JPS59178962A - Switching regulator - Google Patents

Abstract

PURPOSE:To obtain a stable subpower supply output by charging a main power supply condenser which is held at the prescribed voltage by a current generated in the second winding of a current transformer. CONSTITUTION:The first winding 13 of a current transformer 13 is inserted in series with the anode side of a discharging diode 7, and a pulse current is supplied thereto. One end of the second winding 132 is connected to a common potential point through the cathode and anode of a diode 14, and the other end is connected directly to a capacitor 6 connected to the output terminal 2. A diode 4 restricts the charging direction to the capacitor 6 of the current generated in the secondary winding, and prevents the charge of the capacitor 6 from shortcircuiting and discharging through the second winding 132.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in additional functionality of switching regulators. In detail, for example, in switching regulators for main power supplies such as +5V that drive microcomputers, etc., stabilized -15V or +15V sub power supplies that are used to drive digital analog converters, other analog circuits, etc. The present invention relates to the configuration of a switching regulator that has an additional function that can also provide a supply output.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 3, an example of a conventional switching regulator that realizes the configuration and operation of a conventionally known switching regulator as well as additional functions having the same purpose as the present invention will be described.

FIG. 1 shows a conformal configuration of a chopper type switching regulator. Input terminals 1 and 1' are supplied with an unstable DC power source E1, and output terminals 2 and 2' are supplied with a stabilized DC output voltage EO.

The unregulated DC Wi source E1 is connected to a series circuit of a choke coil 4, an overcurrent detection resistor 5, and a capacitor 6 via a transistor constituting the switching means 3, and the voltage between the terminals of the capacitor 6 is the output terminal 2. It is compared with the voltage Ev. The controller supplies a signal ec for controlling the opening/closing ratio of the switching means 3 to a control terminal of the switching means, and controls the duty ratio of eo so that Eo becomes equal to Ei.

Figure 2 shows the signal waveforms of each part of the first part, and (A) shows the choke coil 4, switching means 3, and discharge diode 7.
When the switching means is closed, it is equal to the voltage El of the unregulated DC power supply, and when it is open, it is equal to the direct voltage drop of the discharge diode 7 -VBICK. (The rice shows a waveform of 1° of current flowing through the choke coil 4. During the period when the switching means is closed, the current LA is supplied from the input terminal 1.1' side while increasing at a constant slope due to the integral characteristic of the choke coil. 6 is charged, and during the open period, the energy stored in the choke coil discharges 1A of YL current through the discharging diode 7, decreasing at a constant gradient and charging the capacitor 6.Here, the impedance of the capacitor 6 is Showa 59-17896
2(2) is selected to be sufficiently small compared to that of the choke coil 4, and the charge charged to the capacitor 6 in one cycle of the switching means is selected to be sufficiently small compared to the total accumulated charge. The terminal voltage of No. 6 becomes a substantially smoothed DC voltage Eo. At this time, the current flowing through the choke coil 4 becomes a continuous current that repeatedly rises and falls, as shown in (B), and the current IB flowing through the discharge diode 7 changes during the period when the switching means 3 is off, as shown in (0). Occurs in pulses.

In FIG. 1, the voltage generated across the overcurrent detection resistor 5 is guided to the controller 8 and compared with a constant reference value (not shown), and when it exceeds the reference value, the controller outputs θ. generation is stopped and the switching means 3 is regulated to be open to prevent destruction of the switching means 3 due to overcurrent.

Now, in this configuration, E is the main power supply. Other than that, the current consumption is relatively small. The structure shown in FIG. 3 is known as a structure that adds an independent sub power sag 2 output function. This feature is achieved by replacing the choke coil 4 in FIG. 1 with the primary winding 91 of the transformer 9, rectifying and smoothing the alternating current voltage induced in the secondary winding 92 with a diode 10° capacitor 11, and transmitting it to the terminal 12.
The sub-power sub-2 output ES is obtained at '. In such a configuration, the winding ratio of 91.92 can be freely selected to 3, and the polarity can be freely selected, but the voltage generated across the primary winding 910 of the transformer is E on the output terminal 2 side. On the other hand, the voltage E on the switching means 3 side is constant as shown in FIG. 2(A). goes back and forth between El and VBR,
Since these are not stabilized, the voltage induced in 92 fluctuates due to changes in El and VBE, and therefore the sub power supply output Es has the drawback of not being stabilized.

Structure of the Present Invention In the present invention, in order to eliminate the above-mentioned drawbacks of the conventional structure, a pulsed current IB (the first
Pay attention to figure (C)). Volume 11i of this current transformer
1 and the current generated in the second winding of the current transformer charges the main power sagrai capacitor 6, which is maintained at a constant voltage, thereby keeping the voltage generated in the first winding constant. This voltage is rectified and smoothed to obtain a stabilized sub-power sub-2 output.

Embodiment FIG. 4 is a configuration diagram showing an embodiment of the present invention, in which the first winding 131 of the current transformer 13 is inserted in series with the anode side of the discharge diode 7, and the pulse current IB is supplied to it. be done. One end of the second winding 132 is connected to the common potential point via the cathode/anode of the diode 14, and the other end is directly connected to the capacitor 6 connected to the output terminal 2. The diode 14 has the function of regulating the direction in which the current generated in the second winding charges the capacitor 6 and also prevents the electric charge of the capacitor 6 from being short-circuited and discharged via the second winding 132.

