JPH02168852A - Constant voltage power source circuit - Google Patents

Abstract

PURPOSE:To eliminate almost all ripple components by arranging (n) delay circuits in parallel with a rectifier circuit and further providing an adder circuit for adding and averaging the outputs from the delay circuits. CONSTITUTION:Phases of ripple components are shifted by t1, t2,...tnms(t1 t2 ...tn 10ms), respectively, from that of a rectified output voltage V1 through delay circuits 2, then voltages V1, V2,...Vn are added in an adder 3. By such arrangement, ripple components can be eliminated almost perfectly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a constant voltage power supply circuit, and more particularly to a constant voltage power supply circuit that obtains a constant voltage by reducing ripples generated in a rectifier circuit to a negligible extent.

Conventional technology Conventionally, in this type of power supply circuit, when converting AC into DC, the output appears as a pulsating current (Figure 4b), and a capacitor is inserted in parallel on the output side to alleviate this. Ru. However, a ripple still remains in the output voltage (FIG. 4C). The larger the capacitance of the capacitor, the smaller the ripple and the less voltage fluctuation, but this has the drawback of increasing the size and cost.

Problems to be Solved by the Invention In the conventional power supply circuit described above, the output immediately after converting alternating current to direct current is a pulsating current as shown in Figure 4. In order to smooth this, the output shown in Figure 2 is used. Capacitor C is inserted as follows.

However, even in this case, ripples remain as shown in FIG. 4C. This ripple is determined by the impedance of the load and the time constant of the capacitor C.If the capacitance of the capacitor C is increased, the ripple can be reduced, but on the other hand, there is a problem of large size and high cost.

The present invention has been made in view of the above-mentioned conventional situation,
Therefore, an object of the present invention is to provide a new constant voltage power supply circuit which eliminates the above-mentioned drawbacks inherent in the conventional technology and which makes it possible to obtain a good constant voltage containing almost no ripple components with a simple configuration. Differences between the invention and the prior art: ``Compared to the conventional dual power supply circuit, the constant voltage power supply circuit of the present invention almost eliminates the ripple component.'' Second, the accuracy is almost the same as that of the conventional power supply circuit. It also has the difference that it can be made smaller and has the possibility of lowering the cost l-.

Means for Solving the Problems In order to achieve the above-mentioned object 1, the constant voltage power supply circuit according to the present invention includes a rectifier circuit for converting alternating current into direct current, and n voltage waveforms obtained from the rectifier circuit. n connected in parallel to the rectifier circuit to obtain voltage waveforms with different phases.
The device is configured to include: n parallel delay circuits; and an adder circuit for adding the outputs of the n delay circuits to obtain an averaged constant voltage.

Embodiment Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.

Referring to FIG. 1, a rectifier circuit 1 generates a DC voltage 1 containing ripples (C in FIG. 4). Divided into
These outputs are combined by an adder 3 to obtain an averaged constant voltage -■.

FIG. 4 shows voltage waveforms at various parts of the circuit.

For example, if the original AC voltage (VIN) is 50 [Hz], the rectifier circuit 1 creates a pulsating current (VO) 1D, and the capacitor further increases the voltage (VIN) with a ripple component of 100 [Hz] C. It is said that The period of the ripple component is T
], /f is 10 [ms]. Due to the voltage v1 and the delay circuit 2, the phases are L+, t2 . −
, t, [ms] (1+≠L2≠ ≠shi.≠10m5
) (sloped voltages Vl, V2 (Fig. 4 d, e, f)
By adding them together by the adder 3, a constant voltage (-V) g that can ignore the ripple component is obtained.

As described in detail, according to the present invention, by connecting at least one or two delay circuits and an adder to a rectifier circuit, it is possible to obtain a constant voltage that can almost ignore ripple components. will occur.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of the rectifier circuit shown in FIG. 1, and FIG. 3 is a circuit diagram showing an example of the rectifier circuit shown in FIG. 1. Circuit diagram showing an example, No. 4
This figure is a voltage waveform diagram at a specific position in the circuit shown in FIG. 1. R, l-1, + r2・Resistance, 1(+~n)・Delay time, AO operational amplifier, T=, 1~Lance, D diode, CC11 capacitor, 1・Rectifier circuit, 2・・Delay circuit, 3 Adder, 4 Operational amplifier patent applicant NEC Corporation Representative Patent attorney Yutabe Kumagai■

Claims (1)

[Claims] A rectifier circuit to which an alternating current signal is applied, a plurality of delay circuits to which output signals of the rectifier circuit are applied, and an adder for adding together the output signals of the respective delay circuits, the output of the adder A constant voltage power supply circuit characterized by obtaining a DC signal from a terminal.