JP2018093694A - Power supply circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply circuit device capable of protecting a circuit even in a case of ON failures of a switch.SOLUTION: In a case where no ON failure of a second switch is detected during an IG OFF state in which a first switch SW1 and the second switch SW2 are turned off, a controller 50 controls a bypass switch SW3 so that a bypass path B1 is in an energization state. On the other hand, ON failures of the second switch SW2 are detected on the basis of a detection signal from a voltage detection circuit 60, the controller 50 controls the bypass switch SW3 so that the bypass path B1 is in an energization interruption state. Thereby, in a case of ON failures of the second switch SW2, a lead accumulator battery 11 and a lithium ion accumulator battery 12 can be prevented from being unintendedly connected with each other via the bypass switch SW3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply circuit device applied to a power supply system having a plurality of storage batteries.

  Conventionally, for example, as an in-vehicle power supply system mounted on a vehicle, two storage batteries (for example, a lead storage battery and a lithium ion storage battery) connected in parallel to an electric load are used. A configuration for supplying electric power is known. In this case, switches are provided in the electrical path between the electrical load and the lead-acid battery and the electrical path between the electrical load and the lithium ion storage battery, and the discharge of each storage battery is controlled by opening and closing each switch. .

  Further, a technique is known in which a bypass path is provided so as to bypass a switch in an electrical path between the electrical load and the lead storage battery, and a normally closed bypass relay is provided in the bypass path (see, for example, Patent Document 1). . In such a technique, even when each switch is turned off (opened) while the vehicle is stopped, the dark current can be supplied from the lead storage battery to the electric load by closing the bypass relay.

JP 2012-130108 A

  However, when the vehicle is stopped, the switch that cuts off the electric path between the electric load and the lithium ion storage battery may be in an on failure (closed failure). Thereby, two storage batteries are connected via a bypass relay. In this case, depending on the voltage difference between the storage batteries, an unintended excessive current flows in the bypass relay and the like, and the bypass relay and the like may break down.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a power supply circuit device capable of protecting a circuit even when a switch is turned on.

  In a power supply circuit device applied to a power supply system in which a first storage battery and a second storage battery are connected in parallel, a first invention is provided in a first electrical path to which power of the first storage battery is supplied, Provided in a first switch for energizing or de-energizing the first electric path and a second electric path for supplying power from the second storage battery, and energizing or de-energizing the second electric path A second switch; a bypass switch that is provided in a bypass path that bypasses the first switch, and that makes the bypass path energized or de-energized; and a detection unit that detects an on-failure of the second switch. When an on-failure of the second switch is not detected during an off period in which the first switch and the second switch are turned off, the bypass path is used by the bypass switch. While the state of energization, if the ON failure of the second switch is detected, the bypass path is summarized as being the state of energization cut off by the bypass switch.

  Thereby, when an ON failure occurs in the second switch, it is possible to prevent the first storage battery and the second storage battery from being unintentionally connected via the bypass switch and the second switch. For this reason, it is possible to prevent an excessive current from flowing through the bypass switch or the like and to protect the circuit.

  According to a second aspect of the present invention, the controller includes a control unit that controls the bypass switch by outputting an instruction signal to the bypass switch, the detection unit being connected to the second electrical path, and the second electrical path Is a circuit that outputs a detection signal indicating an on-failure of the second switch based on a voltage or a current in the control circuit, and the control unit is an instruction signal that puts the bypass path into a state of interrupting energization when the detection signal is input Is output to the bypass switch.

  Thereby, since the control part which controls a bypass switch controls a bypass switch based on a detection signal, a bypass path can be appropriately made into the state of interruption | blocking of electricity supply. Further, for example, it is possible to store in the control unit that an on failure has occurred.

  In a third aspect of the invention, the control unit is configured to be able to take a start state or a stop state for executing various controls. When the detection signal is input during the stop state, the control unit is in a start state, and The gist is to control the bypass switch.

  Thereby, even if it is a stop state, a control part will transfer to a starting state by inputting a detection signal. For this reason, it is not necessary to keep the control unit in an activated state for failure monitoring, and power consumption can be suppressed.

  In a fourth invention, the start signal is connected to an external terminal so as to input a start signal instructing start of the power supply system, and is connected to the detection unit so as to input the detection signal. And a logic circuit that outputs a start signal to the control unit when one of the detection signals is input, and the control unit is configured to be able to take a start state or a stop state for executing various controls. When the start signal is inputted during the stop state, the start state is set and the bypass switch is controlled.

  Thereby, the start signal output when the start signal is input is also output when the detection signal is output. For this reason, the control unit does not need to provide a dedicated terminal for the detection signal by sharing the activation signal. Even when the detection signal is output, the activation signal is shifted to the activation state by the activation signal, so that the control at the activation can be made common.

