JP2017059091A - Power source circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power source circuit that allows an EDLC to attain unification of a backup power source for a control unit and memory requiring a plurality of power sources, and surely conducts a startup and end sequence of SoC.SOLUTION: A power source circuit of the present invention comprises: a plurality of power sources composed of a single backup power source; a control unit that is connected to the plurality of power sources; a storage power source that supplies a power source to a storage unit; a backup power source that retains electric charges of the storage power source and the plurality of power sources upon shutting down of the power source; and a disconnection circuit that, when the control unit determines that the back-up power source is not required, shuts down the backup power source. Accordingly, when the control unit such as SoC and the like determines shutdown of the power source, the backup power source is used to conduct processing for retreating data to a memory such as the storage unit and the like, and other devices such as a microcomputer and the like.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply circuit that unifies a control unit and a memory backup power supply.

  Conventionally, when an electric double layer capacitor is used as a backup power source, another multiple power source is not formed from the electric charge stored in the electric double layer capacitor and is not connected to the system control unit, but is stored in the electric double layer capacitor. One having a single power supply structure in which electric charges are directly used as a backup power supply is known (for example, see Patent Document 1 below).

JP 2009-27844 A

  An EDLC (Electric Double Layer Capacitor) is generally used as a backup power source for devices such as a memory used as a storage element that require countermeasures against instantaneous power interruption. By using the EDLC in a SoC (System on a Chip) or the like that controls the storage unit such as the memory and functions as a system control unit, the memory and device save processing at the time of power supply interruption is performed. As a result, the effect of shortening the restart time at the time of power OFF-ON can be expected. However, for a device that requires a plurality of power supplies, since the start-up and termination of the power supply does not operate normally due to the influence of the residual charge of the backup power supply, it is difficult to use the backup power supply as it is.

  The present invention has been made to solve the above problems, and provides a power supply circuit that unifies the power supply of the control unit and the storage unit, and that normally performs control operations at the start and end of the system power supply. Objective.

  In order to achieve the above object, a power supply circuit of the present invention includes a plurality of power supplies comprising a single backup power supply, a control unit connected to the plurality of power supplies, a power supply for a storage unit for supplying power to the storage unit, a power supply instantaneously A power supply for the storage unit and a backup power supply for holding the charges of the plurality of power supplies at the time of disconnection, and a disconnection circuit for disconnecting the backup power supply when the control unit determines that the charge retention of the backup power supply is unnecessary.

  According to the present invention, when the control unit determines that the power supply from the power supply is interrupted for a short time, by using the backup power supply, for example, from a memory such as a storage unit or other device Enables data save processing. In addition, by providing the disconnection circuit and the discharge resistor, when the control unit determines that the backup power supply is unnecessary, the control sequence at the end can be processed normally. In addition, when the system power supply is started immediately after the system power supply is turned off, the restart time can be shortened. Thereby, the start-up time in the whole electronic device system using the power supply circuit can be shortened.

It is a block diagram of a power supply circuit showing an embodiment of the present invention. It is a flowchart at the time of completion | finish for the operation | movement description in one Example of this invention. It is a flowchart at the time of starting for operation | movement description in one Example of this invention.

(Embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram of a power supply circuit according to an embodiment of the present invention. The power supply circuit 1 includes a control unit 2 including a SoC (System on a Chip) that converts an analog signal into a digital signal and performs a control operation such as image processing, and a memory including an SD (Secure Digital), a micro SD, and the like. And a backup power source 4 that performs data saving processing from the control unit 2 to the storage unit 3 when the power source is instantaneously interrupted.

  The control unit 2 has functions of converting analog signals into digital signals and performing control operations such as image processing, and requires a plurality of power supplies. As the plurality of power sources, a power source 6, a power source 7, and a power source 8 described later are power sources necessary for starting the control unit 2.

  The backup power source 4 is composed of an EDLC (Electric Double Layer Capacitor), holds electric charges when the power source is interrupted, and has a storage unit power source 9, a power source 6, a power source 7, and an auxiliary function of the power source 8.

  The system power supply 5 supplies a voltage to the power supply 6, the power supply 7, the power supply 8, and the storage unit power supply 9.

