JPH1198827A - Power supply and flasher - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply capable of preventing objectionable oscillation noise due to fluctuation in load. SOLUTION: A power supply comprises a power supply battery 101, and an oscillating means which increases the voltage of the power supply battery 101 and supplies a load 117 with it. The oscillating means is provided with first oscillating sections (125, 105, 110, 115) of separate-excited oscillation system and second oscillating sections (110, 114, 115) of self-excited oscillation system. In addition, selecting means (111, 118, 119, 126) are provided so that the first oscillating sections are actuated at start, and the second oscillating sections are actuated thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device having an oscillation circuit whose load changes and a flash device.

[0002]

2. Description of the Related Art FIG. 2 shows a circuit of a conventional flash device including a power supply device having a self-excited oscillation type oscillation circuit in which a load changes.

In this flash device, when a power switch 1 is turned on, a known self-excited oscillation circuit composed of an oscillation transformer 16, a transistor 14, resistors 12 and 15, and a capacitor 13 starts operating. From 2, a current starts flowing through the primary winding of the transistor 14 and the transformer 16, and the capacitor 20, which supplies luminous energy to the flash discharge tube 22, is charged via the diode 17.

[0004] Since the capacitor 20 is not charged, the charging current is large, and therefore the current flowing from the battery 2 is also large.

Although the battery voltage drops due to the current, the battery voltage is reduced by a known battery voltage detecting circuit composed of a zener diode 7 and resistors 4, 5, 6 and a comparator 8 so that the zener voltage of the zener diode 7 and the resistor 4 are reduced. , 5, the transistor 11 is turned on and the transistor 14 is turned off.
The collector current of the transistor 14 stops flowing. When this current stops flowing, the battery voltage increases.

Due to this rise, the output of the battery voltage detecting circuit changes, and the transistor 11 is turned off, and the transistor 1
4 is turned on, and a current flows through the primary winding of the oscillation transformer 16 again. As a result, the battery voltage drops and the above operation is repeated. By repeating this, the battery voltage does not fall below the predetermined value.

Accordingly, a voltage sufficient for operation is supplied to the voltage stabilizing circuit 23, and the comparators 2 supplied with the resistors 18, 19, 24, 25 and the voltage stabilizing circuit 23.
6, a load circuit such as a known capacitor voltage detecting circuit and a display circuit formed by the light emitting diode 28 for indicating the completion of charging of the resistor 27 and the capacitor 20 operates stably.

[0008]

However, the on / off repetition frequency of the transistor 14 during the charging operation is not stable because a large current is controlled.

In general, when a large-amplitude current flows through the transformer 16, the winding or a core made of a magnetic material thereof vibrates.

Therefore, as described above, since the repetition frequency is not stable, the vibration sound sounds very unpleasant for the user. This phenomenon continues until the capacitor 20 is charged to some extent, the output of the battery voltage detection circuit is stabilized at a low level, and normal self-excited oscillation operation is performed. When the output level of the battery voltage detection circuit is stabilized at a low level, the booster circuit continues to oscillate at a frequency corresponding to the voltage of the capacitor 20. The oscillating sound at this time is close to a gradually changing sine wave sound, so that if the oscillating sound is low, the user will not feel uncomfortable.

Further, even when the battery voltage detecting circuit is not provided, the frequency of the oscillating sound gradually increases after the power switch is turned on similarly to when the battery voltage detecting circuit does not operate, and the user is uncomfortable. I will not give.

However, when the load increases, the battery voltage drops, and the constant voltage circuit and the capacitor voltage detection circuit connected to the battery may not operate normally.

An object of the invention according to the present application is to provide a power supply device and a flash device which prevent generation of an unpleasant oscillation sound of the oscillation circuit whose load fluctuates.

[0014]

According to a first aspect of the power supply device of the present invention, there is provided a power supply device comprising: a power supply battery; and oscillating means for boosting the voltage of the power supply battery and supplying the boosted voltage to a load. The oscillating means has a first oscillating unit of a separately excited oscillation system and a second oscillating unit of a self-excited oscillation system, and operates the first oscillating unit at the time of starting, and thereafter operates the second oscillating unit. It has a switching means for performing the switching.

