JPS5937663B2 - How to use heat sensitive thyristor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of using a heat-sensitive thyristor in which the anode and cathode are negatively biased for a certain period of time.

In general, setting the temperature differential for temperature control to an appropriate value is important for equipment that performs temperature control. For example, when considering temperature control for compressors such as room coolers and refrigerators, If the differential is too small, it will turn on and off frequently, causing compressor failure.
If the temperature differential is too large, temperature fluctuations will increase.

In addition, conventionally, thermostats have been widely used as sensors and switches for temperature control. However, in thermostats, the temperature differential is determined at the time of manufacture, and not only can the user not adjust it at all, but it also cannot be adjusted at all by the user. There are drawbacks such as very large variations.

FIG. 1 is a diagram showing an example of the usage state of a heat-sensitive thyristor. 1 in the figure is a heat-sensitive thyristor, the anode is connected to a terminal 3 through a load resistor 2, and the gate is connected to a terminal 5 through a resistor 4. In addition, the cathode is directly connected to terminal 5.
It is connected to the.

When an AC half-wave voltage as shown in Figure 1 is intermittently applied as a forward voltage between terminals 3 and 5, with the anode being positive and the cathode being negative, as shown in Figure 2 (the horizontal axis shows the switching It is well known that the switching temperature Ts can be varied by changing the resistance value of the resistor 4, as shown in FIG. Temperature control is performed using changes in breakover voltage VBO in response to changes in Ts. In this Figure 2, a is the resistance value RGK of the resistor 4, which is infinite, and b
is IMΩ, c is 100Ω, and d is IOKΩ. Furthermore, FIG. 3 shows the relationship between breakover voltage VBO and switching temperature Ts when an AC half-wave voltage is applied to a heat-sensitive thyristor element, which has a large effect that the inventor of the present invention calls a memory effect, with the gate open. This is an example.

Here, the switching temperature of the heat-sensitive thyristor is determined by the current amplification rate of the Pnp and Npn transistors forming the Pnpn structure of the thyristor, and the leakage current flowing through the blocking junction formed by the n-p junction located at the center of the Pnpn structure. Therefore, the switching temperature can be set low by increasing the current amplification factor of one or both of the Pnp and Npn transistors, or by increasing the leakage current of the blocking junction. Therefore, if the above-mentioned current amplification rate is set high, the memory effect becomes large. Furthermore, if the sum of the DC current amplification factors of the Pnp and npn transistors is 0.7 or less, almost no memory effect will occur, but if it is greater than this, a memory effect will occur. In this case, the memory effect means that when the temperature of the thermal thyristor rises due to carrier accumulation in the thermal thyristor and it turns on, the breakover voltage remains low for a short period of time, causing a hysteresis effect, which causes the thermal thyristor to turn off. This refers to the effect that the temperature at which the device returns to the on state is lower than the temperature at which it enters the on state.

In this Figure 3, the upper line e shows the voltage that initially turns on, and the lower line f shows the voltage that, when turned on, stores this state for a while and then turns off as the temperature decreases. shows.

In Figure 3, if an AC half-wave voltage with a peak value of 50 is applied to the heat-sensitive thyristor, and if the temperature of the heat-sensitive thyristor is initially sufficiently low and in the OFF state, the heat-sensitive thyristor will be in the ON state. Since the switching characteristic follows curve e until the temperature rises and the temperature of the thermal thyristor reaches T2, the thermal thyristor changes from the off state to the on state, and even if the temperature rises further, the thermal thyristor remains on. maintain condition.

Next, even if the temperature drops from this state to T2, the switching characteristic now follows curve e due to hysteresis, so the heat-sensitive thyristor does not turn off but remains on, and when the temperature drops below T1, the heat-sensitive thyristor turns off. Thyristor returns to off state. In other words, when a heat-sensitive thyristor is turned on at temperature T2, it does not return to the off state until the temperature drops to T2, which is T1 - T2, producing a memory effect, that is, the temperature difference between T2 and T1. Since T2-T1 acts as a temperature differential, when a heat-sensitive thyristor is used for temperature control, it is necessary to control the temperature differential exhibited by the breakover voltage. The present invention has been made in view of the above points, and by applying a reverse bias to the heat-sensitive thyristor, the above-mentioned differential is fixed to FhlWI. The present invention provides a method of using a heat-sensitive thyristor that can be used in a heat-sensitive thyristor.

