JP2006246602A - Power supply controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply controller in which the lifetime of a battery can be prolonged. <P>SOLUTION: When the battery voltage is 2.2 V or above, battery voltage is applied to a step-down DC/DC converter 50e. Consequently, the load on a step-up DC/DC converter 50b and thereby power consumption thereof is reduced. When the battery voltage drops below 2.2 V, a step-up voltage is applied to the step-down DC/DC converter 50e. Consequently, operation of the step-down DC/DC converter 50e is assured even if the battery voltage is lower than 2.2 V at which the step-down DC/DC converter 50e operates. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power supply control device, and more particularly to a power supply control device that is applied to, for example, an IC recorder and includes a plurality of voltage rectifying elements such as a regulator and a DC / DC converter.

An example of a conventional device of this type is disclosed in Patent Document 1. According to this prior art,
The voltage detection means 5 detects the difference between the input voltage Vi and the output voltage Vo. When the input / output voltage difference is equal to or less than the voltage value Vcr, the DC voltage converted by the first DC voltage converting means 3 is set as the output voltage Vo. When the voltage value Vcr is exceeded, the DC voltage converted by the second DC voltage converting means 4 is set as the output voltage Vo. Thereby, the switching between the first DC voltage converting means 3 and the second DC voltage converting means 4 is executed with high accuracy, and a stable output voltage can be obtained efficiently.
Patent Publication No. 2003-84842 [G05F 1/00]

  In the prior art, the stable operation of the battery is ensured by using all the voltage rectifying elements, but this shortens the life of the battery.

  Therefore, a main object of the present invention is to provide a power supply control device capable of extending the life of a battery.

  The power supply control device according to the first aspect of the present invention includes a boosting means (50b) for boosting the battery voltage and outputting the boosted voltage, a selecting means (SW2) for selecting one of the battery voltage and the boosted voltage, and an output of the selecting means Step-down means (50e) for stepping down the voltage and outputting the power supply voltage, judgment means (S7) for judging whether or not the battery voltage is equal to or higher than the first threshold value, selection of the battery voltage when the judgment result of the judgment means is affirmative First request means (S9) for requesting the selection means, and second request means (S11) for requesting the selection means to select a boosted voltage when the determination result of the determination means is negative.

  The boosting means boosts the battery voltage and outputs the boosted voltage, the selecting means selects one of the battery voltage and the boosting means, and the bucking means steps down the output voltage of the selecting means to reduce the power supply voltage. Output. On the other hand, the determination means determines whether or not the battery voltage is equal to or higher than a first threshold value. If the determination result is affirmative, the first requesting unit requests the selection unit to select the battery voltage. If the determination result is negative, the second request means requests the selection means to select the boost voltage.

  That is, when the battery voltage is equal to or higher than the first threshold value, the battery voltage is given to the step-down unit. As a result, the load of the booster, that is, the power consumption of the booster is reduced. On the other hand, when the battery voltage becomes lower than the first threshold value, the boosted voltage is given to the step-down means. Thereby, even when the battery voltage is lower than the lower limit voltage value at which the step-down means operates, the operation of the step-down means is ensured. As a result, the battery life can be extended.

  A power supply control device according to a second aspect of the present invention is dependent on the first aspect, and the first threshold value is a lower limit value of a voltage at which the operation of the boosting means is guaranteed.

  A power supply control device according to a third aspect of the present invention is dependent on the first or second aspect, and further includes a blocking means (50a, S15) for blocking the supply of the battery voltage when the boosted voltage is equal to or lower than the second threshold value.

  A power supply control device according to a fourth aspect of the present invention is dependent on any one of the first to third aspects, wherein the voltage selected by the selection means includes an external power supply voltage and determines whether or not the external power supply voltage is supplied. The second determination means (S1) and the third request means (S17) for requesting the selection means to select the external power supply voltage when the determination result of the second determination means is affirmative. As a result, the power source is switched from the battery voltage to the external power source voltage.

  According to a fifth aspect of the present invention, there is provided a power supply control program for boosting a battery voltage and outputting a boosted voltage, a selecting means for selecting any one of a battery voltage and a plurality of voltages including the boosted voltage, and A determination step for determining whether or not the battery voltage is equal to or higher than a first threshold value for a processor of a power supply control device including step-down means for stepping down an output voltage and outputting a power supply voltage, and when the determination result of the determination step is affirmative A first request step for requesting the selection means to select a voltage and a second request step for requesting the selection means to select a boost voltage when the determination result of the determination step is negative are executed.

