JPS5840426B2 - Thyristor switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cyrisk phase control device.

Conventional light-based ignition control of the thyristor simply turns on the thyristor using light, and it is not possible to control the ignition phase of the thyristor.

It is therefore an object of the invention to provide a thyristor phase control device that is capable of controlling the firing phase of the thyristor.

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 an n-type silicon substrate, 2 is a p+ layer in which p-type impurities are partially diffused on a part of one side of the substrate 1, 3 is an n+ layer on which n-type impurities are diffused at a high concentration, 4 is an n slave station in which n-type impurities are partially diffused in a high concentration on a part of one side of the substrate 1, and 5 is a p-type slave station in which p-type impurities are diffused in the opposite side of the substrate 1.
It is a slave station.

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 of the element 11, that is, the voltage V of the power source 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.

That is, when the light is weak, the frequency is low, and when the light is strong, the frequency is high.

Further, 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.

That is, p+ ten layers, n type substrate 1. The p+10 layer and the n10 layer 3 constitute a silicon risk, and the n10 layer J s n-type substrate 1
) The p-layer 2 and the n-layer 3 constitute an odd transistor.

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

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

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

Here Φ. 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-10 layer 5, and the potential of the p+10 layer increases, making it higher than that of the n-type substrate 1.

Then, p ten layer 5 (anode) - n type substrate 1 - p+
10th layer -n The Si risk of slave station 3 (cathode) is forward biased.

On the other hand, the p slave station 2 is also irradiated with light, and hole-electron pairs are generated within the p slave station 2 as well.

Then, with the applied voltage V shown in FIG.
The junction of is reverse biased.

Therefore, electrons generated within the p+ layer become photocurrents flowing to the n-type substrate 1 due to diffusion and the electric field within the depletion layer.

In addition, electrons generated in the depletion layer of the p+10 layer and the n-type substrate 1 immediately flow to the n-type substrate 1, and some of the holes generated in the n-type substrate 1 are near the junction between the n-type substrate 1 and the p+10 layer. This results in a photocurrent flowing to the p+ layer.

The holes generated within the p slave station 2 increase the potential within the p slave station 2, making it easier for the n slave station 3 to inject electrons.

Therefore, when the photocurrent is defined as IL, the current flowing through the transistors of the n + 10 layers - n type substrate 1 - p slave station 2 - n slave station is as follows.

Here, C1 is the amplification factor of the transistor and depends on 11, and the larger 1 is, the larger it becomes.

Therefore, ■1 becomes large even for a small IL, and since ■1 is large, C1 also becomes large.

In addition, if the amplification factor of the transistor composed of P slave station 5 - N type substrate 1 - P slave station 2 is C2, then since C1 is large, the condition can be satisfied even with a small amount of light irradiation. , as soon as the potential of the p slave station 5 becomes higher than that of the n type substrate 1, the circuit between the p slave station 5 and the n type substrate 'i-p+10 layer -n+10 layer becomes conductive.

That is, the holes in the p layer 5 are injected into the n-type substrate 1, and the electrons in the n+10 layer are injected into the p+10 layer.
A double injection occurs at the junction of the shaped substrate 1, and this junction (21) immediately becomes forward biased.

However, when the holes in the p+10 layer are swept out and electrons from the n+10 layer enter the p slave station 5, the potential of the n+10 layer decreases.
Therefore, holes are no longer injected into the n-type substrate 1 from the p+ layer, and double injection no longer occurs.

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

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

That is, if the applied voltage is V and the load resistance is R,
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 the thyristor (5-12-3) conducts, p
Even if the slave station 5 falls to the ground potential and the junction (1-2) becomes reverse biased, the potential remains close to the ground potential because of the electrons stored in the p slave station 5.

Then, the holes generated in the n-type substrate 1 enter the p+10 layer, thereby increasing the potential of the p+10 layer, and when the potential of the p+10 layer becomes higher than the potential of the n-type substrate 1, the thyristor (5-1 -2-3) becomes conductive, and the transistor (4
-1-2-3) A saturation current Is flows.

