JPS60195832A - Relay drive circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention provides a fail-safe relay drive circuit, in particular,
Regarding transformerless relay drive circuits.

A typical example of a conventional fail-safe relay drive circuit is shown in Fig. 1, in which a power supply circuit 1 supplied with a DC power source Vo is repeatedly operated by an AC input signal 2. In addition, the power supply circuit 1 and the DC relay 4 are connected by a transformer 5, and a rectifier 6 and a capacitor 7 are connected between the secondary coil of the transformer and the relay. Even if capacitor 3 has an open or short circuit failure, relay 4 will not operate, and even if capacitor 7 has an open failure, relay 4 will not operate.

However, while most of the components such as the switching element 3, the rectifier 6, and the capacitor 7 are becoming smaller and smaller, the relay drive circuit as a whole still remains large due to the use of the transformer 5. There is.

In addition, since the switching element 3 is frequently switched between the active region and the cut-off region using the AC input signal 2, the efficiency of power supply is poor, and it requires considerably more power than a non-fail-safe relay drive circuit that uses DC input current. There are drawbacks to doing so.

In view of the above points, it is an object of the present invention to provide a relay drive circuit that is fail-safe, eliminates the need for a transformer, and enables miniaturization.

Next, the present invention will be explained in detail.

11 is an AC input signal S to the relay drive circuit according to the present invention.
It is an AC signal source that gives The relay drive circuit consists of two switch circuits 12 and 13 that are connected in series between power supplies and perform switching operations when each receives an AC input signal S.
and an n-fold voltage rectifier circuit 14 connected between the power source and the connection point of the two switch circuits and driving the DC relay RY+ with its rectified output.

The first switch circuit 12 includes a capacitor c1 that cuts off the DC component of the AC input signal @S, a diode D+ that clamps the AC input signal to the hot side of the power supply, and a diode D+ that has the hot side of the power supply as a base potential. The PNP type transistor Q1 which inputs the AC input signal clamped by D1 between the base and emitter is connected, and the positive input of the AC input horn signal S makes the transistor Q+ conductive, and the voltage on the side 1 of the power supply is connected to the transistor. .

output as a positive output from the collector. Transistor Q1
If the power supply voltage is es (V) and the AC input potential is 82 (V), the potential between the collector and earth (the cold side of the power supply) is (el +62) (V).
It is.

The second switch circuit 13 also includes a capacitor C2 that cuts the DC component of the AC input signal S, a diode D2 that clamps the AC input signal to the cold side of the power source, and a base potential of the cold side of the power source, and the diode D2
The NPN transistor Q2 receives an AC input signal clamped by the AC input signal as input between the base and emitter, and the transistor Q2 is made conductive by the negative input of the AC input signal, and the voltage between the base and emitter of the transistor Q2 (e
2) is output, and the collector of the transistor Q2 is connected to the - field potential of the power supply via the diode D2.

Then, the first switch circuit 12 and the second switch circuit 13
The collector of the former transistor O1 and the collector of the latter transistor Q2 are connected (that is, wired OR), and these two switch circuits 12 and 13 are connected in series between the power supplies. ing.

Further, in the illustrated example, n@voltage rectifier circuit 14 has n = 2
is connected between the positive terminal of the power source and the connection point of the first switch circuit 12 and the second switch circuit 13, and both the transistors Q1. A capacitor C3 connected to the connection point of the collector of Q2, and a diode D3 connected in parallel between one end of this capacitor and the positive pole of the power supply.
, D-, and a capacitor C4 inserted directly into the diode D4. The diode D3.04 has a rectifying effect and connects the outputs of the first switch circuit 12 and the second switch circuit 13 to the pot side of the power supply or to the -
The voltage doubler rectified output is applied to the DC relay RVx by the capacitor "j' C4, and is used as a driving power source.

Next, the operation of the above configuration will be explained.

