JPH0449859A - Load current detection circuit of multi-output power supply circuit - Google Patents

Abstract

PURPOSE:To detect the output composite current accurately even if load changes by converting the detection output of the current transformer between the AC input terminals of a diode bridge rectifier circuit into a load current value. CONSTITUTION:The first connection line between the cathode of the rectifying dlode 131 of a power supply circuit 13 and the output end out1, the second connection line between the cathode of a rectifying diode 132 and the output end out1, and the third connection line between the second terminal B and the AC transmitting capacitor 142 connected with it are put on another, and on this piling part is provided a current transformer 17, and the output generated by this current transformer 17 is led to a current indicator 18, and is converted into a load current value. Hereby, even if load changes, the output composite current can accurately be detected.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field)
The present invention relates to a multi-output power supply circuit used as a TWT power supply that generates a collector current for driving a TWT power supply.

(Prior Art) A multi-output power supply circuit used as a conventional collector multi-stage TWT power supply is generally configured as shown in FIG.

In FIG. 3, reference numeral 11 denotes a voltage-controlled converter. This converter 11 inputs alternating current power, and connects one winding wire m of the converter transformer 12 to terminals at both ends based on its center tap as necessary. Apply AC pulse voltage. Here, the terminals at both ends of the secondary winding m2 of the converter transformer 12 are assumed to be A and B, and the intermediate tap is assumed to be C.

First and second power supply circuits 13 and 14 are connected in parallel to the converter transformer 12. First power supply circuit 1
3 is composed of rectifier diodes 131 and 132 and a smoothing capacitor 133. 11th second rectifier diode 1
Anodes 31 and 132 are connected to terminals A and B of the transformer 12, respectively, and rectifier diodes 131 and 13 are connected to terminals A and B of the transformer 12, respectively.
The two cathodes are commonly connected to each other and connected to the intermediate tap C via a smoothing capacitor 133. The above cathode common connection point is the first output terminal 0Lltl.
It is connected to the collector resistor 15 of .

The other end of this resistor 15 is connected to intermediate tap C.

On the other hand, the second power supply circuit 14 includes a diode bridge rectifier circuit 1411, a pair of AC transmission capacitors 142 and 143, and a smoothing capacitor 144. The diode bridge rectifier circuit 141 has AC input terminals S and C connected to terminals B and A. Reference terminal a of this rectifier circuit 141
is connected to the intermediate tap C of the converter transformer 12,
The DC output terminal d is connected to the intermediate tap C via the smoothing capacitor 144 and the smoothing capacitor 133,
Furthermore, it is connected to the second collector resistor 16 as a second output terminal out2. The other end of this resistor 16 is the center tap C
connected to.

In the above configuration, in the first power supply circuit 13, if terminal A is (+) and terminal B is (-), the current output from terminal A will flow through the diode 131 and capacitor 13.
3, flows through the first collector resistor 15 as the first collector current 11, and is supplied to the intermediate tap C. Next, when terminal A is reversed to (-) and terminal B is (+), the current output from terminal B flows through diode 13.
2 and a capacitor 133, the first
The collector current 11 flows through the collector resistor 15 and is supplied to the intermediate tap C. After this, repeat this operation.

On the other hand, in the second power supply circuit 14, when the terminal A becomes (+) and the terminal B becomes (-), the current output from the terminal A passes through the first AC transmission capacitor 142 to the rectifier circuit 14.
1 and rectified by smoothing capacitors 133 and 144,
It is smoothed, flows through the second collector resistor 16 as the second collector current 12, and is supplied to the intermediate tap C. next,
When terminal A is reversed to (-) and terminal B is (+), terminal B
The current output from the second AC transmission capacitor 143
through the rectifier circuit 14] and the smoothing capacitor 133,
144, the second collector current I
2 through the second collector resistor 16 and intermediate tap C.
supplied to After this, repeat this operation.

