JP6112004B2 - Auxiliary power supply - Google Patents

Description

  The present invention relates to an auxiliary power supply device capable of preventing a voltage drop of a battery.

  In recent years, in order to improve fuel economy and from environmental considerations, an increasing number of vehicles perform idling to stop idling when the vehicle is stopped. In such a vehicle, since the engine is started more frequently than in the conventional vehicle, the power source of the starter for starting the engine is important.

  When starting the engine, since the starter consumes a large current, a cranking phenomenon may occur in which the voltage of the vehicle power supply device temporarily decreases. When a cranking phenomenon occurs, the battery voltage drops suddenly temporarily, so that the operation of an electric load such as a navigation device and an ECU (Electronic Control Unit) that receives power supply from the same power supply device becomes unstable. There was a possibility.

  Therefore, it is considered that a backup battery or an electric double layer capacitor or the like is connected in parallel as an auxiliary power source to the battery (main power source), and a voltage drop during starter driving is suppressed by discharging from the auxiliary power source.

  For example, Patent Document 1 includes a large-capacity capacitor connected in parallel with a battery and a booster circuit, and supplies power charged in the large-capacity capacitor to a load when the battery is lost or when the battery voltage is lowered. An emergency power supply is disclosed. The emergency power supply device disclosed in Patent Document 1 includes a voltage detection circuit that detects a boosted voltage, feeds back a detection signal of the voltage detection circuit to the microcomputer, and the microcomputer uses the boosted detection signal based on the feedback detection signal. The operation is controlled.

JP 2007-60822 A

  However, since the above-described emergency power supply apparatus includes a diode connected between the battery and the voltage detection circuit, there is a problem that an increase in dark current is a concern.

  The present invention has been made in view of such circumstances, and suppresses an increase in dark current due to the provision of a feedback circuit, while boosting the voltage of the capacitor when the battery is lost or when the battery voltage is lowered. An object of the present invention is to provide an auxiliary power supply device that can be applied to a load.

An auxiliary power supply device according to the present invention is connected in parallel with a DC power supply, and when an ignition switch is turned on, a power storage unit to which a voltage is applied from the DC power supply, and an output terminal that boosts the output voltage of the power storage unit And a voltage terminal to which a voltage boosted by the voltage booster is to be applied, and controls the operation of the voltage booster based on the level of the voltage applied to the voltage terminal. In the auxiliary power supply for a vehicle having a boosting control unit that is provided, provided in the middle of a path connecting the output terminal of the boosting unit and the voltage terminal of the boosting control unit, depending on whether the ignition switch is on or off comprises routing means for connecting / interrupting the path, the path control means, in a case where the ignition switch is turned off, the voltage value of the voltage boosted by the boosting unit is predetermined When the above, a configuration was characterized tare Rukoto to maintain the connection state of said path.

  In the present invention, there is a path for feeding back the voltage boosted by the booster to the boost controller, and this path is connected / disconnected in accordance with the on / off of the ignition switch. For example, when the ignition switch is turned off, the feedback path to the boost control unit is cut off, thereby suppressing the dark current from flowing from the DC power supply in a situation where it is not necessary to supply power to the load.

  In the present invention, even when the ignition switch is turned off, when the output voltage of the power storage unit can be sufficiently boosted, the connection state of the feedback path is maintained and the power supply to the load is continuously executed. Further, by blocking the feedback path after the voltage of the power storage unit is sufficiently lowered, the dark current is prevented from flowing from the DC power supply.

  The auxiliary power supply device according to the present invention is configured to acquire the operating voltage of the boosting unit from any one of a voltage supplied from the DC power supply and an output voltage of the power storage unit. .

  In the present invention, the operating voltage of the boosting unit is obtained from one of the voltage supplied from the DC power supply and the output voltage of the power storage unit. However, the booster operates by the voltage obtained from the power storage unit, and necessary power is supplied to the load.

  According to the present application, when the ignition switch is turned off, the dark current flows from the DC power source in a situation where it is not necessary to supply power to the load by cutting off the feedback path to the boost control unit. Can be suppressed.

