JPS5850022A - Power supply transformerless circuit device - Google Patents

Abstract

PURPOSE:To make it possible insert an additional circuit between the ground and a load, by detecting the ground side of an AC power source and performing such switching control that the reference potential point of the device is always connected to the ground side. CONSTITUTION:A ground side detecting circuit 25 inactivates a relay when detecting a cold voltage in the input terminal passing through a resistance R1 and a hot potential in the input terminal passing through a resistance R2, and the circuit 25 activates the relay when detecting the reverse. The switching control is performed through relay contacts S1 and S2. Thus, a reference potential point AG of the device has a potential approximately equal to the potential of a ground point SG of the device, and it is unnecessary to keeps a load 23 insulated from the ground, and consequently, an additional circuit can be inserted easily between the ground and the load 23 as required.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power transformerless circuit device particularly suitable for audio equipment.

Conventionally, a power transformerless circuit device configured as shown in FIG. 1 has been considered.

That is, this is a power source for the amplifier 11 to which audio signals etc. are supplied via the large sword transformer 11! Positive and negative DC voltages obtained by directly rectifying AC voltage from a commercial AC power t (A, c) (not shown) supplied via a lug 10 in a double-wave rectifier circuit 13 without going through a power transformer are supplied. In addition to being driven, the nuclear amplifier 12 is designed to supply an amplified and good signal to a load J4 such as a speaker.

In the figure, reference numeral 15 denotes bidirectional ti, iI! which is controlled via the control circuit 16 in response to fluctuations in the positive (t or negative) DC voltage of the double-wave rectifier circuit 13. xp, chp
,etbK! Z? 1fi voltage.

Stabilization is being attempted.

However, in such a circuit device, the load 1
Since load 4 needs to be completely insulated from the ground, for example in audio amplifiers etc.
There was a problem that the switch between the 4 and 4 was impossible to insert an additional circuit of Kusugo. In other words, this is for safety reasons in consideration of the risk of electric shock.

Therefore, this invention was made in view of the above points, and has a configuration in which the grounding side of a commercial AC power source is detected and switching control is performed so that the reference potential point of the equipment is always connected to the grounding side. In particular, it is possible to insert additional circuits such as switches, switches, etc. between the equipment's reference potential point and the connection point with approximately the same potential between the device and the load without any problems. The purpose is to provide a good power transformerless circuit device.

An embodiment of the present invention will be described in detail below with reference to the drawings.

That is, in FIG. 2, IN is an input terminal of a device to which, for example, an audio signal or the like is supplied. It is connected to the other end of the side and to the ground point S0 of the device. Here, both shoulders of the input cadence 21 on the secondary side are connected correspondingly to both input ends of the amplifier 21 constituting the main body of the device.
Further, the output end of this amplifier 22 is connected to one end of a load 23 such as a speaker.

On the other hand, both ends of the power supply bladder 240 connected to commercial AC power supplies A and C (not shown) are connected to both input ends of the ground side detection circuit 25 via resistors R1 and R snow correspondingly, and this ground side detection circuit Relay contact 81%8 that responds to 21
! are connected correspondingly to each movable contact. Here, the relay contact ``le8g'' is one in which the first contact ``1ead'' and the second contact bleb are connected in a crosswise manner, and among them,
The connection point between III and 18 is connected to one end of the bidirectional synester 26, and is set to al,
The connection point is the device's reference potential point AQ.

It is connected to the. This reference potential point A, is also commonly connected to one end of the input of the amplifier 220 and the other end of the load 2J.

1 and the other end of the bidirectional cylindrical transistor 2σ is connected to the positive power supply terminal ←) and the negative power supply terminal of the amplifier 22 via a diode D1eDl of the illustrated polarity which is branched into two and constitutes a double-wave rectifier circuit 21, respectively. Connected to terminal 0 and smoothing capacitor C1.

It is connected to the reference potential point mu o' via C4. In addition, the connection point between the diode Dl and the capacitor CI is connected to f-) of the bidirectional susceptor 26 via a control circuit 28.

The input reference terminal of the ground side detection circuit 25 is connected to the ground point SG of the device, and the input reference terminal of the control circuit 28 is connected to the reference potential point of the device. ,It is connected to the.

