WO2020183901A1 - Electrification control device - Google Patents

Abstract

This electrification control device is provided with: a semiconductor switch (24) disposed in an energizing path (23) between a power supply (11) and a load (16); and a drive control unit (25) for controlling the driving of the semiconductor switch. In a normal mode, the drive control unit turns the semiconductor switch to an ON-state in which a current flows in a state where the resistance value is lower than that in a standby mode, while in the standby mode, the drive control unit turns the semiconductor switch to an ON-state in which a current flows in a state where the resistance value is higher than that in the normal mode.

Description

Energization control device Cross-reference to related applications

This application is based on Japanese Patent Application No. 2019-042805 filed on March 8, 2019, the contents of which are incorporated herein by reference.

The disclosure in this specification relates to an energization control device.

Patent Document 1 discloses an energization control device. The energization control device includes a switch provided in the energization path between the power supply and the load, and a drive control unit that controls the drive of the switch.

Japanese Unexamined Patent Publication No. 2004-248093

According to the technique described in Patent Document 1, when the operation switch is turned off by the operator and the normal mode is switched to the standby mode, all the circuits constituting the energization control device other than the input circuit from the operation switch are cut off. Will be done. As a result, in the energization control device, all dark currents flowing other than the input circuit can be cut off. However, the gate drive circuit is also turned off and the switch is turned off. Therefore, the dark current cannot be supplied to the load in the standby mode.

One object of the present disclosure is to provide an energization control device capable of supplying dark current to a load in standby mode.

Another object of the present disclosure is to suppress the current consumption of the energization control device while supplying a dark current to the load.

The energization control device according to one aspect of the present disclosure includes a semiconductor switch provided in an energization path between a power source and a load, and a drive control unit for controlling the drive of the semiconductor switch. In the normal mode, the drive control unit controls the semiconductor switch to an on state in which a current flows in a state where the resistance value is lower than in the standby mode, and in the standby mode, the semiconductor switch is operated in a state where the resistance value is higher than that in the normal mode. Control to flow on state.

According to the above-mentioned energization control device, the drive control unit controls the on state of the semiconductor switch to be different between the normal mode and the standby mode. In the standby mode, the drive control unit controls the semiconductor switch so that the semiconductor switch is turned on with a higher resistance value than in the normal mode. In the standby mode, the semiconductor switch is turned on with a high resistance value, so that a dark current smaller than the current flowing in the normal mode can be supplied to the load. As described above, the dark current can be supplied to the load in the standby mode.

The above objectives and other objectives, features and advantages of the present disclosure will be clarified by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is a diagram showing a schematic configuration of a power supply system including an energization control device according to the first embodiment. FIG. 2 is a diagram showing an energization control device. FIG. 3 is a flowchart showing a process executed by the control unit. FIG. 4 is a flowchart showing the standby mode processing. FIG. 5 is a timing chart showing various waveforms in the standby mode. FIG. 6 is a diagram showing a modified example of the first embodiment. FIG. 7 is a diagram showing another modification of the first embodiment. FIG. 8 is a diagram showing another modification of the first embodiment. FIG. 9 is a diagram showing another modification of the first embodiment. FIG. 10 is a diagram showing another modification of the first embodiment. FIG. 11 is a diagram showing another modification of the first embodiment. FIG. 12 is a diagram showing an energization control device according to the second embodiment. FIG. 13 is a diagram showing a drive unit. FIG. 14 is a diagram showing a modified example. FIG. 15 is a diagram showing a modified example of the second embodiment. FIG. 16 is a diagram showing another modification of the second embodiment. FIG. 17 is a diagram showing a schematic configuration of a power supply system including an energization control device according to another embodiment. FIG. 18 is a diagram showing a schematic configuration of a power supply system including an energization control device according to another embodiment.

A plurality of embodiments will be described with reference to the drawings. In a plurality of embodiments, the functionally and / or structurally corresponding parts are assigned the same reference numerals.

(First Embodiment)
The energization control device of this embodiment is applied to a power supply system. In the following, as an example of the power supply system, a redundant power supply system mounted on a vehicle will be shown.

<Power system>
A schematic configuration of the power supply system will be described with reference to FIG. As shown in FIG. 1, the power supply system 10 includes a first power supply 11 and a second power supply 12, buses 13a and 13b, and an energization control device 20, which are vehicle-mounted power supplies. The power supply system 10 is a redundant power supply system including two vehicle-mounted power supplies.

The first power supply 11 and the second power supply 12 are DC voltage sources. As the first power source 11 and the second power source 12, for example, a secondary battery or a capacitor can be adopted. The battery capacity of the second power supply 12 is set to be equal to or less than the battery capacity of the first power supply 11. The first power source 11 may be referred to as a main power source, and the second power source 12 may be referred to as a sub power source.

In this embodiment, a lead storage battery is used as the first power source 11, and a lithium ion battery is used as the second power source 12. The battery capacity of the second power source 12 is set smaller than the battery capacity of the first power source 11. The rated voltage of the first power supply 11 and the second power supply 12 is, for example, 12V.

The first power supply 11 is connected to the energization control device 20 via the bus 13a. The second power supply 12 is connected to the energization control device 20 via the bus 13b. The bus 13a may be referred to as a first power system bus, and the bus 13b may be referred to as a second power system bus. A relay 14 is provided between the second power supply 12 and the bus 13b. The relay 14 is, for example, an electromagnetic relay having mechanical contacts. The relay 14 can be turned on and off by a controller 25, which will be described later, or an Electronic Control Unit (ECU) (not shown), which is different from the energization control device 20.

When the relay 14 is turned on, the second power supply 12 is connected to the bus 13b. When the relay 14 is turned off, the second power supply 12 is electrically disconnected from the bus 13b. The relay 14 is an emergency relay, and is always on at normal times. For example, when a failure such as a ground fault occurs in the second power supply 12, the relay 14 is turned off when the second power supply 12 may be overcharged or overdischarged. In FIG. 1, the relay 14 is provided outside the second power supply 12, but the relay 14 may be provided inside the second power supply 12.

The energization control device 20 is provided between the buses 13a and 13b. In the vehicle, various loads are connected to the buses 13a and 13b. Power for operation is supplied to the various loads from the first power supply 11 and the second power supply 12 via the buses 13a and 13b. At least one load is connected to each of the buses 13a and 13b.

When the semiconductor switch 24 described later is turned on, the bus 13a and the bus 13b are electrically connected. By turning on the semiconductor switch 24, electric power can be transferred between the buses 13a and 13b. When the semiconductor switch 24 is turned off, the bus 13a and the bus 13b are electrically cut off. For example, even if one of the first power supply 11 and the second power supply 12 fails or a ground fault occurs on one of the buses 13a and 13b, the semiconductor switch 24 is turned off to shut off the bus 13a and the bus 13b. Can be done. This makes it possible to prevent all of the loads from becoming inoperable.

As shown in FIG. 1, the first load 15 is connected to the bus 13a, and the second load 16 is connected to the bus 13b. The vehicle is equipped with an ignition switch (hereinafter referred to as an IG switch) (hereinafter referred to as an IG switch) (not shown). The first load 15 is a load that operates by receiving power supply at least when the IG switch is turned on. The second load 16 is a load that operates by receiving power supply not only when the IG switch is turned on but also when it is turned off. The second load 16 is a load that operates by a dark current described later when the IG switch is turned off.

