JPS62160044A - Dc/dc converter with built-in charging circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] DC/DC converters with built-in charging circuits are widely used as power sources for portable small equipment, but are required to be small and lightweight as well as highly reliable. be done. Therefore, we aimed to make the DC/DC converter with a built-in charging circuit smaller and lighter, as well as highly reliable.

[Industrial application field]

This invention is possible! The present invention relates to power supplies for shell-shaped information processing devices, input/output devices, etc., and particularly relates to the configuration of DC/DCC/type controllers with built-in charging circuits.

DC/D that uses an AC adapter or storage battery as a current supply source for general information processing devices such as hand belt computers and small word processors, and various input/output devices used incidentally thereto. C converter is used.

In particular, it is equipped with an internal storage battery and a charging circuit that charges the storage battery, and in places where an AC adapter can be used, the AC adapter is used as a current supply source and charges the storage battery, and in places where an AC adapter cannot be used, the storage battery is used as a current supply source. A DC/DCC/type converter with a built-in charging circuit (referred to as a converter with a charging circuit) is widely used as a power source that can be used over a wide range of applications and can be used for a long time.

The power source used for such applications is naturally required to be small, lightweight, and inexpensive, as well as to be highly reliable, such as having small voltage fluctuations and being able to be used for long periods of time without an AC adapter.

[Conventional technology]

- FIG. 4 is a block diagram showing a conventional converter with a charging circuit.

In the figure, a conventional converter with a charging circuit is composed of a power supply section 1 and an output section 2, and the power supply section 1 is formed of a terminal 11 for connecting an AC adapter 3, a charging circuit 12, and a storage battery 13. The output section 2 also has a power switch 21 and an AC
A terminal 22 that outputs the voltage of the adapter 3 or the storage battery 13 as it is to the first load circuit 4, a voltage conversion circuit 23 that converts the voltage of the AC adapter 3 or the storage battery 13, and a terminal that converts the output voltage of the voltage conversion circuit 23 to the second load circuit 4. It is formed by a terminal 24 that outputs to the load circuit 5.

In such a converter with a charging circuit, when the power switch 21 is turned on without connecting the AC adapter 3 to the terminal 1, current is supplied from the storage battery 13 to the load circuit 4 and the load circuit 5 via the output section 2. 13
The electricity stored in is consumed.

On the other hand, with the power switch 21 disconnected, connect the terminal 11 to AC.
When the adapter 3 is connected, if the voltage of the storage battery 13 is lower than the output voltage of the AC adapter 3, current is supplied from the AC adapter 3 via the charging circuit 12 and the storage battery 13 is charged. Furthermore, when the power switch 21 is turned on in this state, the current supplied from the AC adapter 3 is supplied to the load circuit 4 and the load circuit 5 via the output section 2, and at the same time, the current is supplied from the AC adapter 3 via the charging circuit 12. Current is supplied and the storage battery 13 is charged.

In order to make the AC adapter smaller, lighter, and cheaper, such a converter with a charging circuit is usually configured so that the current passing through the charging circuit is constant, and the current value is equal to the average current value supplied to the load circuit. It is set to be slightly larger. Even if a load circuit and a storage battery are connected to the output side of such a charging circuit, if sufficient power is stored in the storage battery, no current will be consumed in the storage battery.
Since all of the current passing through the charging circuit can be supplied to the load circuit, the current that is causing the voltage drop due to insufficient capacity in the charging circuit is supplied from the storage battery, and no voltage drop due to insufficient capacity in the charging circuit occurs.

[Problem that the invention seeks to solve]

However, in conventional converters with charging circuits, when the power stored in the storage battery is consumed significantly, the total value of the current flowing to the load circuit and the current consumed in the storage battery becomes larger than the current that can pass through the charging circuit, resulting in charging. A voltage drop occurs due to insufficient circuit capacity. Moreover, since the current that can be supplied to the storage battery is small, it takes a long time for the storage battery to recover. As a result, the storage battery may not be full when the AC adapter is removed, and in order to prevent voltage drop and current supply capacity drop during operation, the power switch must be turned off from time to time to charge the storage battery. there were.

[Means for solving problems]

FIG. 1 is a block diagram showing the basic configuration of the present invention. The same objects are represented by the same symbols throughout the figures.