It is a block diagram which shows schematic structure of the auxiliary power supply which concerns on this Embodiment. It is a figure which shows the circuit structure of an auxiliary power supply device. It is a timing chart which shows the output characteristic of an auxiliary power unit.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
FIG. 1 is a block diagram showing a schematic configuration of an auxiliary power supply apparatus according to the present embodiment. The auxiliary power supply device 1 according to the present embodiment is connected between a battery 2 and a load 3 mounted on the vehicle. An ignition switch 4 and a fuse 5A are interposed between the battery 2 and the auxiliary power supply device 1. When the ignition switch 4 is on, power from the battery 2 is supplied to the auxiliary power supply device 1 and the load 3. It is configured to be. Further, even when the battery 2 is lost or when the power supplied from the battery 2 is reduced, the power stored in the auxiliary power supply 1 is supplied to the load. Loads supplied by the battery 2 and the auxiliary power supply 1 include lamp systems such as headlights and tail lamps, motor systems such as power window motors, seat motors and door lock motors, and on-vehicle equipment such as heaters and navigation devices. And ECU.

  The auxiliary power supply 1 includes a power storage unit 20 connected to the battery 2 via the ignition switch 4 and the fuse 5A, a charging voltage control unit 10 that controls a charging voltage to the power storage unit 20, and an output voltage (capacitor voltage) of the power storage unit 20 ), A boost control unit 60 that controls the operation of the boost unit 30, a feedback unit 50 that feeds back the voltage value boosted by the boost unit 30 to the boost control unit 60, and under certain conditions A feedback disconnection circuit unit 40 for connecting / disconnecting the feedback unit 50 is provided.

  The power storage unit 20 is configured by connecting a plurality of capacitors 21, 21, 21 in series, and is connected in parallel to the battery 2. As the capacitor 21 provided in the power storage unit 20, for example, an electric double layer capacitor having a predetermined rated voltage can be used. When the ignition switch 4 is on, a voltage supplied from the battery 2 as a DC power source is applied to the power storage unit 20.

  Auxiliary power supply device 1 according to the present embodiment includes boosting unit 30 that boosts the output voltage of power storage unit 20 in order to reduce the number of capacitors 21 provided in power storage unit 20. The voltage boosted by the boosting unit 30 is fed back to the boosting control unit 60 through the feedback unit 50, and the boosting control unit 60 performs feedback control of the boosting unit 30, so that the voltage applied to the load 3 (voltage after boosting) is substantially reduced. The structure is kept constant.

  In addition, the auxiliary power supply according to the present embodiment is configured to suppress an increase in dark current by connecting / disconnecting a feedback path to the boost control unit 60 in accordance with on / off of the ignition switch 4.

  The auxiliary power supply device 1 has a normal power supply path arranged in parallel to the power supply path, in addition to the power supply path that passes through the booster 30, and directly supplies the power from the battery 2 to the load 3. It is configured so that it can be supplied. This power supply path has a diode 73 connected to the battery 2 via the fuse 5B, and even when the voltage of the battery 2 drops, the current from the power storage unit 20 flows to the battery 2 side. I am trying not to.

  FIG. 2 is a diagram illustrating a circuit configuration of the auxiliary power supply device. As described above, the auxiliary power supply device includes the charging voltage control unit 10, the power storage unit 20, the boosting unit 30, the feedback disconnection circuit unit 40, the feedback unit 50, and the boosting control unit 60.

  The charging voltage control unit 10 includes a P-channel MOS FET 11, a charging voltage control circuit 12, and resistors 13-15. The source of the P-channel MOS type FET 11 is connected to the ignition switch 4 via the fuse 5A, and the gate is controlled to be turned on or off by the charging voltage control circuit 12. The charging voltage control unit 10 starts charging the power storage unit 20 when the ignition switch 4 is turned on. At this time, the capacitors 21, 21, 21 included in the power storage unit 20 are charged by dividing the battery voltage by the resistors 13, (resistors 14 + resistors 15). It is controlled not to exceed.