As described above, in the present embodiment, the battery capacity of the second power supply 12 is set smaller than the battery capacity of the first power supply 11. The relay 14 is turned off in response to the turning off of the IG switch. As a result, over-discharging of the second power supply 12 is suppressed when the IG switch is turned off. When the IG switch is off, power is supplied from the first power supply 11 to the second load 16 via the semiconductor switch 24, and the second load 16 operates. With the relay 14 turned off, power is supplied to the second load 16 from the first power source 11. Therefore, the first power supply 11 corresponds to the power supply. The second load 16 corresponds to a load to which power is supplied from the power source via the semiconductor switch.

The first power supply 11 and the second power supply 12 are secondary batteries that can be charged and discharged. When the vehicle is configured to include a generator (alternator), the first power source 11 and the second power source 12 can be charged by the generator. When the generator is connected to, for example, the bus 13a, the first power source 11 can be charged by the generator. The second power source 12 can be charged by at least one of the first power source 11 and the generator. It is also possible to supply the electric power generated by the generator to the load via the buses 13a and 13b. When the vehicle is provided with a motor for driving a traveling drive and a high-voltage power source as a power source for the motor, the voltage of the high-voltage power source may be stepped down by a DCDC converter to charge the first power source 11 and the like.

<Energization control device>
The energization control device 20 will be described with reference to FIGS. 1 and 2. The energization control device 20 includes terminals 21 and 22 for external connection, a semiconductor switch 24, and a controller 25.

The terminal 21 is connected to the bus 13a on the first power supply 11 side. The terminal 22 is connected to the bus 13b on the second power supply 12 side. An energization path 23 connecting the buses 13a and 13b is provided between the terminals 21 and 22. The energization path 23 is sometimes referred to as wiring.

The semiconductor switch 24 is provided in the energization path 23. The semiconductor switch 24 switches the energization path 23 into a conduction state or a cutoff state. The semiconductor switch 24 switches the buses 13a and 13b into a conductive state or a cutoff state. The semiconductor switch 24 is configured to include a switching element.

In this embodiment, an n-channel MOSFET is used as the switching element. MOSFETs are normally-off type switching elements. Structurally, this MOSFET has a parasitic diode (body diode) between the drain and the source. Since current flows through the parasitic diode even when the MOSFET is turned off, it is not possible to cut off the bidirectional current with only one MOSFET.

In a redundant power supply system, there is a possibility that current will flow in both directions between the bus 13a and the bus 13b. Therefore, the semiconductor switch 24 is composed of a pair of MOSFETs Q1 and Q2 in which the directions of the parasitic diodes are opposite to each other. The MOSFETs Q1 and Q2 have diodes D1 and D2. The diodes D1 and D2 are parasitic diodes. Even if a power failure occurs, by turning off both MOSFETs Q1 and Q2, the current can be completely cut off regardless of the direction in which the current flows.

Specifically, the MOSFET Q1 is arranged on the first power source 11 (bus 13a) side, and the MOSFET Q2 is arranged on the second power source 12 (bus 13b) side. The anodes of the diodes D1 and D2 are connected to each other. MOSFETs Q1 and Q2 have a source common type connection structure in which sources are connected to each other. The drain of the MOSFET Q1 is electrically connected to the terminal 21, and the drain of the MOSFET Q2 is electrically connected to the terminal 22.

The configuration of the semiconductor switch 24 is not limited to the above example. For example, a drain common connection structure in which drains are connected to each other can be adopted. Again, the parasitic diodes are opposite to each other. The cathodes of the parasitic diode are connected to each other. Further, instead of the semiconductor element having a parasitic diode, a semiconductor element having no parasitic diode, for example, an IGBT or a normalion type element may be adopted. In this case, the semiconductor switch 24 can be configured by one semiconductor element.

As shown in FIG. 2, the MOSFETs Q1 and Q2 include capacitors C1 and C2. The capacitor C1 is formed between the gate and the source of the MOSFET Q1. The capacitor C2 is formed between the gate and the source of the MOSFET Q2. Capacitors C1 and C2 are charged when an on-drive signal, that is, a Hi level signal is input to the gates of MOSFETs Q1 and Q2. The capacitors C1 and C2 of this embodiment are parasitic capacitors. Capacitors C1 and C2 correspond to gate capacitors.

The controller 25 controls the drive of the semiconductor switch 24. The controller 25 controls the drive of each of the MOSFETs Q1 and Q2. The controller 25 is sometimes referred to as an electronic control unit. The controller 25 operates by being supplied with electric power from, for example, the first power supply 11. The energization control device 20 may include a power supply terminal separately from the terminal 21. The electric power may be supplied through the terminal 21. The controller 25 corresponds to the drive control unit.

The controller 25 is provided by a control system that includes at least one computer. The control system includes at least one processor (hardware processor) which is hardware. The hardware processor can be provided by the following (i), (ii), or (iii).

(I) The hardware processor may be a hardware logic circuit. In this case, the computer is provided by a digital circuit that includes a large number of programmed logic units (gate circuits). Digital circuits may include memory for storing programs and / or data. Computers may be provided by analog circuits. Computers may be provided by a combination of digital and analog circuits.

(Ii) The hardware processor may be at least one processor core that executes a program stored in at least one memory. In this case, the computer is provided by at least one memory and at least one processor core. The processor core is referred to as, for example, a CPU. The memory is also referred to as a storage medium. Memory is a non-transitional and substantive storage medium that non-temporarily stores "programs and / or data" that can be read by a processor.

(Iii) The hardware processor may be a combination of the above (i) and the above (ii). (I) and (ii) are arranged on different chips or on a common chip.

That is, the means and / or functions provided by the controller 25 can be provided by hardware only, software only, or a combination thereof. In this embodiment, it is realized by using an Application Special Integrated Circuit (ASIC).

The controller 25 and the ECU (not shown) described above can communicate with each other via the bus of the in-vehicle network. The controller 25 determines the control state of the semiconductor switch 24 based on the command value from the ECU which is the upper control device, the storage state of the first power supply 11 and the second power supply 12, and generates a drive signal of the semiconductor switch 24. To do. Then, the generated drive signal is output to the gates (control terminals) of MOSFETs Q1 and Q2. The buses 13a and 13b are provided with voltage sensors for detecting the battery voltages of the first power supply 11 and the second power supply 12, respectively. The controller 25 calculates, for example, the SOC of the second power supply 12, and controls the charge amount and the discharge amount of the second power supply 12 so that the SOC is kept within a predetermined use range. The controller 25 switches the relay 14 on and off so as to prevent overcharging and overdischarging.

As shown in FIG. 2, the controller 25 includes a drive unit 30, a detection unit 31, a determination unit 32, and a control unit 33. The control unit 33 corresponds to an intermittent control unit.

The drive unit 30 is a circuit that outputs a drive signal to the gates of MOSFETs Q1 and Q2 in accordance with an instruction signal from the control unit 33. The drive unit 30 outputs an on drive signal as a drive signal in order to turn on the MOSFETs Q1 and Q2. The drive unit 30 outputs a Hi level signal as an on drive signal. The drive unit 30 outputs an off drive signal as a drive signal in order to turn off the MOSFETs Q1 and Q2. The drive unit 30 outputs a Lo level signal as an off drive signal.

