JPS5846866A - Control type dc-dc converter - Google Patents

Abstract

PURPOSE:To reduce the current effective value component and the ripple component for the titled converter by a method wherein two center taps for an output transformer are provided, and an output waveform is formed into a stepped pulse waveform by switching these taps. CONSTITUTION:The two center taps are provided on the input side wiring of the output transformer 5, and switching transistors 14 and 14' are operated alternately at the phase difference of 180 deg. by the driving pulse sent from a two-phase pulse generator 15. The transistors 14 and 14' are synchronized with the operation of the main switching transistors 4 and 4', maintaining certain phase difference phi, and as a result, the switching waveform is formed into a stepped pulse waveform (b). The high and low time ratio of the switching waveform Vs on the output side is change with varied phase difference ranging 0-180 deg., and the output voltage V0 is controlled. Accordingly, the current Ip on the input side is turned to a stepped waveform, and this enables to reduce the effective value and the ripple component of the titled converter when compared with that of the converter heretofore in use.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DO-no converter that receives a DC power source as an input and outputs a required DC voltage, and particularly relates to a DO-no converter that uses a DC power source as an input and outputs a required DC voltage.
- This relates to a DO converter.

Generally, DO-Do converters are desired to have highly stable output voltage, high conversion efficiency, small size, and light weight. Switching regulators have become widely used to meet this need.The switcher regulator uses a switching element such as a transistor to interrupt the DC input power, converts it into a rectangular wave pulse, and converts it into a rectangular wave pulse. The DC output is obtained through voltage transformation, rectification, and smoothing circuits, and at the same time, the switching pulse width is controlled to stabilize the output.Figure 1 is a configuration diagram showing the basic circuit of this conventional example. In Fig. 1, l is a DC input power supply, and 4.
4' is a switching transistor of push-pull configuration. 5#i output transformer, 6.6' is rectifier diode, 7 is choke coil, 8 is capacitor, 10t
j indicates the output side load, and further indicates a two-phase pulse generator with 111fi drive pulses, 12 a pulse width modulation circuit, and 13 an error voltage detector for detecting the error voltage of the output voltage.
Usually, the above-mentioned 11% 12.13 etc. F11 LgI is used. This circuit is generally called a center-tap push-pull Do-DC converter, and since its operation is well known, it will be briefly explained. The input DC power source IFi is alternately switched at a phase angle of 1800 by the switching transistor 4.4', and a rectangular wave AC pulse is generated at the output side K11i of the output transformer 5. The output pulse of each is diode 6.6'
It is rectified by a full-wave rectifier circuit with center tap ' method, and smoothed by choke coil 7 and condenser f8.
The output side IIc is converted into DC and supplied with a load of 10C. An error voltage detector is connected to the output side IIc, and it is designed to detect and amplify the error when the output voltage deviates from the set value. The detected signal is applied to the pulse width modulation circuit 12, and the width (duty ratio) of the drive pulse is changed to maintain the output voltage at a set value. As shown in FIG. 3(a), the switching voltage and current waveforms of this circuit system can be said to be rectangular wave pulses with large ripple voltages and currents when they swing from the set value to the D potential. Generally, when the ripple voltage and current are large, their effective value becomes large, which causes various problems. For example, in Figure 3 (a
) Regarding the input side current IP at K, this ripple flows to the input capacitor 3, so a large capacitor is required to withstand this, and the ohmitter of other parts of the circuit is also required. The loss is also large9
, it also results in lowering the conversion efficiency. Also, the output side current IL
Similarly, the inductance of the choke coil 7 becomes larger in the case of K'':)-, and the shape becomes larger.As mentioned above, in the conventional method, there was a problem in that the component parts were large and the cooking efficiency was reduced. .

The present invention aims to improve such problems by making the switching waveform step-like, reducing the ripple voltage and current at each part, downsizing the component parts, and reducing circuit loss. Another object of the present invention is to provide a low-cost controlled WIDO-DC converter.