In the multi-output power supply circuit configured as described above, the output composite current 1. To detect +12, conventionally, a current transformer 17 is provided on the output lines of terminals A and B as shown in the figure, and this transformer 17 detects a voltage corresponding to the current flowing in both lines, and the average value of this detected voltage is The current indicator 1
I am trying to display it as 8. However, when looking at the circuit shown in FIG. 3, in reality, not only the collector currents II and 12 but also unnecessary currents flow in the circuit.

That is, when the terminal A is (+) and the terminal B is (~), the intermediate tap C becomes (+) with respect to the terminal B, and the current ■3 output from the intermediate tap C flows through the rectifier circuit 141 and the second It flows to terminal B via AC transmission capacitor 143. Conversely, when the terminal A is (-) and the terminal B is (+), the intermediate tap C becomes (+) with respect to the terminal A, and the current I3 output from the intermediate tap C is connected to the rectifier circuit 141 and the first AC. Flows to terminal A via transmission capacitor 142.

Therefore, the current IT actually flowing through the current transformer 22 is 'i + + 12 + 13. This total current■. is 1. It is equivalent to +r2+12.

Figure 4 shows the situation. Current flowing through collector resistor 1.5.16 1. , I, are rectified and smoothed DC currents, but for convenience of explanation, they are shown as AC waveforms in Figure 4, and the polarity depends on the direction in which the current involved in the generation of collector current r, , I2 flows through the current transformer. . The figure (a) shows the component of the current 11, the figure (b) shows the component of the current I2, and the figure (
C) is an electrician.

(d) of the figure shows the components of the total current Ia, and (+) and (-) indicate the direction of the current.

As described above, when detecting the output composite current in a conventional multi-output power supply circuit, since unnecessary current that is not output in the circuit is added, the detected current value is multiplied by a proportionality constant and displayed in a corrected manner. This method has high display accuracy when I and I2 do not change. However, with this method, TWT
If the value of the collector resistor 15, 16, that is, the load changes due to replacement of the collector resistor 15, 16, etc., and a change occurs in 11 and 12, the change does not match the proportionality constant, so it is necessary to readjust the proportionality constant.

(Problems to be Solved by the Invention) As described above, the conventional load current detection circuit of the multi-output power supply circuit requires complicated adjustment every time the load is changed.

The present invention has been made to solve the above-mentioned drawbacks, and an object of the present invention is to provide a load current detection circuit for a multi-output power supply circuit that can accurately detect the output composite current even if the load changes due to load replacement or the like. With the goal.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the multi-output power supply circuit according to the present invention supplies different DC currents to the first and second loads,
In devices that detect the supplied load current value, AC power is supplied to the primary winding, and the first and second terminals at both ends of the secondary winding are connected to the center tap of the secondary winding in response to the AC input on the primary side. A converter transformer that alternately generates voltages of positive or negative polarity, and one electrodes of first and second rectifier diodes are connected to the first and second terminals, respectively, and one end of the smoothing capacitor is connected to the intermediate tap. and the other end is commonly connected to the other electrode of the second diode, and the first load is connected between this common connection end and the intermediate tap as a first DC output end. A power supply circuit and a reference terminal of a diode bridge rectifier circuit are connected to the intermediate tap, a pair of AC input terminals are connected to the first and second terminals via AC transmission capacitors, and a smoothing capacitor is connected to the diode bridge rectifier circuit. A second load is connected to the DC output terminal of the bridge rectifier circuit, and the second load is connected between this connection point and the intermediate tap as a second DC output terminal.
between the first diode, the second diode, the first terminal, and the second terminal of the first power supply circuit, and the AC input terminal of the diode bridge rectifier circuit connected thereto. A current transformer detects the current flowing in each of the current transformers, and a load current detecting means converts the detected output of the current transformer into a load current value.