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

Changes in the load current I and the potential v5 of the p+ layer are shown in FIGS. 3a and 3b.

A circuit diagram of an embodiment of the cyrisk phase control device of the present invention is shown in FIG.

In the figure, vl is a power supply voltage, RL is a load of the thyristor 12, 13 is a phase delay circuit, Dl is a diode, 14 is a light emitting diode, 15 is a variable resistor, and v2 is a signal power source for the light emitting diode 14.

The phase delay circuit 13 is composed of a resistor R1°R2 and capacitors C1 and C2.

16 is a photocoupler that integrates the photosensitive solid-state oscillation element 11 and the light emitting diode 14.

Note that the resistor R1 or R2 is made a variable resistor, and the phase is adjusted by this resistor.

In operation, when the power supply v1 is applied, the sirisk 1
The voltage waveform applied between the two ends a and b is as shown in FIG. 5a, and this voltage is delayed by the phase delay circuit 13 and rectified by the diode D1.

The voltage waveform between c and b applied to the photosensitive solid-state oscillation element 11 at this time is shown in FIG. 5c.

That is, b is a case where the resistance R2 is made small to make the phase lag small, and C is a case where the resistance R2 is made large to make the phase lag large.

In the case shown in FIG. 5, when the light emitting diode 14 irradiates the transmitting element 11 with an optical signal, the element 11 oscillates, causing the thyristor 12 to conduct.

In this case, when the optical signal is small, oscillation occurs near the peak time t1 of the voltage applied to the element 11, as shown in FIG. 6a, and when the optical signal is large, oscillation occurs at time t2, as shown in FIG. More oscillation occurs.

Therefore, the firing phase angle of the thyristor 12 can be shifted by 90° depending on the intensity of the optical signal.

Also. By changing the resistance R2 (or Rt), t
Since the phase of the thyristor 12 can be shifted by 0 to 180 degrees, the conduction angle of the thyristor 12 can also be freely changed within the range of 0 to 180 degrees.

Thus, in this embodiment, the phase delay circuit 13
When the phase of t2 is determined, the maximum power applied to the load RL is determined, and the firing phase of the thyristor 12 can be controlled by the intensity of light up to a phase delayed by 90' from that phase.

In other words, even if the capacity of the load RL is smaller than the capacity determined by the power supply V It can be done with

Further, by keeping the optical signal constant and shifting the phase using resistor R1 or R2, phase control of 0 to 1800 can be achieved.

Furthermore, since the control signal for the thyristor 12 is light, the signal is unidirectional, and the signal source is not affected by the load circuit.

That is, the load side and signal side are completely separated.

As described above, according to the present invention, the firing phase of the cyrisk can be controlled by adjusting the phase delay amount of the variable phase delay circuit.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an example of a photosensitive solid-state oscillation device used in the present invention, FIGS. 2 and 3 are illustrations of its operation, and FIG.
The figure is a circuit diagram of one embodiment of the cyrisk phase control device of the present invention, and FIGS. 5 and 6 are signal waveform diagrams for explaining its operation. 11...Photosensitive solid state oscillator, 12...
Thyristor, 13... Phase delay circuit, 14...
...Light emitting diode.

Claims (1)

[Claims] 1 A thyristor to which the power supply voltage is applied between the anode and cathode via a load, a variable phase delay circuit that delays the phase of the voltage applied between the anode and cathode of this thyristor, and a rectifier that rectifies the output of this variable phase delay circuit. a rectifying path having a characteristic that the oscillation starting light illuminance changes depending on the applied voltage, and a rectifying diode connected in series between the output end of the variable phase delay circuit and the gate of the Sirisk. A thyristor phase control device comprising a photosensitive solid-state oscillation element and a light source that irradiates the photosensitive solid-state oscillation element with light.