode D3 and the electric paths L2 and LP are connected in series. That is, the back electromotive force generated in the primary winding CL1 can be stored and absorbed in the smoothing capacitor C1. After that, the synchronous switching element Q3 is turned on in synchronization with the switching element Q1.
Will be used effectively.

However, according to this embodiment, the counter electromotive force absorption circuit 11 includes the synchronous switching element Q3, the inflow diode D2 and the feedback diode D3, and is synchronized when the switching element Q1 is turned off. By opening the switching element Q3 synchronously, the counter electromotive force generated in the primary winding CL1 is accumulated and absorbed in the smoothing capacitor C1 and the synchronous switching element Q3 is synchronized when the switching element Q1 is turned on. Since it is configured so that it can be effectively used by closing it, it is possible to provide a secondary DC power generation device with high power efficiency that can smoothly absorb and use back electromotive force while preventing heat generation and saving power.

Further, since the counter electromotive force absorption circuit 11 is composed of the synchronous switching element Q3 and the two diodes D2 and D3, it is compared with the conventional snubber circuit (11P) type including the capacitor C11 and the discharging resistor R11. Thus, the structure is simple, the size is small, and the cost is low.

[0020]

According to the present invention, the counter electromotive force absorption circuit includes the synchronous switching element, the inflow diode and the feedback diode, and the synchronous switching element is opened synchronously when the switching element is turned off. By so doing, the counter electromotive force generated in the primary winding is accumulated and absorbed in the smoothing capacitor, and when the switching element is turned ON, the synchronous switching element is synchronously closed to enable effective use. Therefore, it is possible to provide a secondary DC power supply generation device with high power supply efficiency that can smoothly absorb and use the back electromotive force while preventing heat generation and saving power.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram for explaining a conventional example.

[Explanation of symbols]

 1 Commercial Power Supply 2 Filter 10 Primary DC Power Supply Circuit DB1 Rectifier Circuit LP Positive Electrode Circuit LM Negative Electrode Circuit C1 Smoothing Capacitor Q1 Switching Element 11 Back Electromotive Force Absorption Circuit Q3 Synchronous Switching Element D2 Inlet Diode D3 Feedback Diode L1, L11, L2 Electric circuit 20 Transformer CL1 Primary winding CL2 Auxiliary winding 30 Secondary DC power supply circuit 40 Control circuit Q2 Switching element

Claims (1)

[Claims] 1. A primary DC power supply circuit in which a smoothing capacitor, a primary winding and a switching element connected in series are connected in parallel between a positive electrode and a negative electrode of a rectifier circuit, and the primary DC power supply circuit. Back electromotive force absorption, which includes a power supply circuit and a secondary DC power supply circuit connected via a transformer including the primary winding, and absorbs the back electromotive force of the primary winding on the primary DC power supply circuit side. In a secondary DC power supply generator including a circuit, the counter electromotive force absorption circuit opens and closes in synchronization with opening and closing of the switching element, and a synchronous switching element connected in series with the smoothing capacitor, and an anode side of the synchronous switching element. A flow-in diode connected to an electric path between the primary winding and the switching element and having a cathode side connected to an electric path between the synchronous switching element and the smoothing capacitor, and an anode side connected to a negative electrode of the rectifier circuit. Is and the cathode side is constituted by a connection to the positive electrode has been feedback diode, the secondary DC power generating device, characterized in that.