The AC input signal S is simultaneously input to the first switch circuit 12 and the second switch circuit 13. Then, the AC input signal S
When is positive, in the first switch circuit 12, it is clamped by the diode Ds through the capacitor CI, and becomes the input of the transistor Ql, and its input voltage, that is, the voltage between the base and the first mitter becomes C2, so that the transistor Q+ Turn on. However, in the second switch circuit 13, the voltage is short-circuited to the negative terminal of the power supply via the capacitor C2 and the diode D2, and is not input to the transistor 02, so that the transistor Q2 is OFF.

In addition, when the AC type chi No. 8 s lfi is negative, in the first switch circuit 12, the base of the transistor Ql
Since the voltage between 1 mitter and 1 mitter is short-circuited by the diode Dl, the transistor Q1 is turned off, and the second switch circuit 13
When the voltage between the base and the mitter of transistor Q2 becomes -C2, transistor Q2 turns on.

That is, the transistor Q for inputting the AC input signal S to the first switch circuit 12 and the second switch circuit 13
1. The operation of Q2 is that when one side is ONL, the other side is 0.
It is related to FFn.

Therefore, the ON and OFF of the two switch circuits 12 and 13
When the operation is related to the operation of the n-fold voltage rectifier circuit 14,
When the first switch circuit 12 is ON and the second switch circuit 13 is OFF during the first positive half cycle of the AC input signal S, the output of the first switch circuit 12, as well as the output voltage e2 of the transistor Q1, is , and is charged to capacitor C4 through capacitor C3 and diode D4. Furthermore, when the input S is in a negative half cycle and the first switch circuit 12 is OFF and the second switch circuit 13 is ON, the output of the second switch circuit 13, that is, the output voltage of the transistor Q2 -C2 and the power supply voltage - While the sum of el is -('e50z>, it is applied to capacitor C3 through diode D and charged.

In the next positive half cycle of the AC input signal, voltage is again applied to the capacitor C4 from the first switch circuit 12 by switching off the capacitor C3 and the diode D4, but the capacitor C3
was charged to the previous negative life cycle ( es +
ez ) is added, and a voltage of maximum (el+2(!z)) is charged to the capacitor C4.

The relationship between the amplitudes of the AC input signal S and the inputs of the transistors 1 to 1 of the first switch circuit, the inputs of the transistors of the second switch circuit, and the input of the capacitor C3 is shown in FIG.

The base inputs of the transistors Q+ and Q2 can be connected to the base inputs of the transistors Q+ and Q2 by turning on the transistors. ,Q2
A current that is 0 times the base current 11) (β is the current amplification factor) flows through Dl 0l-C3D-C4 or C3C3Q2 C2. Transistor Q1. Since Q2 amplifies the input and the input of capacitor C3 includes the amplitude of the power supply voltage e1, the heath input horn may be much smaller than the power supply voltage e1.

As mentioned above, the amplified output applied via the first switch circuit 12 or the second switch circuit 13, which is switched by the AC type J'' signal S, is subjected to n-fold voltage rectification by the n-fold voltage rectifier circuit 14. Since the relay RV+ is driven, the relay can be operated reliably at high voltage.

Next, in the embodiment shown in FIG. 2, we will discuss 1. the absence of the relay drive output when a failure occurs in each component.

(a) If the capacitor C+ or C2 is short-circuited (t>L<), then the signal source 11 changes from 1 to level L level between the power supply voltage (e+) and ground (if
Since a positive potential is not applied to the transistor Q+ of the switch circuit 12 or a negative potential is not applied to the transistor Q2 of the second switch circuit 13, no switching operation is performed.

(b) If the diode D1 or C2 is short-circuited, the input signal will not be transmitted to the switch circuit.

Also, if these are opened]
The yi electric shield-1 is gone, and the AC input signal is not transmitted in the same way.

(c) (If helangistor Q+ or Q2 is short-circuited,
Since the collector of Q2 or G, t Q 1 is shorted through the diode D2 or Dl and the transistor is destroyed, the relay does not work. In the case of release, neither the AC input signal nor the power supply voltage is applied to the n-fold voltage rectifier circuit 14.