  As in the first aspect of the invention, when the battery voltage is equal to or higher than the first threshold value, the battery voltage is supplied to the step-down means. As a result, the load of the booster, that is, the power consumption of the booster is reduced. On the other hand, when the battery voltage becomes lower than the first threshold value, the boosted voltage is given to the step-down means. Thereby, even when the battery voltage is lower than the lower limit voltage value at which the step-down means operates, the operation of the step-down means is ensured. As a result, the battery life can be extended.

  According to the present invention, when the battery voltage is equal to or higher than the first threshold value, the battery voltage is supplied to the step-down means. As a result, the load of the booster, that is, the power consumption of the booster is reduced. On the other hand, when the battery voltage becomes lower than the first threshold value, the boosted voltage is given to the step-down means. Thereby, even when the battery voltage is lower than the lower limit voltage value at which the step-down means operates, the operation of the step-down means is ensured. As a result, the battery life can be extended.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

  Referring to FIG. 1, an IC recorder 10 of this embodiment has an audio playback function, an audio recording function, and an external storage function. The audio playback function and the audio recording function are functions realized by the IC recorder 10 alone, and the external storage function is a function realized by the IC recorder 10 and the PC 54.

  When the IC recorder 10 is not connected to the PC 54, that is, in a USB disconnected state, when the power input operation is performed by the key input device 36, the battery voltage is applied to the power supply circuit 50 and is applied to the CPU 42 through the power supply circuit 50. The The CPU 42 controls the power supply circuit 50 according to the voltage. Specifically, it will be described in detail later. Referring to FIG. 2, in the USB non-connected state, switch SW1 is in an off state, and switch SW3 is connected to terminal T5.

  When the IC recorder 10 is connected to the PC 54 via the USB terminal 48, that is, when the IC recorder 10 shifts to the USB connection state, the USB bus power voltage is supplied from the PC 54.

  A GPIO (General Purpose Input / Output) 44 detects that a USB connection state has been established based on a change in USB bus power (L level → H level), and notifies the CPU 42 of this fact via the bus 34. . The CPU 42 recognizes the establishment of the USB connection state by this notification. The GPIO 44 also changes the power switch 50a shown in FIG. 2 from the on state to the off state, changes the switch SW1 from the on state to the off state, and switches the switch SW2 when the USB bus power changes from the L level to the H level. Connect to terminal T4 and connect switch SW3 to terminal T6.

  The USB bus power supplied by the PC 54 is supplied to the regulator 50d, the terminal T4, and the terminal T6. The regulator 50d adjusts the USB bus power supplied from the PC 54 to a desired voltage value (3.3V), and through the diode 50c, the codec 16, I / F 28, LCD 30, LCD controller 32, memory 40, CPU 42 shown in FIG. , GPIO 44 is supplied with a regulated DC voltage.

  When the audio playback operation is performed by the key input device 36 in the USB disconnected state, the CPU 42 sets the DSP 38 and the codec 16 to the expansion mode and the decoding mode, respectively, and the audio file stored in the flash memory 26 is transferred to the I / F 28. Read through. The read audio file is given to the DSP 38 through the memory 40. The DSP 38 decompresses the compressed audio data included in the given audio file and stores the decompressed audio data in the memory 40. The CPU 42 gives the audio data stored in the memory 40 to the codec 16 through the bus 34. The codec 16 decodes the given audio data into an analog audio signal, and outputs the decoded audio signal from the speaker 12 through the amplifier 14. The CPU 42 also instructs the LCD controller 32 to output the mode information “audio playback mode”. The mode information is displayed on the LCD monitor 30. Thus, an audio playback function is realized.

  When an audio recording operation is performed by the key input device 36 in the USB disconnected state, the CPU 42 sets the codec 16 and the DSP 38 to the encoding mode and the compression mode, respectively. The codec 16 encodes the audio signal captured by the microphones 18 and 22 and amplified by the amplifiers 20 and 24 into digital audio data, and supplies the encoded audio data to the CPU 40 through the bus 34. The CPU 42 gives the given audio data to the DSP 38 through the memory 40. The DSP 38 compresses the applied audio data and stores the compressed audio data in the memory 40. The CPU 42 also stores the compressed audio data stored in the memory 40 in the flash memory 26 via the I / F 28 in a file format. Further, the CPU 42 instructs the LCD controller 32 to output the mode information in order to display the mode information “audio recording mode” on the LCD monitor 30. Thus, an audio recording function is realized.

