JPH0624440B2 - Capacitor load device with IC section - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device in which a capacitor is a load, such as an electronic flash device that supplies an electric charge charged in a capacitor to a flash discharge tube to cause it to emit light. The present invention relates to a device capable of maintaining an operating power supply for an IC unit even when the voltage of a DC power supply is being lowered.

2. Description of the Related Art In recent years, the development of large-scale integrated circuits (hereinafter referred to as ICs) has been remarkable, and is widely used in various electronic devices, and the electronic devices are becoming smaller and more excellent in operability and at a low price. It is effective.

Some electronic devices use a capacitor charged by the output of a DC-DC converter that boosts the voltage of a DC power source, such as an electronic flash device for photography, and such a capacitor is used as a load. DC-D for devices that
Since the voltage of the DC power supply drops while the capacitor is being charged by the operation of the C converter, there is a risk that various contents stored in the IC will be erased if the DC power supply is used as the power supply of the IC. ing.

In order to solve the above-mentioned problems, JP-A-58-102223 has been proposed.
In this publication, a capacitor serving as a power source for an IC is charged by a power source battery, and the voltage of the capacitor for the IC power source is lowered due to the decrease in the voltage of the power source battery accompanying the charging of the load capacitor. This is detected by the voltage detection circuit, and when the detection causes the voltage of the capacitor for the IC power supply to reach a level that hinders the memory operation, the oscillation operation of the DC-DC converter is stopped to secure the power supply of the IC.
When the IC power supply capacitor is restored to a sufficient voltage again by stopping the C-DC converter, the IC power supply capacitor voltage is detected and the oscillation of the DC-DC converter is interrupted so that the DC-DC converter oscillates. Go and keep the IC power supply.

Problems to be Solved by the Invention In the above-mentioned conventional example, the IC power supply is secured while the load capacitor is being charged. However, in order to secure the IC power supply, the DC-DC converter inevitably alternates oscillation and stop. The DC-DC converter naturally does not generate an output voltage when the oscillation is stopped. Therefore, the output voltage of the DC-DC converter is used, and the power supply battery is hardly degraded like a capacitor load. It is not effective for other circuits or other electric devices that do not occur.

The present invention has been made to solve the above problems, and an oscillation circuit that boosts a DC power supply during a charging process of a main capacitor that is a load continuously oscillates without stopping the oscillation operation, It is an object of the present invention to provide a device capable of continuously supplying the output voltage of the oscillation circuit to the circuit and the electric element.

Means for Solving the Problems A capacitor load device including an IC unit according to the present invention is a DC power supply, an IC unit, an oscillator circuit for boosting the DC power supply,
A main capacitor charged by the output of the oscillator circuit, a charge switch circuit that turns on to charge the main capacitor by the output of the oscillator circuit, and an auxiliary capacitor charged by the output of the DC power supply or the oscillator circuit. A power supply circuit that forms an operating power supply for the IC unit using a DC power supply as a power supply and supplies the operating power supply to the IC unit, an operating voltage detection circuit that detects a predetermined value of the charging voltage of the auxiliary capacitor, and a charging voltage of the auxiliary capacitor The output of the operating voltage detection circuit when detecting the predetermined value of starts the operation, turns on the charging switch circuit, and turns on the charging switch circuit when the voltage of the operating power supply supplied from the power supply circuit to the IC unit is Switch operation that keeps the charging switch circuit off for a specified time until just before it falls to the minimum level, and turns off the charging switch circuit after the on operation for a specified time. By providing a control circuit, it has achieved the above objects.

Action The main capacitor is charged while the charging switch circuit's switch operation control circuit keeps the charging switch circuit on, and after that period, the charging switch circuit is turned off to stop charging the main capacitor. However, when the charging switch circuit is off, the main circuit capacitor only stops charging, and the oscillation circuit continues to oscillate, and the output of the oscillation circuit can be effectively used by other circuits and electric elements during that time. .