Next, an embodiment of the method of using the heat-sensitive cylinter of the present invention will be explained based on the drawings. Fig. 4 is a circuit diagram applied to one embodiment, and in the case of Fig. 4, a Zener diode is used. Here is an example.

In this FIG. 4, the anode of the thermal thyristor 1 is connected to the terminal 3 through the load resistor 2, and the cathode is connected to the terminal 5.
The connection point is the same as in Fig. 1, but the resistor 4 between the gate and cathode in Fig. 1 is omitted.
Further, a circuit in which a diode 6 and a Zener diode 7 are connected in reverse series is connected between the anode and the cathode.

Now, in FIG. 4, when an AC full-wave voltage V is applied between terminals 3 and 5, the Zener diode 7 clips the voltage during the negative half cycle as shown in FIG. The sum of the clip voltage V1 or 2 and the voltage across the diode 6 is applied as a reverse bias. In this case, the relationship between the breakover voltage BO of the heat-sensitive thyristor 1 and the switching temperature Ts is as shown in FIGS. 6 to 8. Figure 6 shows the case where the clip voltage of the Zener diode 7 is 5, and Figures 7 and 8 show the case where the clip voltage is 12V and 144V, respectively.
This is the case. In these figures 6 to 8,
The upper line e shows the voltage at which the heat-sensitive thyristor 1 is turned on, as in FIG. Indicates the voltage that turns off accordingly.

By reverse-biasing the heat-sensitive thyristor 1, the voltage drop that turns off in the region where this memory effect occurs is reduced, and by increasing the reverse bias, the region where the memory effect disappears is also widened. It's summery. Here, if we pay attention to the case where the applied voltage is 50V, when the reverse bias in FIG. 6 is 5V, the temperature differential is largest at T4-T3, and when the reverse bias is 12 in FIG. -T5 has a rather small temperature differential, whereas the reverse bias is 44V.
In FIG. 8, ON and OFF are performed only at T7, and no temperature differential occurs.

That is, the magnitude of the temperature differential has a relationship of 5V>12>44V on the reverse bias. In this way, by reverse biasing the heat sensitive thyristor 1, the memory effect can be controlled and the temperature differential can be controlled.

As can be seen from FIGS. 6 to 8, the characteristics of breakover voltage VBO and switching temperature Ts change depending on the amount of reverse bias. Therefore, by changing the amount of reverse bias, the switching temperature can be changed. In addition, when the heat-sensitive thyristor 1 is used with a pulse voltage such as an AC half-wave, square wave, or sawtooth wave, the heat-sensitive thyristor 1 is The same effect as described above can be obtained by superimposing a negative voltage so that the anode and cathode of is reverse biased.

As described above, according to the present invention, by reverse biasing the heat sensitive thyristor and selecting the reverse bias voltage, the memory effect of the heat sensitive thyristor can be controlled, and the temperature differential can be controlled. I can do it.

[Brief explanation of drawings]

Figure 1 is a circuit diagram when applying an AC half-wave voltage to a conventional heat-sensitive thyristor, Figure 2 is a diagram showing the relationship between breakover voltage and switching temperature of the heat-sensitive thyristor in the circuit of Figure 1, and Figure 3. 4 is a diagram showing the relationship between the breakover voltage and switching temperature of a thermal thyristor with a large memory effect when no reverse bias is applied, and FIG. 4 is a circuit diagram applied to an embodiment of the method of using the thermal thyristor of the present invention. Figure 5 is a diagram showing the clipped voltage due to the Zener diode in the circuit of Figure 4, and Figures 6 to 8 are diagrams showing the clipped voltage by the Zener diode in the circuit of Figure 4, respectively, and a reverse bias of 5V, 112V, and 144V was applied to the heat-sensitive thyristor. FIG. 3 is a diagram showing the relationship between switching temperature and breakover voltage in the case of FIG. 1...Thyristor, 2...Load resistance,
6... Diode, 7... Zener diode.

Claims (1)

[Claims] 1. A method of using a heat-sensitive thyristor, in which a forward voltage is intermittently applied between the anode and cathode of the heat-sensitive thyristor, and temperature control is performed using changes in breakover voltage in response to changes in switching temperature in the heat-sensitive thyristor. A reverse bias voltage in a direction opposite to the forward voltage is applied between the anode and the cathode when the forward voltage is not applied, and the temperature differential exhibited by the breakover voltage is controlled by selecting the reverse bias voltage. A method of using a heat-sensitive thyristor characterized by: