JP3285974B2 - Failure diagnosis method and protection method for charging circuit and charging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing a failure in a charging circuit for charging a secondary battery, a method for protecting the same, and a charging apparatus.

[0002]

2. Description of the Related Art Conventionally, there is an electronic apparatus provided with a charging circuit for charging a secondary battery. Such an electronic device has a first operation mode (charge mode) for charging the secondary battery and a second operation mode that operates independently of the charge mode and is operated while switching from the charge mode. Further, it has a failure diagnosis function of diagnosing whether or not a charging circuit for charging the secondary battery has failed, and performs a failure diagnosis of the charging circuit at the start of the operation in the charging mode. If the charging circuit is out of order, a warning is issued to the user of the electronic device and the charging operation is stopped.

[0003]

However, in the above conventional example, the failure diagnosis of the charging circuit is performed during the execution of the charging mode, but the failure diagnosis of the charging circuit is not performed during the execution of the second operation mode. . Therefore, for example, when the charging circuit malfunctions and becomes charged due to a failure of an element of the charging circuit during the execution of the second operation mode, for example, this cannot be detected, and the use of the device cannot be detected. This means that charging cannot be stopped unless the user finishes using the apparatus and turns off the power of the apparatus, and the battery may be left in an overcharged state. If such an overcharged state continues, there is a problem that the life of the battery is shortened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and enables a failure diagnosis of a charging circuit to be performed in a state other than a charging mode for charging a battery. It is an object of the present invention to provide a failure diagnosis method, a protection method, and a charging device for a charging circuit for preventing the failure.

[0005]

In order to achieve the above object, a failure diagnosis method for a charging circuit according to the present invention comprises the following steps. That is, a method of diagnosing a failure of a charging circuit for charging a battery, wherein charging power is supplied to the battery via a backflow prevention element, and a supply path of the charging power is opened / closed before the backflow prevention element. A supply step of performing the following steps: an opening / closing step of instructing the supply path to open / close in the supply step; a detection step of detecting a voltage value at a stage preceding the backflow prevention element; and an opening instruction of the supply path by the opening / closing step. And performing a failure diagnosis of the charging circuit based on the voltage value detected in the detection step.

Further, a method for protecting a charging circuit according to the present invention for achieving the above object includes the following steps. That is, a method for protecting a charging circuit for charging a battery, in which charging power is supplied to the battery via a backflow prevention element, and a supply path of the charging power is opened and closed at a stage preceding the backflow prevention element. A supply step to be performed, an open / close step of instructing the supply path to open / close in the supply step, a detection step of detecting a voltage value at a stage preceding the backflow prevention element, and an instruction to open the supply path by the open / close step. In the state where
A diagnosis step of performing a failure diagnosis of the charging circuit based on the voltage value detected by the detection step; and protection for stopping supply of charging power by the supply step when a failure of the charging circuit is found by the diagnosis step. And a step.

Further, a charging device according to the present invention for achieving the above object has the following configuration. That is, a charging device for charging a battery, which supplies charging power to the battery via a backflow prevention element and opens and closes a supply path of the charging power at a stage preceding the backflow prevention element. An opening / closing unit that instructs the supply unit to open / close the supply path, a detection unit that detects a voltage value at a stage preceding the backflow prevention element, and a state in which the supply path is instructed to open by the opening / closing unit. Diagnostic means for diagnosing a failure of the charging circuit based on the voltage value detected by the detecting means.

[0008]

In the above-described process or configuration, a backflow prevention element is provided in a supply path of a charging circuit for supplying charging power, and the supply path is opened and closed in front of the backflow prevention element. Then, in a state where an opening instruction is given to the supply path,
A voltage value at a preceding stage of the backflow prevention element is detected, and a failure diagnosis of the charging circuit is performed based on the voltage value. Further, based on the result of the failure diagnosis, the power supply to the charging circuit is stopped.

[0009]

Embodiment 1 A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1> In Embodiment 1, there is a first operation mode (charge mode) in which the charger of the secondary battery functions, and a second operation mode (printer mode) in which the recording apparatus functions. The recording device with a charging function will be described.

FIG. 1 is a block diagram showing a control configuration of the printing apparatus according to the first embodiment.

In FIG. 1, reference numeral 1 denotes an AC-DC conversion circuit, which converts AC commercial power into DC power. Reference numeral 2 denotes a first current switch, which opens and closes a current supply path to a charging circuit 15 for charging the secondary battery 17. In this embodiment, AC−
The output V1 of the DC conversion circuit is stepped down and the stabilized power output V2
Is a switching transistor of the chopper type power supply circuit 8. The chopper type power supply circuit 8 may be replaced with, for example, an electromagnetic relay switch. A charging circuit 15 controls charging of the secondary battery 17.

In the charging circuit 15, reference numeral 9 denotes a second current switch (transistor), which opens and closes a charging current supply path to the secondary battery 17. In this embodiment, the constant current power supply output V3 is obtained by further combining the constant voltage diode 11 and the resistor 12. However, for example, a constant current power supply circuit may be used instead. Reference numeral 13 denotes a diode for preventing backflow of the battery output current, reference numeral 16 denotes a voltage detection circuit for detecting the output V3, and reference numeral 19 denotes a switch for connecting a secondary battery to a device. Reference numeral 18 denotes a one-chip microcomputer which is a controller of the recording apparatus. The microcomputer 18 is supplied with power from a first power supply circuit 29, controls the operation / stop of a second power supply circuit, and outputs a control signal 14 for opening / closing a transistor 9. An alarm and a control signal are provided to the device according to the output signal of the voltage detection circuit 16. The driver 10 opens and closes the transistor 9 according to the opening and closing control signal 14 input from the microcomputer 18.
17 is a secondary battery. The above is the configuration of the charger according to the present embodiment. The description of the functions of the other elements in the chopper type power supply circuit 8 and the charging circuit 15 is omitted here.

The configuration other than the above in FIG. 1 shows a typical basic configuration of the recording apparatus. Reference numeral 21 denotes a printer driving circuit which drives each device of the recording apparatus (for example, a carriage motor 22, a line feed motor 23, a print head 26, etc.) under the control of the microcomputer 18. The console 24 inputs commands to the recording apparatus. The interface 25 receives recording information from the host computer.

In the above configuration, when commercial power is supplied to the apparatus, power is supplied to each section of the apparatus from the power output V1 of the AC-DC conversion circuit 1, and the microcomputer 18 which is the controller of the present recording apparatus operates the microcomputer 18 of the recording apparatus. Operation control is started. The microcomputer 18 first outputs a power control output signal 28 to operate the second power circuit 20. When the power supply circuit 20 rises, the pulse width control circuit 3 starts operating, and the chopper type power supply circuit 8 outputs a power output V2 obtained by adjusting the voltage of V1. The microcomputer 18 controls the opening and closing of the transistor 9 by the opening and closing control output signal 14 and the driver 10.

If the open / close control output signal 14 is an open command,
The transistor 9 is turned off, and the charging current is cut off.
In this state, the value of V3 input to the voltage detection circuit 16 is
Since the backflow preventing diode 13 is provided, the voltage is almost equal to the GND level (VGND) regardless of the output voltage value of the secondary battery 17.

However, the emitter of the transistor 9
A failure occurs when the collectors are short-circuited, or a driver 10 for driving the transistor 9 or an output port of the microcomputer 18 for outputting the opening / closing control signal 14 fails. The transistor 9 may be in a closed state (ON) in spite of outputting the open command. In such a case, the value of the voltage V3 input to the voltage detection circuit 16 is equal to the sum of the voltage of the secondary battery and the forward voltage of the diode 13 lower than the GND level when the secondary battery is connected. Value (VBAT). When a secondary battery is not connected, the voltage value of V3 becomes equal to V2, and V2 is input to the voltage detection circuit 16. Therefore, the voltage detection circuit 16
Have the following relationship in the above three cases.

V2>VBAT> VGND Accordingly, the following three information can be obtained by monitoring the voltage value of V3 during the printer mode. That is, (1)
The transistor 9 is off (open) (VGND).
(2) The transistor 9 is turned on (closed) due to the element failure, and the charging current is flowing into the secondary battery (VBA
T). (3) The transistor 9 is in an ON (closed) state due to a failure of the element, but no charging current flows because the secondary battery is not connected (V2).

As described above, according to the configuration of the first embodiment, the output voltage (V
By monitoring 3), it is possible to reliably detect a failure of the charger.

Next, a description will be given of a control procedure by software for detecting a failure of the charger in the printer mode in the recording apparatus with a charging function described above, with reference to FIGS.

First, in FIG. 2, when the power supply of the recording apparatus is turned on in step S1, an initial process at power-on is performed in step S2. In this initial processing, initialization of hardware and initialization of software parameters and flag data used in each processing are performed. Next, in step S3, a power supply 20 for supplying electric power to each unit other than the microcomputer 18 is started. Next, in step S4, as a self-diagnosis process of the apparatus, an operation check of a memory installed in the printer drive circuit 21 and accessible by the microcomputer 18, that is, a RAM and a ROM (not shown) is performed.

Next, in steps S5 to S8, a failure diagnosis of the charger is performed. First, in order to turn off (open) the transistor 9 in step S5, the open / close control output signal 14 is set to an open command. Here, in step S6, the output voltage value V3 of the transistor 9 is detected by the microcomputer 18 via the voltage detection circuit 16.
To detect. Then, in steps S7 and S8, a failure determination of the charger is performed based on the detection result. First, in step S7, the transistor 9 fails due to a device failure.
Is not controllable and is in the on state. That is, if the voltage value at V3 is VGND, it is determined that the voltage is normal, and if the voltage value is VBAT or V2, it is determined that a failure has occurred. If not, the process proceeds to step S11, and if it has, the process proceeds to step S8.

In step S8, it is determined whether or not a battery is connected based on the voltage value of V3 detected in step S6. If the voltage at V3 is VBAT, it is determined that the secondary battery is connected, and the process proceeds to step S9,
The protection processing (interruption of current supply to the secondary battery) when the secondary battery is connected is executed. This protection processing will be described later.

On the other hand, if the voltage value at V3 is V2, it is determined that the secondary battery is not connected, and step S
Proceed to 10. Step S10 is a protection process when a failure of the charging circuit is detected and the battery is not connected to the device. When the secondary battery is not connected, no charging current flows even if the charging circuit is broken and the transistor 9 is turned on, and there is no problem in operating in the printer mode or the like. Therefore, in step S10, only a warning is given to the user of the device that the charging circuit is out of order, and the subsequent processing is continued. As a result, if the battery is not connected even if the charging circuit fails, the printer mode of the apparatus can be used. Thus, the initial processing at power-on is completed.

When the initial processing at power-on is completed, FIG.
The process proceeds to step S11 to select the operation mode of the recording apparatus. If there is a charge start request, the process proceeds to step S25;
The charging mode for charging the next battery is set. On the other hand, if there is no request to start charging, the process proceeds to step S12 to enter the printer mode.

In the printer mode, first, in step S12, the open / close control output signal 14, which is a charge control signal, is set to an open command, the transistor 9 is turned off (open), and the charging current to the secondary battery is cut off. Next, in step S13, it is determined whether or not recording start information such as image recording information from the host device has been generated. If not, the process proceeds to step S14. In order to periodically perform a failure diagnosis of the charger while waiting for the recording start information, a timer of software is used to measure time. Until the software timer value reaches a preset value “X”, the determination in step S14 is No, and steps S11 to S14 are repeated. If the soft timer value becomes equal to or more than "X", the soft timer is reset in step S15, and failure diagnosis of the charger is performed in steps S16 to S18 in the same procedure as steps S6 to S8. If the diagnosis result is "no abnormality", steps S11 to S18 are performed until recording start information is generated in step S13.
Repeat the above steps. Failure of the charging circuit is detected, and two more
If the next battery is connected, the process proceeds from step S18 to step S9 to execute the above-described protection processing. If the failure of the charging circuit is detected and the secondary battery is not connected, the process proceeds from step S18 to step S102,
After the error display of the charging circuit is performed, the process returns to step S11.

On the other hand, if the recording start information is generated in step S13, the flow advances to step S19 to start the failure diagnosis processing of the charger. This failure diagnosis processing is performed in step S19.
To S23, which is performed in the above-described step S23.
Since the procedure is the same as 14 to S18, the description is omitted.
If the charger has not failed, the process proceeds from step S22 to step S24, after one line of image is recorded, and returns to step S11. If a failure of the charging circuit is detected and a secondary battery is connected, step S2
The process proceeds from step 3 to step S9, and the above-described protection processing is executed. If the failure of the charging circuit is detected and the secondary battery is not connected, the process proceeds from step S23 to step S1.
In step S01, an error display of the charging circuit is performed, and then the process proceeds to step S24.

Next, the protection processing in step S9 will be described with reference to the flowchart of FIG. Steps S34 to S37 are protection processing procedures when a failure of the charging circuit is detected by the control procedures of FIGS. 2 and 3 and a secondary battery is connected to the device. If the charging circuit 15 has failed and the transistor 9 (FIG. 1) has been turned on in a state where the secondary battery is connected, the transistor 9 (FIG. 1) is left unattended as long as the user of the device does not power off the device. Therefore, the charging current continues to flow.

If the secondary battery is left in an overcharged state, the life of the battery may be shortened, a failure may occur, and smoke or fire may occur. In order to avoid this, in the present embodiment, first, in step S34, the device is brought into a non-line state with the host device. In step S35, all operations as a printer are prohibited. Next, in step S36, the user is warned of the failure of the charging circuit. Then, in step S37, the power supply to the pulse width control circuit 3 of the chopper type power supply 8 is stopped by stopping the output of the second power supply circuit 20 by the microcomputer 18.
As a result, the off duty of the first current switch (switching transistor) 2 becomes 100%, and the output V2
Is cut off, and the power supply in the charging circuit 15 is cut off.

The above procedure ensures the safety of the apparatus even if the charging circuit fails during the printer mode.

As described above, according to the recording apparatus of the present embodiment, failure diagnosis of the charger circuit can be performed even when the apparatus is operating not as a charger but as a recording apparatus (printer mode). It is possible to reliably detect a malfunction of the charger due to an element failure or the like during the execution of the printer mode, and to provide an alarm / control signal to the recording apparatus.

<Embodiment 2> Next, Embodiment 2 will be described. Also in the second embodiment, a case where the present invention is applied to a recording device with a charging function having a first operation mode (charge mode) serving as a charger for a secondary battery and a second operation mode (printer mode) serving as a recording device Will be described.

FIG. 5 is a block diagram showing a control configuration of the printing apparatus according to the second embodiment. FIG. 9 shows a configuration in which a battery detection circuit 27 is added to the control configuration of the recording apparatus according to the first embodiment. This battery detection circuit 27 is a circuit dedicated to battery presence detection,
In the recording apparatus of the first embodiment, the detection of the presence or absence of the battery, which is also used by the voltage detection circuit 16, is performed independently. Thereby, in the recording apparatus of the first embodiment, the transistor 9 is turned on (closed).
The presence or absence of the connection of the secondary battery, which cannot be determined otherwise, can be determined regardless of the open / close state of the transistor 9.

The control procedure of the recording apparatus of the second embodiment having the above configuration will be described with reference to the flowcharts of FIGS. In the flowcharts of FIG. 6 and FIG. 7, the same processes as those in the flowcharts of FIG. 2 and FIG. 3 described above are denoted by the same reference numerals, and description thereof is omitted here.

In the control procedure of the second embodiment shown in FIGS. 6 and 7, the presence or absence of a battery is determined by the battery detection circuit 27 before the failure detection processing of the charging circuit performed in the control procedure of the first embodiment (step S1). S30, S31, S32),
The failure detection of the charging circuit is performed only when the battery is connected. This means that even if the charging circuit breaks down and the transistor turns on, the charging current will not flow into the secondary battery unless a battery is connected, thus shortening the battery life or causing smoke or ignition. Since there is no danger to the printer mode, which is the second operation mode, when the battery is not connected, the failure detection processing of the charging circuit is omitted and the control by software is simplified. It is a thing.

Third Embodiment A third embodiment will be described below. In the third embodiment, the procedure of the protection process (step S9) in the second embodiment is changed. FIG. 8 is a flowchart for explaining the control operation of the third embodiment. In the configuration (FIG. 5) of the method for diagnosing the failure of the charging circuit described in the second embodiment (FIG. 5), the control circuit of FIG. It shows a protection procedure when a failure is detected.

In FIG. 6 or FIG. 7, when it is determined that the charging circuit 15 has failed while the secondary battery is connected to the device, the protection process is performed in steps S38 to S47 in FIG. Perform

In the figure, in step S38, the apparatus is brought into a non-line state with the host apparatus. In step S39, all operations as a printer are stopped. Next, in step S40, the user of the device warns of the failure of the charging circuit. In step S41, the user notices the alarm, and the battery detection circuit 27 (FIG. 5) detects whether or not to disconnect the battery from the device, and determines whether or not the battery should be disconnected. If the result of the determination is that the secondary battery has been disconnected, the charging circuit error is canceled in steps S44 to S46, and the printer mode is automatically returned to a usable state again. Therefore, the process proceeds from step S46 to step S11. Then, in the processing after step S11, since no battery is detected, failure diagnosis is not performed, and normal processing is performed.

On the other hand, in the determination in step S41, 2
If the next battery is still connected, steps S40 to S42 are performed to wait for the user to disconnect the battery from the device for a time t that does not cause the battery to be overcharged.
repeat. If the time t has elapsed, the process proceeds to step S43, in which the output of the second power supply circuit is stopped in order to interrupt the charging current to the secondary battery and protect the device and the battery.

As described above, according to the charging circuit of the third embodiment, even if the charging circuit is out of order, the operation in the printer mode is not affected at all unless the secondary battery is connected. It is possible to respond to a user who wants to operate the apparatus in the printer mode instead of the charging mode.

As described above, in the recording apparatus of each of the above-described embodiments, the first operation mode (charging mode) for charging the secondary battery and the first operation mode are switched so as not to operate in parallel. And a second operation mode (print mode) for performing printing in a print mode. When a failure occurs in the charging circuit during operation in the print mode, control is performed so as to cut off power supply to the secondary battery. For this reason, the danger that the charging circuit cannot be controlled due to a failure of the element or the like and the secondary battery continues to be overcharged can be more reliably avoided. This makes it possible to provide a highly secure electronic device.

In each of the embodiments described above, the charging device of the present invention is applied to a recording device. However, the present invention is not limited to this, and may be applied to any electronic device using a secondary battery. Needless to say.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus.

[0044]

As described above, according to the method for diagnosing failure of a charging circuit, the protection method, and the charging apparatus of the present invention, it is possible to diagnose the failure of a charging circuit in a state other than the charging mode for charging a battery. This has the effect of preventing overcharging of the battery in the non-charge mode.

[0045]

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a control configuration of a printing apparatus according to a first embodiment.

FIG. 2 is a flowchart illustrating a failure diagnosis procedure of the charging circuit according to the first embodiment.

FIG. 3 is a flowchart illustrating a failure diagnosis procedure of the charging circuit according to the first embodiment.

FIG. 4 is a flowchart illustrating a protection processing procedure when a failure occurs in a charging circuit.

FIG. 5 is a block diagram illustrating a control configuration of a printing apparatus according to a second embodiment.

FIG. 6 is a flowchart illustrating a failure diagnosis procedure of a charging circuit according to the second embodiment.

FIG. 7 is a flowchart illustrating a failure diagnosis procedure of the charging circuit according to the second embodiment.

FIG. 8 is a flowchart illustrating a protection processing procedure according to a third embodiment.

[Explanation of symbols]

 2 First current switch 3 Pulse width control circuit 8 Chopper type power supply circuit 9 Transistor 15 Charging circuit 16 Voltage detection circuit 17 Secondary battery 18 Microcomputer 20 Second power supply circuit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junichi Arakawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yuichi Kaneko 3-3-2-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-4-271279 (JP, A) JP-A-4-108340 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02J 7/00 -7/36

Claims (6)

(57) [Claims] 1. A method of diagnosing a failure of a charging circuit for charging a secondary battery, comprising: supplying charging power to the secondary battery via a backflow prevention element; A supply step of opening and closing the supply path of the charging power; an opening and closing step of instructing the supply path to open and close in the supply step; a detection step of detecting a voltage value at a stage preceding the backflow prevention element; A diagnosis step of performing a failure diagnosis of the charging circuit based on the voltage value detected in the detection step in a state in which the supply path opening instruction is given, the failure diagnosis method for a charging circuit. 2. A method for protecting a charging circuit for charging a secondary battery, comprising: supplying charging power to the secondary battery via a backflow prevention element; A supply step of opening and closing a power supply path; an opening and closing step of instructing the supply path to open and close in the supply step; a detection step of detecting a voltage value at a stage preceding the backflow prevention element; In a state where a road opening instruction is given, a diagnosis step of performing a failure diagnosis of the charging circuit based on the voltage value detected in the detection step, and when a failure of the charging circuit is found in the diagnosis step,
And a protection step of stopping supply of power to the charging circuit. 3. A secondary battery detecting step for detecting whether or not the secondary battery is connected to the charging circuit, wherein the diagnosing step is instructed to open the supply path by the opening / closing step. 3. The method according to claim 2, wherein in the state, the failure diagnosis of the charging circuit is performed based on the voltage value detected by the detection step. 4. 4. A charging device for charging a secondary battery, wherein the charging power is supplied to the secondary battery via a backflow prevention element, and the charging power is supplied before the backflow prevention element. Supply means for opening / closing a path; opening / closing means for instructing the supply means to open / close the supply path; detection means for detecting a voltage value at a stage preceding the backflow prevention element; opening of the supply path by the opening / closing means And a diagnostic unit for performing a failure diagnosis of the charging circuit based on the voltage value detected by the detection unit in a state where the instruction is given. 5. The charging apparatus according to claim 4, further comprising protection means for stopping supply of power to the charging circuit when a failure of the charging circuit is found by the diagnosis means. 6. A secondary battery detecting means for detecting whether or not the secondary battery is connected to the charging circuit, wherein the diagnostic means is connected to the secondary battery by the secondary battery detecting means. When it is detected that the supply path is opened by the opening / closing means,
The charging device according to claim 4, wherein failure diagnosis of the charging circuit is performed based on the voltage value detected by the detection unit.