The drive unit 30 has a drive unit 30a corresponding to the MOSFET Q1 and a drive unit 30b corresponding to the MOSFET Q2. The drive units 30a and 30b each include a booster circuit 300 and a driver 301. The booster circuit 300 is, for example, a circuit that boosts the voltage supplied from the first power supply 11, and is configured to include a capacitor (not shown) or the like. As the booster circuit 300, for example, a charge pump circuit can be adopted. The driver 301 is a drive circuit that generates a drive signal and outputs the drive signal to the gate. The driver 301 outputs an on drive signal corresponding to the boosted voltage by the booster circuit 300.

The detection unit 31 is a circuit that detects the gate voltage with reference to the source. The detection unit 31 has a differential amplifier 31a. The detection unit 31 outputs a voltage signal VGS according to the difference between the voltage VG of the gate of the MOSFET Q1 arranged on the side of the first power supply 11 and the voltage VS of the source. A reference voltage Vref-a is input to the non-inverting input terminal of the differential amplifier 31a. When the voltage VG is higher than the voltage VS, the differential amplifier 31a outputs a voltage signal VGS higher than the reference voltage Vref-a by the amount corresponding to the difference. In the following, the voltage signal VGS may be referred to as a gate voltage VGS.

The determination unit 32 is a circuit that determines the voltage level of the voltage signal VGS. The determination unit 32 has two comparators 32a and 32b. The comparator 32a compares the voltage signal VGS with the threshold voltage Vth1. The comparator 32b compares the voltage signal VGS with the threshold voltage Vth2. The threshold voltage Vth1 is a voltage higher than the threshold voltage Vth2. As the threshold voltage Vth2, a limit value at which current does not flow, a so-called threshold voltage (Vt), may be set, or a value higher than the threshold voltage may be set by adding a margin.

In this embodiment, the threshold voltage Vth2 is set to a limit value at which current does not flow. Further, when the gate voltage exceeds the threshold voltage Vth1, the MOSFET is held in the full-on state. That is, the MOSFET is held in the half-on state within the range where the gate voltage is the threshold voltage Vth2 or more and the threshold voltage Vth1 or less. Half-on is a state in which the on-resistance is larger than that of full-on, although it is substantially on and current flows.

When the voltage signal VGS becomes larger than the threshold voltage Vth1, the comparator 32a outputs a Hi level signal indicating that the voltage signal VGS is large to the control unit 33. When the voltage signal VGS becomes smaller than the threshold voltage Vth2, the comparator 32b outputs a Lo level signal indicating that the voltage signal VGS is small to the control unit 33.

The control unit 33 outputs an instruction signal to the drive unit 30. A signal (hereinafter referred to as an IG signal) that correlates on and off of the IG switch is input to the control unit 33 from, for example, an ECU that is a higher-level control device. As described above, the determination result by the determination unit 32 is input to the control unit 33.

The controller 25 has an overcurrent detection unit (not shown). Overcurrent flows when an abnormality such as a vehicle power failure, a bus ground fault, or a load ground fault occurs. The overcurrent detection unit determines whether or not an overcurrent is flowing based on the current and / or voltage of the buses 13a and 13b and the energization path 23. The overcurrent detection result is also input to the control unit 33. The control unit 33 is configured to be able to switch the control mode according to the IG signal, the determination result by the determination unit 32, the overcurrent detection result, and the like. The control unit 33 outputs an instruction signal corresponding to the control mode to the drive unit 30.

<Processes executed by the control unit>
An example of the process executed by the control unit 33 will be described with reference to FIGS. 2 to 4. The control unit 33 is configured so that a plurality of control modes can be set. As a plurality of control modes, there are a conduction mode in which the buses 13a and 13b are in a conductive state and a cutoff mode in which the buses 13a and 13b are in a cutoff state. Further, as the conduction mode, there are a normal mode and a standby mode.

FIG. 3 shows a process executed by the control unit 33. The control unit 33 is supplied with electric power for operation, for example, from the first power supply 11 not only during the period when the IG switch is turned on but also during the period when the IG switch is turned off. While the power is turned on, the control unit 33 repeatedly executes the following processes at a predetermined cycle.

As shown in FIG. 3, the control unit 33 first determines whether or not the semiconductor switch 24 needs to shut off (S10). The control unit 33 determines whether or not to shut off is necessary based on the output of the overcurrent detection unit.

When it is determined in S10 that shutoff is necessary, the control unit 33 then sets the shutoff mode (S11). When the cutoff mode is set, the control unit 33 outputs an off instruction signal to the drive units 30a and 30b, and ends a series of processing. Due to the off instruction signal, the booster circuit 300 does not boost the drive units 30a and 30b, and the booster voltage is not supplied to the driver 301. An off drive signal is output from the driver 301. As a result, both MOSFETs Q1 and Q2 are turned off, and the buses 13a and 13b are cut off.

On the other hand, if it is determined in S10 that the cutoff is not necessary, the control unit 33 determines whether or not the IG switch is turned on based on the IG signal (S12). When the IG switch is turned on, the control unit 33 sets the normal mode as the conduction mode (S13).

When the normal mode is set, the control unit 33 outputs an ON instruction signal to the drive units 30a and 30b regardless of the determination result of the determination unit 32. Then, a series of processes is completed. The booster circuit 300 is boosted in the drive units 30a and 30b by the ON instruction signal. The driver 301 operates in response to the on instruction signal and outputs an on drive signal in response to the boosted voltage. As a result, the MOSFETs Q1 and Q2 are both turned on, and the buses 13a and 13b are brought into a conductive state. During the setting period of the normal mode, the drive units 30a and 30b continuously output the on drive signal.

In the normal mode, the voltage signals VGS of MOSFETs Q1 and Q2 are all held at a value higher than the threshold voltage Vth1. As a result, the MOSFETs Q1 and Q2 are driven in a fully on state with a small resistance value (on resistance).

When it is determined in S12 that the IG switch is not turned on, that is, turned off, the control unit 33 sets the standby mode as the conduction mode (S14). When the standby mode is set, the control unit 33 outputs an instruction signal corresponding to the determination result of the determination unit 32 to the drive unit 30, and ends a series of processing. The process executed by the control unit 33 is not limited to the above example.

<Standby mode>
FIG. 4 shows the standby mode processing executed by the control unit 33. As shown in FIG. 4, first, the control unit 33 outputs an off instruction signal to the drive unit 30b of the MOSFET Q2 (S20). Due to the off instruction signal, the drive unit 30b does not boost the voltage in the booster circuit 300, and the driver 301 outputs an off drive signal (Lo level signal). As a result, the MOSFET Q2 is turned off. A current flows from the bus 13a to the bus 13b through the diode D2.

Next, the control unit 33 determines whether or not the mode is switched from the normal mode (S21). In the case of the timing immediately after switching from the normal mode, the control unit 33 switches the instruction signal for the drive unit 30a of the MOSFET Q1 to the off instruction signal (S22), and shifts to S23. Due to the off instruction signal, the booster circuit 300 does not execute the booster operation in the drive unit 30a, and the driver 301 outputs an off drive signal to the MOSFET Q1. If it is not immediately after the switch, the process proceeds to S23 without going through the process of S22.

Next, the control unit 33 determines whether or not the voltage signal VGS of the MOSFET Q1 is smaller than the threshold voltage Vth2 (S23). The control unit 33 determines whether or not the voltage signal VGS is smaller than the threshold voltage Vth2 based on the output of the comparator 32b.

When the voltage signal VGS is smaller than the threshold voltage Vth2, the control unit 33 switches the instruction signal output to the drive unit 30a to the on instruction signal (S24). In response to the ON instruction signal, the booster circuit 300 executes a boost operation in the drive unit 30a, and the driver 301 outputs an ON drive signal (Hi level signal) to the MOSFET Q1.

