JPH0644316Y2 - Power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a power supply device for a regulator using a transistor element.

[Conventional technology]

FIG. 5 is a circuit diagram of a conventional device. In the figure, (10)
Is a commercial power supply for AC input, and its amplitude is (V)
It is represented by Vsinωt (where ω is an angular frequency). (11)
Is a capacitor, (12) to (17) are rectifying diodes, (1
8) is a Zener diode, (19) and (20) are smoothing capacitors and load capacitors, (21) and (22) are output terminals to the main power load, and (21) and (23) are auxiliary power loads. Output terminal, (30) is an auxiliary power supply circuit, and (1) is a bridge rectifier circuit.

FIG. 6 is an equivalent circuit diagram of its principle. In this circuit, when the amplitude (V) of the commercial power source (10) is 240 volts, for example, the load capacitor (20) has both terminals (21) and (22). The output amplitude is about (2V = 480V). this is,
This is because the potential at point (c) is (Vsinωt + V) and the potential at point (d) is (Vsinωt−V).
On the other hand, the magnitude of the DC voltage output from the auxiliary power supply between terminals (21) and (23) is determined by the rating of the Zener diode, but is about 10V. Therefore, FIG. 6 is an equivalent circuit diagram when the points (d) and (e) are considered to have the same potential for convenience. In this case, the potential at the point (b) is 0 volt. Therefore, when the potential at the point (a) is (V) volt, the capacitor (11) is charged to (V) volt. When the potential at the point (a) is (-V) volt,
The potential at point (d) is (-2V) volts. At this time,
Since the potential at the point (c) is 0 volt, the load capacitor (20) is charged with (2V) volt.

[Problems to be solved by the invention]

That is, the operation of the conventional device is
It seems that voltage is rectified by the impedance of 1). Then, a high voltage is applied between both terminals of the load capacitor (20). When the load capacitor (20) is an electrolytic capacitor as shown in the figure, there is a problem in that its capacity is large and large, and doubling the withstand voltage also increases its cost and space.

This invention was made in order to solve the above problems, and a balancing capacitor is inserted and connected between one end of the commercial power supply and the circuit after rectification to ensure that the voltage applied to the load capacitor is not loaded. However, the purpose is to obtain a power supply device that is suppressed to the same level as the normal operating voltage.

[Means for solving problems]

A power supply device having an auxiliary power supply according to the present invention has, for example, a balancing capacitor inserted and connected between points (b) and (d).

[Action]

In this invention, the amplitude of the voltage between the terminals of the load capacitor connected between the load terminals of the main power source by the balancing capacitor becomes the amplitude value of the AC signal in the commercial power source or half of that.

[Example of device]

FIG. 1 is a block diagram showing a power supply device according to an embodiment of the present invention, and FIG. 2 is an actual circuit diagram thereof. In both figures,
The same parts as those in FIG. 5 are designated by the same reference numerals, and the re-explanation thereof will be omitted. In FIG. 1, (1) is a bridge type rectifier circuit including rectifier diodes (12) to (15), and (30)
Is an auxiliary power supply circuit including rectifier diodes (16), (17), zener diode (18) and capacitor (19). (31) is a balancing capacitor, and (32) and (33) are electrolytic capacitors of equal capacity connected in series between the load terminals (21) and (22). FIG. 3 is a principle equivalent circuit diagram according to FIG. 6, and the potential of each part is shown as follows according to the previous example. That is, the potential at the point (a) is (Vsinωt) volt, the potential at the point (b) is 0 volt, the potential at the point (c) is {(+ V / 2) + (Vsinωt / 2)} volt, and the potential at the point (d) is {. (−V / 2) + (Vsinωt / 2)} volts, so
The potential between both terminals of the load capacitor (20) is (V) volt. In this case, if the capacitance values of the capacitors (11) and (31) and (20) are C ₁ , C ₂ and C ₃ , then (C ₁ = C ₂ ) <C ₃
Is. If the other end of the balancing capacitor (31) is connected to the common connection point (f) of the two electrolytic capacitors (32) and (33) as in the second case, the withstand voltage of the capacitor (31) becomes It becomes half of 11). The signal waveforms of these respective parts are shown in FIG.

The other end of the balancing capacitor (31) was connected to the common connection point (f) of the electrolytic capacitors (32) and (33). It may be connected to either terminal (22) or (21).

[Effect of device]

As described in detail above, this invention is practically effective because the withstand voltage of the load capacitor connected between the main power source load terminals is sufficient at the amplitude value of the input AC or less.

In addition, although the electrolytic capacitor is used as the load capacitor (20) and the smoothing capacitor (19) in the above-mentioned embodiment, it can be applied to a high dielectric constant ceramic capacitor or a power supply device using other capacitors regardless of the type of the capacitor. It is obvious that the present invention is carried out and has an effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing a power supply device according to an embodiment of the present invention, FIG. 2 is an actual circuit diagram thereof, FIG. 3 is its theoretical equivalent circuit diagram, and FIG. 4 is a waveform of each part for explaining its operation. FIG. 5 and FIG. 5 are circuit diagrams showing a conventional power supply device, and FIG. 6 is a principle equivalent circuit diagram thereof. In the figure, (1) is a bridge rectifier circuit, (10) is an AC power supply, (11) and (31) are capacitors, (12) to (17) are rectifier diodes, (18) is a zener diode, and (19). ),
(20), (32) and (33) are load capacitors, (30) is an auxiliary power supply circuit, (21) and (22) are main power supply load terminals, and (2
1) and (23) are auxiliary power load terminals. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Scope of utility model registration request] A power supply having a bridge type full-wave rectifier circuit (1), a load capacitor (20), a first capacitor (11), a second capacitor (31), and an auxiliary power supply (30). In the device, the load capacitor (20) is one or more capacitors (32, 3
3) is connected and has two or more terminals,
The two are connected to the output side terminals (c, d) of the bridge type full wave rectifier circuit (1), and the auxiliary power supply (30) has a rectifier circuit (16, 17, 18) and a smoothing capacitor (19). Then, one end is connected to one (d) of the output side terminals of the bridge type full wave rectifier circuit (1) and the other end is connected to the input side of the bridge type full wave rectifier circuit (1) via the first capacitor (11). Connected to one terminal (a) of the output terminal (23)
Outputs an auxiliary DC signal, and the second capacitor (31) is connected to the other terminal (b) on the input side of the bridge type full-wave rectifier circuit (1) and any terminal of the load capacitor (20). Power supply. 2. The load capacitor (20) is composed of two capacitors (32, 33) whose capacitance values are substantially equal to each other, and the midpoint (f) thereof is connected to the second capacitor (31). The power supply device according to claim 1 of the utility model registration claim.