  In a fifth aspect, when the control unit shifts from the stop state to the start state based on the input of the detection signal, the control unit is in a stop state after outputting an instruction signal for setting the bypass path in a power-off state. This is the gist.

  As a result, after the instruction signal is output, the state shifts to the stop state, so that power consumption can be suppressed.

  In a sixth aspect of the invention, the detection unit is a circuit that is connected to the second electric path and outputs a detection signal indicating an on failure of the second switch based on a voltage or current in the second electric path, The gist of the bypass switch is connected to the detection unit, and when the detection signal is input from the detection unit, the bypass path is set in a state where current is cut off.

  Thereby, since the detection signal is input to the bypass switch, for example, the bypass path can be quickly turned off as compared with a case where a control unit or the like is interposed.

  In a seventh aspect of the invention, the first storage battery and the second storage battery are applied to a power supply system connected in parallel to an electric load, and when the power supply system is turned off, the first switch and the The second switch is turned off, and the bypass switch is a normally closed relay switch. When an on-failure of the second switch is not detected during the off period, the bypass switch The gist is that the bypass path is energized and dark current is supplied from the first storage battery to the electric load via the bypass path.

  Thereby, even during the off period set when the power supply system in which the first storage battery and the second storage battery are connected in parallel to the electrical load is turned off, the electrical load is passed through the bypass path. Thus, dark current is supplied from the first storage battery. For this reason, a load in which power supply failure is not allowed can be used as the electrical load. When the second switch is turned off, no current flows through the bypass switch. For this reason, a bypass switch can be designed on the assumption that dark current flows when the power supply system is turned off.

  In an eighth aspect of the invention, the second switch includes a plurality of switch units and diodes connected in parallel to the plurality of switch units, and the plurality of switch units are connected in parallel to the switch units. The diodes are connected in series so as to be opposite to each other, and the detection unit turns on the second switch when a current flows through any of the plurality of diodes with the plurality of switch units turned off. The gist is to detect a failure.

  Thereby, in the state which turned off all the several switch parts, it becomes possible to interrupt | block the electricity supply in a 2nd electrical path | route completely. For this reason, when an unintended current flows through any one of the diodes, it can be detected that any one of the plurality of switch units has failed. That is, when any of the plurality of switch units fails to turn on, an unintended current flows through a diode on the side of the switch unit different from the switch unit that has failed to turn on. By detecting this current, an on failure is detected. be able to.

The electric circuit diagram which shows a power supply system. (A) is a figure which shows the electricity supply state in IG ON state, (b) is a figure which shows the electricity supply state in IG OFF state. The figure which shows the electricity supply state when a 2nd switch carries out an on failure. The flowchart which shows a circuit protection process. The electric circuit diagram which shows the power supply system of another example.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. In the present embodiment, an in-vehicle power supply system that supplies electric power to various devices of the vehicle in a vehicle that runs using an engine (internal combustion engine) as a drive source is embodied.

  As shown in FIG. 1, this power supply system is a dual power supply system having a lead storage battery 11 as a first storage battery and a lithium ion storage battery 12 as a second storage battery. Each storage battery 11, 12 can be charged by an alternator 13 as a generator, and each storage battery 11, 12 can supply power to a starter 14 and various electric loads 15, 16. ing. In this system, the lead storage battery 11 and the lithium ion storage battery 12 are connected in parallel to the alternator 13, and the lead storage battery 11 and the lithium ion storage battery 12 are connected in parallel to the electrical loads 15 and 16.

  The lead storage battery 11 is a well-known general-purpose storage battery. On the other hand, the lithium ion storage battery 12 is a high-density storage battery that has less power loss during charging / discharging than the lead storage battery 11, and has a high output density and energy density. The lithium ion storage battery 12 may be a storage battery having higher energy efficiency during charging / discharging than the lead storage battery 11. Moreover, the lithium ion storage battery 12 is comprised as an assembled battery which has a some single cell, respectively. These storage batteries 11 and 12 have the same rated voltage, for example, 12V.

  Although the detailed description by illustration is omitted, the lithium ion storage battery 12 is housed in a housing case and configured as a battery unit U integrated with a substrate. The battery unit U has output terminals P1 and P2. Among these, the lead storage battery 11, the alternator 13, the starter 14, and the electric load 15 are connected to the output terminal P1, and the electric load 16 is connected to the output terminal P2. ing.

  The rotating shaft of the alternator 13 is connected to an engine output shaft (not shown) via a belt or the like, and is configured such that the rotating shaft of the alternator 13 rotates with the rotation of the engine output shaft. The alternator 13 generates power (regenerative power generation) by rotating the engine output shaft and the axle.