In S23, when the voltage signal VGS is not smaller than the threshold voltage Vth2, it is determined whether or not the voltage signal VGS of the MOSFET Q1 is larger than the threshold voltage Vth1 (S25). The control unit 33 determines whether or not the voltage signal VGS is larger than the threshold voltage Vth1 based on the output of the comparator 32a. When the voltage signal VGS is larger than the threshold voltage Vth1, the control unit 33 switches the instruction signal output to the drive unit 30a to the off instruction signal (S26). Due to the off instruction signal, the drive unit 30a does not boost the voltage in the booster circuit 300, and the driver 301 outputs an off drive signal.

In S25, when the voltage signal VGS is not larger than the threshold voltage Vth1, that is, when Vth2 ≦ VGS ≦ Vth1, the control unit 33 holds the current instruction signal output to the drive unit 30a (S27).

FIG. 5 shows various waveforms in the standby mode. The instruction signal shown in FIG. 5 is a signal output from the control unit 33 to the drive unit 30a on the MOSFET Q1 side. In FIG. 5, the voltage signal VGS on the MOSFET Q1 side is shown as VGS (Q1), and the voltage signal VGS on the MOSFET Q2 side is shown as VGS (Q2). FIG. 5 shows a state in which a predetermined time has elapsed, not immediately after switching to the standby mode.

As described above, the MOSFET Q1 includes the capacitor C1. When the voltage signal VGS (Q1) falls below the threshold voltage Vth2 at time t1, the control unit 33 outputs an ON instruction signal to the drive unit 30a. As a result, the drive unit 30a outputs an on drive signal to the gate of the MOSFET Q1. The on drive signal charges the capacitor C1 and raises the voltage signal VGS (Q1).

When the voltage signal VGS (Q1) rises and exceeds the threshold voltage Vth1 at time t2, the control unit 33 outputs an off instruction signal to the drive unit 30a. As a result, the drive unit 30a stops the boosting operation and outputs an off drive signal to the gate of the MOSFET Q1. The voltage signal VGS (Q1) gradually drops due to the charge accumulated in the capacitor C1. When the voltage signal VGS (Q1) falls below the threshold voltage Vth2 at time t3, the control unit 33 outputs an ON instruction signal to the drive unit 30a again.

In this way, the control unit 33 alternately executes the output of the on instruction signal and the output of the off instruction signal in the standby mode. The control unit 33 causes the drive unit 30a to intermittently execute the output operation of the on drive signal. The drive unit 30a outputs an on drive signal between times t1 and t2, and outputs an off drive signal between times t2 and t3. Due to the effect of the capacitor C1, the period for outputting the off drive signal is longer than the period for outputting the on drive signal in one cycle of operation.

When the voltage signal VGS (Q1) falls below the threshold voltage Vth2, the control unit 33 immediately switches to the on instruction signal. When the voltage signal VGS (Q1) exceeds the threshold voltage Vth1, the control unit 33 immediately switches to the off instruction signal. The control unit 33 controls so that the voltage signal VGS (Q1) is within the range of the threshold voltage Vth2 or more and the threshold voltage Vth1 or less. Therefore, during almost the entire period of the standby mode, the MOSFET Q1 is held in an on state in which a current flows in a state where the resistance value is higher than that in the normal mode. In the standby mode, the MOSFET Q1 is held in the half-on state. In the present embodiment, the voltage signal VGS (Q1) is lowered as compared with the full-on by the above-mentioned intermittent operation, so that the half-on state is set.

As described above, the control unit 33 outputs an off instruction signal to the drive unit 30b during the standby mode. Therefore, as shown in FIG. 5, the voltage signal VGS (Q2) is set to a predetermined voltage at which the MOSFET Q2 does not turn on, for example, 0V. The MOSFET Q2 is turned off. In the standby mode, a current flows through the MOSFET Q1 and the diode D2.

<Summary of the first embodiment>
In the present embodiment, the control unit 33 controls the on state of the semiconductor switch 24 to different states in the normal mode in which the IG switch is turned on and the standby mode in which the IG switch is turned off. The control unit 33 controls the MOSFET Q1 constituting the semiconductor switch 24 so as to be turned on (fully on) in a state where the resistance value is low in the normal mode. The control unit 33 controls the MOSFET Q1 so as to be turned on (half-on) in a state where the resistance value is higher than that in the normal mode in the standby mode. In the standby mode, since the semiconductor switch 24 is turned on with a high resistance value, a current (dark current) smaller than the current (normal current) flowing in the normal mode is supplied to the second load 16 via the semiconductor switch 24. Can be done. As described above, the dark current can be supplied to the load in the standby mode. The standby mode is sometimes referred to as a dark current supply mode.

Further, in the standby mode, the resistance value of the semiconductor switch 24 is increased by lowering the voltage (gate voltage) of the on drive signal as compared with the normal mode. In the standby mode, for example, the voltage of the on drive signal is lowered by stopping the operation of the booster circuit 300 as described above. Therefore, the current consumption of the energization control device 20 can be reduced.

In the present embodiment, in the standby mode, the control unit 33 temporarily outputs an ON instruction signal. The control unit 33 alternately outputs an on instruction signal and an off instruction signal. As a result, the drive unit 30a operates intermittently and temporarily outputs an on drive signal. The capacitor C1 of the MOSFET Q1 is charged by the output of the on drive signal. Even if the signal is switched to the off drive signal, the MOSFET Q1 is held in the half-on state due to the electric charge accumulated in the capacitor C1. By intermittently operating the drive unit 30a in this way, it is possible to reduce the current consumption of the energization control device 20 while supplying dark current in the standby mode.

In the present embodiment, the semiconductor switch 24 is configured to include two MOSFETs Q1 and Q2. Sources of MOSFETs Q1 and Q2 are connected to each other. The anodes of the diodes D1 and D2 are connected to each other. Then, the control unit 33 intermittently operates the drive unit 30a and continuously outputs an off instruction signal to the drive unit 30b. Therefore, a dark current flows through the MOSFET Q1 and the diode D2 in the half-on state. Since the MOSFET Q2 is turned off, the current consumption of the energization control device 20 can be further reduced.

In the present embodiment, the source-referenced gate voltage VGS is detected, and the drive unit 30a is intermittently operated according to the level of the gate voltage VGS. Since the gate voltage VGS is monitored, it is easy to switch the operating state of the MOSFET Q1.

<Modified example of the first embodiment>
The configurations of the power supply system 10 and the energization control device 20 are not limited to the above examples. For example, in the modification shown in FIG. 6, the power supply system 10 includes only one power supply 11A. The energization control device 20 is arranged between the power supply 11A and the load 16A. The semiconductor switch 24 constituting the energization control device 20 has only one MOSFET Q1. In such a configuration, the above control is applied. The control unit 33 (not shown) of the controller 25 controls the semiconductor switch 24 so that the ON state is different between the normal mode and the standby mode. Specifically, the ON state of the MOSFET Q1 is controlled so as to be turned on (full on) with a low resistance value in the normal mode and turned on (half on) with a high resistance value in the standby mode. In the standby mode, the MOSFET Q1 can be held in the half-on state by intermittently operating the drive unit 30a (not shown).