The circuit configuration according to the present invention includes a DC inflow terminal, two main switching transistors connected thereto, an output lance, and a first two main switching transistors that drive the main switching transistors.
A center-tap type push-pull inverter circuit consisting of a phase pulse generator, etc., an output section of this inverter circuit connected to a sensor-tap type rectifier circuit, and a transistor input type LO connected in series to this. In a Do-DO converter consisting of a filter circuit and an output terminal (in particular, in the output transformer of the inverter circuit, the center tap of the primary winding is located at two locations symmetrically from the center of the winding). a second center tap switching transistor provided with two center tap switching switching transistors connected in series to each of the center taps, and further provided with a phase control input terminal and a frequency synchronization input terminal for driving the tap switching switching transistors; A two-phase pulse generator and an error detector connected to the output terminal to detect an error in the output voltage are added, and the synchronizing signal of the first two-phase pulse generator is applied to the second two-phase pulse generator. is connected to the frequency synchronization input terminal, and the detection signal of the error voltage detector is connected to the second frequency synchronization input terminal.
This configuration is connected to the phase control input terminal of a two-phase pulse generator.

That is, the present invention achieves its purpose by providing two center taps on the output transformer of the inverter circuit, and by switching between them, the output waveform becomes a stepped pulse waveform, and the effective value and ripple components are eliminated. It is.

FIG. 3 is a switching waveform diagram for explaining the difference in waveforms. Figure 3 (1) shows the input side current IP of the conventional method.
The switching current waveform is shown as an example, and the third [
(b) shows a switching current waveform corresponding to (3) in the same figure according to the present invention. The average m ′I! in (a) of the same figure. 011 Current t! I, /,, but give,! Since it is standardized, it becomes Ton. Average current Fi in Figure 3(b)
IP@T'on + Ip (IIIIN)・T'off
However, if Ip (WIN) = Ton (WIN) is input as the initial condition, the result is 〒'on + Ton (MIN) e T'Off
becomes. Therefore, Ton = −T'on + Ton (M I N )
-'I"off"-= (1) is obtained.

Further, the effective component for each average power in FIG. 3 (11) and (b) is shown by the following equation.

Effective portion of Section 311(a)' = 1/Ton −”
−==”” Concave curve [21 The effective component ratio of Figure 3 (hot) and (b), that is, Figure 3 (b) effective component / Figure 3 (a) effective component is (1)
, (2) and (3). however,? 'off =
1- It is 'F' country.

? 113 Wi (C
) is a graph with Ton (MIN) as a parameter, and Ton (WIN) is determined depending on the required control limit value, but is usually o, 5 to 0.7. Third
[From Dala 7 in (C), it can be seen that the effective component of the current is lower in the circuit system according to the present invention, that is, the CJ circuit shown in FIG. 3(b). Furthermore, the portion indicated by parallel diagonal lines in Fig. 311 (11) and (b) is the ripple component, but in Fig. 3 (a), the beater value is larger than 1, and the actual ripple current is It can be seen that it becomes larger.

FIG. 4 shows a circuit configuration of a first embodiment according to the present invention.

In Fig. 4, the components with the same symbols as the circuit configuration of the conventional example shown in Fig. 1 have exactly the same function and operation as this, i.e., basically the center tap. This is a push-pull DO-DO converter. Only the differences will be explained below. . Output transformer 50 input side winding IK: Two center taps are provided,
This is located symmetrically to the center of the winding. Tiger,
The transistor 14.14' is a switching transistor for alternately switching these two taps, and this switching transistor 14.14' is driven by a drive pulse from the second two-phase pulse generator 15 with a phase difference of 180°. Works alternately. This two-phase pulse generator 15 is a first two-phase pulse generator.
It is synchronized with the synchronizing signal from the phase pulse generator 15ll and receives phase control by the output signal of the error detector 15. That is, the tap switching F range metal 14.14' operates in synchronization with the operation of the main switching transistor 4.4' and with a phase difference φ corresponding thereto. Therefore, the switching waveform becomes a step-like pulse waveform. This pattern becomes clear when looking at the switching waveforms of each part shown in t@(b). In other words, in the same figure, the switching waveform of transistor 4.4' and the switching waveform of transistor 4.14 are shown.
The switching waveforms ' have synchronized periods and have a phase difference φ (in this case, the phase difference between transistors 4 and 14') - this phase difference φ is O~1
80@By changing the output side switching waveform v
It can be seen that the output voltage is controlled by changing the high/low time ratio of 8. The height difference Ili of this waveform v8 is determined by the positions of the two center taps of the output voltage, and its value is determined by the required control of the output voltage V. During this control, the maximum output voltage V,
@ Output voltage V which is usually set to about 030-50%
When , shifts to one side, the second phase difference φ is controlled to be small by the output signal of the error voltage detector, and as a result, V, decreases, and therefore, V, is stabilized at a negative value. Ru. Since the current IP on the input side has a waveform similar to the MR shape shown in the figure, its effective value and ripple are smaller than in the conventional example, as described above. Furthermore, on the output side, the current (2) is also reduced by the amount of ripple. This is the ripple of ΔIL, which is expressed as ΔIL=,6 in the case of this embodiment.
Since φ in this formula is smaller than the conventional example, ΔILI/
'i becomes smaller. Note that the switching transistor 14.
When the value of 14', vc, becomes high, it is necessary to use a bidirectional transistor that can withstand this.