FIG. 5 is a diagram for explaining the operation of the current transformer 13. ~A current ID flowing forward through the diode 14 is generated in the second winding 132 by the pulse current 1B flowing from the common potential side toward the anode of the discharging diode 7 via the first winding 131. 1st. The ratio of the second winding is n:m
Then, n・1D2m・ID holds, so ID=
It will be Bon IB.

This current ID charges the capacitor 6, but the accumulated charge of the capacitor is sufficiently large compared to 1D of one cycle.
Since the voltage is maintained at a constant value, the capacitor 7 functions equivalently to a battery with a constant voltage E0.

Therefore, the peak value of the voltage f3B induced in the first winding 131 of the current transformer by iD is once .E.

It becomes a negative voltage in the town. Since Eo is constant, this voltage maintains a constant value and is unrelated to fluctuations in E1.

@ In Figure 4, 15.16 is this negative constant barnu °C pressure e
A diode for rectifying and smoothing B is installed. In this case, the value of x13 is E. If current transformation = 5v, fl-3, EEI will be a constant linear voltage of approximately -15V.

Other Embodiments Although the embodiment shown in FIG. 4 shows a case where a negative sub-power supply voltage E8 is obtained, FIG. 6 shows an embodiment in which a positive sub-power supply voltage can also be obtained at the same time. This embodiment also shows an example of a circuit configuration in which temperature fluctuations are reduced using diodes.

An additional winding 1 is added to the second winding 132 of the current transformer 13.
33, and set the polarity of the induced current as shown. 13
A connection point 134 between 2 and 133 is connected to the capacitor 6 via the diode 14, and the other end of 132 is connected to a common potential. The other end of the additional winding 133 is connected to the smoothing closed capacitor 21 through an anode-cathode series circuit of diodes 19 and 2Q.
, and generates a positive sub-power sagrai output F'S2 at terminals 22 and 22'. The difference from the case of FIG. 4 in the negative sub power sag 2 output ES10 circuit obtained via the first volume m131 is that a diode 18 is added to one stationary column.

The voltage generated in the second winding 132 is exactly (Ko+eD), assuming that the voltage of the diode 14 is eD. Eo
When is 5V, respectively EB1+E82 is +12V
, if you want to get -12V, winding 131.132.13
When the ratio of 3 is n:l:m, l:(l+m)=5:
12, or l:n=5:12. For example, the voltage QB+ generated in the winding 131 at 9 is the voltage QB+ generated in the winding 132
Since the voltage 1r” (5+ e D ), eB1
= nx(5+eD)/', assuming fJ) = 0, 7
At V, eB=13.68V. This is rectifier 1
5.18, a voltage drop of 2eD occurs, resulting in an output of E81-12.287. The same is true for the positive sub-power sub2'82.Here, the voltage drop eD of the diode changes depending on the ambient temperature, etc.
．． When the voltage changes by 6VK, the output voltage is -1 using the same calculation.
The voltage becomes 2.24V, and a @degree fluctuation of 0.04V occurs.

If, for example, only 1501 rectifiers are required, the temperature fluctuation will increase by 0.14 VK.

That is, temperature fluctuations due to the diode 14 can be minimized by selecting the number of rectifiers connected in series to be n for ES4 and to a number close to m/(l+m) for ES2.

Effects As explained above, according to the present invention, by adding a simple current transformer and rectifying and smoothing means, the unstable DC power source E
It is possible to obtain stable positive and negative DC outputs for sub-power sagrais that are independent of fluctuations in i and stable against temperature fluctuations, making it possible to provide inexpensive power supplies for systems that require various levels of ti voltage. And it can be realized compactly.

The application of the present invention is not limited to chopper type switching regulators as in the embodiments, but can be applied to any type of regulator such as inverter type switching regulators.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a well-known switching regulator, Fig. 2 is an explanatory diagram of its operation, Fig. 3 is a block diagram showing an example of a conventional sub-power supply output function, and Fig. 4 is a block diagram showing an example of the present invention. FIG. 5 is a diagram illustrating its operation, and FIG. 6 is a diagram illustrating another embodiment of the present invention. Ei: Unstable DC power supply Eo: Stabilized DC output heavy pressure 3 switching means 4: Choke coil 6: Capacitor 7: Discharge diode 13: Current transformer
Es: Suppower Safly Output Patent Applicant Hokushin Electric Manufacturing Co., Ltd. Representative Masahiro Shimizu Figure 1 Figure 2 Figure 6

Claims (1)

[Claims] A series circuit of a choke coil and a capacitor connected to an unstable direct power supply whose opening and closing are controlled by a switching means,
In a switching regulator comprising a discharge diode connected in parallel to the series circuit and a controller that controls the switching ratio of the switching means based on the terminal voltage of the capacitor, a first winding is connected in series with the discharge diode. a current transformer connected to the current transformer; and means for connecting a current generated in a second winding of the current transformer to charge said capacitor; and means for connecting a current generated in a second winding of said current transformer to charge said capacitor; A switching regulator equipped with means for rectifying and smoothing induced voltage.