  When the USB mass storage mode selection operation is performed by the key input device 36 in the USB connection state, the CPU 42 accesses the flash memory 26 in accordance with an access request from the PC 54. If the access request requests writing of a file, the CPU 42 writes the file simultaneously given from the PC 54 to the flash memory 26 through the bus 34. If the access request is a request to read a file, the CPU 42 reads a desired file stored in the flash memory 26 through the bus 34, and reads the read file through the USB controller 46 and the USB terminal 48 to the PC 54. Forward to. Further, the CPU 42 resets the microphone mode flag 26 f and instructs the LCD controller 32 to output the mode information “USB mass storage mode”. Thus, the external storage function is realized.

  Referring to FIG. 2, when power switch 50a provided in power circuit 50 is turned on, the battery voltage is applied to boost DC / DC converter 50b, terminal T2, terminal T5, and CPU 42 via power switch 50a. Is done.

  The step-up DC / DC converter 50b raises the battery voltage to 3.3 V, and the step-up voltage is applied to the codec 16, I / F 28, LCD 30, LCD controller 32, memory 40, CPU 42, GPIO 44 and terminal T3 shown in FIG. Apply (3.3V).

  Returning to FIG. 2, when the switch SW3 is connected to the terminal T5, that is, in the USB non-connected state, the battery voltage applied to the terminal T5 is applied to the step-down DC / DC converter 50f. The step-down DC / DC converter 50f drops the battery voltage to 1.2V and applies the reduced voltage (1.2V) to the DSP 38 shown in FIG.

  The CPU 42 detects the battery voltage and controls the power switch 50a and the switch SW2 according to the voltage. Specifically, when the voltage is 2.2 V or more, the CPU 42 connects the switch SW2 to the terminal T2, and when the voltage is 1.6 V or more and less than 2.2 V, the CPU 42 connects the switch SW2 to the terminal T3. If the voltage is less than 1.6V, the CPU 42 turns off the power switch 50a.

  When the switch SW2 is connected to the terminal T2, the battery voltage is applied to the step-down DC / DC converter 50d through the switch SW2. The step-down DC / DC converter 50d drops the battery voltage to 2.0V and applies the stepped-down voltage (2.0V) to the DSP 38 and the USB controller 46 shown in FIG. Since the switch SW2 is connected to the terminal T2, the connection between the step-up DC / DC converter 50b and the step-down DC / DC converter 50d is cut off, so that the load on the step-up DC / DC converter 50b is reduced. Consumption efficiency is improved.

  Returning to FIG. 2, when the switch SW2 is connected to the terminal T3, the step-up DC / DC converter 50b applies the step-up voltage (3.3V) to the step-down DC / DC converter 50d through the terminal T3. The step-down DC / DC converter 50d drops the applied boosted voltage to 2.0V, and applies the reduced voltage (2.0V) to the DSP 38 and the USB controller 46 shown in FIG.

  When the power switch 50a is turned off, the IC recorder 10 stops.

  When the power operation is performed, the CPU 42 executes a power control task according to the flowchart shown in FIG. A control program corresponding to this flowchart is stored in the flash memory 26.

  According to FIG. 3, it is determined in step S1 whether or not the voltage input to the CPU 42 is a battery voltage. If it is determined that the input voltage is a battery voltage, the process proceeds to step S3, and the voltage value of the battery voltage is detected.

  In step S5, it is determined whether or not the detected voltage value is 1.8V or higher. If the determination result is NO, it is determined that the battery voltage cannot operate the IC recorder 10 normally, and the process proceeds to step S15. On the other hand, if the determination result is YES, it is determined that the battery voltage can operate the IC recorder 10 normally, and the process proceeds to step S7.

  In step S7, it is determined whether or not the detected voltage value is 2.2V or higher. If the determination result is YES, in step S9, the switch SW2 is connected to the terminal T2, and then the process proceeds to step S13. If the determination result is NO, in step S11, the switch SW2 is connected to the terminal T3, and then the process proceeds to step S13. Therefore, when the voltage value applied to CPU 40 is 2.2 V or more, the battery voltage is applied to step-down DC / DC converter 50d. If the voltage value supplied to the CPU 40 is 1.8V to 2.2V, the boosted voltage of the step-up DC / DC converter 50b is applied to the step-down DC / DC converter 50d.

  In step S13, it is determined whether a power-off command has been received. At this time, when a power button (not shown) of the key input device 36 is operated or when there is a notification from the GPIO 44 that the USB connection state has been established, it is determined YES, and the process proceeds to step S15. Further, when the power button (not shown) of the key input device 36 is not operated, or when there is no notification that the USB connection state is established from the GPIO 44, it is determined NO, and the process proceeds to step S3. In step S15, the power switch 50a is turned off, and this task is completed.