Embodiment FIG. 1 is a basic block diagram showing an embodiment of a capacitor load device having an IC section according to the present invention. In the figure, 1 is a DC power supply, 2 is a power switch, and 3 is an IC using the DC power supply 1 as a power supply. A power supply circuit that forms an operating power supply for the unit 9 and supplies it to the IC 9 unit. 4 is a well-known oscillator circuit that boosts the DC power supply 1 to charge the main capacitor 8 that is a capacitor load. 5 is the charging voltage of the auxiliary capacitor SC. The reference numeral 6 denotes an operation voltage detection circuit for detecting the charging voltage, and 6 denotes a switch operation control circuit for controlling the operation of the charging switch circuit 7 in response to the operation of the operation voltage detection circuit 5.

The charging switch circuit 7 is turned on / off to control the charging operation of the main capacitor 8 by the output of the oscillation circuit 4,
The auxiliary capacitor SC is a DC power supply 1 or an oscillator circuit 4.
Is charged by being supplied with the output of the IC unit 9 and thus the charging voltage value is the IC unit 9 formed by the power supply circuit 3.
The voltage value corresponds to the operating power supply of.

In the device having the above configuration, when the power switch 2 is turned on, the oscillation circuit 4 oscillates. Now, assuming that the auxiliary capacitor SC is powered by the DC power supply 1, the auxiliary capacitor SC is started to be charged, and this charging voltage is When the operating voltage detection circuit 5 for detecting the predetermined value detects a predetermined value, the switch operation control circuit 6 starts its operation by the detection output, and at the same time the operation starts, the charging switch circuit 7 is turned on, whereby the main capacitor 8 is charged. Start.

When the charging of the main capacitor 8 is started by turning on the charging switch circuit 7, the voltage of the DC power supply 1 also drops, as is well known, whereby the voltage of the operating power supply supplied to the IC unit 9 by the power supply circuit 3 is reduced. It will decrease.

On the other hand, the switch operation control circuit 6 has a function of starting operation when a predetermined voltage is detected by the operation voltage detection circuit 5 and turning off the charging switch circuit 7 after a certain period of operation. The operation period is supplied by the power supply circuit 3. The period of time during which the voltage of the operating power supply is equal to or higher than the minimum power supply voltage level required for the operation of the IC unit 9, that is, the operating power supply voltage
If it is set so that the predetermined period until just before the minimum level required for the operation of the section 9 is reached, the power supply necessary for the operation of the IC section 8 is ensured during the ON period of the charging switch circuit 7. You can do it.

Then, when the switch operation control circuit 6 operates for a predetermined period, the switch operation control circuit 6 turns the charging switch circuit 7 off, charging of the main capacitor 8 is stopped, and charging of the auxiliary capacitor SC is started again by the DC power supply 1. However, since the charging of the auxiliary capacitor SC compensates only the amount of decrease in SC during the charging period of the main capacitor 8, the voltage of a predetermined value is reached in a short time, and the switch operation control circuit 6 operates again by the operating voltage detection circuit 5. After the start, the main capacitor 8 is charged while repeating the above operation.

That is, according to the present invention, the adverse effect on the IC unit 9 and the like due to the voltage drop of the DC power supply 1 generated during the charging of the main capacitor 8 which is a capacitor load and the connection of the oscillation circuit 4 is prevented. Is removed by controlling the connection between the main capacitor 8 and the oscillation circuit 4 without performing on / off control.

In other words, in the present invention, the voltage of the operating power supply of the IC unit 9 formed by the power supply circuit 3 operates the IC unit 9 by detecting that the charging voltage value of the auxiliary capacitor SC has reached a predetermined value. Therefore, the main capacitor 8 and the oscillation circuit 4 are connected to each other on the assumption that the voltage is sufficient for the above operation, and the connection state between the main capacitor 8 and the oscillation circuit 4 causes the voltage of the DC power supply 1 to drop, whereby the above operation is performed. The voltage of the power source is maintained until a predetermined period elapses immediately before the voltage drops to the minimum level required for the operation of the IC unit 9.

As a result, the IC unit 9 can be supplied with operating power having a voltage value equal to or higher than the minimum level necessary for the operation of the IC unit 9 without stopping the operation of the oscillation circuit 4.

