JPH1066274A - Power circuit for electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power circuit for electronic equipment that enhances the reliability of the state of charge of secondary batteries. SOLUTION: This power circuit for electronic equipment contains a primary battery detecting section 3 that detects the presence or absence of a primary battery 1; a voltage detecting section 8 that detects the voltage of a secondary battery 7; and a switch means 6 placed between a primary power supply and a secondary battery. The power circuit is so constituted that, when the presence of a primary power supply is detected at the primary power supply detecting section 3 and the voltage of the secondary battery 7 detected at the said voltage detecting section 8 is equal to or below a specified value, the said switch means 6 is closed to charge the secondary battery 7 from the primary battery 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit for an electronic device, and more particularly to a portable wireless terminal or the like having a primary power supply and a rechargeable secondary battery and consuming the secondary battery. The present invention relates to a power supply circuit of an electronic device configured to supplement the generated power by a primary power supply.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a configuration of a power supply circuit used in a conventional portable radio terminal. The conventional portable wireless terminal includes a secondary battery 105 that supplies power to the transmission unit 106, and a primary battery 101 that is provided to supplement the power consumed by the secondary battery 105. Usually, a disposable manganese battery or an alkaline battery is used as the primary battery 101. As shown in FIG. 3, the voltage of the primary battery 101 is boosted by a booster circuit 102 and supplied to a secondary battery 105 via a control unit 103 and a switch 104. The control unit 103 includes the transmitting unit 10
A transmission control signal S201 for controlling the operation of
In step S 6, a charge control signal S 202 for controlling the charging operation from the primary battery 101 to the secondary battery 105 is output to the switch 104. The transmission unit 105 performs transmission in accordance with the transmission control signal S201, while the switch 104 performs charging.
The secondary battery 105 is charged by connecting the booster circuit 102 and the secondary battery 105 according to 202.

FIG. 4 is a timing chart of a transmission control signal S201 and a charge control signal S202. As shown in FIG. 4, the control unit 103 is set to turn on the charge control signal S202 for a predetermined time at the end of transmission, that is, after the transmission control signal S201 switches from on to off output.

When transmission is performed in the transmission section 106 in response to the ON output of the transmission control signal S201, the control section 10
3 to the switch 104, the charging control signal S20
2 is turned off, and in response, the switch 104 is turned off. Therefore, the transmitting unit 106 is disconnected from the primary battery 101 and operates using the secondary battery 105 as a power supply.

On the other hand, when the transmission control signal S201 output from the control unit 103 switches from on to off, the transmission operation of the transmission unit 106 is stopped, and the charging control signal S202 output from the control unit 103 is output for a predetermined time. Turns on. In response to this, the switch 104 is connected, the output of the booster circuit 102 is supplied to the secondary battery 105, and the secondary battery 105 is charged. Thereby, the power of the secondary battery 105 consumed by the transmission is supplemented.

[0006]

However, in the conventional power supply circuit, the secondary battery 105 is charged for a predetermined time with respect to the power consumed at the time of transmission. When the secondary battery 105 is not turned on, self-discharge or leakage current to the transmission unit causes
This causes a problem in that a voltage drop occurs during the next transmission and an operation failure occurs at the next transmission. If the primary battery is not mounted at the end of the transmission because of a battery change or the like, the secondary battery 105 is not charged. Therefore, there is still a problem that the next transmission operation is not performed well.

[0007]

In order to solve the above-mentioned problems, a power supply circuit of an electronic apparatus according to the present invention comprises a rechargeable secondary battery and a primary power supply for replenishing power consumed by the secondary battery. In a power supply circuit of an electronic device including: a primary power supply detection unit that detects the presence or absence of connection of a primary power supply; a voltage detection unit that detects a voltage of a secondary battery; and a power supply circuit provided between the primary power supply and the secondary battery. Primary power supply detecting unit detects that the primary power supply is connected, and
When the voltage of the secondary battery detected by the voltage detector is equal to or lower than a predetermined voltage, the switch is closed and the primary power supply charges the secondary battery.

In the power supply circuit configured as described above, when the primary power supply detection section detects the output of the primary power supply, and when the voltage of the secondary battery detected by the voltage detection section is lower than a predetermined voltage, In addition, since the secondary battery is configured to be charged from the primary power supply, the secondary battery is charged even when the voltage of the secondary battery drops due to self-discharge or the like. Therefore, even if the transmission has not been performed for a long period of time, no malfunction occurs in the next transmission. In addition, not only at the end of transmission, but also when the primary power supply is present and the voltage of the secondary battery is equal to or lower than the specified value, charging is performed. Never.