  The electric loads 15 and 16 have different requirements for the power supply voltage supplied from the storage batteries 11 and 12. Among these, the electric load 16 includes a constant voltage required load that requires the voltage of the supplied power to be constant or fluctuate within a predetermined range. On the other hand, the electric load 15 is a general electric load other than the constant voltage required load. It can be said that the electric load 16 is a protected load. In addition, it can be said that the electric load 16 is a load that does not allow a power supply failure, and the electric load 15 is a load that allows a power supply failure compared to the electric load 16.

  Specific examples of the electric load 16 that is a constant voltage request load include various ECUs such as a navigation device, an audio device, a meter device, and an engine ECU. In this case, by suppressing the voltage fluctuation of the supplied power, it is possible to suppress an unnecessary reset or the like in each of the above devices, and to realize a stable operation. As the electric load 16, a traveling system actuator such as an electric steering device or a brake device may be included. Specific examples of the electric load 15 include a seat heater, a heater for a defroster for a rear window, a headlight, a wiper for a front window, and a blower fan for an air conditioner.

  Next, the battery unit U will be described. In the present embodiment, the battery unit U is configured as a power supply circuit device. Hereinafter, the electrical configuration of the battery unit U will be described in detail. As shown in FIG. 1, the battery unit U has an energization path L1 that connects the output terminals P1 and P2 and an energization path that connects the connection point N1 on the energization path L1 and the lithium ion storage battery 12 as an in-unit electrical path. L2 is provided. Among these, the first switch SW1 is provided in the energization path L1, and the second switch SW2 is provided in the energization path L2.

  Speaking of the electrical path connecting the lead storage battery 11 and the lithium ion storage battery 12, the first switch SW1 is provided on the lead storage battery 11 side of the connection point N1, and the lithium ion storage battery 12 side of the connection point N1. Is provided with a second switch SW2. As described above, the electrical path from the output terminal P1 to the connection point N1 becomes the first electrical path, and the energization path L2 becomes the second electrical path.

  Each of the first switch SW1 and the second switch SW2 includes a pair of semiconductor switches 21a, 21b, 31a, and 31b. The semiconductor switches 21a, 21b, 31a, 31b are MOSFETs, and are connected in series so that the parasitic diodes of the pair of MOSFETs are opposite to each other.

  For example, the second switch SW2 will be described in detail. The semiconductor switches 31a and 31b are connected in series. The semiconductor switches 31a and 31b inevitably have rectifying means due to their internal structure. That is, the internal circuit of the semiconductor switch 31a is a circuit in which the switch unit S1 and the parasitic diode D1 are connected in parallel. Similarly, the semiconductor switch 31b is a circuit in which the switch unit S2 and the parasitic diode D2 are connected in parallel. These semiconductor switches 31a and 31b are connected in series so that the parasitic diodes D1 and D2 are opposite to each other. For convenience, the description has been given using the second switch SW2, but the first switch SW1 is configured similarly. In FIG. 1, the parasitic diodes D1 and D2 are connected to each other at the anodes, but the cathodes of the parasitic diodes D1 and D2 may be connected to each other.

  By configuring the first switch SW1 and the second switch SW2 as described above, for example, when the second switch SW2 is turned off, that is, when the semiconductor switches 31a and 31b are turned off, the parasitic switch Current flow through the diodes D1, D2 is completely blocked. That is, unintentional discharge from the lithium ion storage battery 12 to the lead storage battery 11 and unintentional charging from the lead storage battery 11 to the lithium ion storage battery 12 can be avoided.

  As the semiconductor switches 21a, 21b, 31a, 31b, IGBTs or bipolar transistors can be used instead of MOSFETs. When an IGBT or a bipolar transistor is used as a switch unit, diodes that replace the parasitic diodes D1 and D2 may be connected in parallel to the switch unit. Further, in the first switch SW1 and the second switch SW2, a plurality of pairs of MOSFETs may be provided, and the plurality of sets of MOSFETs may be connected in parallel.

  Further, the battery unit U is provided with a bypass path B1 that bypasses the first switch SW1. One end of the bypass path B1 is connected to a connection point N2 existing between the output terminal P1 and the first switch SW1 on the energization path L1. The other end of the bypass path B1 is connected to the connection point N1 on the energization path L1. That is, the bypass path B1 is provided in parallel with the energization path L1. By this bypass path B1, the lead storage battery 11 and the electrical load 16 can be connected without going through the first switch SW1.

  On the bypass path B1, a bypass switch SW3 composed of a normally closed mechanical relay is provided. The bypass switch SW3 is a relay module (relay switch) having a coil 40a excited by energization, a movable contact 40b that moves in response to the excitation of the coil 40a, a relay drive switch 40c, and the like.