  On the other hand, if it is determined in step S1 that the USB connection state has been established from the GPIO 44, NO is determined. At this time, the power switch 50a is turned off by the GPIO 42, the switch SW1 is turned off by the GPIO 44, the switch SW2 is connected to the terminal T4 by the GPIO 44, and the switch SW3 is connected to the terminal T6 by the GPIO 44. The power source is switched from the battery 50 to USB bus power by the PC 54.

  In step S17, the process waits until the connection between the IC recorder 10 and the USB terminal 48 is released. When there is a notification from the GPIO 44 that the USB disconnected state has been established, this task is finished.

  As can be seen from the above description, the boost DC / DC converter 50b boosts the battery voltage and outputs the boost voltage, and the switch SW2 selects either the boost voltage or the battery voltage obtained thereby. The step-down DC / DC converter 50d steps down the voltage applied via the switch SW2 and outputs a step-down voltage. The CPU 42 determines whether or not the battery voltage is 2.2V or higher. If the determination result is positive, the CPU 40 requests the switch SW2 to select the battery voltage, and if the determination result is negative, the CPU 40 requests the switch SW2 to select the boost voltage.

  That is, when the battery voltage is 2.2 V or higher, the battery voltage is supplied to the step-down DC / DC converter 50e. Thereby, the load of the step-up DC / DC converter 50b, that is, the power consumption of the step-up DC / DC converter 50b is reduced. On the other hand, when the battery voltage becomes less than 2.2V, the boosted voltage is applied to the step-down DC / DC converter 50e. Thereby, even when the battery voltage is less than 2.2V at which the step-down DC / DC converter 50e operates, the operation of the step-down DC / DC converter 50e is ensured. As a result, the battery life can be extended.

  The efficiency of the DC / DC converter is approximately 70% to 90%, although it depends on the input voltage, output voltage, and load voltage. Assuming that the step-up DC / DC converter is 80% and the step-down DC / DC converter is 90%, when stepping down from the step-up voltage, the efficiency of the step-down DC / DC converter is 80% × 90% = 72%. For this reason, when the battery voltage is directly stepped down from the battery while the voltage is 2.2 V or more, the efficiency of the pressure DC / DC converter can be 90%.

It is a block diagram which shows the structure of one Example of this invention. 3 is a block diagram illustrating an example of a configuration of a power supply circuit 50. FIG. It is a flowchart which shows a part of operation | movement of CPU42 applied to the FIG. 1 Example.

Explanation of symbols

10 ... IC recorder 36 ... Key input device 42 ... CPU
44… GPIO
48 ... USB terminal 50 ... power supply circuit 50a ... power switch 50b ... step-up DC / DC converter 50d ... regulator 50e ... step-down DC / DC converter 50f ... step-down DC / DC converter 52 ... battery 54 ... PC

Claims (5)

Boosting means for boosting the battery voltage and outputting the boosted voltage;
Selecting means for selecting any one of a plurality of voltages including the battery voltage and the boosted voltage;
Step-down means for stepping down the output voltage of the selection means and outputting a power supply voltage;
First determination means for determining whether the battery voltage is equal to or higher than a first threshold;
First determination means for requesting the selection means to select the battery voltage when the determination result of the first determination means is affirmative; and when the determination result of the first determination means is negative A power supply control device comprising second request means for requesting selection from the selection means.   The power supply control device according to claim 1, wherein the first threshold value is a lower limit value of a voltage at which the operation of the boosting unit is guaranteed.   3. The power supply circuit according to claim 1, further comprising a blocking unit that blocks supply of the battery voltage when the boosting unit is less than a second threshold value. The voltage selected by the selection means includes an external power supply voltage,
Second determination means for determining whether or not the external power supply voltage is supplied; and third request means for requesting the selection means to select the external power supply voltage when the determination result of the second determination means is affirmative The power supply control device according to claim 1, further comprising: Boosting means for boosting the battery voltage and outputting the boosted voltage;
In a processor of a power supply control device comprising: selecting means for selecting any one of a plurality of voltages including the battery voltage and the boosted voltage; and a step-down means for stepping down the output voltage of the selecting means and outputting a power supply voltage.
A determination step of determining whether the battery voltage is equal to or higher than a first threshold;
A first request step for requesting the selection means to select the battery voltage when the determination result of the determination step is affirmative; and the selection of the boost voltage when the determination result of the determination step is negative A power supply control program for causing a means to execute a second request step requested.

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