A second configuration of the power supply device according to the present invention is a power supply device having a power supply battery and an oscillating means for boosting the voltage of the power supply battery and supplying the boosted voltage to a load, wherein the oscillating means is separately excited. It has a first oscillating unit of an oscillation system and a second oscillating unit of a self-excited oscillation system, and detects the state or voltage of the load. Switching means for activating the first oscillating section when the value is lower than a predetermined value, and operating the second oscillating section when the load state is lower than a predetermined state or when the detected voltage is higher than a predetermined value. It has.

According to a third configuration of the power supply device of the invention according to the present application, the first oscillating unit of the separately excited oscillation system includes a primary oscillating unit for the power supply battery and an oscillation transformer according to an output of the separately excited oscillation circuit. It controls switch means for turning on and off the power supply to the side.

In a fourth configuration of the power supply device according to the present invention, the load is a capacitor.

The configuration of the flash device according to the invention according to the present application is such that the power device is provided, and the capacitor supplies the luminous energy to the flash discharge tube.

[0019]

FIG. 1 shows a first embodiment of the present invention.

FIG. 1 is a circuit diagram of a flash device provided with a power supply having an oscillation circuit whose load varies.

Reference numeral 101 denotes a power supply battery. Reference numeral 102 denotes a switch having one end connected to the positive pole of the power supply battery and the other end connected to an emitter of a transistor 109 described later. 103 is a capacitor connected in parallel to the power supply battery 101. 1
Reference numeral 04 denotes a resistor having one end connected to the gate of the FET 105 and the other end connected to the negative pole of the power supply battery 101. 10
5 is an FET, the gate is connected to one end of the resistor 104,
The source is connected to one end of the resistor 106 described later, and the drain is connected to the base of the transistor 110 described later.

Reference numeral 106 denotes a resistor, one end of which is connected to the FET1.
The source 05 and the other end are connected to the negative pole of the power supply battery 101, respectively. Reference numeral 107 denotes a resistor, one end of which is connected to the base of the transistor 110 described later, and the other end of which is connected to the emitter of the transistor 110. 1
A capacitor 08 is connected in parallel with the resistor 107.

Reference numeral 109 denotes a resistor, one end of which is a FET described later.
The other end of the gate 111 is connected to the negative pole of the power supply battery 101. 110 is a PNP transistor, the base of which is the drain of the FET 105,
The emitter is connected to the positive pole of the power supply battery, and the collector is connected to one end of a primary winding of an oscillation transformer 115 described later.

Reference numeral 111 denotes an FET. The gate has one end of the resistor 109; the source has one end of a feedback winding of an oscillation transformer 115 described later;
Connected to the base.

Reference numeral 112 denotes a diode, the anode of which is the negative electrode of the power supply battery, and the cathode of which is the FET 11
1 source. A resistor 113 is connected in parallel with the diode 112.
A resistor 114 is connected to one end of a feedback winding of an oscillation transformer 115 described later.

Reference numeral 115 is an oscillation transformer for oscillation. One end of a primary winding is connected to the collector of the transistor 110, the other end is connected to the negative pole of the power supply battery 101, and one end of a feedback winding is connected to the FET 111. , And the other end is connected to one end of the resistor 114, respectively.

Further, one end of the secondary winding is connected to the FET 111
And the other end is connected to an anode of a diode 116 described later. A diode 116 has an anode connected to one end of the secondary winding of the oscillation transformer, and a cathode connected to an anode of a capacitor 117 described later.

Reference numeral 117 denotes a capacitor for storing energy for flash light emission. The anode is connected to the cathode of the diode 116, and the cathode is connected to the negative pole of the power supply battery 101.

Numerals 118 and 119 are resistors connected in series, the series circuit of which is connected in parallel with the capacitor 117. Reference numerals 120 and 121 denote resistors connected in series, and the series circuit includes the capacitor 117.
Are connected in parallel.

Reference numeral 122 denotes a light emission start signal forming circuit for forming a light emission start signal, which outputs a light emission start signal to a trigger circuit 123 described later. Reference numeral 123 denotes a trigger circuit which receives the output of the light emission start signal forming circuit 122 at an input 1 and applies a high frequency high voltage from an output 2 to a trigger electrode of a flash discharge tube 124 described later. Reference numeral 124 denotes a flash discharge tube which discharges the electric charge of the capacitor 117 to generate a flash. The anode has the anode of the capacitor 117 and the cathode has the capacitor 1
17 cathodes respectively.