  One end side of the coil 40a is connected to a power source, and the other end side of the coil 40a is grounded. A relay drive switch 40c is provided in the energization path of the coil 40a. When the relay drive switch 40c is turned on, a current flows through the coil 40a. When a current flows through the coil 40a and is excited, the magnetic contact causes the movable contact 40b to move away from the fixed contact, and the bypass switch SW3 is opened (turned on). Thereby, bypass path B1 will be in the state of interruption of energization.

  On the other hand, when the relay drive switch 40c is turned off and no current flows through the coil 40a, or when no power is supplied from the power source, the movable contact 40b moves to the fixed contact side by the biasing force of the return spring, and bypass The switch SW3 is closed (off). Thereby, bypass path B1 will be in an energized state.

  By closing the bypass switch SW3, the lead storage battery 11 and the electrical load 16 are electrically connected via the bypass path B1 even if the first switch SW1 is turned off (opened). For example, in a state where the power switch (ignition switch) of the vehicle is turned off (hereinafter referred to as IG off state), dark current is supplied to the electric load 16 via the bypass switch SW3.

  The battery unit U includes a control unit 50 that controls on / off (opening / closing) of the switches SW1, SW2, and SW3. The control unit 50 is configured by a microcomputer including a CPU, a ROM, a RAM, an input / output interface, and the like. The control unit 50 has a backup memory 51 that can retain the stored contents even after the power is turned off. The control unit 50 is connected to an ECU 100 outside the battery unit U. That is, the control unit 50 and the ECU 100 are connected by a communication network such as CAN and can communicate with each other, and various data stored in the control unit 50 and the ECU 100 can be shared with each other.

  The control unit 50 controls on / off of the switches SW1, SW2, and SW3 based on the storage state of each of the storage batteries 11 and 12 and a command value from the ECU 100 that is the host control device. For example, the control unit 50 performs charge / discharge using the lead storage battery 11 and the lithium ion storage battery 12 selectively.

  More specifically, a voltage sensor that detects the battery voltage of the lead storage battery 11 is connected to the energization path of the lead storage battery 11, and the battery voltage of the lithium ion storage battery 12 is detected to the energization path of the lithium ion storage battery 12. A voltage sensor is connected. The controller 50 calculates the SOC (remaining capacity: State Of Charge) of each of the storage batteries 11 and 12 based on the battery voltage acquired from these voltage sensors. The control unit 50 controls on / off of the first switch SW1 and the second switch SW2 so that the calculated SOC is maintained within a predetermined use range, thereby controlling charging and discharging of the storage batteries 11, 12.

  Moreover, the control part 50 is comprised so that the starting state which performs various control and a stop state can be taken. Here, the structure for the control part 50 to be in an activation state is demonstrated. The battery unit U has an input terminal P3 as an external terminal, and inputs a start signal notifying the state where the power switch (ignition switch) of the vehicle is turned on (hereinafter referred to as the IG on state) via the input terminal P3. To do. Inside the battery unit U, the input terminal P3 is connected to the control unit 50 via an OR circuit A1 (OR circuit). The OR circuit A1 outputs a start signal to the control unit 50 when a start signal or a detection signal described later is input.

  When the activation signal is input, the control unit 50 enters an activated state and executes various controls at predetermined intervals. That is, the control unit 50 controls on / off of the switches SW1, SW2, and SW3 based on the storage state of the storage batteries 11 and 12 and the command value from the ECU 100.

  On the other hand, when the ECU 100 receives a stop command associated with turning off the ignition switch (when the ignition switch is turned off), the control unit 50 closes the bypass switch SW3 (off), and then sets the first switch SW1 and Control is performed so that the second switch SW2 is turned off. Thereafter, the control unit 50 shifts to a stopped state. Since the first switch SW1 and the second switch SW2 are turned off during the IG off state, it can be said that the off period is set (during the off period).

  Next, the state of the battery unit U in the IG on state will be described. As shown in FIG. 2A, the first switch SW1 and the second switch SW2 are on (closed), and the bypass switch SW3 is open (on). If power generation by the alternator 13 is carried out in such a state, the generated power is supplied to the lead storage battery 11 and the electric load 15, and the lithium ion storage battery 12 is supplied via the energization paths L 1 and L 2 of the battery unit U. The generated power is supplied to the electric load 16.

  In the IG on state, on / off is appropriately controlled so that at least one of the first switch SW1 and the second switch SW2 is on. For this reason, it is possible to supply electric power to the electric loads 15 and 16 from at least one of the lead storage battery 11 and the lithium ion storage battery 12. Further, when the alternator 13 is generating electric power, the generated electric power can be supplied to the lead storage battery 11, the lithium ion storage battery 12, and the electric loads 15 and 16.