FIG. 2 is a specific circuit diagram of the block diagram of FIG. 1, in which a power supply circuit 3 includes a capacitor 10 charged from a DC power supply 1 and a constant voltage circuit for making the charging voltage of the capacitor 10 constant. 11 is an auxiliary capacitor that is charged by the constant voltage output of the constant voltage circuit 11 of the power supply circuit 3, and the charging voltage of the auxiliary capacitor 12 is the operating voltage detected by the operating voltage detection circuit 5. It also serves as the power supply voltage for the IC unit 9. As is well known, the oscillating circuit 4 is mainly composed of an oscillating transformer 20 having a primary winding 20-1, a secondary winding 20-2 and an auxiliary winding 20-3, and an oscillating transistor 21. The circuit 5 includes resistors 13 and 1 for dividing the charging voltage of the auxiliary capacitor 12.
4, the switch operation control circuit 6 operates in response to the comparator 16, to which the generated voltage of the resistor 14 and the generated reference voltage of the resistor 15 are applied, and the output level of the comparator 16. The charge switch circuit 7 includes an oscillation circuit 4 and a main capacitor 8.
And an SCR 22 which is connected between the SCR 22 and the transistor 19 of the switch operation control circuit 6.

Next, the operation of the device of the present invention having the above configuration will be described with reference to FIG. 4 showing the voltage waveforms of the main capacitor and the auxiliary capacitor.

Now, when the power switch 2 is turned on at the time T ₁ in the unused state of the device, the capacitor 10 is charged by the DC power source 1, the constant voltage is output from the constant voltage circuit 11, and the auxiliary capacitor 12 of FIG. Is charged. When the charging voltage of the auxiliary capacitor 12 reaches the value of VZ at the time of T ₂ , the voltage generated by the resistor 14 in the operating voltage detection circuit 5 exceeds the reference voltage generated by the resistor 15 applied to the other input terminal of the comparator 16. The comparator 16 goes to the L level, and the transistor 19 that has been conducting due to the H level up to that point is turned on.
Becomes non-conductive, a voltage is applied to the gate electrode of the SCR 22, and the SCR 22 becomes conductive.

When the power switch 2 is turned on, the oscillation circuit 4 oscillates, and the high voltage generated from the secondary winding 20-2 of the oscillation transformer 20 charges the main capacitor 8 via the SCR 22 as shown in FIG. 4A. It will start at T ₂ . SC
When the charging of the main capacitor 8 is started by conducting the R22, the voltage of the DC power supply 1 is reduced as is well known, (especially voltage decreases as the initial charging significant) whereby the voltage of the auxiliary from the time of T ₂ capacitors 12 Is lowered, the output of the comparator 16 is immediately inverted to the H level, the SCR 22 becomes non-conductive, the charging of the main capacitor 8 is immediately stopped, and the auxiliary capacitor 12 is recharged to the L level of the output of the comparator 16. Thus, the main capacitor 8 is charged in a short cycle such that the SCR 22 becomes conductive and the main capacitor 8 is charged by the reversal.

However, due to the combination circuit of the comparator 16 and the comparator 17 of the switch operation control circuit 6, the main capacitor 8 is not charged in a short cycle.

That is, when the charging voltage of the auxiliary capacitor 12 becomes VZ and the output of the comparator 16 is inverted to the L level, even if the voltage of the auxiliary capacitor 12 drops due to the resistance value setting of the comparator 17 and the resistor 18, the comparator 16 immediately. Output does not become H level and continues to maintain L level for a certain period, and if this L level period is made longer, there is no intermittent charging of the main capacitor 8 in the above-mentioned short cycle, and it is efficient. Will be charged.
However, if the L-level output maintaining period of the comparator 16 is set too long, the auxiliary capacitor 1 is not charged during the charging of the main capacitor 8.
Since the voltage of No. 2 continues to drop, the IC unit 9 will eventually reach the required minimum power supply voltage or less, and the stored contents will be erased.

However, the L level maintaining period of the comparator 16 is set in consideration of charging the main capacitor 8 and securing the minimum necessary power supply voltage of the IC unit 9, and the time is T ₃ −T ₂ in FIG. ing. _Therefore, T 2 -T comparator 16 is ₃ times
Of the main capacitor 8 because the transistor 19 is non-conducting and the SCR 22 is conducting during that time, the output of the main capacitor 8 is maintained at the L level.
Continue to charge, while the voltage of the auxiliary capacitor 12 drops, but the minimum power supply voltage of the IC unit 9 is secured, and at the time of T ₃ , the output of the comparator 16 is inverted to H level. Then, the transistor 19 is turned on, no voltage is generated at the gate of the SCR 22, the SCR 22 is turned off, and the charging of the main capacitor 8 is stopped. SCR22
The oscillator circuit 4 continues to oscillate even when is turned off. While charging of the main capacitor 8 at of T ₃ is performed charging again the auxiliary capacitor 12 be stopped, the charge in this case to supplement the voltage drop at the time the charging time T ₃ -T ₂ of the main capacitor 8 alone So, in a relatively short time T
VZ is reached at the time of ₄ , and the comparator 16 is set to L as described above.
Inverted to the level and the transistor 19 is non-conductive, SCR22
There is charged again to the main capacitor 8 becomes conductive, the output of the comparator 16 is the time charging of T ₅ -T ₄ that maintains L level.