Reference numeral 125 denotes an oscillation circuit for separately excited oscillation. When oscillation is being performed, a repetition signal having a predetermined duty ratio is output to the output 2, and when the input 1 is at a high level, the oscillation operation is prohibited. When the signal is at the low level, the oscillation operation is performed.

Reference numeral 126 denotes a comparator supplied with power by a constant voltage circuit 127 described later. The negative input is connected to a reference voltage generating circuit (not shown) supplied by the constant voltage circuit 127 described later. 119
The output is connected to the oscillation circuit 125.
1 and the gate of the FET 111.

The resistors 118 and 119 and the comparator 126
And a reference voltage generating circuit (not shown) forms a first capacitor voltage detecting circuit.

Reference numeral 127 denotes a constant voltage circuit. The input 1 is connected to the anode of the capacitor 103, and the output 2 is connected to one end of a resistor 128 described later. A resistor 128 has one end connected to the output of the constant voltage circuit and the other end connected to a minus input of a comparator 130 described later. Reference numeral 129 denotes a resistor, one end of which is connected to a minus input of a comparator 130 described later, and the other end of which is connected to a minus pole of the power supply battery 101, respectively.

A comparator 130 has a minus input connected to a connection point between the resistors 128 and 129, a plus input connected to a connection point between the resistors 120 and 121, and an output connected to a resistor 131 described later. Here, resistors 120, 121,
A second capacitor voltage detection circuit is formed by 128, 129 and the comparator 130.

A resistor 131 has one end connected to the output of the comparator 130 and the other end connected to a cathode of an LED 132 described later. 132 is the capacitor 1
LED 17 indicates the state of charge. The anode is connected to one end of the resistor 131, and the cathode is connected to the negative pole of the power supply battery 101.

Next, the operation of the flash device shown in FIG. 1 will be described below.

It is assumed that no electric charge is stored in the capacitor 117. When the switch 102 is closed in this state, the constant voltage circuit 127 operates to supply power to the comparator 130, the oscillation circuit 125, and the comparator 126, and also to a reference voltage generation circuit (not shown).

Thus, the reference voltage is applied to the minus input of the comparator 126, and the capacitor 117
Since is not charged, the plus input of the comparator 126 is 0 potential. Therefore, the comparator 126
Output is low. This low level causes FE
T111 is off, and the oscillation circuit 125 outputs an oscillation waveform having a duty ratio of a predetermined (constant) high level and a low level.

When the output of the oscillating circuit 125 goes high, the FET 105 turns on, and the base current of the transistor 110 flows through the resistor 106, turning on the transistor 110. This causes a collector current to flow through the primary winding of the oscillating transformer 115, and thus the capacitor 17 via the diode 116 connected to the secondary winding.
Is charged. Although the collector current increases and the battery voltage drops, the output of the oscillation circuit 125 changes to a low level before the battery voltage drops to a voltage at which the constant voltage power supply circuit 127 can operate.

The time during which the oscillation output is at the high level is predetermined. While the oscillation output is at the low level, the FET 105 is off, so that the transistor 11
Since the zero collector current does not flow, the battery voltage recovers.
The time during which this low level is output is also predetermined.

Next, when the oscillation output goes high again, the FET 105 is turned on again, the transistor 110 is also turned on, and the capacitor 117 is charged as described above. After a lapse of a predetermined time, the oscillation output becomes low level, and the transistor 110 is turned off as described above. Thereafter, this operation is repeated. That is, the operation of the separately excited oscillation method is performed.

By repeating this, the capacitor 117 is gradually charged, so that the voltage at the connection point between the resistors 118 and 119 also increases. When the voltage at this connection point exceeds the reference voltage applied to the minus input of the comparator 126, the output of the comparator 126 changes from a low level to a high level. The oscillation circuit 1
The oscillation of 25 is prohibited, and the FET 105 is turned off.

The high level causes the FET 111
Turns on. This turns on the transistors 110 and F
ET111, oscillation transformer 115, resistor 107, resistor 1
13, resistor 114, capacitor 108, diode 11
The known self-excited oscillation circuit constituted by 2 starts operation.
The on-state current of the transistor 110 at the start of the operation of the self-excited oscillation circuit is not large because the capacitor 117 has already been charged to a predetermined value, and the voltage of the power supply battery 101 does not become lower than the voltage at which the constant voltage circuit operates. . In addition, charging of the capacitor 117 proceeds by the self-excited oscillation method, and the voltage at the connection point between the resistor 120 and the resistor 121 is changed to the comparator 13.
If the voltage exceeds the negative input voltage of 0, the comparator 13
The output of 0 becomes a high level, and the LED 132 is turned on.
The voltage of the capacitor 117 when the LED 132 is turned on is set to a voltage sufficient for the discharge tube 124 to emit light.