The above-mentioned problems are small (in both cases, the power supply section 1 consists of an input terminal 11 to which the AC adapter 3 is connected, a charging circuit 12, a storage battery 13, and a comparison circuit 14 that compares the output voltage of the AC adapter 3 and the output voltage of the storage battery 13). , at least a power switch 21, an output terminal 22 that outputs the output voltage of the power supply section 1 as it is to the load circuit 4, a voltage conversion circuit 23 that converts the output voltage of the power supply section 1, and a voltage conversion circuit 23 that converts the output voltage of the voltage conversion circuit 23 to the load circuit 5. Output section 2 consisting of an output terminal 24 that outputs to
The problem is solved by a converter with a charging circuit according to the present invention, which comprises the following and in which the comparator circuit 14 is constituted by two diodes 15 and 16.

[Effect]

In FIG. 1, when the storage battery 13 is exhausted and the voltage drops below the output voltage of the AC adapter 3, current is supplied to the output section 2 from the AC adapter 3 via the diode 15, and this is caused by insufficient capacity of the charging circuit 12. No voltage drop occurs. Moreover, the current passing through the charging circuit 12 is
3, the storage battery 13 can be recovered relatively quickly and can be kept fully charged at all times.

In other words, it is small, lightweight, inexpensive, has low voltage fluctuations, can always supply current from a full storage battery when the AC adapter is removed, and can be used for long periods of time without an AC adapter, making it a highly reliable power source. It can be realized.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is a block diagram showing a modification of the present invention.

In FIG. 1, when the power switch 21 is turned on, the comparison circuit 14 compares the output voltage of the AC adapter 3 with the storage battery 13.
For example, if the output voltage of the AC adapter 3 is higher than the output voltage of the storage battery 13, the diode 15 becomes forward biased, the diode 16 becomes reverse biased, and the current supplied from the AC adapter 3 becomes It is supplied to the output section 2 via the diode 15. At the same time A
Current is supplied from the C adapter 3 via the charging circuit 12 and the storage battery 13 is charged.

In addition, when the AC adapter 3 is not connected to the input terminal 11, or when the output voltage of the AC adapter 3 is lower than the output voltage of the storage battery 13 due to an increase in current consumption, etc., the diode 15 is reverse biased and the diode 16 is forward biased. Then, current is supplied from the storage battery 13 to the output section 2 via the diode 16.

As a result, the electric power stored in the storage battery 13 is consumed and the voltage becomes lower than the output voltage of the AC adapter 3, and the diode 15 becomes forward biased and the diode 16 becomes reverse biased, and the current supplied from the AC adapter 3 becomes Current is supplied to the output unit 2 via the diode 15, and at the same time, current is supplied from the AC adapter 3 via the charging circuit 12 to charge the storage battery 13.

Note that when the power switch 21 is disconnected, the AC terminal 11 is connected.
When the adapter 3 is connected, the storage battery 13 is charged by the current supplied from the AC adapter 3 via the charging circuit 12.
can be charged to.

According to the above configuration, when the storage battery 13 is exhausted and the voltage drops below the output voltage of the AC adapter 3, the output unit 2
Current is supplied from the C adapter 3 via the diode 15, and a voltage drop due to insufficient capacity of the charging circuit 12 does not occur. Moreover, the current passing through the charging circuit 12 is only the current supplied to the storage battery 13, so that the storage battery 13 can be recovered relatively quickly and can always be maintained in a full state.

In other words, it is small, lightweight, inexpensive, has low voltage fluctuations, can always supply current from a full storage battery when the AC adapter is removed, and can be used for long periods of time without an AC adapter, making it a highly reliable power source. It can be realized.

However, in the basic configuration shown in FIG. 1, when the output voltage of the AC adapter 3 is lower than the output voltage of the storage battery 13, all the current is supplied to the output section 2 from the storage battery I3, and the storage battery 1
The consumption of 3 is large. Therefore, in one embodiment of the present invention shown in FIG. 2, only a part of the current is supplied from the storage battery 13.

As shown in FIG. 2, in one embodiment of the present invention, the output section 2 is equipped with an electromagnetic relay 25, and a relay contact 26 is inserted into a circuit that supplies current to the voltage conversion circuit 23. When the AC adapter 3 is not connected to the input terminal 11, the electromagnetic relay 25 does not operate, and when the power switch 27, which turns on and off two circuits at the same time, is turned on, current is supplied from the storage battery 13 to the voltage conversion circuit 23 and output. It flows into the load circuit 5 through the terminal 24. A current is supplied from the storage battery 13 to the load circuit 4 connected to the negative output terminal 22 via the diode 16 .

When the AC adapter 3 is connected to the input terminal 11, the electromagnetic relay 25 operates, and when the relay contact 26 is switched and the power switch 27 is turned on, current is supplied from the AC adapter 3 to the voltage conversion circuit 23, and the current is supplied to the load circuit through the output terminal 24. 5, and on the other hand, the comparison circuit 14 compares the output voltage of the AC adapter 3 and the output voltage of the storage battery 13.

