JP2000196428A - Switching circuit having self-holding function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an ON voltage from being increased when expanding the main current capacity of a switching means through an active element means by providing the voltage-driven type active element means having no self-holding function, an ON direction driving means for driving the active element means and an OFF driving means for off-driving the active element means. SOLUTION: According to the conducted state of OFF state of equivalent circuit of a thyristor formed from transistors 1 and 2, a transistor 7 is driven in ON direction by the serial circuit of a DC power source 81 and a resistor 82 or is off-driven by a resistor 83 so that the transistor 7 can expand the main current capacity of equivalent circuit of the thyristor. Further, since the serial circuit of the DC power source 81 and the resistor 82 can not supply a sufficient ON driving voltage to the transistor 7, the ON voltage of the switching circuit is not increased. When the main current of the switching circuit is zero and the equivalent thyristor is turned on, the current value of the resistor 82 is smaller than the holding current of the equivalent thyristor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a "switching circuit having a self-holding function" in which the main current capacity of a switching means having a self-holding function is expanded by voltage-driven active element means.

[0002]

2. Description of the Related Art FIGS. 2 and 3 show a "switching circuit having a self-holding function" in which a main current capacity of a switching means having a self-holding function is enlarged by an active element means as a prior art.
Show one by one. In the switching circuit of FIG. 2, the bipolar transistor 80 expands the main current capacity of the “equivalent circuit of the thyristor formed by the transistors 1 and 2”, and in the switching circuit of FIG. 3, “the equivalent of the thyristor formed by the transistors 1 and 2” The voltage-driven transistor 7 expands the main current capacity of the circuit. However, since the voltage-driven transistor generally has a higher on-drive voltage than the bipolar transistor, the switching circuit shown in FIG. 3 has a problem that “the on-voltage is large”.
(Problem) In view of the above, the present invention provides a switching circuit having a self-holding function that does not increase the on-voltage when the main current capacity of the switching means having a self-holding function is expanded by a voltage-driven active element means. It is intended to be. (
Object of the invention)

[0003]

That is, the present invention does not form a pair with a voltage-driven active element having no self-holding function, a switching means having a self-holding function, and a drive signal input for the active element. It is connected in series with the switching means between the main terminal and the control terminal, operates based on the conduction state of the switching means, and increases the magnitude of the main current of the switching means to reduce the main current of the active element means. ON-direction driving means for driving the active element means in a direction of increasing the size, and connected between the `` main terminal paired with the control terminal for inputting a drive signal of the active element means '' and the control terminal, A switching circuit having a self-holding function, comprising: an off-drive means for driving the active element means off when the switching means is off.

Accordingly, the active element means is driven in the on direction by the on-direction driving means or the off-driving means is driven off in accordance with the conduction state or the off state of the switching means. The means expands the main current capacity of the switching means. In addition, since the on-direction driving means can supply a sufficient on-driving voltage to the active cable means, the on-voltage of the switching circuit does not increase.
(Effect)

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In order to describe each invention in more detail, the invention will be described below with reference to the accompanying drawings. In the embodiment of FIG. 1, each corresponds to each component described above. a) The transistor 7 is the active element means described above. b) "Equivalent circuit of thyristor formed by transistors 1 and 2" is the switching means described above. c) The gate terminal, the source terminal, and the drain terminal of the transistor 7 are the control terminal, the main terminal that forms a pair, and the main terminal that does not form a pair. d) The "series circuit of the DC power supply 81 and the resistor 82" is the ON-direction driving means described above. e) The resistor 83 serves as the above-described off-driving means.

When the main current of the switching circuit is zero,
When the equivalent thyristor is on, the current value of the resistor 82 must be smaller than the holding current of the equivalent thyristor. Otherwise, the equivalent thyristor will remain on, meaning that the switching circuit will remain on.

FIGS. 4 to 20 and FIGS. 24 to 40 show one embodiment of the "switching circuit having a self-holding function" of each invention.
Show one by one. In the embodiments of FIGS. 7, 9, 11, 12, 15, 15, 17, 19, 20, 31, and 33 to 38, for example, the switch is turned on while the switching circuit is not turned on. Then, the capacitor for supplying the ON drive voltage is charged. In each of the embodiments shown in FIGS. 13 to 20, the main current detecting means of the thyristor equivalent circuit to which the current mirror circuit is applied is used. Embodiments of the switching circuit using each embodiment of the "main current detecting means" are also possible. (Reference: Japanese Utility Model Application 55-44690)
JP-A-58-50825, JP-A-2-1609
issue)

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIGS. 2 to 3 are circuit diagrams showing one example of a conventional self-holding switching circuit.

FIGS. 4 to 40 are circuit diagrams showing one embodiment of each invention.

Claims (1)

[Claims] 1. An active element means of a voltage drive type having no self-holding function, a switching means having a self-holding function, a main terminal and a control terminal not forming a pair for inputting a drive signal of the active element means. Connected in series with the switching means, operates based on the conduction state of the switching means, and increases the magnitude of the main current of the active element means with respect to the increase of the magnitude of the main current of the switching means. ON-direction driving means for driving the active element means, and connected between the "main terminal paired with the control terminal for inputting a drive signal of the active element means" and the control terminal,
A switching circuit having a self-holding function, comprising: an off-drive means for driving off the active element means when the switching means is off.