An example is shown in which the drive unit 30a of the MOSFET Q1 on the first power supply 11 side is intermittently operated to turn off the MOSFET Q2 on the second load 16 side, but the present invention is not limited to this. In a configuration including two MOSFETs Q1 and Q2 in which the semiconductor switches 24 are connected in series, the MOSFET Q2 may be controlled to a state similar to that of the MOSFET Q1, that is, a half-on state. In this case, the drive unit 30 can be shared by the MOSFETs Q1 and Q2. A dark current can be supplied from the first power supply 11 to the second load 16 through the MOSFETs Q1 and Q2 in the half-on state. The intermittent operation of the drive unit 30 can reduce the current consumption of the energization control device 20. As described above, when the MOSFET Q2 is turned off, the current consumption can be further reduced.

The control unit 33 has shown an example of switching the instruction signal based on the gate voltage VGS, but the present invention is not limited to this. Instead of the gate voltage VGS, the voltage across the semiconductor switch 24 may be detected as in the modified example shown in FIG. That is, the state of the current flowing through the semiconductor switch 24 may be detected based on the voltage across the semiconductor.

In FIG. 7, the differential amplifier 31a of the detection unit 31 outputs a voltage signal V12 according to the difference between the voltage V1 on one end side and the voltage V2 on the other end side of the semiconductor switch 24. Hereinafter, the voltage signal V12 may be referred to as a voltage across V12. When the voltage V1 is higher than the voltage V2, the differential amplifier 31a outputs a voltage signal V12 higher than the reference voltage Vref-b by the amount corresponding to the difference. The determination unit 32 has two comparators 32a and 32b as described above. The comparator 32a compares the voltage signal V12 with the threshold voltage Vth3. The comparator 32b compares the voltage signal V12 with the threshold voltage Vth4. The threshold voltage Vth3 is a voltage higher than the threshold voltage Vth4. The threshold voltage Vth3 is the upper limit threshold value, and the threshold voltage Vth4 is the lower limit threshold value. For example, when only the drive unit 30a is operated intermittently, the control unit 33 switches the instruction signal output to the drive unit 30a to the on instruction signal when the Hi signal is output from the comparator 32a. When the Lo signal is output from the comparator 32b, the signal is switched to the off instruction signal output to the drive unit 30a.

FIG. 7 shows an example of the voltage across the semiconductor switch 24 as the voltage across V12, but the voltage is not limited to this. As in the modified example shown in FIG. 8, a shunt resistor 26 for current detection may be provided, and the voltage across the shunt resistor 26 may be a voltage V12 across the shunt resistor 26. In FIG. 8, a shunt resistor 26 is provided between MOSFETs Q1 and Q2 in the energization path 23. Instead of this, it may be provided between the terminal 21 and the MOSFET Q1 and between the terminal 22 and the MOSFET Q2. The examples shown in FIGS. 7 and 8 can be applied to both a configuration in which only the drive unit 30a is intermittently operated and a configuration in which the drive units 30a and 30b are intermittently operated.

Although not shown, the voltage across the diode D2 may be the voltage across V12. It can be applied to a configuration in which the drive unit 30a is operated intermittently to turn off the MOSFET Q2. In the standby mode, the MOSFET Q2 on the second load 16 side is turned off, and a dark current flows through the diode D2. Therefore, the instruction signal of the control unit 33 can be switched based on the voltage across the diode D2.

An example of continuously supplying dark current in the standby mode is shown, but the present invention is not limited to this. Depending on the function of the second load 16, the dark current may be supplied intermittently. In the above example, the MOSFET Q1 is controlled to be in the half-on state for almost the entire period of the standby mode, but it may be controlled so that the half-on state and the off state are alternately repeated. By providing the off state, it is possible to provide a period during which the dark current is not supplied. Further, it may be controlled to repeat in the order of full-on state, half-on state, and off state. The control state may include at least a half-on state.

Although the control unit 33 has shown an example of switching the instruction signal based on the gate voltage VGS and the voltage across the ends V12, the present invention is not limited to this. As in the modified example shown in FIG. 9, the controller 25 may be configured to include the timer unit 34. The timer unit 34 is a circuit including a timer counter and the like. The timer unit 34 generates a signal that repeats on and off at a predetermined cycle, and outputs the signal to the control unit 33. The timer unit 34 generates a timing signal for the control unit 33 to switch the instruction signal in the standby mode. In the standby mode, the control unit 33 outputs an on instruction signal during the time T1 and then outputs an off instruction signal during the time T2. When the time T2 is longer than the time T1, the current consumption can be further reduced.

By appropriately setting the times T1 and T2, both a configuration in which the dark current is continuously supplied and a configuration in which the dark current is intermittently supplied are possible. At that time, the timer unit 34 may be operated intermittently. The intermittent operation can reduce the current consumption of the energization control device 20. In the other configuration described above, the detection unit 31 and the determination unit 32 may be operated intermittently. As a result, the current consumption of the energization control device 20 can be reduced. In addition, the intermittent operation enables intermittent supply of dark current.

Examples of the parasitic capacitors of MOSFETs Q1 and Q2 are shown as the capacitors C1 and C2, but the present invention is not limited to this. As the capacitors C1 and C2, an external capacitor can be adopted as in the modified example shown in FIG. Capacitors C1 and C2 shown in FIG. 10 are set to have a larger capacitance than the gate-source parasitic capacitors included in MOSFETs Q1 and Q2 in order to hold the gate voltage VGS.

Capacitor C1 is connected in series with switch SW1 between the gate and source of MOSFET Q1. The capacitor C2 is connected in series with the switch SW2 between the gate and the source of the MOSFET Q2. The switches SW1 and SW2 are turned off in the normal mode and turned on in the standby mode by, for example, the control unit 33. Since the capacitances of the capacitors C1 and C2 are larger than those of the parasitic capacitors, the gate voltage VGS can be held at the threshold voltage Vth2 or higher for a longer time after switching to the off instruction signal.

Although not shown, the semiconductor switch 24 and the controller 25 constituting the energization control device 20 may be separated. For example, the semiconductor switch 24 may be a switch module together with the terminals 21 and 22 and the energization path 23, and the controller 25 may be an electronic control unit separate from the switch module.

The load connected to the buses 13a and 13b is not limited to the above example. Other loads may be connected to the bus 13a together with the first load 15. Other loads may be connected to the bus 13b together with the second load 16.

An example is shown in which one energization control device 20 is arranged between the buses 13a and 13b, but the present invention is not limited to this. For example, a plurality of energization control devices 20 may be connected in parallel between the buses 13a and 13b.

The power supply system 10 was a system in which the second power system was simply added to the first power system via the energization control device 20. The application of the energization control device 20 is not limited to such an add-on type power supply system 10. For example, it can be applied to a backbone type system in which three or more power systems are connected in series via an energization control device 20.

The modified example shown in FIG. 11 is a backbone type power supply system 10 provided with two energization control devices 20A and 20B as the energization control device 20. In FIG. 11, the energization control device 20A is arranged between the buses 13a and 13c, and the energization control device 20B is arranged between the buses 13b and 13c. The first power supply 11 is connected to the bus 13a, and the second power supply 12 is connected to the bus 13b. A load 16B is connected to the bus 13c. When the IG switch is turned off, a dark current is supplied to the load 16B from, for example, the first power supply 11 via the semiconductor switch 24 of the energization control device 20. In the configuration shown in FIG. 11, the energization control device 20B also functions as the relay 14 described above.

Although not shown, the energization control device 20 can also be applied to the ring-type power supply system 10. The ring-type power supply system 10 has a structure in which backbone structures as shown in FIG. 11 are connected in an annular shape.