For example, when the output voltage of the AC adapter 3 is higher than the output voltage of the storage battery 13, the diode 15 becomes forward biased, the diode 16 becomes reverse biased, and the current supplied from the AC adapter 3 passes through the diode 15. The current flows to the load circuit 4 connected to the output terminal 22. At the same time A
Current is supplied from the C adapter 3 via the charging circuit 12 and the storage battery 13 is charged. Furthermore, if the output voltage of the storage battery 13 is higher than the output voltage of the AC adapter 3, the storage battery 1
3 flows through the diode 16 to the load circuit 4 connected to the output terminal 22.

That is, according to this embodiment, when the output voltage of the AC adapter 3 is lower than the output voltage of the storage battery 13, the current supplied from the storage battery 13 to the output section 2 is only the current flowing to the load circuit 4. Therefore, it is possible to realize a power source that has the advantages of the basic configuration shown in FIG. 1 and further reduces consumption of the storage battery when the AC adapter 3 is connected.

In this embodiment, the relay contact 26 is inserted into the circuit that supplies current to the load circuit 5, but conversely, the relay contact 26 is inserted into the circuit that supplies current to the load circuit 4, and the relay contact 26 is inserted into the circuit that supplies current to the load circuit 5. A similar effect can be obtained by connecting a circuit that supplies current to the comparator circuit 14.

In addition to the power supply unit 1 and the output unit 2, the modification of the present invention shown in FIG. 12 is provided.

The voltage monitoring unit 6 includes a voltage detection circuit 61 and a signal sending terminal 62.
, a signal input terminal 63 , and an opening/closing circuit 64 , the output voltage of the power supply section 1 is detected by the voltage detection circuit 61 , and a corresponding signal is sent to an external device via the signal sending terminal 62 . . When the output voltage of the power supply section l falls below a predetermined voltage, a power down signal is input from the external device to the switching circuit 64 via the signal input terminal 63, and the current supplied from the power supply section l to the voltage conversion circuit 23 is reduced. will be cut off.

The control unit 7 has an AC adapter connected to the input terminal 11, and a diode 72 that operates the control circuit 71 with the current supplied from the storage battery 13 when the power switch 21 is turned on when the AC adapter 3 is not connected to the input terminal 11. 3
When connected, the diode 73 operates the control circuit 71 by the current supplied from the AC adapter 3 regardless of the power switch 21.

When current is supplied from the AC adapter 3 to the load circuit, the output voltage of the power supply section 1 rarely drops below a predetermined voltage. However, when current is supplied from the storage battery 13 to the load circuit, the output voltage of the power supply unit 1 may drop below a predetermined voltage due to consumption of the storage battery 13. Therefore, by providing a voltage monitoring section 6 that monitors the output voltage of the power supply section 1 and a control section 7 that controls the charging circuit 12 as shown in FIG. The reliability of the power supply can be improved by cutting off the output of the voltage conversion circuit 23 and operating the charging circuit 12 during that time to quickly recover the power.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a highly reliable power source that is small, lightweight, and inexpensive, and has small voltage fluctuations and can be used for a long time without an AC adapter.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, FIG. 3 is a block diagram showing a modification of the present invention, and FIG. 4 is a block diagram showing a conventional charging system. This is a block diagram showing a converter with circuit. In the figure, 1 is a power supply section, 2 is an output section, 3 is an AC adapter, 4.5 is a load circuit, 6 is a voltage monitoring section, 7 is a control section, 11 is an input terminal,
12 is a charging circuit, 13 is a storage battery, 14 is a comparison circuit, 15.16 is a diode, 21 is a power switch, 22.24 is an output terminal, 23 is a voltage conversion circuit, 2
5 is an electromagnetic relay, 26 is a relay contact, 27 is a power switch, 61 is a voltage detection circuit, 62 is a signal sending terminal, 63 is a signal input terminal, 64 is an opening/closing circuit,
71 is a control circuit, 72.73 is a diode, Kaya 2 (a)

Claims (1)

[Claims] At least an input terminal (1) to which an AC adapter (3) is connected
1), charging circuit (12), storage battery (13), and AC
A power supply unit (1) consisting of a comparison circuit (14) that compares the output voltage of the adapter (3) and the output voltage of the storage battery (13), at least a power switch (21), and a power supply unit that maintains the output voltage of the power supply unit (1) as it is. Output terminal (
22), an output section (22) consisting of a voltage conversion circuit (23) that converts the output voltage of the power supply section (1), and an output terminal (24) that outputs the output voltage of the voltage conversion circuit (23) to the load circuit (5); 2), and the comparison circuit (14) is configured by two diodes (15 and 16).