JPS5855750B2 - zero volt switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a zero-volt switching device that performs a switching operation near zero volts.

Conventional zero-volt switching devices of this type consist of a phototransistor, a zero-volt detection circuit, and a triac, but the phototransistor's low withstand voltage requires a transformer to reduce the power supply voltage, and the phototransistor's output is small. This needs to be amplified by a zero volt detection circuit, and this zero volt detection circuit itself is complicated.

Therefore, the entire zero-volt switching device had a complicated circuit configuration.

Therefore, an object of the present invention is to provide a zero-volt switching device with a simple circuit configuration.

FIG. 1 shows a structural diagram of an example of a photosensitive solid-state oscillation device used in the present invention.

In the figure, 1 is a moon-shaped silicon substrate, 2 is a p-type layer with p-type impurities partially diffused on a part of one side of the substrate 1, and 3 is an n-type layer with high concentration of n-type impurities diffused thereon. Layer 4 is an n layer in which n-type impurities are partially diffused at a high concentration on a part of one side of substrate 1, and layer 5 is a p-type layer in which p-type impurities are diffused on the opposite side of substrate 1.
There are ten layers.

6, 7 and 8 are ohmic electrodes provided on layers 3, 4 and 5, respectively; 9 is a load resistor; 10 is a power source; L is light; 11 is a photosensitive solid-state oscillation element.

When the applied voltage to the element 11, that is, the voltage (2) of the power supply 10 is kept constant and light is irradiated, the element 11 starts to oscillate in a pulsed manner, and the oscillation frequency changes depending on the light intensity of the light.

In other words, when the light is weak, the frequency is low, and when the light is strong, the frequency is high.

Furthermore, when the applied voltage V is changed, the light illuminance at the start of oscillation of the oscillation element 11 has a relationship such that when the applied voltage V is high, the oscillation start light illuminance is weak, and when the applied voltage V is low, the oscillation start light illuminance is strong.

This relationship is shown in FIG. The structure of the element 11 is a combination of a silice and a phototransistor.

In other words, the p-layer 5, the n-type substrate 1, the p-layer 2, and the n-layer 3 constitute a silicon risk, and the n-layer 4, the n-type substrate 1, the p-layer
The tenth layer 2 and the nth layer 3 constitute a phototransistor.

When the element 11 is irradiated with light, hole-electron pairs are generated within the n-type substrate 1.

Among these generated hole-electron pairs, holes that are minority carriers in the substrate 1 flow to the p-type intermediate layer 5 by diffusion.

The generation rate of holes within the substrate 1 is expressed by .

Here, Φ0 is the luminous flux, α is the absorption coefficient in silicon, and X is the distance from the surface.

The generated holes enter the p-middle layer 5, and the potential of the p-middle layer 5 increases, becoming higher than that of the n-type substrate 1.

Then, the silicon risks of the p-middle layer 5 (anode) - the n-type substrate 1 - the p-middle layer 2 - the n-layer 3 (cathode) are forward biased.

On the other hand, the p-middle layer 2 is also irradiated with light, and hole-electron pairs are generated within this p-cow intestine 2 as well.

Then, at the applied voltage ■ in Fig. 1, the p layer 2 and the n type substrate 1
The junction of is reverse biased.

Therefore, electrons generated in the p-type bovine intestine 2 become a photocurrent flowing to the n-type substrate 1 due to diffusion and the electric field in the depletion layer.

In addition, electrons generated in the depletion layer of the p-type intermediate layer 2 and the n-type substrate 1 also flow immediately to the n-type substrate 1, and among the holes generated in the n-type substrate 1, there are holes near the junction between the n-type substrate 1 and the p-type substrate 2. This becomes a photocurrent flowing to the p-type intermediate layer 2.

Then, the holes generated in the p-type bovine intestine 2 increase the potential in the p-type bovine intestine 2, making it easier to inject electrons from the n-middle layer 3.

Therefore, assuming that the photocurrent is ■L, the current ■t flowing through the transistors of the n-middle layer 4 - the n-type substrate 1 - the p-middle layer 2 - the n-middle layer 3 is as follows.

Here, α1 is the amplification factor of the transistor and depends on Io, and becomes larger as It becomes larger.

Therefore, ■1 becomes large even for small ■L, and since It is large, α1 also becomes large.

Furthermore, if α2 is the amplification factor of the transistor composed of p-middle layer 5 - n-type substrate 1 - p-middle layer 2, since α1 is large, the condition can be satisfied even with a small amount of light irradiation. As soon as the potential of the p-middle layer 5 becomes higher than that of the n-type substrate 1, the p-middle layer 5-, the n-type substrate 1-, the p-middle layer 2-n+M
The Cyrisk of 3 becomes conductive.

That is, holes in the p-middle layer 5 are injected into the n-type substrate 1, electrons in the n-middle layer 3 are injected into the p-middle layer 2, and the p-middle layer 2 and n-type substrate 1 are injected into each other.
A double injection occurs at the junction of the shaped substrate 1, and this junction (2-1) immediately becomes forward biased.

but. When holes in the p-middle layer 5 are swept out and electrons from the n-middle layer 3 enter the p-middle layer 5, the potential of the p-middle layer 5 decreases,
Therefore, no holes are injected into the n-type substrate 1 from the p-middle layer 5, and double injection no longer occurs.

However, junction (2-1) has accumulated excessive carriers and remains forward biased until these carriers are removed.