  As described above, the power storage unit 20 is configured by connecting a plurality of capacitors 21, 21, 21 in series, and is charged by a voltage applied through the charging voltage control unit 10.

Note that the voltage (IG voltage) input to the auxiliary power supply device 1 by turning on the ignition switch 4 and the capacitor voltage of the power storage unit 20 are not shown in the figure via diodes 71 and 72, respectively. It is wired so that it may be input to. The power supply regulator receives the higher voltage of the IG voltage or the capacitor voltage, and the power supply regulator converts the constant voltage Vcc obtained from either the IG voltage or the capacitor voltage to the boost IC 61 of the boost control unit 60 and The feedback cutting circuit unit 40 is configured to supply both.
In this embodiment, the constant voltage Vcc is supplied by the power supply regulator. However, the power supply regulator is not an essential component, and the connection portion of the diodes 71 and 72 is directly connected to the boost IC 61 and the feedback as shown in the figure. It is good also as a structure which supplies a voltage with respect to both the cutting circuit parts 40. FIG.

  The booster unit 30 includes two capacitors 31 and 34, an inductor 32, and a Zener diode 33. The positive terminal of one capacitor 31 is connected to one terminal of the power storage unit 20 and the inductor 32, and the negative terminal is grounded. The positive terminal of the other capacitor 34 is connected to the cathode of the Zener diode 33 and the cathode of the Zener diode 41 included in the feedback disconnection circuit unit 40, one terminal of the resistor 47, and the source of the P-channel MOS type FET 42, and the negative electrode is grounded. Has been. Further, the drain of the N-channel MOS FET 62 included in the boost control unit 60 is connected between the other terminal of the inductor 32 and the anode of the Zener diode 33.

  The feedback disconnection circuit unit 40 includes a Zener diode 41, a P-channel MOS FET 42, an NPN transistor 43, and resistors 44 to 47.

  The constant voltage Vcc from the power supply regulator is input to the base of the NPN transistor 43 through the resistor 44. The collector of the NPN transistor 43 is connected via a resistor 45 to the anode of the Zener diode 41, the other terminal of the resistor 47, and the gate of the P-channel MOS FET 42. The emitter of the NPN transistor 43 is grounded, and a resistor 46 is interposed between the emitter and the base.

  On the other hand, the voltage boosted by the booster 30 is applied to the cathode of the Zener diode 41, one terminal of the resistor 47, and the source of the P-channel MOS FET 42. The drain of the P-channel MOS FET 42 is connected to one terminal of a resistor 51 provided in the feedback unit 50.

  The feedback unit 50 is configured as a voltage dividing circuit including resistors 51 and 52, and the divided voltage is applied to the voltage terminal 60 a of the boost control unit 60.

  The step-up control unit 60 includes a step-up IC 61 configured by a microcomputer and an N-channel MOS type FET 62. The output voltage output from the booster IC 61 is input to the gate of the N-channel MOS FET 62. The source of the N-channel MOS FET 62 is grounded, and the drain is connected to the other terminal of the inductor 32 and the anode of the Zener diode 33 in the boosting unit 30.

Next, the operation of the auxiliary power supply device will be described.
FIG. 3 is a timing chart showing the output characteristics of the auxiliary power supply device. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the voltage (signal level) of each part. The battery voltage indicates a voltage supplied from the battery 2 to the auxiliary power supply device 1. In the example shown in FIG. 3, a constant voltage is supplied as the battery voltage, and the supply is stopped when the battery is lost.

  The IG voltage represents the signal level of the IG signal that is switched according to whether the ignition switch 4 is turned on or off. When the ignition switch 4 is turned on, the example shown in FIG. 3 shows that the IG signal is switched from a low level to a high level, and when the ignition switch 4 is turned off, the ignition switch 4 is switched from a high level to a low level. Yes.

  The capacitor voltage indicates the voltage of the capacitor 21 in the power storage unit 20. In the example shown in FIG. 3, when the ignition switch 4 is turned on and the battery voltage is supplied from the battery 2, the capacitor voltage gradually increases with time until the battery is fully charged, and the ignition switch 4 is turned off. It has been shown that if the battery is lost or if the battery is lost, the capacitor voltage gradually decreases over time.

