JPH04149994A - Converter circuit for stroboscope - Google Patents

Abstract

PURPOSE:To reduce a voltage increasing time in a converter circuit for a strobo scope by setting a level of a pulse volatge obtained in generating an AC voltage to be a multiplied level of a power supply voltage. CONSTITUTION:A supply voltage from a DC power supply 10 is not charged directly to a main capacitor MC through transformer 3, but it is charged through diodes D1, D2, D4, D8. An electric charge charged to the maqin capacitor MC is outputted from a terminal 40 in response to a push to a shutter button of a camera. Noise generated at a circuit 100 is restricted by a protective circuit 9, in addition. A voltage increasing time can thus be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a strobe converter circuit suitable for charging electric charge during strobe light emission.

[Summary of the invention]

The present invention relates to a strobe converter circuit suitable for charging electric charge during strobe light emission, in which an alternating current voltage generated from a direct current power source is applied to a capacitor via a transformer, and the alternating current voltage is obtained when the alternating current voltage is generated. Pulse voltage (
The voltage rise time (boosting time) of the voltage applied to the capacitor is shortened by the configuration in which the voltage (the level of which is multiplied by the voltage a) is rectified and applied to the capacitor.

[Conventional technology]

In a strobe used when taking pictures with a camera, light is emitted from a discharge tube to which a high voltage is applied, and the high voltage is obtained by discharging electric charges stored in a capacitor.

Generally, a converter circuit is used to charge a capacitor, and in that converter circuit, the level of AC voltage generated from DC voltage is increased by a transformer (
The boosted AC voltage is rectified and applied to the capacitor.

In other words, it includes two switching elements (transistors) that are controlled to turn on and off alternately, and two diodes that are arranged so that they are in the forward direction when each transistor is on. When a DC voltage is supplied to the two transistors, an AC voltage is generated in response to the switching operation of each transistor.

The generated AC voltage is applied to the primary coil of the transformer, and an induced voltage (AC) whose level is multiplied is generated in the secondary coil.

The induced AC voltage is rectified by a rectifier circuit, and is converted into a substantially DC voltage by a smoothing circuit and applied to the capacitor.

[Problem to be solved by the invention]

Therefore, the time it takes for the capacitor to charge to the desired voltage level (step-up time) depends on the responsiveness of the transformer, so if the shutters are pressed one after another, charging may not be possible in time. Therefore, it has been desired to shorten the boost time.

An object of the present invention is to provide a strobe converter circuit that can shorten boost time.

[Means to solve the problem]

In order to achieve the above object, the strobe converter circuit according to the present invention includes a primary coil (3a) to which an AC voltage generated from a DC power supply (10) is supplied, and a primary coil (3a). A transformer (3) equipped with a secondary coil (3b) in which an induced voltage is generated, and the induced voltage generated in the secondary coil (3b) is applied via a first rectifier circuit (5). and a second rectifier circuit (adhesive), (D2) in which the AC voltage is rectified and applied to the capacitor (MC).

[Effect]

In the strobe converter circuit according to the present invention, an AC voltage generated from a DC power supply is applied to a capacitor via a transformer, and a pulse voltage (the level of which is multiplied by the power supply voltage) is obtained when the AC voltage is generated. ) is directly rectified and applied to the capacitor.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a strobe converter circuit according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a converter circuit (10
0) is shown, and the circuit (100) is connected to a DC power supply (10
), an AC voltage generation circuit (1) in which an AC voltage is generated from
Transformer (3), first rectifier circuit (5), smoothing circuit (7)
, a main capacitor (MC), and a protection circuit (9).

The AC voltage generation circuit (1) has transistors (Ql) and (Q2) that are turned on and off according to control signals input from terminals (20) and (30), respectively, and these transistors (Qυ, By the switching operation of (Qz), a pulse voltage (AC voltage) is supplied to the primary coil (3a) of the transformer (3).

In the transformer (3), when an induced voltage is generated in the secondary coil (3b) by the primary coil (3a), the induced voltage is rectified by the rectifier circuit (5), and the induced voltage is rectified by the smoothing circuit (7). The main capacitor (MC) is charged through the diode (D8).

In this case, the DC type! Immediately after the voltage supply from (10) starts, transistors (Q, ), (Q2
) is operated until its supply voltage is connected to the diode (attached)
, (D2), (D4), and (D,), the main capacitor (MC) is charged.

Next, when the transistors (Ql) and (Q2) are operated (turned off), the pulse voltage generated accordingly is at the level of the power supply (10) (for example, 25 volts).
is multiplied by 2 to 3 times (for example, around 100 ports)
Then, the pulse voltage is applied to the diode (attached), (D2)
(second rectifier circuit) and charged to the capacitor (C).

Then, the voltage level charged in the capacitor (C) is
Zener diode (D,
), the charge stored in the capacitor (C) is lower than the Zener voltage level of the diode (D4), (D
8) is charged to the main capacitor (?lC).

On the other hand, when the voltage level charged in the capacitor (C) becomes higher than the Zener voltage of the Zener diode (D,), the charge charged in the capacitor (C) is transferred to the resistor (R) and the diode (D,). , transistor (Q).

In other words, the transistor (Q
1) and (Q2) are protected against breakdown voltages, and noise generated in the circuit (100) is suppressed.

The charge charged in the main capacitor (MC) in this manner is outputted from the terminal (40) in response to, for example, pressing the camera shutter.

As explained above, in this embodiment, the DC power supply (10)
Before the supply voltage from the main capacitor (MC) is charged through the transformer (3), the diode (Dl),
The main capacitor (MC) is charged via (D2), (D4), and (D,), so the step-up time is shortened compared to the conventional case where it is charged only via the transformer (3). (For example, the conventional time of 2 seconds becomes about 1.6 seconds).

[Effects of the Invention] As can be understood from the above description, in the strobe converter circuit according to the present invention, an AC voltage generated from a DC power supply is applied to a capacitor via a transformer, and the AC voltage generation is The resulting pulsed voltage is directly rectified and applied to the capacitor.

Since the level of the pulse voltage becomes a level obtained by multiplying the voltage ri, the voltage and the voltage, the voltage applied to the capacitor is rapidly increased, and as a result, the boosting time is shortened.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a preferred embodiment of a strobe converter circuit according to the present invention. (1) is an AC voltage generation circuit, (3) is a transformer, (5) is a first rectifier circuit, (7) is a smoothing circuit, (9) is a protection circuit, (10) is a DC power supply, (100) is the converter circuit,
(hole) is the main capacitor, (Q) to (Q,) are transistors, and (patch) to (D8) are diodes. Agent Hidemori Matsukuma

Claims (1)

[Claims] A primary coil to which an alternating current voltage generated from a direct current power supply is supplied, and a second coil to which an induced voltage is generated by the primary coil.
a transformer including a secondary coil; a capacitor to which the induced voltage generated in the secondary coil is applied via a first rectifier circuit; and a capacitor to which the AC voltage is rectified and applied to the capacitor. 1. A strobe converter circuit comprising: a two-rectifier circuit; and a strobe converter circuit.