  The storage unit power supply 9 supplies a voltage to the storage unit 3.

  The power supply 6, the power supply 7, and the power supply 8 increase in potential in this order, and the power supply 8 has the highest potential. In the control unit 2 that requires a plurality of power supplies, the power supplies are generally started in ascending order of potential. Since the current flows from the higher potential to the lower potential, if the power source having a higher potential is activated first, the current flows in a direction that does not originally flow inside the control unit 2, and as a result, the control unit 2. This is because a phenomenon that destroys itself (around the power supply) occurs. In order to prevent damage to the control unit 2 caused by the power wraparound, it is necessary to start in the order of the power source 6, the power source 7, and the power source 8 at the timing when the system power source 5 is turned on. Further, at the timing when the system power supply 5 is turned off, it is necessary to end the power supply 8, the power supply 7, and the power supply 6 in this order.

  The backup power supply 4 holds electric charges at the same time as energization is started from the system power supply 5. Further, when the power supply from the system power supply 5 is cut off when the power supply is instantaneously cut off, the backup power supply 4 functions as a backup power supply for the storage unit power supply 9, the power supply 6, the power supply 7, and the power supply 8, and writes data or the like to the storage unit 3. The operation of the storage unit 3 and the control unit 2 is continued in order to ensure the time necessary for the storage.

  The disconnection circuit 10 of the backup power supply 4 does not need to supply a voltage from the backup power supply 4 after the data writing in the storage unit 3 is completed when a time necessary for writing data in the storage unit 3 has elapsed by the backup power supply 4 at the momentary power interruption. Become. For this reason, the voltage supply from the backup power supply 4 is cut off by the cutting circuit 10.

  When the backup power supply 4 is disconnected by the disconnection circuit 10, the resistor 11, the resistor 12, and the resistor 13 are discharge resistors for normally terminating power supply in the order of the power supply 8, the power supply 7, and the power supply 6. Become.

The diode 14 and the diode 15 are diodes for protection against reverse current from the storage unit power supply 9, the power supply 6, the power supply 7, and the power supply 8, respectively.

  In the power supply circuit configured as described above, an end sequence of the power supply circuit 1 when the system power supply 5 is turned off will be described with reference to FIG.

  First, when an instantaneous power interruption occurs from the normal startup (power ON state) of the power supply circuit 1 or when the system power supply 5 is turned OFF (energization interruption) (step S1), the backup power supply 4 starts to be discharged (step S1). S2 step).

  When the power interruption occurs or the power is turned off, the control unit 2 shifts to an end process to safely shut down other devices such as the storage unit 3 and the microcomputer. If the data write request in the storage unit 3 has not been completed, the backup power source 4 continues to discharge the control unit 2 (NO in step S3). On the other hand, when the control unit determines that it is not necessary to hold the charge of the backup power supply 4, a signal for opening the switch is sent from the control unit 2 to the disconnection circuit 10 to the disconnection circuit 10 that disconnects the backup power supply. That is, when the data writing from the storage unit 3 and other devices is completed, the control unit 2 determines that no further discharge of the backup power supply 4 is necessary, and shifts the power supply from the backup power supply 4 to the disconnection process (S3). YES of step).

  The control unit 2 sends a signal for releasing the switch of the backup power supply disconnecting circuit 10 and shuts off the power supply of the backup power supply 4 (step S4).

  When the disconnecting circuit 10 of the backup power source 4 is cut off, the control unit 2 shifts the storage unit power source 9 and the power source 8 to the power OFF state. At this time, if the power is not turned off in the order of voltage, the power supply wraparound may occur and damage may occur, so that the control unit 2 sets the resistances 11, 12, and 13 as discharge resistances to appropriate resistance values. The power supply 8 is first turned off (step S5).

  If the power supply 8 is turned off, the control unit 2 next turns off the power supply 7 (step S6).

  When the control unit 2 detects that the power source 7 is turned off, the control unit 2 finally turns off the power source 6 (step S7). Thus, when the power supply 6 is turned off, the power supply to the control unit 2 is completely stopped, and the termination sequence of the power supply circuit 1 is completed (step S8).

  Next, the startup sequence of the power supply circuit 1 when the system power supply 5 is started (ON) after the completion sequence of the power supply circuit 1 is completed will be described with reference to FIG.

