JPS59178960A - Switching regulator - Google Patents

Abstract

PURPOSE:To correct the abrupt drop of the voltage of other output due to the abrupt voltage rise of a main output by connecting the main output and the other output through a capacitor. CONSTITUTION:An inverter has an output transformer 2, an output transistor 3 and a controller 4. The induced output of the secondary winding 22 of the transformer 2 is converted by a rectifying and smoothing circuit 5 into a DC output. Resistors 6, 7 for detecting the current and voltage are provided the main output side of a DC24V, these outputs are applied to the controller 4. The main output side and the other output side are connected via a capacitor 8, thereby correcting the abrupt drop of the voltage of the other output by the abrupt voltage rise of the main output.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a multi-output type switching regulator.

(Background of the Invention) Conventionally, multi-output switching regulator systems have been designed to apply negative feedback loop control from only the main output to the primary side to stabilize the output voltage of this main output and, in turn, other output voltages. Are known.

By the way, in such a switching regulator, other outputs may be affected by a sudden change in the load of the main output, for example, if the load of the main output or the rated load becomes an open load, the voltage of the other outputs may drop instantly. This has the disadvantage that, for example, the contents of the memory connected to the other output may be erased, causing malfunction of the equipment connected to the other output.

(Object of the Invention) In view of the problems with the conventional type described above, the present invention provides a multi-output type switching regulator in which feedback is applied only to the main output, in which the main output and other outputs are connected via a capacitor. Based on the concept,
The purpose is to reduce changes in other outputs, especially drops, when the main output load suddenly changes.

(Explanation of Examples) The present invention will be described in detail below using the drawings.

FIG. 1 shows a circuit diagram of a multi-output switching power supply according to an embodiment of the present invention. In the figure, ■ is an impark section, which is equipped with an output transformer 2, an output transistor 3 that energizes the primary winding 21 of the output transformer, and a control m+ circuit 4 that drives the output transistor 3. Does not generate high frequency output than DC power supply. The output transformer 2 has a plurality of secondary windings 22, and the induced output of each secondary winding 22 is controlled by a rectifying and smoothing circuit 5 consisting of a diode, an inductor, a capacitor, etc., for example, C, 24V and D.
It is converted to a DC output of 1 C, 9V. Also, DC24
The main output of V has resistors 6 and 7 for current and voltage detection.
The outputs of these resistors 6.7 are input to the control circuit 4 on the primary side of the output transformer. Accordingly, in the control circuit 4, the output voltage of the main output is stabilized by changing the duty ratio or frequency of switching by the transistor 3. 8 is a capacitor that is a feature of the present invention.

Figure 2 shows the switching power supply shown in Figure 1, with the rated load of the main output (DC24V) disconnected.
The voltage change (a) of the 24V output and the voltage change (b) of the DC9V output are shown. If capacitor 8 is not present, D09v
The output voltage change reached a maximum of 3 cm as shown by the solid line in the figure, but by adding capacitor 8, the DC
The voltage change of the -9V output is as shown by the dotted line in the same figure.
]V or less.

(Effects of the Invention) As described above, according to the present invention, if the main output suddenly changes due to the overshoot of the negative feedback loop control in other outputs, for example, if the main output suddenly increases, the negative feedback circuit will correct it. By doing so, a sudden drop in voltage occurring in other outputs is corrected by a sudden rise in voltage of the main output, so that a sudden drop in other outputs can be suppressed to a large extent. Similarly, other fluctuations in output when the main output suddenly drops can also be suppressed.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a switching power supply according to an embodiment of the present invention, and FIG. 2 is an output voltage waveform diagram of the main output (a) and other outputs (b) of the switching power supply of FIG. 1. 1... Inverter section, 2... Output transformer, 4... Control circuit, 5-... Rectifier smoothing circuit,
7...Resistor, 8...Capacitor. Patent Applicant Toshiba Electric Materials Corporation Agent Patent Attorney Tatsuo Ito Attorney Patent Attorney Tetsuya Ito

Claims (1)

[Claims] 1 It has an output I lance and a switching circuit that switches the primary current of this output lance, rectifies the secondary winding induced output of this output lance to generate a plurality of DC outputs, and also generates a plurality of DC outputs. In a switching regulator that uses one output as the main output and stabilizes the main output voltage and other output voltages by negatively circulating the main output voltage to the primary side, the output terminal of the main output and at least A switching regulator characterized in that it is connected to another output terminal of the same polarity via a capacitor.