Thereafter, the trigger circuit 123 operates according to the light emission start signal of the light emission start signal forming circuit 122, and the discharge tube 12
4 emits light. After the discharge tube 124 emits light, the voltage of the capacitor 117 becomes low again. When the capacitor voltage is low as in the above-described operation, the boosting operation is performed by the separately excited oscillation method, and when the capacitor voltage exceeds a predetermined value, the self-excited oscillation method is performed. Performs the boost operation.

(Correspondence between Invention and Embodiment) In the above-described embodiment, the oscillation circuit 125 for separately excited oscillation, the FE
The transistor T105, the transistor 110, and the oscillation transformer 115 correspond to the first oscillation unit of the separately excited oscillation system of the present invention, and the transistor 110, the resistor 114, and the oscillation transformer 115 correspond to the second oscillation unit of the self-excited oscillation system of the invention. I do.

[0047]

According to the first aspect of the present invention, the first oscillating section of the separately excited oscillation type is operated at the time of starting, and thereafter, the switching transistor between the power supply battery and the primary side of the oscillating transformer is turned on. Since the self-excited second oscillating unit that performs step-up by repeatedly turning off is operated, it is possible to prevent unpleasant vibration sound due to self-excited oscillation from occurring.

According to the second aspect of the present invention, when the load state is higher than the predetermined state or when the detected voltage is lower than the predetermined value, the first oscillating unit of the separately excited oscillation type is operated. When the load state is lower than the predetermined state or when the detected voltage is higher than the predetermined value, the switching transistor between the power supply battery and the primary side of the oscillation transformer is repeatedly turned on and off to boost the voltage. Since the self-excited second oscillating unit is operated, it is possible to prevent the occurrence of unpleasant vibration sound due to the self-excited oscillation. Further, the state of the load can be easily detected with high accuracy.

According to the third aspect of the present invention, in addition to the effects of the above-described aspects of the present invention, since a large current does not flow through the switch means, stable boost control can be performed.

According to the fourth aspect of the present invention, it can be used for a power supply device such as a flash device.

According to the fifth aspect of the present invention, the oscillation method is determined by detecting the voltage of the capacitor that supplies the luminous energy of the flash device as the load. No unpleasant oscillation sound is generated.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a flash device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional flash device.

[Explanation of symbols]

101: power supply battery 102: switch 103, 108, 117 ... capacitor 104, 106, 107, 109, 113, 114, 1
18 to 121, 128, 129, 131 Resistance 105, 111 FET 110 Transistor 112, 116 Diode 115 Oscillation transformer 122 Light emission start signal forming circuit 123 Trigger circuit 124 Discharge tube 125 Oscillation circuit for other excitation 126, 130 Comparator 127 Constant voltage Circuit 132 LED

Claims (5)

[Claims] 1. A power supply device comprising: a power supply battery; and an oscillating means for boosting a voltage of the power supply battery and supplying the boosted voltage to a load, wherein the oscillating means includes a first oscillating unit of a separately excited oscillation method and a self-excited oscillation method. A power supply device, comprising: a second oscillating unit; and a switching unit that operates the first oscillating unit at the time of startup and then activates the second oscillating unit. 2. A power supply device comprising: a power supply battery; and an oscillating means for boosting a voltage of the power supply battery and supplying the boosted voltage to a load, wherein the oscillating means includes a first oscillating unit of a separately excited oscillation method and a self-excited oscillation method. Detecting the state or voltage of the load and operating the first oscillator when the load state is higher than a predetermined state or when the detected voltage is lower than a predetermined value. And a switching unit for operating the second oscillating unit when the load state is lower than a predetermined state or when the detection voltage is higher than a predetermined value. 3. The oscillating circuit according to claim 1, wherein the first oscillating unit of the separately excited oscillating method turns on the power supply between the power supply battery and the primary side of the oscillation transformer in accordance with an output of the separately excited oscillating circuit. A power supply device for controlling switch means for turning off the power. 4. The power supply device according to claim 1, wherein the load is a capacitor. 5. A flash device comprising the power supply device according to claim 4, wherein said capacitor supplies luminous energy to a flash discharge tube.