JP2769475B2 - DC power supply - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a DC power supply.

[Conventional technology]

Conventionally, there has been a series control switching power supply circuit as shown in FIG. There is also a power supply circuit in which switches are connected in parallel. This is a booster circuit in a DC power supply (FIG. 7 (b)) or a circuit for correcting input current distortion (Japanese Patent Laid-Open No. 2-106171). No.).

Further, as shown in FIG. 8, there is a parallel type regulator power supply unit suitable for a current source, but it is considered that it is not suitable for a large capacity power supply due to low efficiency.

Under such circumstances, there is a demand in the electric industry for the development of a DC power supply device that is small, has high efficiency, and does not generate noise.

[Problems to be Solved by the Invention] Accordingly, an object of the present invention is to provide a DC power supply device that is small, has high efficiency, and does not generate noise.

[Means for solving the problem]

A DC power supply device according to the present invention includes a rectifier circuit (3) connected between AC power supply terminals, a smoothing capacitor (4) connected between output terminals of the rectifier circuit (3), and the rectifier circuit (3). The capacitor (C
1) and a parallel control switch (2) connected in parallel between the output terminals of the rectifier circuit (3), wherein the comparator circuit (2) detects the voltage across the smoothing capacitor (4). 6) and the output voltage of the rectifier circuit (3) is
A zero volt detection circuit (7) for detecting 0 V is provided, and a parallel control switch (2) is provided by a logical product output signal of an output signal of the comparison circuit (6) and an output signal of the zero volt detection circuit (7). To drive.

This DC power supply basically includes a rectifier circuit (3) connected between AC power supply terminals, a smoothing capacitor (4) connected between output terminals of the rectifier circuit (3), and the rectifier circuit (3). 3) Capacitor (C1) connected to the input terminal side
And a parallel control switch (2) connected in parallel between the output terminals of the rectifier circuit (3).
It is small and highly efficient.

The DC power supply device further comprises a comparison circuit (6) for detecting a voltage between terminals of the smoothing capacitor (4), and a zero volt detection circuit (7) for detecting that the output voltage of the rectifier circuit (3) is 0V. And the parallel control switch (2) is driven by the logical product output signal of the output signal of the comparison circuit (6) and the output signal of the zero volt detection circuit (7). Therefore, noise is not generated.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the DC power supply of this embodiment
A current limiting impedance element (1) is connected in series to a commercial AC power supply, and a parallel control switch (2) is connected in parallel. Further, a smoothing capacitor (4) and a rectifier circuit on the AC power supply side are connected to the AC power supply. And (3) in parallel.

In this device, when the parallel control switch (2) is turned off, the output current becomes substantially equal to the fixed current of the current source.
If the fixed voltage of the commercial AC power supply is Ui, the impedance of the source flow element is Zi, and the total load is ZL, the fixed current Ii is: Ii
= Ui / (Zi + ZL). Here, when the parallel control switch (2) is turned on, the output current is substantially equal to zero. Therefore, a required output current can be obtained by opening and closing the parallel control switch (2). It becomes a DC pulse current source via the rectifier circuit (3). Further, it passes through the smoothing capacitor (4) to suppress ripples and at the same time convert to a DC low voltage source.

Next, the DC power supply device shown in FIG. 2 is almost the same as that described above, except that the rectifier circuit (3) in FIG. 1 also functions as a backflow prevention diode.
In FIG. 2, a backflow preventing diode (5) is provided separately from the rectifier circuit (3).

The current limiting impedance element 1 provided in the DC power supply device described above can be a capacitor (see FIG. 3).

The DC power supply shown in FIG. 3 is an embodiment corresponding to the conventional MAX610 circuit of MAXIM, USA. This DC power supply is basically a MAX610 circuit (see Fig. 8),
A comparison circuit (6) for detecting an output voltage and a zero volt detection circuit (7) are provided on the output circuit. A parallel output signal of the output signal of the comparison circuit (6) and the output signal of the zero volt detection circuit (7) is used. The shape control switch is driven.

More specifically, as shown in FIG. 3, the zener diode (Dz) is replaced by a thyristor (SCR) for a parallel control switch, and the zener diode (Dz) is used as a simple comparator in FIG. Connect as
Resistance (R3), diode (D2) and transistor (Tr)
Thus, a simple zero volt detection circuit (7) was constructed. Terminal voltage of smoothing capacitor (4) is Zener diode (Dz)
And the thyristor (SCR) is turned on when the output voltage of the rectifier circuit (3) becomes zero. Otherwise, the configuration is the same as the conventional one. Note that (R1) is a power thermistor for controlling inrush current, and (R2) is a resistor for discharging accumulated charge of the capacitor (C1).