Therefore, when this junction is forward biased, a saturation current of 18 flows through the transistor (4-1-2-3').

That is, if the applied voltage is ■ and the load resistance is R, then
becomes.

Then, when the excess carriers in this junction (2-1) disappear, this junction (2-1) is reverse biased and the current is expressed by the equation (
It is only based on the photocurrent expressed by 1).

On the other hand, when Cyrisk (5-1-2-3) becomes conductive,
Even if the p-middle layer 5 drops to the ground potential and the junction (1-2) is biased in the reverse direction, the potential remains close to the ground potential because of the electrons stored in the p-middle layer 5.

Then, the holes generated in the n-type substrate 1 enter the p-middle layer 5, thereby increasing the potential of the p-middle layer 5, and when the potential of the p-middle layer 5 becomes higher than the potential of the n-type substrate 1, the silicon risk (5-1 -2-3') becomes conductive, and the transistor (
A saturation current Is flows through 4-1-2-3).

The above is the oscillation mechanism of the oscillation element 11 by light irradiation.

The changes in this load current (2) and the potential v5 of the p-type intermediate layer 5 are shown in FIGS. 3a and 3b.

A circuit diagram of an embodiment of the zero-volt switching device of the present invention is shown in FIG.

In the figure, reference numeral 12 denotes a phase delay circuit, which is designed to have a phase delay of 90 degrees with respect to the voltage of a power supply 13.

14 is a full-wave rectifier circuit, and 15 is a voltage nonlinear element such as a varistor or a Zener diode.

In this case, a simple resistance may be used.

16 is a transformer, the output of which is connected between the gate and cathode of the triac 17.

18 is a transistor, and RL is a load. 19 is a light emitting diode that irradiates light to the photosensitive solid state oscillation element 11, 20 is a DC power supply, and 21 is a variable resistor.

In operation, the voltage waveform of the power supply 13 as shown in FIG. Obtained between terminals A and B.

This voltage is a peak voltage when the voltage of the power supply 13 is zero volts.

If the resistance value of the non-linear element 15 is selected so that it decreases rapidly when the voltage ■s is reached, a current flows to the base of the transistor 18 in the voltage range above ■s, and the transistor 18
turns on when the voltage is higher than ■s.

Therefore, a voltage near the peak value is applied to the photosensitive solid-state oscillation element 11, and when the voltage becomes less than Vs, the transistor 18 is turned off and no voltage is applied to the oscillation element 11.

This state is shown in FIG. 5C. As can be seen from the figure, voltage is applied to the oscillation element 11 only when the voltage of the power supply 13 is near zero.

Next, as shown in FIG. 5d, from time tt3 to time t
14 development The photodiode 19 lights up and light is emitted to the oscillation element 1
1, oscillation occurs only when voltage is applied to the oscillation element 11.

That is, as shown in FIG. 5e, from time t2 to 13.14
Oscillation is performed only between times 15 and 16 and t7, and the triac 17 is conductive between times t2 and t1□, as shown in FIG. 5f.

In this way, even if the light emitting diode 19 is lit, the triac 17 will not conduct unless the voltage of the power supply 13 becomes near zero volts.

As described above, according to the zero-volt switching device of the present invention, a transformer for lowering the power supply voltage and an amplifier circuit for driving the sirisk are unnecessary, so that the circuit configuration is simplified.

In addition, since control is performed using optical signals, signal transmission is unidirectional, and the signal side does not receive noise from the output side, so there is no malfunction, and insulation resistance and withstand voltage between the signal side and output side are expensive.

In addition, since the conduction of Cyrisk (TRIAC 17) always takes place near zero volts of the power supply voltage, there is no inrush current or noise generated when conduction occurs, and the zero volt detection circuit can be configured with a simple circuit consisting of a switching element and an oscillation element. ing.

Furthermore, since the voltage applied to the oscillation element can be increased, the oscillation output can also be increased, and it is also possible to drive a very large capacitance.

Furthermore, the gate current of Cyrisk is a continuous oscillation pulse, so there are no ignition errors.

Furthermore, since the optical response of the oscillation element is very fast, it can respond even when the frequency of the load power source and the frequency of the signal become high.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of an example of a photosensitive solid-state oscillation device used in this invention, FIGS. 2 and 3 are signal waveform diagrams for explaining its operation, and FIG. 4 is an example of a zero-volt switching device of this invention. The circuit diagram of the embodiment, FIG. 5, is a signal waveform diagram for explaining its operation. 11...Photosensitive solid state oscillator, 12...
Phase delay circuit, 13...Power supply, 15...
・Voltage nonlinear element, 17...triac, 1
8...Transistor, 19...Light emitting diode.

Claims (1)

[Claims] 1. A sirisk in which an AC voltage is applied between an anode and a cathode via a load, a phase shift circuit that shifts the phase of the AC voltage by 90 degrees, and a level discrimination output near the peak value of the output of this phase shift circuit. a level discrimination circuit that generates a signal, a switching element that conducts in response to the level discrimination output of this level discrimination circuit, and a photosensitive solid-state oscillation element that is connected to an output terminal of the phase shift circuit via this switching element; 1 in the path from the phase shift circuit to the photosensitive solid state oscillation element.
a transformer in which a secondary winding is inserted and connected and a secondary winding is connected between the gate and cathode of the silisk; and a light source that lights up in response to a switch-on signal and irradiates the light-sensitive solid-state oscillation element. Zero volt switching device with.