An example of supplying a dark current from the first power supply 11 to the second load 16 via the semiconductor switch 24 has been shown, but the present invention is not limited to this. For example, the first power supply 11 may be cut off from the bus 13a, and a dark current may be supplied from the second power supply 12 to the first load 15 via the semiconductor switch 24.

(Second Embodiment)
This embodiment is a modification based on the preceding embodiment. The description of the prior embodiment can be incorporated. In the preceding embodiment, the semiconductor switch 24 (MOSFET Q1) is turned on by the intermittent operation of the drive unit 30 so that the current flows in a state where the on resistance is higher than that in the normal mode. Instead of this, by switching the drive unit 30 used in the standby mode, the semiconductor switch 24 may be put into an on state in which a current flows in a state where the on resistance is higher than that in the normal mode.

The configuration of the power supply system 10 is the same as that of the preceding embodiment (see FIG. 1). The energization control device 20 of this embodiment also includes terminals 21 and 22 for external connection, a semiconductor switch 24, and a controller 25. The configuration of the semiconductor switch 24 is also the same as that of the prior embodiment (see FIG. 1).

As shown in FIG. 12, the controller 25 includes a drive unit 30 and a control unit 33. The control unit 33 outputs an instruction signal to the drive unit 30. An IG signal and an overcurrent detection result are input to the control unit 33. The control unit 33 is configured to be able to switch the control mode according to the IG signal, the overcurrent detection result, and the like. The control unit 33 outputs an instruction signal corresponding to the control mode to the drive unit 30.

The drive unit 30 outputs a drive signal to the gates of MOSFETs Q1 and Q2 in accordance with the instruction signal from the control unit 33. The drive unit 30 outputs an on drive signal as a drive signal in order to turn on the MOSFETs Q1 and Q2. The drive unit 30 outputs an off drive signal as a drive signal in order to turn off the MOSFETs Q1 and Q2.

FIG. 13 shows the drive unit 30 of the controller 25. As shown in FIGS. 12 and 13, the drive unit 30 includes a drive unit 30c having a booster circuit 300 and drive units 30d and 30e not having a booster circuit 300.

The drive unit 30c has a booster circuit 300 and a driver 301, as in the drive units 30a and 30b shown in the preceding embodiment. When the ON instruction signal is input, the booster circuit 300 executes a booster operation. The driver 301 operates in response to the on-instruction signal, and outputs an on-drive signal in response to the boost voltage by the booster circuit 300. In this embodiment, the drive unit 30c is common to the MOSFETs Q1 and Q2. Both MOSFETs Q1 and Q2 are turned on by the on drive signal output from the drive unit 30c.

The drive unit 30d has a low voltage circuit 302 and a driver 301. The low voltage circuit 302 outputs a voltage lower than the boost voltage of the booster circuit 300 to the driver 301. The driver 301 operates in response to the on instruction signal, and outputs an on drive signal in response to the low voltage of the low voltage circuit 302. The drive unit 30d outputs an on drive signal to the gate of the MOSFET Q1.

As shown in FIG. 13, the low voltage circuit 302 has a differential amplifier 302a. The low-voltage circuit 302 outputs a voltage signal Vout1 corresponding to the difference between the voltage V21 on the terminal 21 side and the voltage V22 on the terminal 22 side in the energization path 23. The voltage signal Vout1 is represented by the following equation.
(Equation 1) Vout1 = (V21-V22) × (R1 / R2) + V22

The voltage V22 is also input to the non-inverting input terminal of the differential amplifier 302a. When the voltage V21 is higher than the voltage V22, the differential amplifier 302a outputs a voltage signal Vout1 higher than the voltage V22 by the amount corresponding to the difference. The driver 301 outputs an on-drive signal corresponding to the voltage signal Vout1 to the gate of the MOSFET Q1 with reference to the source voltage VS.

The drive unit 30e has a low voltage circuit 303 and a driver 301. The low voltage circuit 303 also outputs a voltage lower than the boost voltage of the booster circuit 300 to the driver 301. The driver 301 operates in response to the on instruction signal, and outputs an on drive signal in response to the low voltage of the low voltage circuit 303. The drive unit 30e outputs an on drive signal to the gate of the MOSFET Q2.

As shown in FIG. 13, the low voltage circuit 303 has a differential amplifier 303a. The low voltage circuit 303 outputs a voltage signal Vout2 corresponding to the difference between the voltage V22 and the voltage V21. The voltage signal Vout2 is represented by the following equation.
(Equation 2) Vout2 = (V22-V21) × (R5 / R6) + V21

The voltage V21 is also input to the non-inverting input terminal of the differential amplifier 303a. When the voltage V22 is higher than the voltage V21, the differential amplifier 303a outputs a voltage signal Vout2 higher than the voltage V21 by the amount corresponding to the difference. The driver 301 outputs an on-drive signal corresponding to the voltage signal Vout2 to the gate of the MOSFET Q2 with reference to the source voltage VS. Note that R1, R2, R3, R4, R5, R6, R7, and R8 indicate the resistance value of each resistor. VS indicates the voltage of the source of MOSFETs Q1 and Q2.

The voltage signals Vout1 and Vout2 are lower than the boosted voltage. Therefore, the on-drive signal output from the drive units 30d and 30e has a lower voltage than the on-drive signal output from the drive unit 30c.

<Processes executed by the control unit>
Although not shown, the control unit 33 executes the same processing as in the preceding embodiment (see FIG. 3). When the cutoff mode is set, the control unit 33 outputs an off instruction signal to the drive unit 30c and ends a series of processing. Due to the off instruction signal, the drive unit 30c does not boost the voltage in the booster circuit 300, and the driver 301 outputs an off drive signal. As a result, both MOSFETs Q1 and Q2 are turned off, and the buses 13a and 13b are cut off.

When the normal mode is set, the control unit 33 outputs an on instruction signal to the drive unit 30c and ends a series of processing. The booster circuit 300 is boosted by the ON instruction signal in the drive unit 30c. The driver 301 operates in response to the on instruction signal and outputs an on drive signal in response to the boosted voltage. As a result, the MOSFETs Q1 and Q2 are both turned on, and the buses 13a and 13b are brought into a conductive state.

In the normal mode, a signal corresponding to the boosted voltage is input to the gates of MOSFETs Q1 and Q2 as an on-drive signal. This on-drive signal is sufficiently higher than the threshold voltage (Vt) of MOSFETs Q1 and Q2. Therefore, the MOSFETs Q1 and Q2 are driven in a fully on state where the resistance value (on resistance) is small.

When the standby mode is set, the control unit 33 outputs an on instruction signal to the drive units 30d and 30e. The control unit 33 switches the output destination of the ON instruction signal from the drive unit 30c to the drive units 30d and 30e as the mode is switched from the normal mode to the standby mode. In the standby mode, signals corresponding to the corresponding voltage signals Vout1 and Vout2 are input to the gates of MOSFETs Q1 and Q2 as on-drive signals.

When voltage V21> voltage V22, the on-drive signal corresponding to the voltage signal Vout1 is higher than the threshold voltage (Vt), but lower than the on-drive signal according to the boosted voltage. Therefore, the MOSFET Q1 is driven in a half-on state in which the resistance value (on resistance) is larger than in the normal mode. As a result, in the standby mode, a dark current smaller than the current flowing in the normal mode flows. When voltage V21> voltage V22, an off drive signal is output from the driver 301 of the drive unit 30e. Therefore, the MOSFET Q2 is turned off. A dark current flows from the first power supply 11 to the second load 16 through the MOSFET Q1 and the diode D2.

