JPS59126325A - Selective driving circuit - Google Patents

Abstract

PURPOSE:To supply a pulse which rises at a high speed by interposing an diode between the emitter and base of a transistor (TR) in an electrostatic recording device which uses a multistylus electrode. CONSTITUTION:The diode D4 is interposed between the emitter and base of the TR2. When the TR2 turns off, i.e. when a TR1 turns off, a current is supplied through a resistance R1 and a current is supplied through the diode D4 for the transient phenomenon of the TR1, a Zener diode D1, and the TR2 to speed up the operation of a switching circuit while preventing a high-potential reverse bias from being applied between the base and emitter of the TR1 when it is off.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a selective driving circuit, and particularly to a circuit for selectively driving needle electrodes of an electrostatic recording apparatus using multi-needle electrodes.

An electrostatic recording device records and creates an electrostatic latent image on a p-recording medium by applying electric signals to multi-needle electrodes in a calligraphic pattern. In this recording, if the signal applied to the electrode is scanned instead of scanning the electrode, the recording speed becomes faster, so this recording method has been exclusively used recently. In addition, it is necessary to apply a full predetermined high voltage to the selected electrodes at high speed, and the selection drive circuit must have a circuit configuration with low power consumption due to its integration.

However, this conventional loincloth selection drive circuit has the drawback that the rise of the output electric signal relative to the control input is slow. In order to control the output state of a high-voltage electrical signal using a micro-voltage control input, a switching element circuit of some kind is required, but due to the characteristics of this switching element circuit, the output electrical This is because the signal will be affected.

FIG. 1 shows an example of the circuit configuration of a conventional selection drive circuit of this type. According to this, the transistor TRI
When is in the on state, a Zener voltage is applied to the pace of the transistor TR2 by the Zener diode D1, and its emitter is reverse biased with respect to the υ pace by ■2 applied through the diode D2. Therefore, the transistor TR2 is in an off state. On the other hand, when the transistor TRI is in the off state, the pace current is supplied to the pace of the transistor TR2 via the power supply V and the resistor R1, so the pace current is supplied to the pace of the transistor TR2.
is in the on state. In this case, when the transistor TR2 changes from the off state to the on state, that is, the diode D
2. When the intermediate connection point 0 of D3 changes from the voltage value v2 to V, the current supplied to the pace of the transistor TR2 is only supplied through the resistor R1, and the presence of the diode D3 prevents this. Diode D
There was a limit to how high the speed could be increased due to the switching operation of No. 3.

The present invention has been made in view of the above points, and in order to perform high-speed switching at the 0 point, the diode D3 is removed and a diode is inserted between the emitter and pace of the transistor TR2, thereby making it possible to supply a high-speed rising pulse. The object of the present invention is to provide a selection drive circuit.

A preferred embodiment circuit of the present invention is shown in FIG. As shown in the figure, a diode D4 was inserted between the emitter and base of the transistor TR2. As a result, when the transistor TR2 is turned on from off, that is, the transistor TRI
A current is supplied through the resistor R1 when the state changes from the on state to the off state, and a current is supplied through the diode D4 in response to the transient phenomena of TRI, Dl, and TR2.
The speed of the switching circuit has been increased to prevent high-potential reverse bias from being applied between the pace emitter and the pace emitter when the 2 is turned off.

As a result, if the Zener voltage of the Zener diode in the circuit shown in Figure 1 is 5V, V is 400V, and V2 is 7■, the rise from the 0 point of approximately +6V to +400■ is approximately 5V.
By using the circuit configuration shown in FIG. 2, the current time was reduced to about 3 microseconds. Furthermore, in the configuration shown in Fig. 3 in which a capacitor C1, which is an energy storage element, is connected to both ends of the Zener diode D1, the characteristics of the Zener diode D1 can be improved by supplying energy from the capacitor C1 during transient switching of the transistor. A high-speed switching circuit that is less affected by
The rise is about 1μ at V+, V2, and D1 as above.
A switching circuit with extremely high speeds reduced to seconds has been realized.

Of course, the same effect can be obtained by using a series connection of diodes or resistance division to obtain a constant voltage instead of using the Zener diode D1 as a constant voltage source.

Also, replace the transistor with a FET, VMO8.

The same is true even if an equal node circuit is formed using 5MO8 or the like.

Further, although the present invention has been described by taking a multi-stylus drive circuit for electrostatic recording as an example, it is of course applicable to a wide range of circuit configurations that perform switching.

As explained above, an extremely high-speed switching circuit has been realized with a simple circuit configuration.

[Brief explanation of drawings]

FIG. 1 is a side view of a conventional circuit, FIG. 2 is a selection drive circuit diagram of this embodiment, and FIG. 3 is a selection drive circuit diagram of another embodiment. In the figure, Dl... Zener diode, D2 to D
4...Switching diode, TRI, TR2...
・Transistor, C1...Capacitor, R1-R5・
...It is resistance.

Claims (1)

[Claims] The collector of the emitter grounded transistor circuit is connected to the power supply KW via the Zener diode and the first resistor, and the connection point between the Zener diode and the first resistor is connected to the collector grounded transistor circuit through the second resistor. The anode terminal of the first diode is connected to the emitter of the grounded collector transistor, the cathode terminal is connected to the base of the transistor, and a third resistor is connected to the emitter of the grounded collector transistor to connect the collector of the grounded emitter transistor. A constant voltage is applied to the emitter of the grounded collector transistor through a second diode so that the emitter of the grounded collector transistor is connected in a forward direction when the grounded emitter transistor is turned on. A selection drive circuit characterized in that the selection drive circuit is configured to output more output than the other.