JPS6025793Y2 - Ultrasonic pulse switch transducer drive circuit - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a vibrator drive circuit for an ultrasonic pulse switch.

Background Art Ultrasonic pulse switches are based on the basic principle of emitting ultrasonic pulses into space, receiving the reflected waves, and detecting the presence of an object based on the presence or absence of the reflected waves or the difference in delay time. To achieve this, it is necessary to increase the ultrasonic output in order to increase the signal-to-noise ratio and to reduce the reception sensitivity as much as possible to reduce the influence of external noise as much as possible.

Therefore, the ultrasonic output usually depends on the amplitude that can be amplified by an amplifier inserted between a vibrator acting as a transmitter and an oscillator, and the amplitude that can be amplified by the amplifier is determined by the magnitude of the power supply voltage. depends on.

Therefore, in order to increase the amplitude that can be amplified by the amplifier, it is conceivable to increase the power supply voltage applied to the entire circuit, but this would (a) cause a high Although no power supply voltage is required, a similar voltage is applied to such a receiver.

(b) It is necessary to use high-voltage circuit elements such as transistors and capacitors, which is uneconomical.

(c) If the voltage is stepped down as necessary in a circuit section that does not require a large voltage, it will cause heat generation and waste power.

There were drawbacks such as.

Therefore, in the past, as shown in Fig. 4, a first secondary winding having a large number of windings and a second secondary winding having a small number
A transformer 16' having a secondary winding is inserted between the power supply and the output end of the first secondary winding is connected to a transmitter and an amplifier in the preceding stage of the transmitter through a first rectifier circuit 17'. The output end of the second secondary winding is connected to the second rectifier circuit 18' by connecting only the first block A' containing the winding, and applying a high voltage to increase the amplifiable amplitude of the amplifier. through said first
The first block A' was excluded and connected to the second block B'.

Although this makes it possible to increase the amplitude that can be amplified by the amplifier in the front stage of the transmitter, it requires two types of secondary windings for the transformer inserted between the power supply and the manufacturing and assembly process. There was a drawback that the work was complicated.

Note that the reason why the two secondary windings cannot be of the center-tapped type is because the current capacity of each circuit section is different, and since the transmitter amplifier sends out ultrasonic pulses intermittently, the average power is This is because the peak value is large, although it is not very large, so the secondary winding on the first book side needs to be thick in order to supply that power.

Furthermore, it is clear that it is even more undesirable in terms of shape and cost to make the secondary winding on the second block B' side also have the same thickness.

Purpose of the Invention The present invention has been proposed in view of the above points, and an object thereof is to provide a vibrator drive circuit for an ultrasonic pulse switch that eliminates the above-mentioned drawbacks.

Disclosure of invention The present invention will be explained below with reference to the drawings.

Figures 1 to 3 show one embodiment of the present invention. Figure 1 is a block diagram of the entire ultrasonic pulse switch, and Figure 2 is a circuit diagram showing details of the power supply section. , FIG. 3 is a circuit configuration diagram showing details of the transmitting section.

In FIGS. 1 to 3, reference numeral 1 denotes an oscillator, which is connected to a first amplifier 3 via a first gate circuit 2, and a transmitter 4 is connected to the output terminal of the first amplifier 3. It is forced to connect.

A receiver 5 receives reflected waves of the ultrasonic waves transmitted from the transmitter 4 by an object m such as a person.

Reference numerals 6 and 7 indicate second and third amplifiers, which are inserted between the receiver 5 and the detector 8.

A pulse amplifier 9 is inserted between the detector 8 and the second gate circuit 10, and a counting circuit 11 is inserted between the second gate circuit 10 and the subsequent relay 12. ing.

13 is a clock signal generation circuit, and a pulse width determination circuit 14
is connected to the control end of the first gate circuit 2 via the detection position setting circuit 15, and connected to the second gate circuit 10 via the detection position setting circuit 15.
is connected to the control end of.

A power transformer 16 is inserted between the power source and the ultrasonic pulse switch.

A first rectifier circuit 17 is inserted between the first block A including the first amplifier 3 and transmitter 4 and the power transformer 16, and outputs a high voltage.

A second rectifier circuit 18 is inserted between the second block B excluding the first block A and the power transformer 16.

FIG. 2 specifically shows the first and second rectifier circuits 17 and 18.

The configuration of the first rectifier circuit 17 is as follows.

C1 is a first capacitor, one end of which is connected to the cathode end of a first diode D1 whose anode end is grounded, and the other end of which is connected to one end of the secondary winding of the power transformer 16.

C2 is a second capacitor, one end of which is grounded, and the other end connected to the cathode end of a second diode D2 whose anode end is connected to the cathode end of the first diode D1. .

A is the output terminal of the first rectifier circuit 17, which is drawn out from the connection point of the second diode D2 and the second capacitor C2.

Further, the configuration of the second rectifier circuit 18 is as follows.

C3 is a third capacitor, one end of which is grounded, and the other end connected to the cathode end of a third diode D3 whose anode end is connected to the one end of the power transformer 16.