  Next, the state of the battery unit U in the IG off state will be described. In the IG off state, as shown in FIG. 2B, the first switch SW1 and the second switch SW2 are off (open), and the bypass switch SW3 is closed (off). In such a state, dark current is supplied from the lead storage battery 11 to the electric load 16 via the bypass path B1.

  By the way, during this IG OFF state, the semiconductor switch 31a of the second switch SW2 may be turned on. The on-failure refers to a state in which the switch unit S1 is fixed on due to heat of a transient current generated when the connection state is switched. In this case, depending on the voltage difference between the lead storage battery 11 and the lithium ion storage battery 12, a situation occurs in which current flows unintentionally. FIG. 3 shows a case where a current flows unintentionally through the switching unit 31 due to an on failure of the semiconductor switch 31a.

  When the voltage of the lead storage battery 11 is larger than the voltage of the lithium ion storage battery 12 when the semiconductor switch 31a shown in FIG. 3 is turned on, a current flows from the lead storage battery 11 to the lithium ion storage battery 12 through the semiconductor switch 31a. Flows. That is, when the semiconductor switch 31a is turned on due to an on-failure and the parasitic diode D2 of the semiconductor switch 31b is turned on, a current flows through the lithium ion storage battery 12. In this case, an unintended current flows through the electrical path connecting the lead storage battery 11 and the lithium ion storage battery 12, the bypass switch SW3, and the parasitic diode D2. The electrical path connecting the lead storage battery 11 and the lithium ion storage battery 12 is, for example, the bypass path B1, the energization path L2, the path from the output terminal P1 to the connection point N2, and the like. When an unintended current flows, there is a concern that the electric path, the bypass switch SW3, and the parasitic diode D2 may be damaged depending on the allowable current.

  Therefore, in the battery unit U, when the IG is off (when the first switch SW1 and the second switch SW2 are turned off (opened)), and the second switch SW2 that is turned off is turned on (closed), bypass is performed. The switch SW3 is opened (turned on). That is, the bypass path B1 is brought into a state where the energization is cut off by the bypass switch SW3. The configuration and control for that purpose will be described below.

  First, detection of an on failure of the second switch SW2 will be described. As shown in FIG. 1, a voltage detection circuit 60 that detects (monitors) the voltage at the intermediate point N10 is provided at the intermediate point N10 between the semiconductor switch 31a and the semiconductor switch 31b.

  The voltage detection circuit 60 is a voltage dividing circuit having a pair of resistors 60a and 60b. One end side of the voltage dividing circuit (resistance series circuit) is connected to the intermediate point N10, and the other end side is grounded. And the detection signal which shows the voltage between resistance 60a, 60b is output to the control part 50 and OR circuit A1.

  Here, for example, if one of the semiconductor switch 31a and the semiconductor switch 31b is in an ON state, the voltage value of the divided voltage divided based on the voltage at the intermediate point N10 becomes a predetermined value (for example, 3V) or more. . On the other hand, if both the semiconductor switch 31a and the semiconductor switch 31b are in an off state, the voltage value of the divided voltage is less than a predetermined value.

  The voltage detection circuit 60 in the present embodiment is an A / D conversion circuit (FIG. 5) that outputs a detection signal (high signal) indicating an ON failure of the second switch SW2 when the voltage value of the divided voltage is equal to or greater than a predetermined value. Not shown).

  For this reason, on-failure of the second switch SW2 can be detected based on the detection signal output from the voltage detection circuit 60. In other words, when the second switch SW2 is turned on, the voltage detection circuit 60 detects the detection signal indicating that the second switch SW2 is turned on based on the voltage at the intermediate point N10 in the energization path L2 (the divided voltage is a predetermined value). It can be said that the circuit outputs a signal indicating the above. Therefore, the voltage detection circuit 60 is a detection unit that detects an ON failure of the second switch SW2.

  The OR circuit A1 outputs an activation signal when receiving a detection signal indicating an on failure of the second switch SW2. When the activation signal (high signal) is input to the activation terminal during the IG off state, the control unit 50 shifts from the stop state to the activation state. Then, the control unit 50 determines an on failure of the second switch SW2 based on the detection signal input from the voltage detection circuit 60.

  That is, the control unit 50 has input a detection signal indicating that the divided voltage is equal to or higher than a predetermined value from the voltage detection circuit 60 in spite of the IG OFF state and the second switch SW2 being OFF. In this case, it is determined that the second switch SW2 is on.