  When the system power supply 5 is turned on, energization of the power supply circuit 1 is started (step S9). First, the power supply 6 is activated and power supply to the control unit 2 is started (step S10). When the power supply 6 is activated, the power supply 7 is activated next, and power is supplied to the control unit 2 (step S11). When the power source 7 is activated, the power source 8 is finally activated, and power supply to the control unit 2 is started (step S12).

  When voltage supply is performed in the order of the power source 6, the power source 7, and the power source 8, the control unit 2 is activated (step S13).

  Here, the control unit 2 starts monitoring the charging voltage of the backup power supply 4, and if the backup power supply 4 is not fully charged (No in step S14), the charging of the backup power supply 4 is continued (step S15). .

  When the control unit 2 detects that the charging has been completed (Yes in step S14), the control unit 2 sends a signal for short-circuiting the switch of the backup power supply disconnection circuit 10 from the control unit 2 to the disconnection circuit 10 for the backup power supply 4 and the storage unit. The power source 9, the power source 6, the power source 7, and the power source 8 are energized with the disconnection circuit 10 (step S16). That is, when the control unit determines that the charge supply from the backup power source 4 is unnecessary, the energization control of the backup power source 4 and the storage unit power source 9, the power source 6, the power source 7, and the power source 8 is possible via the disconnection circuit 10. It becomes.

  Thus, when the system power supply 5 is turned on, the power supply circuit 1 is activated immediately.

  When the control unit 2 determines that the power supply of the system power supply 5 is instantaneously interrupted, voltage supply from the backup power supply 4 is started and the voltage supply is maintained until data writing from the control unit 2 to the storage unit 3 is completed. To do.

  As described above, the power supply circuit according to the present invention includes a plurality of power supplies including a single backup power supply, a control unit connected to the plurality of power supplies, a power supply for a storage unit that supplies power to the storage unit, and an instantaneous power interruption. Since the power supply for the storage unit and the backup power supply for holding the charges of the plurality of power supplies are sometimes provided, the backup power supply is immediately shut down when the control unit determines that the backup power supply is unnecessary.

  As a result, when a control unit such as SoC determines that the power supply is instantaneously interrupted, data backup processing of a memory such as a storage unit or other devices such as a microcomputer can be performed by using a backup power supply. In addition, by providing the disconnection circuit and the discharge resistor, when the control unit determines that the backup power supply is unnecessary, the control sequence at the end can be processed normally. Further, after the system power is turned off, the restart time for driving the control unit when the system power is started can be shortened. For this reason, the start-up time in the entire electronic device system using the power circuit can be shortened.

  It can be used for a power supply circuit in a backup power supply system such as an electronic device.

DESCRIPTION OF SYMBOLS 1 Power supply circuit 2 Control part 3 Memory | storage part 4 Backup power supply 5 System power supply 6 Power supply 7 Power supply 8 Power supply 9 Power supply for memory | storage parts 10 Cutting circuit 11 Resistance 12 Resistance 13 Resistance 14 Diode 15 Diode

Claims (4)

A plurality of power sources composed of a single backup power source, a control unit connected to the plurality of power sources, a power source for a storage unit that supplies power to the storage unit, a power source for the storage unit and a charge of the plurality of power sources at the time of instantaneous power interruption With a backup power supply to hold,
A power supply circuit comprising: a disconnect circuit that disconnects the backup power supply when the control unit determines that the charge retention of the backup power supply is unnecessary.   The power supply circuit according to claim 1, wherein each of the plurality of power supply units connected to the control unit includes a discharge resistor in addition to the disconnection circuit. The control unit monitors a charging voltage of the backup power source,
Upon detecting that the charging of the backup power supply is completed, a signal for short-circuiting the switch of the cutting circuit is sent to the cutting circuit,
Through the cutting circuit,
The power supply circuit according to claim 1, wherein energization of the backup power supply, the storage unit power supply, and the plurality of power supplies is controlled.   2. The control unit starts voltage supply from the backup power source when determining an instantaneous power interruption, and holds the voltage supply until data writing from the control unit to the storage unit is completed. Power supply circuit.

Images