When voltage V22> voltage V21, the on-drive signal corresponding to the voltage signal Vout2 is higher than the threshold voltage (Vt), but lower than the on-drive signal according to the boosted voltage. Therefore, the MOSFET Q2 is driven in a half-on state in which the resistance value (on resistance) is larger than in the normal mode. As a result, in the standby mode, a dark current smaller than the current flowing in the normal mode flows. When the voltage V22> the voltage V21, the off drive signal is output from the driver 301 of the drive unit 30d. Therefore, the MOSFET Q1 is turned off. A dark current flows from the second power source 12 to the first load 15 through the MOSFET Q2 and the diode D1.

The drive unit 30c corresponds to the first drive unit. The on-drive signal output by the drive unit 30c corresponds to the first on-drive signal. The drive units 30d and 30e correspond to the second drive unit. The on-drive signals output by the drive units 30d and 30e correspond to the second on-drive signals. The control unit 33 corresponds to the switching unit.

<Summary of the second embodiment>
In the present embodiment, the control unit 33 controls the on state of the semiconductor switch 24 to different states in the normal mode in which the IG switch is turned on and the standby mode in which the IG switch is turned off. The control unit 33 controls the MOSFETs Q1 and Q2 constituting the semiconductor switch 24 so as to be turned on (fully on) in a state where the resistance value is low in the normal mode. For example, when voltage V21> voltage V22, the control unit 33 controls the MOSFET Q1 so as to be turned on (half-on) in a state where the resistance value is higher than that in the normal mode in the standby mode. Therefore, a current (dark current) smaller than the current (normal current) flowing in the normal mode can be supplied to the second load 16 via the semiconductor switch 24. As described above, the dark current can be supplied to the load in the standby mode.

Further, in the standby mode, the resistance value of the semiconductor switch 24 is increased by lowering the voltage of the on drive signal as compared with the normal mode. In standby mode, no boost is required to generate the on-drive signal. Therefore, the current consumption of the energization control device 20 can be reduced.

In the present embodiment, in the normal mode, the control unit 33 drives the drive unit 30c provided with the booster circuit 300. As a result, in the normal mode, an on drive signal corresponding to the boosted voltage is output, and the MOSFETs Q1 and Q2 are in a fully on state. On the other hand, in the standby mode, the control unit 33 drives, for example, the drive unit 30d not provided with the booster circuit 300. As a result, in the standby mode, an on drive signal having a lower voltage than in the normal mode is output, and the MOSFET Q1 is held in the half-on state. Therefore, it is possible to reduce the current consumption of the energization control device 20 while supplying the dark current in the standby mode.

Also in this embodiment, the semiconductor switch 24 is configured to include two MOSFETs Q1 and Q2. Sources of MOSFETs Q1 and Q2 are connected to each other. The anodes of the diodes D1 and D2 are connected to each other. In the standby mode, the control unit 33 outputs an ON instruction signal to the drive units 30d and 30e. One of the drive units 30d and 30e outputs an on drive signal, and the other outputs an off drive signal. Therefore, the current consumption of the energization control device 20 can be further reduced as compared with the configuration in which the on-drive signal is output from both the drive units 30d and 30e.

<Modified example of the second embodiment>
The configurations of the power supply system 10 and the energization control device 20 are not limited to the above examples. For example, it can be combined with the configuration shown in the modified example of the preceding embodiment (see FIG. 6). The energization control device 20 is arranged between the power supply 11A and the load 16A. The semiconductor switch 24 constituting the energization control device 20 has only one MOSFET Q1. In such a configuration, the above control is applied. The control unit 33 controls so that the ON state of the MOSFET Q1 differs between the normal mode and the standby mode. Specifically, the ON state of the MOSFET Q1 is controlled so as to be turned on (full on) with a low resistance value in the normal mode and turned on (half on) with a high resistance value in the standby mode. The control unit 33 outputs an on instruction signal to the drive unit 30c described above in the normal mode, and outputs an on instruction signal to the drive unit 30d in the standby mode. As a result, the MOSFET Q1 can be held in the half-on state in the standby mode.

In the standby mode, one of MOSFETs Q1 and Q2 is in the half-on state and the other one is in the off state, but the present invention is not limited to this. Both MOSFETs Q1 and Q2 may be in the half-on state. In this case, the drive units 30d and 30e for the standby mode can be combined (shared) into one. For example, when it is sufficient to consider only the configuration in which the dark current is supplied from the first power supply 11 to the second load 16, only the drive unit 30d may be provided for the standby mode. By outputting the on drive signal from the drive unit 30d to the MOSFETs Q1 and Q2, both the MOSFETs Q1 and Q2 are put into the half-on state.

In the standby mode, the drive units 30d and 30e output an on drive signal corresponding to Vout1 and Vout2, and the MOSFETs Q1 and Q2 are in a half-on state, but the present invention is not limited to this. For example, the configuration shown in the modified example of FIG. 14 may be adopted.

In the standby mode, the drive unit 30d outputs an on drive signal corresponding to the voltage V21 with reference to the voltage VS. The drive unit 30e outputs an on drive signal corresponding to the voltage V22 with reference to the voltage VS. Therefore, when the voltage V21> the voltage V22, the on drive signal is output from the drive unit 30d, and the MOSFET Q1 is controlled to the half-on state. MOSFET Q2 is controlled to the off state. On the other hand, when the voltage V22> the voltage V21, the on drive signal is output from the drive unit 30e, and the MOSFET Q2 is controlled to the half-on state. MOSFET Q1 is controlled to the off state. Therefore, in the standby mode, it is possible to supply dark current in both directions. When the dark current supply direction is determined in one direction, the drive units 30d and 30e can be combined into one drive unit in FIG.

Depending on the function of the load to which the dark current is supplied, the dark current may be supplied intermittently. In the modified example shown in FIG. 15, the controller 25 of the energization control device 20 has a timer unit 35. The timer unit 35 has, for example, a timer counter. The timer unit 35 starts counting when an on instruction signal is output from the control unit 33 to the drive units 30d and 30e, and outputs a permission signal to the drive units 30d and 30e when a predetermined time elapses. The drive units 30d and 30e are driven for a predetermined time after the permission signal is output. When the timer unit 35 outputs the permission signal, the timer unit 35 clears the count value and starts counting again. When the ON instruction signal to the drive units 30d and 30e is stopped, the timer unit 35 stops counting and clears the count value.

When voltage V21> voltage V22, the drive unit 30d operates intermittently based on the permission signal from the timer unit 35. As a result, an on-drive signal corresponding to the voltage signal Vout1 is intermittently output to the MOSFET Q1. Therefore, the current consumption of the energization control device 20 can be reduced. The timer unit 35 is sometimes referred to as an intermittent control unit because it controls the intermittent operation of the drive units 30d and 30e. The timer unit 35 may output a standby signal instead of the permission signal. When the predetermined time elapses from the start of counting, the timer unit 35 outputs a standby signal to the drive units 30d and 30e. The drive units 30d and 30e stop driving for a predetermined time after the standby signal is output. When the timer unit 35 outputs the standby signal, the timer unit 35 clears the count value and starts counting again. In the standby mode, the drive units 30d and 30e stop driving in a drive stop period based on the standby signal, and drive in a period excluding the drive stop.

Although the example in which the drive unit 30c that operates in the normal mode and the cutoff mode is common to the two MOSFETs Q1 and Q2 is shown, they may be provided individually.