By adding a small number of components as described above, almost the same specifications as those of the related art were maintained, the efficiency was considerably improved, and noise was not generated. For example, while the maximum loss of the MAX610 circuit is 0.75 W, the maximum loss of the circuit shown in FIG. 3 is about 0.2 W. In other words, the circuit of FIG. 3 can output three times as much current as the conventional one with the same loss of 0.75 W (however, (R1), (C1) and the series regulator (8) change. There must be). And the higher the output voltage, the better.

FIG. 4 shows a DC constant voltage power supply device capable of adjusting a large output current and an output voltage widely. Compared to Fig. 3, when the parallel control switch (2) is ON, no current flows through the rectifier circuit (3), and the parallel control switch (2) is OFF.
Sometimes the backflow preventing diode (5) does not enter, so that it is more efficient. Further, by applying the comparison circuit (6) to both ends of the series regulator (8), the voltage at both ends of the series regulator (8) does not change even if the output voltage is arbitrary. Therefore, a wide range of output voltage can be adjusted with one volume (W1). Of course, if the capacity of the smoothing capacitor (4) is sufficient, the series regulator (8) can be omitted.

 Here, a modified embodiment will be described.

FIG. 5 can be said to be the simplest DC power supply. When the terminal voltage of the smoothing capacitor (4) reaches the breakover voltage, the DIAC or SBS enters the negative resistance region, so that the passing voltage can be prevented.

FIG. 6 shows a charging circuit in which the current limiting impedance element utilizes an electric device (9) in use. A major advantage is that it can handle voltages of any country, and can be smaller because no current-limiting impedance element is included in the case.

The charging voltage can be adjusted with W1, but care must be taken so that it does not significantly affect the electrical equipment used.

The charging current can be adjusted with W2, but it goes without saying that it is only the current consumption of the electrical equipment used.

Here, the reason for using the relay (RY) is that the relay is small and loss is small. If you don't mind it,
It may be replaced with a triac as shown in the figure. The full charge detection circuit is not limited to voltage detection. There are many others, but they are omitted.

In FIG. 6, a photothyristor (LED-SCR) is used to turn on the thyristor during charging and turn off when the thyristor is fully charged. The drive current then flows through the drive coil, turning on the relay and ending charging. (C1) is a current limiting capacitor,
(D1) is a half-wave rectifier diode, and (R1) and (C2) serve as both a filtering circuit and a delay circuit.

〔The invention's effect〕

Since the present invention has the above configuration, the following effects can be obtained.

As is clear from the contents described in the section of means for solving the problems, a DC power supply device that is small, has high efficiency, and does not generate noise can be provided.

[Brief description of the drawings]

1 and 2 are circuit diagrams of a parallel control switching power supply device on which the present invention is based. FIG. 3 is an explanatory diagram of a circuit of a DC power supply device in which the present invention is applied to a MAX610 circuit of MAXIM, USA. FIG. 4 is an explanatory diagram of a circuit of a DC constant voltage power supply device which can adjust a large output current and a wide output voltage according to the present invention. FIG. 5 is an explanatory diagram of a circuit in which the parallel control switch of the present invention is replaced with a two-terminal switch. FIG. 6 is a circuit diagram in which the current limiting impedance element of the present invention is replaced with an electric device in use. FIG. 7A shows a conventional series-controlled switching power supply, and FIG. 7B shows a booster circuit in a conventional DC power supply or for correcting distortion of an input current. FIG. 8 shows a conventional parallel regulator power supply device. (1) Impedance element, (2) Parallel control switch (3) Rectifier circuit, (4) Smoothing capacitor (5) Backflow prevention diode, (6) Comparison circuit ( 7) Zero volt detection circuit, (8) Series regulator (9) Electric / electronic equipment

Claims (1)

(57) [Claims] A rectifier circuit (3) connected between AC power supply terminals, a smoothing capacitor (4) connected between output terminals of the rectifier circuit (3), and an input terminal of the rectifier circuit (3). And a parallel-type control switch (2) connected in parallel between the output terminals of the rectifier circuit (3). A comparison circuit (6) for detecting a voltage between terminals and a zero volt detection circuit (7) for detecting that the output voltage of the rectifier circuit (3) is 0 V are provided. A direct-current power supply device wherein a parallel control switch (2) is driven by an AND output signal with an output signal of a detection circuit (7).