  Then, when it is determined that the second switch SW2 is on-failed, the control unit 50 outputs an instruction signal that instructs opening (on) of the bypass switch SW3. Specifically, the control unit 50 outputs an instruction signal for turning on the relay drive switch 40c, turns on the relay drive switch 40c, and causes a current to flow through the coil 40a. Thereby, the coil 40a is excited, the movable contact 40b is separated from the fixed contact, and the bypass switch SW3 is opened (turned on). That is, the bypass path B <b> 1 is in an energized state, and the connection between the lead storage battery 11 and the lithium ion storage battery 12 is disconnected.

  Thereby, the lead storage battery 11 and the lithium ion storage battery 12 are not connected via the bypass path | route B1. Therefore, even if the second switch SW2 is turned on and the energization path L2 is unintentionally connected, no unintended current flows through the bypass switch SW3 and the parasitic diode D2.

  The relay drive switch 40c of the bypass switch SW3 is kept open until an instruction signal for instructing closing (off) of the bypass switch SW3 is input in principle when an instruction signal for instructing opening of the bypass switch SW3 is input. To do. That is, the current continues to flow through the coil 40a.

  Next, circuit protection processing executed by the control unit 50 when a start signal is input during the stop state (IG off state) will be described with reference to the flowchart of FIG. This circuit protection process is executed when an activation signal is input.

  The control unit 50 determines whether or not the IG is off (step S101). After inputting the stop command from ECU 100, control unit 50 determines that the IG is in the OFF state until a start command is input in response to the ignition switch being turned on. On the other hand, after the start command is input, it is determined that the IG is on until the stop command is input. Whether the IG is on or not is stored in the memory 51 or the like. When not in the IG off state (step S101: NO), the control unit 50 ends the circuit protection process.

  If the IG is off (step S101: YES), the controller 50 determines whether or not the second switch SW2 has an on failure (step S102). Specifically, the control unit 50 determines whether or not the second switch SW2 is on by determining whether or not a detection signal is input from the voltage detection circuit 60.

  If it is determined that an on-failure has occurred (step S102: YES), the control unit 50 controls the bypass switch SW3 so as to place the bypass path B1 in the energization cut-off state (step S103). That is, the control unit 50 outputs an instruction signal for opening (turning on) the bypass switch SW3 to the relay drive switch 40c of the bypass switch SW3.

  Further, the control unit 50 stores a detection result (failure history, diagnostic data) indicating that the second switch SW2 is on-failed in the memory 51 (step S104). When the detection result indicating that the second switch SW2 is on-failed is stored in the memory 51, the control unit 50 outputs a signal indicating that the second switch SW2 is on-failed to the ECU 100 after the IG is on. . Further, the control unit 50 controls on / off of the switches SW1, SW2, and SW3 on the assumption that an on failure has occurred.

  If it is not determined that an on failure has occurred (step S102: NO), or after the process of step S104, the control unit 50 shifts to a stop state (step S105) and ends the circuit protection process.

  According to the embodiment described in detail above, the following excellent effects can be obtained.

  During the IG-off state in which the first switch SW1 and the second switch SW2 are turned off, when the on-failure of the second switch SW2 is not detected, the bypass path B1 is energized by the bypass switch SW3. Thereby, dark current is supplied to the electric load 16 from the lead storage battery 11. On the other hand, when the on-failure of the second switch SW2 is detected, the bypass path B1 is turned off by the bypass switch SW3. Thereby, when the second switch SW2 is turned on, the lead storage battery 11 and the lithium ion storage battery 12 can be prevented from being unintentionally connected via the bypass switch SW3 and the second switch SW2.

  That is, when the semiconductor switch 31a fails to turn on, the lead storage battery 11 and the lithium ion storage battery 12 are connected via the bypass switch SW3 and the parasitic diode D2, and current supply from the lead storage battery 11 to the lithium ion storage battery 12 is possible. Become. In this case, the control unit 50 opens the bypass switch SW3 so that the bypass path B1 is in a state of interrupting energization. For this reason, it is possible to prevent an excessive current from flowing through the parasitic diode D2 of the bypass switch SW3 or the second switch SW2, and to protect the circuit.

  The control unit 50 that controls the bypass switch SW3 inputs a detection signal from the voltage detection circuit 60, and performs an on-failure determination based on the detection signal. Then, the control unit 50 controls the bypass switch SW3 based on the determination result. For this reason, even if there is noise or the like in the detection signal, it is possible to reliably perform the on-failure determination and appropriately place the bypass path B1 in the state of interrupting energization. In addition, for example, it is possible to store in the control unit 50 that an on failure has occurred. Thereby, when it will be in an IG ON state, the control part 50 can perform the various control based on an ON failure.

  Even when the control unit 50 is in the stopped state, when the detection signal indicating that the second switch SW2 is turned on is output, the control unit 50 shifts to the activated state. For this reason, it is not necessary to keep the control unit 50 in an activated state for failure monitoring, and power consumption can be suppressed.

