JPS6133516A - Regulated power supply - Google Patents

Abstract

PURPOSE:To make the output voltage of the secondary side stable and efficient by feeding back a voltage amplitude signal of a DC output voltage to the primary winding side to control the number of execution turns of the primary winding. CONSTITUTION:Three AC outputs are obtained from an AC power supply 1, on the secondary side of a voltage transformer, rectified by respective rectifiers 4-6 and then smoothed by capacitors 8-10. The smoothed voltages are stabilized by regulators 11, 12 and outputted as DC voltages. After being smoothed by the capacitor 10, the 3rd AC output is connected to a dummy resistor load 13 and its terminal voltage is used for the output voltage monitoring of the secondary winding. The voltage is inputted to an A/D converter 7 and voltage amplitude signals are outputted as gate signals GS1-GSn. The gate signals GS1-GSn actuate the primary side switches SW1-SW3 of the voltage transformer 3 so as to short-circuit them every turn of the primary winding. When the AC input is increased, the number of execution turns of the primary winding is increased and the secondary side output voltage is dropped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a stabilized power supply, and more details K42. The present invention relates to a stabilized power supply that can be applied to power supplies for printers, floppy disk devices, computer systems, etc.

[Prior art]

An example of a conventional stabilized power supply is shown in Fig. 4.
The AC input of the AC power supply 1 is made to be 5 to obtain 3 AC outputs to the secondary @ through the transformer 3. These three AC outputs are rectified by rectifiers 4 and 5.6, respectively, and then smoothed by smoothing capacitors 8°9.10. Thereafter, the regulators 11, 12, and 14 drop the excess voltage to output stabilized DC voltages v1 to 2. In a stabilized power supply with this type of configuration, the regirator input voltage is usually calculated by adding the regirator output voltage, the regirator saturation voltage, the regulator input fluctuation due to load fluctuation, the regirator input fluctuation due to AC input fluctuation, etc. It is designed to cover all of these.

For this reason, in the normal operation state of such a stabilized power supply, the voltage drop of the regulator is extremely large, that is,
When the margin is, for example, 30 to 40% K, heat generation increases, efficiency decreases, and costs increase due to the increased size of the device and the need for cooling, which are disadvantageous.

〔the purpose〕

An object of the present invention is to eliminate the drawbacks of the above-mentioned prior art, realize power saving, low heat generation, and high efficiency, and provide a wide range of AC
It is an object of the present invention to provide a stabilized power supply that can adapt to power input.

〔composition〕

In order to achieve the above object, the present invention uses a transformer to input an AC voltage and output a DC voltage. This is characterized by stabilizing the secondary output voltage by feeding back and controlling the effective number of turns of the primary winding. The present invention will be specifically described below based on one embodiment. In addition, in the accompanying drawings, the same or equivalent parts will be described with the same reference numerals.

In Figure 1, AC input from AC power supply 1 is connected to transformer 3.
, respectively, to obtain three AC outputs on the secondary side. These three AC outputs are connected to rectifiers 4, 5 .
6, and then smoothed by smoothing capacitors 8, 9, and 10. The regulator 11.12 then drops the excess voltage to provide a regulated DC voltage of V and V.
, outputs. The third AC output is connected to a dummy resistive load 13 after being smoothed by a smoothing capacitor lO.

The terminal voltage of this dummy resistive load 13 is used for monitoring the output voltage of the secondary winding. A/D converters 7 and 4 are connected between the smoothing capacitor 10 and the dummy resistive load 13, and the A/D converter 7 converts the terminal voltage of the dummy resistive load 13 into A/A and converts the voltage amplitude signal into a gate signal. G
Output as SI~Q8n. In this case, n of the gate signal QSn increases as the terminal voltage of the dummy resistive load 13 increases, and as the terminal voltage decreases, n of the gate signal GSn decreases.

Switches SWI to SW3 provided on the primary side of transformer 3
is configured to short-circuit each turn of the primary winding of the transformer 30 and to be activated by gate signals GSI to G8nK. That is, when the AC input increases and the secondary output voltage increases, the effective number of turns of the 11th winding increases, causing the secondary output voltage to decrease. On the other hand, when the AC input becomes smaller and the secondary output voltage becomes smaller, the effective number of turns of the primary winding decreases and the 2' output voltage increases. As can be understood from this explanation, the above-mentioned feedback is performed smoothly, and in this embodiment, the influence of AC input voltage fluctuation is reduced, and as a result, the voltage drop of the regulators 11 and 12 is designed to be small. becomes possible.