(Function) In the load current detection circuit of the multi-output power supply circuit with the above configuration, in the first power supply circuit, the first
, the smoothing capacitor connected from the positive terminal to the intermediate tap via the first or second diode due to the potential difference generated between the positive terminal and the intermediate tap each time the second terminal alternately reverses the polarity. A charging current flows through, is rectified and smoothed, becomes a DC output, and is supplied to the first load. on the other hand,
Every time the polarity of the first and second terminals of the secondary winding of the converter transformer is reversed, the potential difference generated between the intermediate tap and the negative terminal causes the negative polarity side to flow from the intermediate tap through the diode bridge rectifier circuit. A charging current is supplied to the AC transmission capacitor, and a discharge current is output from the AC transmission capacitor on the positive terminal side due to the potential difference generated between the positive terminal and the intermediate tap. This discharge current becomes a DC output of the diode bridge rectifier circuit, is smoothed by a smoothing capacitor, and then supplied to the second load. Therefore, current flows between the first diode, the second diode, and either one of the first terminal and the second terminal of the first power supply circuit and the AC input terminal of the diode bridge rectifier circuit connected thereto. By detecting this with a current transformer and converting the detection output of this current transformer into a load current value, it is possible to detect a current value that is proportional to the load current.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. However, in FIG. 1, the same parts as in FIG. 3 are denoted by the same reference numerals, and the different parts will be explained here.

FIG. 1 shows its configuration. As is clear from FIG. 1, the configuration of this power supply circuit itself is exactly the same as the conventional circuit shown in FIG. The difference is the location where the current transformer 17 is installed.

That is, here, a first connection line between the cathode of the rectifier diode 331 and the output terminal OUT of the first power supply circuit 13, a second connection line between the cathode of the rectifier diode 132 and the output terminal OUT, Second terminal B
and the third connection line between the AC transmission capacitors 142 connected thereto are overlapped as shown in the figure, and the current transformer 17 is provided in this overlapping part.
7 is led to a current display 18, where it is converted into a load current value and displayed.

In the above configuration, looking at the current waveform of each line, the first
When the terminal A of the terminal A becomes (+) and the second terminal B becomes (-), the cathode of the rectifier diode 131 and the output terminal out
As shown in FIG. 2(a), a current 1a flows through the current transformer 17 in the direction of the arrow in the figure (positive direction) in the connection line of Ml between the two.

At this time, the intermediate tap C has a positive potential with respect to the terminal B, so the current re flows to the third connection line through the intermediate tap C1 rectifier circuit 141 and the capacitor 142 to the terminal B.
(When terminal A is (10) and terminal B is (-), this value is smoothed from terminal A through capacitor 143 and rectifier circuit 141 by smoothing capacitor 144, and collector resistor 1
It is equal to the value of the current I2 flowing through B. ) flows. In addition, a second connection line between the cathode of the rectifier diode 132 and the output terminal out+ includes a diode 13
Since a reverse voltage is applied to the polarity of 2, current Ib does not flow as shown in FIG. 2(b). On the other hand, the third terminal between the second terminal B and the AC transmission capacitor 142 connected thereto
The connection line includes an AC transmission capacitor 143 from terminal B.
, a current flows to the intermediate tap C via the rectifier circuit 141,
A current 1c flows through the current transformer 17 from below the arrow in the figure to above (in the negative direction). In this way, ji! 1 terminal A is (+), jf! When terminal B of 2 is (-), positive currents 1a and Ic flow in the first and third lines, and current 1b does not flow in the second line, so current transformer 17 detects the current. The current IT is shown in Figure 2(d).
As shown in , Ia+Ic.

Conversely, when the first terminal A becomes (-) and the second terminal B becomes (+), the first connection line between the cathode of the rectifier diode 131 and the output terminal OUT is connected to the diode ]3.
Since a voltage opposite to the polarity of 1 is applied, the current 1a does not flow as shown in FIG. 2(a). In addition, a second connection line between the cathode of the rectifier diode 132 and the output terminal outr has a current of 1b flowing through the current transformer 17 from the bottom to the top (in the negative direction) as shown in FIG. 2(b). flows.

