JPS5813021A - High-speed switch circuit - Google Patents

Abstract

PURPOSE:To switch voltages to a load at high speed by connecting a fast rising transistor (TR) in parallel to a switch element for short-circuiting the load, and turning on this TR in the beginning of signal application. CONSTITUTION:A signal from a control circuit 18 is applied through a transformer 7 to a rectifying circuit 6, which drives a bipolar TR3. The signal from the control circuit 18 is applied through a transformer 21 to a fast rising TR19, which is turned on. The TR19 is turned on continuously until the TR3 is turned on. Thus, voltages to a load 4 are switched at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switch circuit that requires DC insulation and that switches the voltage of a load at high speed.

A conventional switch circuit that requires direct current insulation is shown in FIG. In the figure, +11 is the power supply, 12) is the protection resistor,
(8) is a bipolar transistor, (4) is a load,
(5) is a base limiting resistor, (6) is a rectifier circuit, and these constitute a switch circuit portion. (71 is a transformer, and (8) is a control circuit. The control circuit (81 and the switch circuit portion are connected to the transformer 17) for DC insulation.

Next, the operation will be explained. When the transistor (8) is off, most of the output voltage of the power supply (1) is applied to the load (4). Next, when the input signal enters the control circuit (8), the M1m circuit (8)
Oscillation is performed so that alternate currents flow through the transformer (7) in the same manner as the converter. At this time, a current as shown in FIG. 2 flows through the secondary side of the transformer (7). By passing this through the rectifier circuit (6), a current as shown in FIG. 3 flows as the base current of the transistor (3). This base current makes the transistor 181 conductive, short-circuits both ends of the load (4), and the load voltage becomes zero.

When the input signal is turned off, the oscillation of the control circuit (8) stops and the pace current stops flowing, so the transistor (8) becomes non-conductive again.

As described above, the load voltage is controlled by the control circuit (8). Here, the control circuit (8) and the switch circuit portion are DC-insulated by a transformer (7).

Since the conventional switch circuit is configured as described above, the switching time is affected by the performance of the transistor (13), but as the withstand voltage of the transistor (3) increases, the switching speed tends to vary. Therefore, there was a drawback that the switching speed was limited by the voltage of the power supply (1:).For example, when the withstand voltage s'oov, the general switching speed was l
ll5 is the limit.

This invention was made to improve the drawbacks of the conventional ones as described above, and it connects bipolar transistors with fast rise times in parallel and drives the fast rise transistors through a pulse transformer. Give a signal, compensate for the rising part of the signal with this transistor,
It is an object of the present invention to provide a switch circuit that can change the voltage applied to a load at variable speeds and also provide direct current insulation.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. , In FIG. 4, the same reference numerals as in FIG. 1 indicate the same or equivalent products. Also, (18) is the control circuit 1, α is a fast rising transistor (hereinafter referred to as a transistor), and (4) is a resistor 1. (21) is a pulse transformer.

Next, the operation will be explained. The signal from the control circuit (18) passes through the transformer (7) and is transferred to the bipolar transistor (3).
and is connected in parallel with the bipolar transistor (8) via a pulse transformer (21). It is supplied to the transistors (19) and controls each of them to perform speed change switching. According to the switch circuit with such a configuration, the delay in the on time of the transistor (81) can be compensated for by the transistor (19) as follows. First, when the transistor (81 and the transistor 19) is in the off state, 1. The voltage of the power supply 11+ is almost the same as the load (4
) is applied. Next, the input signal is the control circuit (18)
Once in the pulse transformer (21), the transistor (
A gate voltage of a constant pulse width is applied in the direction of making the transistor 131 conductive (71) and the rectifier circuit (6) at the same time.
A driving current as shown in FIG. 3 flows through the capacitor.

In this way, the load is first short-circuited quickly by the transistor (19) with a short switching time.Then, by the time this transistor α9 becomes non-conductive, the transistor (8)
is in a conductive state, so the short-circuited state of the load (41) is maintained.After that, by applying a small pace current determined by the power supply voltage, protection resistance value, and DC amplification factor of the transistor (8), Only the load (4:) can be kept short-circuited.

FIG. 6 shows the waveforms of each part at this time. In the figure, (a) is an input signal from the control circuit α8). (b) is the output waveform when only the transistor (8) is operated, (C) is the pulse transformer (2
1) is the voltage waveform applied to the gate of the transistor (19), and (d) is the output waveform when only the transistor (19) is operated.

If the drive pulse width of the transistor (19) is made longer than the width of the switch of the transistor (31), an output waveform with a fast rise as shown in Fig. 6e can be obtained. This is the voltage that was initially applied to the load.

According to the switch circuit configured based on the above concept, the voltage of the load can be switched at a speed of about a/μS at the voltage to ov.

Note that in the above embodiment, the conventional switch Example of using a transistor as a chip However, the vacuum tube type switch It is the same as the above example even when using Poisoning effect.

As described above, according to the present invention, the battery Ipolar transistor and rise speed By connecting two transistors in parallel, Each is driven via a transformer. DC insulation can be performed. and switch the voltage quickly The effect that can be obtained is obtained.

[Brief explanation of drawings]

FIG. 1 shows the configuration of a conventional switch circuit. FIGS. 1, 2, and 3 are diagrams showing waveforms of drive signals for transistors (8). FIG. 4 shows a high-speed switch circuit according to an embodiment of the present invention. FIG. 5 is a diagram showing the relationship between input signals and operating waveforms of each part in the embodiment. (!1...DC power supply, Se2)...Protective resistor, 1
8)...Transistor, (41...Load, (5
)...Limiting resistance, (6)... Rectifier circuit, (71
...Transformer, (81...Control circuit, αω...
...Fast rise transistor, ■)...Resistance, Q
υ...Pulse transformer. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. □ Figure 1 Figure 2 Figure 3 Figure 14 Figure 15

Claims (1)

[Claims] The power supply and the protection connected in series with it. protection resistor and connected to both ends of the series circuit. connected in parallel with said load. Both ends of this load are controlled according to the control signal. The short-circuited switch element and this switch Rise speed connected in parallel to from the large transistor and the split signal source. A control signal is transmitted between the switch element and the trigger. Direct current is isolated and transmitted to the transistor. High-speed switch circuit with transformer Road.