FIG. 5 shows a circuit diagram of the second embodiment. This embodiment is compared to the first embodiment in which the output voltage control stabilization circuit based on tap switching is moved from the input side to the output side. That is, two center taps are provided on the output side winding of the output transformer, and switching transistors 14 and 14' for tap switching are connected to these center taps, and the operation thereof is the same as that of the first embodiment, so the description thereof will be omitted. do. In this second embodiment, the output voltage is stabilized on the output side, so in the case of a multi-output configuration, each output can be easily stabilized by applying this stabilizing circuit to each output.

As can be seen from the above explanation, according to the present invention, the effective value of the current in each part is small and the ripple component is also small, so circuit loss is reduced, the input capacitor is made smaller, and the output side converter coil is made smaller. This makes it possible to realize a highly efficient and compact controlled Do-Do converter as a whole. In particular, in the case of a multi-output type, each output can be stabilized with a simple circuit, so a low-cost multi-output control type DO-Do converter can be realized.

[Brief explanation of the drawing]

No. 111 IIi A circuit configuration diagram showing a conventional example, FIG. 2 is a diagram showing operation waveforms of each part of the conventional example and a tenth embodiment according to the present invention, and No. 311! Conventional example and implementation according to the present invention. FIG. 4 is a circuit configuration diagram of the first embodiment according to the present invention, and No. 5vli is a circuit configuration diagram of the second embodiment according to the present invention. 1...Input DC power supply, 2.2'...Input terminal,
3... Input capacitor, 4.4'... Main switching F tensor, 5-i1
$Casillance, 6.6'...Diode, 7...Catacoil, 8...Capacitor, 9.9'...
・Output terminal, 10...Load, 11...102nd
Phase pulse generator, 12... Pulse width modulator, 13... Error voltage detector, 14.14'... Switching transistor for tap change, 15... Second two-phase pulse generator. Agent Patent Attorney Toshikichi Somekawa Figure 2 (a) (b) Figure 3

Claims (1)

[Claims] (1) Consists of a DC input terminal, two main switching transistors connected to this, an output lance, and a first two-phase pulse generator for driving the main switching transistor. An inverter circuit is connected to a center-tap pushbutton that takes out a square wave AC output. A center-tap full-wave rectifier circuit is connected in cascade to the output side of the inverter circuit, a choke input type I0 filter circuit, and an output terminal. D composed of and
In the O-DO converter, in particular, in the most quadrant of the inverter circuit, the center taps of the primary winding are provided at two locations on the toilet lid symmetrically from the center of the winding, and each of the center taps is Two switching transistors for switching taps are connected in series to the switching transistors for switching taps, and an input terminal for phase control and a frequency synchronization terminal for driving the switching transistors for switching taps are connected in series. #2t) A two-phase pulse generator equipped with a power terminal and an error voltage detector connected to the output terminal to detect and amplify the error in the output voltage, connecting a synchronization signal to a frequency synchronization input terminal of the second two-phase pulse generator; connecting an output signal of the error voltage detector to a phase control input terminal of the second two-phase pulse generator; The center tap of the controlled DO-DO cosiper characterized in that the center tap and the constituent parts of the tap switching switching transistor connected thereto are transferred to the output side winding center tap side of the output transformer. Claim W No. 1111e Lt characterized by
Control HD O-D O=i InA-fi