Further, the power supply circuit of the present invention is arranged such that when the circuit operating with the secondary battery as a power supply is operating, the switch means is opened so that the secondary battery is not charged from the primary power supply. It is preferred to configure. In the power supply circuit configured as described above, the power supply to the secondary battery and the operation of a circuit (especially, a transmission unit or the like) that operates using the secondary battery as a power supply are performed alternatively. The circuit scale can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating an example of a configuration of a power supply circuit of the portable wireless terminal according to the present embodiment. The portable wireless terminal of the present embodiment is a primary battery 1 composed of a disposable manganese battery or an alkaline battery.
A booster circuit 2 for boosting the voltage of the primary battery 1, a primary battery detector 3 for detecting whether or not the primary battery 1 is mounted, and a controller for controlling a transmission operation and a charging operation for the secondary battery. 4, a transmission unit 5, a secondary battery 7 acting as a power source for the transmission unit 5, a switch 6 for controlling ON / OFF of charging of the secondary battery 7, and a voltage detection unit for detecting a voltage of the secondary battery 7. And 8.

The voltage of the primary power supply 1 is boosted through a booster circuit 2 and supplied to a controller 4. The control unit 4 includes a transmission unit 5
, And a charge control signal S23 to the switch 6. The transmission unit 5 transmits the transmission control signal S2
2 to perform a transmission operation. The output of the booster circuit 2 is
Since it is configured to be supplied to the secondary battery 7 via the switch 6, the secondary battery 7 is charged according to the ON / OFF operation of the charge control signal S23. The primary battery detection unit 3 detects whether or not the primary battery 1 is mounted on the device, and when the primary battery 1 is mounted, detects a primary battery detection signal S21.
Is supplied to the control unit 4. The voltage detector 8 detects the voltage of the secondary battery 7 and outputs a voltage detection signal S24 to the controller 4.

FIG. 2 is a timing chart showing a primary battery detection signal S21, a secondary battery voltage detection signal S24, a transmission control signal S22, a charging control signal S23, and a voltage state of the secondary battery 7 input to and output from the control unit 4. It is a chart. As shown in FIG. 2, the primary battery detection unit 3 outputs a primary battery detection signal S21 to the control unit 4 if the primary battery 1 is mounted. On the other hand, the voltage detector 8 detects the voltage of the secondary battery,
When the voltage is equal to or higher than a predetermined value, a high level voltage detection signal S24 is output to the control unit 4 when the voltage is equal to or lower than the predetermined value.

In the control section 4, a primary battery detection signal S21 is supplied from the primary battery detection section 3 and a signal S2
When the signal 4 is at a low level and the transmission unit 5 is not transmitting, the charging control signal S23 is turned on. As a result, the switch 6 is closed and power is supplied from the primary battery 1 to the secondary battery 7.

When the primary battery 1 is not mounted on the device, the signal S21 is not output from the primary battery detector 3, so that the charge control signal S23 output from the controller 4 to the switch 6 is turned off, and the switch 6 is turned off. Become open. Therefore, power is not supplied to the secondary battery 7 but the switch 6
Are open, the amount of self-discharge and the amount of leak current of the secondary battery 7 can be suppressed to be small, and a voltage drop of the secondary battery can be prevented.

When the primary battery 1 is mounted, a signal S21 is output from the primary battery detector 3, and the controller 4 recognizes that the primary battery 1 is mounted. At this time, if the output signal S24 of the voltage detection unit 8 is at a low level, that is, if the voltage of the secondary battery 7 is equal to or lower than a predetermined value and the transmission unit 6 is not transmitting, the control unit 4 Charge control signal S
23 is turned on and the switch 6 is closed. Thus, the output of the primary battery 1 boosted by the booster circuit 2 is supplied to the secondary battery 7 side, and the secondary battery 7 is charged.
When the charging of the secondary battery 7 progresses and its voltage becomes equal to or higher than a predetermined value, the output signal S24 of the voltage detecting unit 8 becomes high level, the charging control signal S23 is turned off, and the switch 6 is opened to charge. Ends.