C1 is a fourth capacitor, one end of which is grounded, and the other end connected to the third diode D3 via the first resistor R1.
is connected to the cathode end of the

b is the output terminal of the second rectifier circuit 18, and the first resistor R
1 and the fourth capacitor C1.

FIG. 3 specifically shows a first block A including a first amplifier 3 and a transmitter 4. In FIG.

The configuration of the first amplifier 3 is as follows.

The first transistor Tr is of the NPN type, has an emitter grounded, a base connected to the second block B via the second resistor R2, and a third transistor Tr, one end connected to the ground.

The collector is connected to the output terminal a of the first rectifier circuit 17 via a fourth resistor R1.

Tr2 is a second transistor, which is of NPN type, and whose base is connected to the first transistor Tr1 through a fifth resistor.
The collector of the first rectifier circuit 17 is connected to the output terminal a of the first rectifier circuit 17 .

Tr3 is a third transistor of the PNP type, and has an emitter connected to the emitter of the second transistor Tr2, and a base connected to the collector of the first transistor Tr1 via the fifth resistor R5. and the collector is grounded.

C3 is a fifth capacitor, which is inserted between the connection point of the emitters of the second and third transistors Tr2 and Tr3 and the output terminal.

Furthermore, the transmitter 4 has one end grounded and the other end connected to the first
It consists of a vibrator M connected to the output terminal of an amplifier 3.

Next, the operation of the present invention will be explained.

Pulse width determination circuit 14 by clock signal generation circuit 13
The driving force causes the first gate circuit 2 to open and close.

When the first gate circuit 2 is open, the output of the oscillator 1 is
The signal is applied to the amplifier 3 for large amplification and is emitted into space from the transmitter 4.

When an object m exists in space, the transmitted signal is reflected,
Then, the signal is received by the receiver 5, subjected to small amplification by the second and third amplifiers 6.
The signal is applied to the second gate circuit 10 through the .

The second gate circuit 10 includes a clock signal generation circuit 1
When in the open state, the output of the pulse amplifier 9 is applied to the counting circuit 11 to drive the relay 12.

The first rectifier circuit 17 includes first and second diodes D,...
D2 performs voltage double rectification, while the second rectifier circuit 18
performs normal half-wave rectification, and a higher power supply voltage is applied to the first block A than to the second block B.

Therefore, by setting the amplitude of the first amplifier 3 to a sufficient magnitude, the ultrasonic output can be increased.

Effects of the Invention As described above, the vibrator driving circuit of the present invention connects a power transformer to a power source, connects first and second rectifier circuits to the same secondary winding of the power transformer, and The output end of the first rectifier circuit is connected to the first block, the output end of the second rectifier circuit is connected to a second block from which the first block is removed, and the power supply voltage of the first block is By increasing the amplification amplitude and sending the signal into the air, and applying a low power supply voltage to the second block, (a) the ultrasonic output is increased, so the S/N ratio can be improved.

(b) Compared to the conventional configuration shown in Figure 4, the transformer
Since only one secondary winding is required, the structure of the transformer can be simplified,
Manufacturing and assembly work becomes easier.

(c) Since a low voltage is applied to the receiving section which does not require a large power supply voltage, there is no need to step down the voltage, and power consumption due to heat generation is eliminated.

(d) Since most of the circuit parts operate at low voltage 2, the withstand voltage of the element can be set low.

(e) Therefore, it is economical.

It can produce very practical effects such as.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIGS. 2 and 3 are detailed circuit diagrams of the same parts, and FIG. 4 is a conventional configuration diagram. 1...Oscillator, 2.10...Day 1~
Circuit, 3゜6.7...Amplifier, 4...
Transmitter, 5... Receiver, 8... Detector, 9... Pulse amplifier, 11... Counting circuit, 12... Relay, 13...Clock signal generation circuit, 14...Pulse width determination circuit, 15...Detection position setting circuit, 16...
・Power transformer, 17.18... Rectifier circuit,
A, B...Block, m...Object.

Claims (2)

[Scope of utility model registration request] (1) In an ultrasonic pulse switch that uses ultrasonic pulses to monitor the intrusion of objects into a predetermined area and switch on subsequent devices, one of the power transformers is connected to the power source.
A second rectifier circuit constituting a voltage doubler rectifier circuit is connected to the secondary winding of this power transformer, and a first rectifier circuit that includes a transmitter and an amplifier before the transmitter is connected to the secondary winding of this power transformer. 1
Connect the power terminal of the block, and connect the secondary winding to the secondary winding.
A vibrator drive circuit for an ultrasonic pulse switch, comprising: a rectifier circuit connected to the second rectifier circuit; and a power terminal of a second block excluding the transmitter and amplifier connected to the second rectifier circuit. (2) One end of the first series circuit of the first capacitor and the first diode is an input terminal, the other end is grounded, and the connection point between the first capacitor and the first diode is connected to the ground point. A first rectifier circuit is constructed by inserting a second series circuit of a second diode and a second capacitor into the circuit, and connecting the coupling point of the second diode and the second capacitor to the output end. A vibrator drive circuit for an ultrasonic pulse switch according to claim 1 of the above-mentioned utility model registration.