In the above configuration, power supply is applied to the amplifier 22 to which audio signals and the like are supplied from the input terminal IN via the input transformer 21. It is driven by supplying positive and negative DC voltages obtained by directly rectifying AC voltages from commercial AC power sources A and C (not shown) supplied via a lug z4 in a double-wave rectifier circuit 11 without going through a power transformer. By this, the amplifier 2
2 to a load 23 such as a speaker is similar to the conventional case of FIG. 1.

In this case, if the bidirectional sinister 26 is controlled via the control circuit 28 in response to fluctuations in the positive (or negative) DC voltage of the double-wave rectifier circuit 21, the DC voltage This is also the same as in Figure 1.

However, with this invention, the power source! Immediately after the lug 24, a commercial AC power source A, CO (not shown) is connected via the ground side detection circuit 25.
By detecting the ground side, the reference potential point G of the equipment is constantly blocked and a source of stains! The lug 24 is characterized in that switching control is performed so that it can be connected to the ground side (earth ground) of the commercial AC power source M, C, regardless of the connection polarity of the lug 24.

That is, as shown in the figure, the ground side detection circuit 25 detects a state in which the input terminal via the resistor mu is at the call P voltage and the input terminal via the resistor R is at the hot potential, and deenergizes the relay. In the opposite case, the relay is energized, and the relay contacts 8t*8st'' are activated in response to this, thereby realizing the switching control described above.

As a result, the reference potential point Aa of the device becomes the ground point 8 of the device.
1! : Since it can be made to have almost the same potential as the load 23
It is no longer necessary to maintain the switch insulated from the earth, so that the switch can be inserted between the switch and the load 23 without any problems if necessary. Become.

In addition, as shown in FIG. 2, the load 23 and the reference potential point A
A delay relay contact 8s is inserted between G; and when the power is turned on and off, the relay contacts sl and s mentioned above have completely completed their switching operation when the stain source is turned on or cut off by the -tinda circuit 29. It is even more convenient if the delay relay contact SS is set to perform a closing operation. This delay relay contact 8 is connected to the ground side detection circuit 2 described above.
Alternatively, as shown in the figure, a dedicated drive circuit 29 may be used.

FIG. 3 shows another embodiment in which the input transformer 1) in FIG. 2 is omitted and in its place are relay contacts S, , St, which are interlocked with the delay relay contact S3. This is the case when

It goes without saying that the present invention is not limited to the embodiments shown above and illustrated, and that various modifications and applications can be made without departing from the gist of the invention.

Therefore, as detailed above, according to the present invention, by detecting the ground side of the commercial AC power supply and controlling switching so that the reference potential point of the device is always connected to the ground side, the device An extremely good power transformer circuit device is provided in which the reference potential point and the ground point of the circuit are set at approximately the same potential so that additional circuits such as switches, switches, switches, etc. can be inserted between the load and the load without any problem. It becomes possible to provide

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the configuration of a conventional power transformerless circuit device, Figure 2 is a diagram illustrating an embodiment of the power transformerless circuit device according to the present invention, and Figure 3 is a diagram illustrating the configuration of a power transformerless circuit device according to the present invention. FIG. 2 is a diagram illustrating the configuration of an embodiment. IN...(signal) input terminal, 21...input transformer, SG...ground point, 22...amplifier, 23...load, 24'...power supply! Lug, 25... Ground side detection circuit, S1+81... Relay contact, 26... Bidirectional size jx, A.1... Reference potential point, 2. ...Double wave rectifier circuit, 28...Control circuit, S3...Delay relay contact, 29...Drive circuit. Applicant's agent Patent attorney Takehiko Suzue No. 211I

Claims (1)

[Claims] A rectifier that directly rectifies AC voltage from a commercial AC power supply, a device that is driven by being supplied with the DC voltage from the rectifier, and a load that is supplied with the output from this device.
a detection means for detecting the ground side of the commercial AC power supply; and a switching control means for controlling switching so that the reference potential point of the front-end equipment is always connected to the ground side of the commercial AC power supply according to the detection result of the detection means. A power supply transformer-less circuit device book, characterized in that the device is equipped with the following, and an additional circuit can be inserted into the output system of the device.