(d) If the resistors Rs and Rz are open, the switch circuit 12.13 does not operate, so the relay drive voltage II cannot be obtained.

(e) If capacitor C3 is short-circuited, no AC voltage is generated at the terminal of diode D3, and the collector of transistor Q2 is directly short-circuited to the power supply via diode D3, destroying the transistor. Therefore, no relay drive voltage is accumulated in capacitor C4.

(f) If diode D3 is short-circuited, diode A-D
The horns cannot be conveyed directly. Furthermore, if it is opened, the discharge loop I. of the capacitor C3 is not formed, so that similarly no input is transmitted to the diode D4.

(g) If diode D4 is short-circuited, capacitor O
ak: DC voltage for driving the relay is not generated. If it is open, no input is transmitted to capacitor C4.

(ch)] If relay C4 is short-circuited, relay RV+
has no input. If it is open, it will be an AC output, so
DC relay RV+ is not activated.

(S) Also, when one of the capacitors C1 and 02 series fails and only the other outputs output, the amplitude of el of the AC input signal S is not generated in the capacitor 03, which is necessary to drive the relay. I can't get proper output.

As described above, in the relay drive circuit according to the present invention, even if any component fails, the relay drive output will not be generated even though there is no relay drive input, so it is fail-safe. is clear.

FIG. 2 shows an embodiment in which a positive voltage doubler rectifier circuit clamped to a positive potential is used, but as shown in FIG. Even if a rectifier circuit is used, exactly the same effect can be obtained.

As mentioned above, according to the present invention, since no transformer is used, the circuit can be made very compact, and
It is fail-self and can reliably drive the relay with small electric power.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a conventional fail-safe type relay drive circuit. FIG. 112 is a circuit diagram showing an embodiment of the present invention, and FIG. 3 is a time chart showing the waveforms of the AC input signal, the input to the transistor of the first switch circuit, and the input to the transistor of the second switch circuit. FIG. 4 is a circuit diagram showing another embodiment. 11...AC 13 source S...AC input signal 12...First switch circuit 13...Second switch circuit 14...t>(8ffi pressure rectification pressure path flow 1.Q2... Transistor CL-CI!...Capacitor D1~D1...Diode R1/L, RV2...Relay Patent applicant Nippon Signal stock trial/award agent Patent attorney Mitsu Ishizuki lji1, / @ Menritsu, ?J (also 1. Second country (Figure 1 υ^ Figure 3 (Between BE) Procedure width ■ 3- (method) % formula % 2. Name of invention Relay drive circuit 3. Case of person making amendment Relationship with Patent applicant name (465) Nippon Signal Co., Ltd. 4, Agent 105 Address 3-15-5-5 Shinbashi, Minato-ku, Tokyo Date of amendment order I1 July 31, 1980 (shipment date ) 6. Drawings subject to amendment 7. Contents of amendment

Claims (1)

[Claims] An AC input signal is clamped to the hot side of an m source by a diode through a capacitor, and ON/OFF operation is performed as an input between the base and emitter of a PNPN upper type transistor whose base potential is the hot side of the power source. and the PNPt-
a first switch circuit that obtains the positive output of a transistor]; and an NPN circuit that clamps the AC input signal to the cold side of the power supply by a diode through a converter circuit and sets the cold side of the N source as a base potential. It is operated as 0N-OFF input between the base and emitter of a type transistor,
1 as the negative output of the ]rector of the NPN transistor.
and a second switch circuit that connects the collector of the PNPN upper type transistor of the first switch circuit and the output of the wire A7-door of the collector of the NPN type transistor of the second switch circuit to the hot side of the power supply via a capacitor. A relay drive circuit consisting of an n-fold voltage rectifier circuit which clamps the output voltage to the output voltage and uses the rectified output voltage J as the relay drive power supply.