  When a start signal for informing the IG on state (instructing the start of the power supply system) is input from the outside, or when a detection signal indicating that the second switch SW2 has failed is input, a start signal is sent to the control unit 50. An OR circuit A1 is provided as an output logic circuit. Thereby, the start signal output when the start signal is input is also output when the detection signal indicating that the second switch SW2 is on-failed is output. For this reason, the control part 50 can transfer to an activation state using an activation signal, when the ON failure of 2nd switch SW2 in an IG OFF state is detected. This eliminates the need to provide a detection signal input terminal. In addition, the control at the start of activation can be shared.

  When shifting to the activated state during the stopped state, the control unit 50 shifts to the stopped state after outputting an instruction signal for setting the bypass path B1 in the energized cutoff state. For this reason, power consumption can be suppressed.

  The second switch SW2 includes a plurality of switch units S1 and S2 connected in series, and parasitic diodes D1 and D2 connected in parallel to the plurality of switch units S1 and S2, respectively. D2 is arranged so as to be opposite to each other. Thereby, in the state which all switch part S1, S2 which comprises 2nd switch SW2 was turned off, it becomes possible to interrupt | block the electricity supply in the electricity supply path | route L2 completely. For this reason, when an unintended current flows through any of the parasitic diodes D1 and D2, it can be detected that one of the switch units S1 and S2 has failed. That is, when one of the switch units S1 and S2 is turned on, an unintended current flows through the parasitic diodes D1 and D2 on the side of the switch units S1 and S2 different from the switch units S1 and S2 that are turned on. For this reason, it is possible to detect the on-failure of the second switch SW2 by detecting this current or by detecting the voltage between the switch portions S1 and S2.

(Other embodiments)
The present invention is not limited to the above embodiment, and may be implemented as follows, for example. In the following, parts that are the same or equivalent to each other in the respective embodiments are denoted by the same reference numerals, and the description of the same reference numerals is used.

  -In above-mentioned embodiment, although the lead storage battery 11, the alternator 13, the starter 14, and the electrical load 15 were connected to the output terminal P1, the control part 50 was applied to the power supply system to which the electrical load 16 was connected to the output terminal P2. The present invention may be applied to other power supply systems.

  For example, the present invention is applied to a power supply system in which each storage battery 11, 12 is connected in parallel to an ISG (Integrated Starter Generator) as a generator and each storage battery 11, 12 is connected in parallel to an electric load 16. May be.

  This power supply system will be described in detail. As shown in FIG. 5, the first switch SW11 is provided in the energization path L1 between the lead storage battery 11 and the ISG 70, and the second energization path L2 between the lithium ion storage battery 12 and the ISG 70 is provided in the second path. A switch SW12 is provided. A third switch SW13 is provided in the energization path L3 between the lead storage battery 11 and the electric load 16, and a fourth switch SW14 is provided in the energization path L4 between the lithium ion storage battery 12 and the electric load 16. Each of the switches SW11 to SW14 has the same configuration as the second switch SW2.

  Further, in this power supply system, a bypass path B1 that bypasses the first switch SW11 is provided, and a first bypass switch SW15 is provided in the bypass path B1. In the power supply system, a bypass path B2 that bypasses the third switch SW13 is provided, and a second bypass switch SW16 is provided in the bypass path B2. Each bypass switch SW15, SW16 has the same configuration as the bypass switch SW3.

  In such a power supply system, the control unit 50 turns off the switches SW11 to SW14 and closes the bypass switches SW15 and SW16 during the IG off state. When the second switch SW12 is in an on failure during the IG off state, the control unit 50 sets the bypass path B1 to the power-off state by the first bypass switch SW15. Similarly, when the fourth switch SW14 is in an on failure during the IG off state, the control unit 50 causes the bypass path B2 to be in a power-off state by the second bypass switch SW16. Thereby, it is possible to prevent an excessive current from flowing through the bypass switches SW15 and SW16.

  When the voltage detection circuit 60 and the bypass switch SW3 are directly connected, and the bypass switch SW3 inputs a detection signal indicating an on failure (a detection signal indicating that the voltage value of the divided voltage is equal to or higher than a predetermined value). In addition, the bypass path B1 may be in a state where the energization is cut off. That is, when a detection signal is input to the relay drive switch 40c, a current may flow through the coil 40a. Thereby, after the control unit 50 performs the on-failure determination, it is possible to open the bypass switch SW3 quickly as much as the processing by the control unit 50 is not performed, compared to the case where the bypass switch SW3 is opened.

