CS224896B1 - Circuit for control of diode bridge switch - Google Patents

Description

The present invention relates to a circuit for controlling a diode bridge switch, while solving the problem of simultaneously closing all bridge diodes.

The prior art diode bridge switch control diodes in which a pulse transformer is not used do not guarantee that all bridge diodes close simultaneously, which may be a malfunction in some applications. Mapř. in the construction of fast sampling circuits where a memory capacitor is connected to the output of the diode bridge switch; if all bridge diodes are not closed at the same time, tc may result in a voltage change at the memory capacitors and thus an error. Therefore, in the control circuit, for fast sampling circuits with a diode bridge switch, a pulse transformer is usually used to ensure that all bridge diodes are closed simultaneously. However, the design of a pulse transformer may be difficult, expensive to manufacture, and requires special high-frequency magnetic cores.

The above disadvantages are overcome by the control circuit of the bridge switch according to the invention. It is based on the fact that the positive terminal of the first voltage source is connected both to one terminal of the controlled electronic switch and to the output terminal of the first current source. The negative terminal of this voltage source is connected to the terminal formed by the bridge anode connection. The terminal formed by the bridge cathode junction is connected to the positive terminal of the second voltage source. The negative terminal of this voltage source is connected both to the second terminal of the controlled electronic switch and to the input terminal of the second power source. The advantage of this circuit is that such a control circuit ensures that the voltage change at both control nodes is stepped

224 896

224 896 of the diode bridge occurs simultaneously, thereby also closing the bridge diodes simultaneously.

One example of wiring is shown in the drawing.

The circuitry consists of two current sources 2 and 5, two voltage sources ^{28 and 24 of the} diode bridge 6 and a controlled electronic switch 7.

The positive terminal of the voltage source 3 is connected to the controlled electronic switch 7 and at the same time to the output terminal of the current source 2. The negative terminal of the voltage source 2 is connected to the terminal formed by the anode diode of diode bridge 6. the positive terminal of the power supply 4 is connected. The negative terminal of the power supply £ is connected both to the controlled electronic switch 1 and to the input terminal of the power supply 2 ·

The operation of the control circuit is as follows. When the controlled electronic switch 2 is open, .teče current from the current source 2 via the voltage source voltage U ⁰ 2 ^ through the diode bridge 6 and the voltage source 4 through a voltage to current source 2 · bridge diodes 6 and thus current flows through the bridge it acts as a closed switch between the input and output terminals. When the electronically controlled switch 1 closes, the voltage at both terminals of the electronically controlled switch 2 changes ^{to a} value close to zero and simultaneously the voltage at both control nodes of the diode bridge 6 - at the node; formed by the anode junction of the diode bridge 2 ^{to a} value close to -Uj and at the node formed by the cathode junction of the diode bridge G a near value.

the third magnitude of voltage respectively. are selected so that the diodes - all diodes - of the bridge 6 are reliably closed for the required input or output range. output voltage,

For example, a series connection of a positive voltage source and a resistance can be used as a current source 2, for example a series connection of a negative voltage source and a resistance can be used as a current source 2. As a voltage source 2 resp. 4 can be used, for example, a monocouple, but also a parallel connection of a Lener diode and a capacitor, etc. As a controlled electronic switch 1, for example, a bipolar transistor can be used.

The diode bridge switch with control circuit according to the invention can be used in all more demanding applications where high switching and opening speeds are required, with low on-state resistance and high on-state resistance at the same time. Especially suitable for applications where very fast opening of the switch is required. When using Schottky bridged diodes in a bridge and Schottky bipolar transistor as a controlled electronic switch, it allows the construction of a diode bridge switch with an open time of less than 1 ns, which is suitable eg for very fast sampling circuits with a sampling frequency higher than 10 MHz.

Claims (1)

Bridge diode switch control circuit, consisting of a controlled electronic switch, two power sources and two voltage sources, characterized in that the positive terminal of the beer power supply (3) is connected to one terminal of the controlled electronic switch (1) and to the output terminal of the first power supply (2), the negative terminal of the first voltage source (3) being connected to the terminal formed by the bridge diode anode connection (6) and the negative terminal of the second voltage source (4) connected to the second terminal of the controlled electronic switch (1) and the input terminal of the second power supply (5), the positive terminal of the second power supply (4) being connected to the terminal formed by the cathode connection of the bridge diodes (6).