The main capacitor 8 is charged while repeating the above operation.

Although the auxiliary capacitor 12 also serves as a power source for the IC unit 9, the power source for the IC unit 9 may be supplied by another capacitor.

FIG. 3 is an electric circuit diagram showing another embodiment of the device of the present invention, and those having the same reference numbers as those in the previous embodiment have the same functions, and the description thereof will be omitted in particular.

In this embodiment, an auxiliary capacitor is connected to the output side of the oscillation circuit, and while the SCR 22 is conducting and the main capacitor 8 is being charged, the output of the oscillation circuit 4 flows toward the main capacitor 8 and the auxiliary capacitor 23 receives a current. Does not flow and the charging voltage of the auxiliary capacitor 23 decreases while the main capacitor 8 is being charged. Therefore, even if the auxiliary capacitor 23 is connected to the output side of the oscillation circuit 4, the same operation as in the previous embodiment can be performed. .

As described above, the device of the present invention connects the main capacitor and the oscillation circuit by detecting the charging voltage of the auxiliary capacitor, while the voltage of the DC power supply is lowered during charging of the main capacitor in this connection state. By doing so, the voltage of the operating power supply is maintained until a predetermined period of time immediately before the voltage drops to the minimum level necessary for the operation of the IC section. It is possible to supply an operating power supply having a voltage value higher than the minimum level required above without stopping the operation of the oscillation circuit.

In other words, the device of the present invention has an I value due to the voltage drop of the DC power supply that occurs during the charging of the main capacitor that is the capacitor load.
Since the adverse effect on the C section etc. is eliminated by controlling the connection state between the main capacitor and the oscillation circuit without stopping the oscillation operation of the oscillation circuit, the output of the oscillation circuit is removed from other electric circuits or electric elements. Effectively available for.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a capacitor load device having an IC section of the present invention, FIG. 2 is a specific circuit diagram of the block diagram according to FIG. 1, and FIG. 3 is another embodiment of the device of the present invention. FIG. 4 is a waveform diagram for explaining the operation of the embodiment of FIG. 2, FIG. 4A is the charging voltage of the main capacitor, and FIG. 4B is the charging voltage of the auxiliary capacitor. It is a waveform diagram of. 1 ... DC power supply, 3 ... power supply circuit, 4 ... oscillation circuit, 5 ... operating voltage detection circuit, 6 ... switch operation control circuit, 7 ... charging switch circuit, 8 ... main capacitor,
9 ... IC part, 12/22 / SC ... Auxiliary capacitor.

Claims (1)

[Claims] 1. A DC power supply, an IC section, an oscillation circuit for boosting the DC power supply, a main capacitor charged by the output of the oscillation circuit, and a main capacitor charged by the output of the oscillation circuit to the main capacitor by the output of the oscillation circuit. A charging switch circuit for charging the battery, an auxiliary capacitor charged on the basis of the output of the DC power supply or the oscillation circuit, and an operating power supply for the IC unit using the DC power supply as a power supply and supplying the operating power supply to the IC unit. A power supply circuit, an operating voltage detection circuit that detects a predetermined value of the charging voltage of the auxiliary capacitor, and an operating voltage detection circuit when the operating voltage detection circuit detects a predetermined value of the charging voltage of the auxiliary capacitor. Start operation by output, turn on the charging switch circuit,
The charge switch circuit is kept on for a predetermined time until just before the voltage of the operating power supply supplied from the power supply circuit to the IC section falls to the minimum required level, and after the on operation for a predetermined time, the charge switch circuit is turned on. A capacitor load device comprising an IC unit having a switch operation control circuit for turning off.