An example is shown in which the driver 301 is individually provided for each drive unit 30c, 30d, 30e, but the present invention is not limited to this. The driver 301 may be shared in the drive unit 30. In the modified example shown in FIG. 16, the controller 25 has drive units 30c and 30d. In the drive units 30c and 30d, the driver 301 is shared (also used). A drive unit 30c is configured with a booster circuit 300 and a driver 301. The drive unit 30d is provided with the low-voltage circuit 302 and the driver 301.

In the normal mode, the control unit 33 outputs an ON instruction signal to the drive unit 30c. As a result, the booster circuit 300 executes the booster operation, and the booster voltage is supplied to the driver 301. Then, the driver 301 outputs an on-drive signal according to the boosted voltage. In the standby mode, the control unit 33 outputs an ON instruction signal to the drive unit 30d. As a result, the low voltage circuit 302 operates and a low voltage is supplied to the driver 301. Then, the driver 301 outputs an on-drive signal corresponding to the low voltage.

Although not shown, the semiconductor switch 24 and the controller 25 constituting the energization control device 20 may be separated. For example, the semiconductor switch 24 may be a switch module together with the terminals 21 and 22 and the energization path 23, and the controller 25 may be an electronic control unit separate from the switch module.

The load connected to the buses 13a and 13b is not limited to the above example. Other loads may be connected to the bus 13a together with the first load 15. Other loads may be connected to the bus 13b together with the second load 16.

An example is shown in which one energization control device 20 is arranged between the buses 13a and 13b, but the present invention is not limited to this. For example, a plurality of energization control devices 20 may be connected in parallel between the buses 13a and 13b.

The power supply system 10 was a system in which the second power system was simply added to the first power system via the energization control device 20. The application of the energization control device 20 is not limited to such an add-on type power supply system 10. It can also be applied to backbone type systems. It can also be applied to the ring-type power supply system 10.

(Other embodiments)
Disclosure in this specification, drawings and the like is not limited to the illustrated embodiments. The disclosure encompasses the illustrated embodiments and variations on them based on them. For example, disclosure is not limited to the parts and / or combinations of elements shown in the embodiments. Disclosure can be carried out in various combinations. The disclosure may have additional parts that may be added to the embodiments. The disclosure includes parts and / or elements of the embodiment omitted. Disclosures include replacement or combination of parts and / or elements between one embodiment and another. The disclosed technical scope is not limited to the description of the embodiments. Some technical scopes disclosed are indicated by the statements of the claims and should be understood to include all modifications within the meaning and scope equivalent to the statements of the claims.

Disclosure in the description, drawings, etc. is not limited by the description of the scope of claims. The disclosure in the specification, drawings, etc. includes the technical ideas described in the claims, and further covers a wider variety of technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure of the description, drawings, etc. without being bound by the description of the claims.

As shown in FIG. 17, a semiconductor switch 24 composed of p-channel type MOSFETs Q1 and Q2 may be used. In FIG. 17, the drains of MOSFETs Q1 and Q2 are connected to each other. Further, the anodes of the diodes D1 and D2 are connected to each other. The Lo level signal output from the controller 25 causes the buses 13a and 13b to become conductive. Therefore, the dark current can be supplied to the load without operating the booster circuit 300.

A semiconductor switch 24 may be configured by combining a normally-off type switching element and a normally-on type switching element. In the example shown in FIG. 18, MOSFET Q1 is a normalization type and MOSFET Q2 is a normal off type. Due to the Lo level signal output from the controller 25, the MOSFET Q1 is turned on and the MOSFET Q2 is turned off. Therefore, a dark current can be supplied from the first power supply 11 to the second load 16 through the MOSFET Q1 and the diode D2. Dark current can be supplied without operating the booster circuit 300.

Claims (10)

1. A semiconductor switch (24) provided in the energization path (23) between the power supply (11) and the load (16), and
   A drive control unit (25) that controls the drive of the semiconductor switch,
   With
   The drive control unit
   In the normal mode, the semiconductor switch is controlled to an on state in which a current flows in a state where the resistance value is lower than that in the standby mode.
   An energization control device that controls the semiconductor switch in the standby mode to an on state in which a current flows in a state where the resistance value is higher than that in the normal mode.
2. In the energization control device according to claim 1, which is mounted on a vehicle,
   The drive control unit executes the control of the normal mode during the period when the ignition switch of the vehicle is on, and executes the control of the standby mode during the period when the ignition switch is off. ..
3. The semiconductor switch has gate capacitors (C1, C2) and has.
   The drive control unit
   A drive unit (30) that outputs a drive signal to the gate of the semiconductor switch,
   In the standby mode, an on drive signal for turning on the semiconductor switch is temporarily output as the drive signal, and an off drive signal for turning off the semiconductor switch is output at a timing different from the on drive signal. It has an intermittent control unit (33) that intermittently operates the drive unit so as to output.
   In the standby mode, the gate capacitor is charged by the temporary output of the on drive signal, and when the off drive signal is output, the semiconductor switch is brought into a state of high resistance value by the electric charge accumulated in the gate capacitor. The energization control device according to claim 1 or 2, which is held.
4. The semiconductor switch consists of two switching elements (Q1, Q2) arranged side by side in the energization path and diodes (D1, D1, which are connected in parallel to the two switching elements and arranged in opposite directions to each other. The energization control device according to claim 3, which has D2) and.
5. In the semiconductor switch, the anodes of the diodes are connected to each other.
   In the standby mode, the drive control unit intermittently outputs the on drive signal only to the switching element on the power supply side, and to the load through the diode connected in parallel to the switching element on the load side. The energization control device according to claim 4, wherein a current is supplied.
6. The drive control unit
   A detection unit (31) for detecting the gate voltage of the semiconductor switch and
   It further has a determination unit (32) that compares the detected gate voltage with a predetermined upper limit threshold value and lower limit threshold value, and outputs the comparison result to the intermittent control unit.
   The energization control device according to any one of claims 3 to 5, wherein the intermittent control unit intermittently operates the drive unit based on the comparison result.
7. The drive control unit
   A detection unit (31) that detects voltage or current in the energization path, and
   It further has a determination unit (32) that compares the value detected by the detection unit with a predetermined upper limit threshold value and lower limit threshold value and outputs the comparison result to the intermittent control unit.
   The energization control device according to any one of claims 3 to 5, wherein the intermittent control unit intermittently operates the drive unit based on the comparison result.
8. The drive control unit
   A drive unit (30) that outputs a drive signal to the gate of the semiconductor switch, and is a first drive unit that outputs a first on drive signal corresponding to a boosted voltage as an on drive signal for turning on the semiconductor switch. (30c), and the second drive unit (30d, 30e) that outputs a second on drive signal having a voltage lower than that of the first on drive signal.
   A switching unit (33) that switches the drive unit so as to output the first on drive signal in the normal mode and output the second on drive signal in the standby mode.
   The energization control device according to claim 1 or 2.
9. The semiconductor switch consists of two switching elements (Q1, Q2) arranged side by side in the energization path and diodes (D1, D1, which are connected in parallel to the two switching elements and arranged in opposite directions to each other. The energization control device according to claim 8, which has D2) and.
10. In the semiconductor switch, the anodes of the diodes are connected to each other.
    In the standby mode, the switching element on the power supply side is turned on, the switching element on the load side is turned off, and a current is supplied to the load through the diode connected in parallel to the switching element on the load side. The energization control device according to claim 9.

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