On the other hand, in the third connection line between the second terminal B and the AC transmission capacitor 142 connected thereto, a current 1c flows from the second terminal B to the output terminal out 2 via the AC transmission capacitor 142 and the rectifier circuit 141. A current 1c flows through the current transformer 17 from the bottom to the top (negative direction) in the figure. In this way, when the first terminal A is (-)-1 and the second terminal B is (+), negative currents 1b and Ic flow in the second and third lines, and the first The line has a current Ia
does not flow.

The current I↑ detected by the current transformer 17 is shown in Figure 2 (
As shown in d), Ib+Ic.

Here, the amplitude values of 1a and Ib are the same, and the positive and negative amplitude levels of Ic are also the same. Therefore, the current detected by the current transformer 17 is equivalently 1. +I2. Therefore, if the detected voltage obtained by the current transformer 17 every half cycle is averaged and this is displayed on the current display 18, the total value of Il + I2 will be equivalently displayed, and the accuracy will not deteriorate due to load changes. does not occur.

In the above embodiment, the first rectifier circuit 13 and the second rectifier circuit 14 both take out current from the first and second terminals of the converter transformer 12, but if the output voltages are different, Depending on the ratio, intermediate taps may be provided on the secondary winding m2 as appropriate, and the windings may be taken out from different locations. Further, it goes without saying that the same effect can be obtained even if the smoothing capacitor 144 of the second power supply circuit 14 is connected between the DC output terminal d of the rectifier circuit 141 and the intermediate tap C.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a multi-output power supply circuit that can accurately detect the output composite current even if the load changes due to load replacement or the like.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of a multi-output power supply circuit according to the present invention, Fig. 2 is a waveform diagram for explaining the operation of the same embodiment, and Fig. 3 is a configuration of a conventional multi-output power supply circuit. FIG. 4 is a waveform diagram for explaining the operation of the conventional circuit. 11... Voltage control converter, 12... Converter transformer, 13... First power supply circuit, 1.31. ,
1.32... Rectifier diode, 133... Smoothing capacitor, 14... Second power supply circuit, 141... Diode bridge rectifier circuit, 142, 143... AC transmission capacitor, 144... Smoothing Capacitor, 15・
...First collector resistance, 1B...Second collector resistance, 17...Current transformer, 18...Current indicator, I,, I,...Collector current. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 3 Figure 4

Claims (2)

[Claims] (1) In a load current detection circuit of a multi-output power supply circuit that supplies different DC currents to the first and second loads and detects the supplied load current value, AC power is supplied to the primary winding, and the A converter transformer that alternately generates a voltage of positive polarity or negative polarity at first and second terminals at both ends of the center tap of the winding in accordance with the AC input on the primary side, and first and second rectifiers. One electrode of a diode is connected to the first and second terminals, one end of a smoothing capacitor is connected to the intermediate tap, and the other end is commonly connected to the other electrode of the first and second diodes. a first power supply circuit to which the first load is connected between the common connection terminal and the intermediate tap as a first DC output terminal; a reference terminal of a diode bridge rectifier circuit is connected to the intermediate tap; The input terminals are respectively connected to the first and second terminals via AC transmission capacitors, a smoothing capacitor is connected to the DC output terminal of the diode bridge rectifier circuit, and a second terminal is connected between this connection point and the intermediate tap. a second load to which the second load is connected as a DC output end;
between the first diode, the second diode, the first terminal, and the second terminal of the first power supply circuit, and the AC input terminal of the diode bridge rectifier circuit connected thereto. A load current detection circuit for a multi-output power supply circuit, comprising: load current detection means for detecting the current flowing in each of the current transformers using a current transformer, and converting the detection output of the current transformer into a load current value. (2) The load current detection circuit for a multi-output power supply circuit according to claim 1, wherein one end of the smoothing capacitor of the second power supply circuit is connected to an intermediate tap of the converter transformer.