  -Even if it will be in an IG OFF state, the control part 50 may maintain a starting state. In addition, when it is determined that the second switch SW2 is on, the activation state may be maintained without shifting to the stop state after outputting the instruction signal to the bypass switch SW3.

  -You may change the structure of 2nd switch SW2. For example, the second switch SW2 may be configured by one or a plurality of mechanical relays. Further, the second switch SW2 may be configured by only the semiconductor switch 31a.

  -Although the voltage detection circuit 60 was used as a detection part which detects the ON failure of 2nd switch SW2, another structure may be employ | adopted. For example, the on-failure may be detected using a circuit or device that measures the current flowing through the second switch SW2. Further, the control unit 50 may determine an on failure by monitoring a voltage or current in the second switch SW2.

  -It is not necessary to provide an A / D conversion circuit. That is, it may be directly connected to the voltage dividing circuit, and the on-failure of the second switch SW2 may be detected based on whether the voltage value of the divided voltage is equal to or higher than a predetermined value. In this case, when a signal having a voltage equal to or higher than a predetermined value is input, a detection signal indicating an ON failure of the second switch SW2 is input.

  DESCRIPTION OF SYMBOLS 11 ... Lead storage battery, 12 ... Lithium ion storage battery, 60 ... Voltage detection circuit, B1 ... Bypass path, L1 ... Current supply path, L2 ... Current supply path, SW1 ... First switch, SW2 ... Second switch, SW3 ... Bypass switch, U ... battery unit.

Claims (8)

In the power supply circuit device (U) applied to the power supply system in which the first storage battery (11) and the second storage battery (12) are connected in parallel,
A first switch (SW1) that is provided in a first electrical path (L1) to which power of the first storage battery is supplied, and that energizes or shuts off the first electrical path;
A second switch (SW2) that is provided in a second electrical path (L2) to which power of the second storage battery is supplied, and puts the second electrical path into a state of energization or de-energization;
A bypass switch (SW3) that is provided in a bypass path (B1) that bypasses the first switch, and that energizes or shuts off the bypass path;
A detection unit (60) for detecting an on-failure of the second switch,
When an on-failure of the second switch is not detected during the off period in which the first switch and the second switch are turned off, the bypass path is energized by the bypass switch, A power supply circuit device in which when the on-failure of the second switch is detected, the bypass path is turned off by the bypass switch. A controller (50) for controlling the bypass switch by outputting an instruction signal to the bypass switch;
The detection unit is a circuit that is connected to the second electric path and outputs a detection signal indicating an on-failure of the second switch based on a voltage or a current in the second electric path;
2. The power supply circuit device according to claim 1, wherein, when the detection signal is input, the control unit outputs an instruction signal for setting the bypass path in a state of interrupting energization to the bypass switch.   The control unit is configured to be able to take a start state or a stop state in which various controls are executed, and when the detection signal is input during the stop state, the control unit enters the start state and controls the bypass switch. Item 3. The power supply circuit device according to Item 2. The start signal and the detection are connected to the external terminal (P3) so as to input a start signal instructing start of the power supply system, and connected to the detection unit so as to input the detection signal. A logic circuit (A1) that outputs a start signal to the control unit when any of the signals is input;
The control unit is configured to be able to take a start state or a stop state in which various controls are executed, and when the start signal is input during the stop state, the control unit enters the start state and controls the bypass switch. Item 3. The power supply circuit device according to Item 2.   5. The control unit according to claim 3 or 4, wherein when the control unit shifts from a stopped state to an activated state based on an input of the detection signal, the control unit outputs an instruction signal for setting the bypass path in a state of interrupting energization, and then enters the stopped state. The power supply circuit device described. The detection unit is a circuit that is connected to the second electric path and outputs a detection signal indicating an on-failure of the second switch based on a voltage or a current in the second electric path;
The said bypass switch is connected with the said detection part, and when the said detection signal is input from the said detection part, it makes the said bypass path | route the state of interruption | blocking of electricity supply. Power supply circuit device. The first switch and the second switch are applied to a power supply system in which the first storage battery and the second storage battery are connected in parallel to an electric load (16), and the power supply system is turned off. Is to be turned off,
The bypass switch is a normally closed relay switch,
During the off period, when an on failure of the second switch is not detected, the bypass path is energized by the bypass switch, and the first storage battery is connected to the electric load via the bypass path. The power supply circuit device according to claim 1, wherein a dark current is supplied. The second switch includes a plurality of switch units (S1, S2) and diodes (D1, D2) connected in parallel to the plurality of switch units, and the plurality of switch units are connected to each switch unit. The diodes connected in parallel are connected in series so that they are opposite to each other,
The said detection part detects the ON failure of a said 2nd switch, when an electric current flows into either of several diodes in the state in which the several switch part was turned off. The power supply circuit device according to 1.

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