FIG. 2 shows another embodiment of the present invention, in which there is one DC output on the secondary side, and the AC input from the AC power source 1 is passed through the transformer 3 to the secondary side. Ki AC outputs are obtained, and this AC output is rectified by a rectifier 4 and then smoothed by a smoothing capacitor 8. After that, the regulator 11 lowers the excess voltage and outputs 1 as a stabilized DC voltage. Smoothing capacitor 8
An A/D converter 7 is connected between the regulator 11 and the regulator 11, and the A/D converter 7 performs D/A conversion on the terminal voltage of the regulator 11 and outputs gate signals GS1 to GSn. Switches 8W1 to 8W3 operated by these gate signals are provided on the primary side of the transformer 30, and these switches SW1 to SW3 are configured to short-circuit each turn of the primary winding of the transformer 30. The operating principle in this embodiment is the same as that in the embodiment shown in FIG. This is effective against load fluctuations as well as power supply voltage input fluctuations, and the efficiency of the stabilized power supply can be further improved.

In addition to the embodiments shown in FIGS. 1 and 2, a method in which feedback is applied from the input terminal of regulator 11 or regulator 12 and the dummy resistive load is omitted in the embodiment shown in FIG. It will be done.

Furthermore, in the embodiments shown in FIGS. 1 and 2, a zero-cross detection means (not shown) for detecting AC zero-cross is provided between the analog switches 8W1 to 8W3 and the A/D converter 7, and from the zero-cross detection means It is desirable for noise countermeasures to switch the switch in synchronization with the zero cross by ANDing the signal.

Next, a case where the stabilized power supply according to the present invention is applied to a printer will be described together with the general configuration of the printer.

Figure 3 is a schematic perspective view showing the basic unit of the printer.
20 is a space mechanism unit that moves the carriage unit 21, which is a printing section, left and right, and includes a space motor,
It includes a carriage base, etc. The carriage unit 21 is attached with mechanisms necessary for printing, such as a selector motor, a ribbon feed motor, and a shift magnet. The reference numeral indicates a vapor feed unit, which drives a platen unit 24 for setting printing paper. An interface bracket unit 25 is used to attach a connector for connecting electrical signals between the printer and a host converter (not shown).
All printer operations such as interfaces, motors, magnets, etc. are controlled by a control unit 26. Reference numeral 27 is a power supply unit that supplies power to this printer, and reference numeral 28 is a fan bracket unit that cools the heat dissipation of the control board unit 26 with forced air.

Power supply unit for a printer having the above configuration) 27
By using the stabilized power source according to the present invention, for example, even if the AC input power source is different in different countries around the world, the same transformer can be used in each country without changing the transformer. Namely.

Currently, the AC power supply used differs from 100V in Japan, 120V in the United States and Canada, and 220V in Germany and other countries.1 For example, when exporting printers from Japan to these countries, a dedicated power supply is required for each country. Although it is necessary to install a power supply unit, by using the stabilized power supply according to the present invention, the effective number of turns on the primary side can be selected to match the AC power supply of each country! Pressure selection becomes possible. In addition, when performing such automatic voltage selection, it is most effective to increase the power supply voltage from the lowest one.

As described above, according to an embodiment of the present invention, AC input fluctuations that greatly affect the voltage drop of a regulator in a conventional regulated power supply are controlled by a foot control circuit, thereby achieving a specified secondary DC output. It is possible to reduce the margin conventionally adopted for VC- by a factor of 1, thereby making it possible to reduce the decrease in efficiency due to the heat generated by the extra voltage corresponding to the margin VC- by a factor of 1. Further, although the printer has been described as an application example, the same effect can be obtained when the present invention is applied to a floppy disk device, a computer system, or the like.

〔effect〕

As described above, according to the present invention, at least one voltage amplitude signal of the DC output voltage is fed back to the primary winding, and the secondary output voltage is controlled by controlling the effective number of turns of the primary winding. Since the stabilization is made, it is possible to obtain a stabilized power source with low power consumption, low heat generation, and high efficiency.For example, it is possible to obtain a stabilized power source with low power consumption, low heat generation, and high efficiency. 5. It is possible to provide a stabilized power source with five significant effects.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the stabilized power supply according to the present invention, Fig. 2 is a circuit diagram showing another embodiment, and Fig. 3 shows the configuration of a printer to which the stabilized power supply according to the present invention is applied as a power supply. The schematic perspective view shown in FIG. 4 is a circuit diagram illustrating a conventional example. 1... AC power supply, 3... Transformer, 4
* 5 * 6...If-fi! ,7...
・・A/D converter, B p 9s tO・・
...Smoothing capacitor, 11,12...Regulator, 13...Dummy resistive load,! 381~
GSn...Voltage amplitude signal, SWI~SWn...
····switch. Figure 2 Figure 3 Figure 4 Procedural amendment Yari JL December 78, 1982

Claims (1)

[Claims] In a stabilized power supply that inputs AC voltage and outputs DC voltage using a transformer, at least one voltage amplitude signal of the DC output voltage is fed back to the primary winding side, and the effective number of turns of the primary winding is determined. A stabilized power supply characterized by stabilizing a secondary side output voltage by controlling it.