As described above, in the power supply circuit of the present invention, the voltage detector 8 is provided to monitor the voltage of the secondary battery 7 and charge the secondary battery 7 when the voltage becomes lower than a predetermined value. Therefore, it is possible to flexibly cope with a drop in the voltage of the secondary battery 7 regardless of whether the transmission operation is performed. Further, it is detected whether or not the primary battery 1 is mounted, and when the primary battery is mounted and the voltage of the secondary battery becomes lower than a predetermined value, the switch 6 is connected to perform charging. . Therefore, at other times, the switch 6 is always open, so that the self-discharge of the secondary battery 7 and the occurrence of leak current can be minimized.

When transmission is being performed in the transmission unit 5 when the primary battery 1 is mounted, the charging control signal S23 output from the control unit 4 to the switch 6 is turned off, and the switch 6 is opened in response to this. . Therefore, the transmission unit 5 is disconnected from the primary battery 1 and the transmission unit 5 operates using the secondary battery 7 as a power supply. If the level of the secondary battery 7 detected by the voltage detection unit 8 is equal to or lower than a predetermined value when the transmission is completed in the transmission unit 5, the charging control signal S2 output from the control unit 4
3 becomes the ON output. In response to this, the switch 6 is closed, the output of the booster circuit 2 is supplied to the secondary battery 7, and the secondary battery 7 is charged.

As described above, the control section 4 selectively outputs the transmission control signal S22 and the charging control signal S23 so that the transmission operation of the transmission section 5 and the charging operation of the secondary battery 7 are not performed simultaneously. Like that. Therefore, even if the size of the primary power supply is small, it is possible to sufficiently charge the secondary battery, and the transmission operation of the transmitting unit 5 and the secondary battery 7
The circuit scale of the primary battery 1 can be smaller than that of a power supply circuit that simultaneously charges the battery.

In this embodiment, a disposable manganese battery or an alkaline battery is used as a primary power source, but a detachable rechargeable battery or an AC power source may be used. In order to detect whether or not the primary battery is mounted in the primary battery detection unit 3, a method of detecting using a voltage from the primary battery 1 or a method using an optical sensor, a pressure sensor, or the like can be considered.

[0020]

As described above, in the power supply circuit of the electronic apparatus of the present invention, the primary battery detector detects the presence or absence of the output from the primary battery, and the voltage detector monitors the voltage level of the secondary battery. When the primary battery is mounted on the device and the voltage level of the secondary battery is equal to or lower than a predetermined value, the charge control signal output from the control unit is turned on, and the secondary battery is charged. As described above, regardless of the presence or absence of transmission, the secondary battery is charged even when the voltage of the secondary battery is reduced due to self-discharge and leakage current to the transmission unit, and so these are the causes. No malfunction occurs during transmission.

Further, since the presence / absence of the primary battery is detected and the switch for controlling the charging operation is turned off when the primary battery is not mounted, the voltage drop of the secondary battery can be prevented. Furthermore, since the charging operation of the secondary battery is not performed at the time of transmission, there is an effect that the circuit scale of the primary battery can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a power supply circuit of an electronic device according to the present invention.

FIG. 2 is a timing chart showing the operation of the circuit shown in FIG.

FIG. 3 is a block diagram illustrating a configuration of a power supply circuit of a conventional electronic device.

FIG. 4 is a timing chart showing the operation of the circuit shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 primary battery 2 booster circuit 3 primary battery detector 4 controller 5 transmitter 6 switch 7 secondary battery 8 voltage detector S22 transmission control signal S23 charge control signal

Claims (2)

[Claims] 1. A power supply circuit of an electronic device having a rechargeable secondary battery and a primary power supply for replenishing power consumed by the secondary battery, wherein a primary power supply detection for detecting whether the primary power supply is connected or not. Unit, a voltage detector for detecting the voltage of the secondary battery, and switch means provided between the primary power supply and the secondary battery, wherein the primary power supply is connected to the primary power supply. And when the voltage of the secondary battery detected by the voltage detector is equal to or lower than a predetermined voltage, the switch means is closed to charge the secondary battery from the primary power supply. A power supply circuit for an electronic device, comprising: 2. The power supply circuit for an electronic device according to claim 1, wherein, when another circuit that operates using the secondary battery as a power supply is operating, the switch is opened to release the secondary power supply from the primary power supply. A power supply circuit for an electronic device, wherein the power supply circuit does not charge a secondary battery.