  The feedback voltage indicates a voltage (voltage that the feedback unit 50 feeds back to the boosting control unit 60) that is input through the voltage terminal 60a of the boosting control unit 60. As described above, the constant voltage Vcc obtained from either the IG voltage or the capacitor voltage is input to the voltage terminal 60a of the boost control unit 60, and the boost control unit 60 operates using the constant voltage Vcc as an operating voltage. Is configured to do. When the ignition switch 4 is switched from off (IG voltage is low level) to on (IG voltage is high level), electric charge is accumulated in the capacitor 21 of the power storage unit 20 and the boosting unit 30 operates. As a result, the capacitor voltage of the power storage unit 20 is boosted by the boosting unit 30, and a high-level feedback voltage is input through the voltage terminal 60 a of the boosting control unit 60.

  Further, when the ignition switch 4 is switched from on (IG voltage is high level) to off (IG voltage is low level), charging to the power storage unit 20 is stopped, but the booster unit 30 is driven by the capacitor voltage of the power storage unit 20. As a result, the capacitor voltage can be boosted, so that a high-level feedback voltage is input through the voltage terminal 60 a of the boost control unit 60.

  When discharging from the power storage unit 20 proceeds and the operating voltage of the boosting unit 30 cannot be sufficiently obtained, the feedback disconnection circuit unit 40 turns off the P-channel MOS type FET 42 to thereby provide a feedback path to the boosting control unit 60. The feedback unit 50 is cut. As a result, the feedback voltage input through the voltage terminal 60a of the boost control unit 60 becomes a low level.

  The post-boosting output voltage indicates the output voltage from the power feeding path via the boosting unit 30. The boosted output voltage is maintained at a constant value while the constant voltage is supplied from the battery 2. Even when the battery 2 is lost, the boosted output voltage is kept constant while the capacitor voltage of the power storage unit 20 can be boosted by the boosting unit 30. Further, when the discharge from the power storage unit 20 progresses and the operating voltage of the booster unit 30 is not sufficiently obtained, the feedback disconnection circuit unit 40 disconnects the feedback unit 50 that is a feedback path to the booster control unit 60. Therefore, the post-boost output voltage thereafter becomes the value of the voltage remaining in the power storage unit 20.

  As described above, in the present embodiment, even when the ignition switch 4 is turned off, when the output voltage of the power storage unit 20 can be sufficiently boosted, the connection state of the feedback path is maintained and the load 3 is connected. The power supply can be continued. In addition, the feedback path can be interrupted after the voltage of the power storage unit 20 is sufficiently lowered, and the dark current can be prevented from flowing from the battery.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. In addition, the technical features described in each embodiment can be combined with each other.

DESCRIPTION OF SYMBOLS 1 Auxiliary power supply device 2 Battery 3 Load 4 Ignition switch 10 Charging voltage control part 20 Power storage part 30 Boosting part 40 Feedback disconnection circuit part 50 Feedback part 60 Boosting control part

Claims (2)

A power storage unit connected in parallel with the DC power source and applied with a voltage from the DC power source when the ignition switch is turned on, and a booster unit that boosts the output voltage of the power storage unit and supplies the output voltage from the output terminal to an external load And a boosting control unit that has a voltage terminal to which a voltage boosted by the boosting unit is to be applied, and controls the operation of the boosting unit based on the height of the voltage applied to the voltage terminal. In the auxiliary power supply of
Path control means provided in the middle of a path connecting the output terminal of the boosting unit and the voltage terminal of the boosting control unit, and connecting / cutting off the path according to on / off of the ignition switch ;
The route control means includes
In a case where the ignition switch is turned off, the voltage value of the voltage boosted by the boosting unit when the predetermined value or more, and configured characterized tare Rukoto to maintain the connection state of the path Auxiliary power supply.   2. The auxiliary power supply device according to claim 1, wherein the operation voltage of the boosting unit is configured to be acquired from any one of a voltage supplied from the DC power supply and an output voltage of the power storage unit. .

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