JPH03201002A - Power controller - Google Patents

Abstract

PURPOSE:To improve the reliability for supply of power to a microcomputer by providing a main power supply inhibiting means which inhibits the supply of power to a peripheral equipment from a main power circuit before the power voltage supplied from a secondary power circuit exceeds a prescribed set level. CONSTITUTION:A voltage comparison part 9 is provided with a comparator 91 which compares the voltage VS1 of resistances 73 and 74 contained in a secondary power control part 7 with the reference voltage VR of a reference voltage generator 3 and an inverter 92. The output of the comparator 91 is kept at a high level as long as VR>VS1 is secured because a battery B is connected. At the same time, a transistor TR 54 is turned off regardless of the output of an OP amplifier 53 of a main power control part 5. Meanwhile a TR 11 is not turned on and therefore no power is supplied to a peripheral equipment X like a sensor, etc., from a main power output terminal TM. Therefore the signal voltage VIN which is inputted to a microcomputer X never exceeds the voltage level where the power voltage VDD of the microcomputer Y is produced at a diode D. Thus the reliability is improved for supply of power to the microcomputer T.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention [Field of Industrial Application] The present invention relates to a power supply control device, and more particularly to a power supply control device that supplies power to an on-vehicle arithmetic unit that controls a vehicle and its peripheral devices.

[Prior Art] Conventionally, a power supply control device that supplies power to an in-vehicle arithmetic unit (hereinafter referred to as a microcomputer) and its peripheral devices has a main power supply circuit that supplies and cuts off power in conjunction with an ignition switch. It is equipped with two systems: a sub-power circuit that constantly supplies power without being linked to the ignition switch, and both are supplied with power from the vehicle battery and supply power after stabilizing the voltage. A microcomputer, which requires a constant power supply because it is equipped with a backup RAM, etc., is connected to a sub power supply circuit, while peripheral devices are connected to a main power supply circuit. In order to suppress consumption of the vehicle battery, a MOS type semiconductor with low power consumption is used for the microcomputer, and the output current of the sub power supply circuit is set low.

This schematic configuration is shown in FIG. The power supply control device C supplied with power from the vehicle battery B is connected to the ignition switch I.
In conjunction with GS, peripheral devices such as various sensors (rotation speed, water, intake temperature sensor, etc.) (transistor T that connects the two power supplies VCC, and the output voltage of transistor T by controlling the base current of the transistor T) It consists of a main power supply control section that keeps VM constant, and a sub power supply circuit (output voltage vs.
The main power supply circuit is composed of the main power supply control section and the main power supply control section.

Note that the main power supply control section and the sub power supply circuit are incorporated as one IC.

In such a power supply configuration, the microcomputer controls the internal combustion engine, air conditioning equipment, etc. based on signals (input voltage VIN) from various sensors.

[Problem to be solved by the invention] However, the power supply control device C having the above configuration
Now, if the on-board battery B is connected while the ignition switch IGs is on while replacing or charging the on-board battery B (2. The following problem has occurred. In other words, the power supply control In device C, the current output capability of the sub power supply circuit is lower than the capacitor capacity of the circuit and load, so the rise of the power supply voltage vS supplied to the microcontroller is
As a result, the input voltage VIN from peripheral devices such as various sensors exceeds the power supply voltage VDD of the microcontroller.
At this time, in a microcomputer using a MOS type semiconductor, a parasitic current flows in a circuit connected to the sensor, causing a latch-up phenomenon, which may cause the microcomputer to malfunction.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power supply control device that solves the above-mentioned problems, improves the reliability of power supply to a microcomputer, and maintains the minimum running performance of a vehicle.

The structure of the present invention that achieves the above object will be described below.

[Means for Solving the Problems] The power supply control device of the first invention includes a main power circuit that is supplied with power from an on-vehicle battery and supplies and cuts off power to on-vehicle peripheral devices such as sensors, and In a power supply device equipped with a sub power supply circuit that constantly supplies power to an in-vehicle arithmetic unit using a MOS type semiconductor device that controls the vehicle and has a smaller output capacity, the value of the power supply voltage supplied by the sub power supply circuit is set in advance. The gist of the present invention is to provide a main power supply inhibiting means for inhibiting power supply from the main power circuit to the in-vehicle peripheral device until a set value is exceeded.

The power supply control device of the second invention includes a main power supply circuit that is supplied with power from an on-vehicle battery and supplies and cuts off power to on-vehicle peripheral devices such as sensors, and a main power supply circuit that has a smaller output capacity than the main power supply circuit and is difficult to control the vehicle. In a power supply device equipped with a sub power supply circuit that constantly supplies power to an in-vehicle arithmetic unit using a MOS type semiconductor device, after the main power supply circuit is in a state where it can supply power to an in-vehicle peripheral device, The main feature of the present invention is to provide main power supply start means for causing the main power supply circuit to supply power to the in-vehicle peripheral device regardless of the state of the auxiliary power supply circuit when a predetermined period of time has elapsed.

The power supply control device of the third invention includes a main power circuit that is supplied with power from an on-vehicle battery and supplies/cuts off power to in-vehicle peripheral devices such as sensors, and a main power circuit that has a smaller output capacity than the main power circuit and is difficult to control the vehicle. A power supply device comprising a sub-power circuit that constantly supplies power to an in-vehicle arithmetic unit using a MOS type semiconductor device, wherein power is supplied from the main power circuit to the in-vehicle peripheral device, and Sub-power supply prohibition means is provided for prohibiting power supply from the sub-power circuit to the in-vehicle arithmetic unit when the power supply voltage value supplied by the sub-power circuit does not exceed a preset value. The gist is that.

The power supply control device of the fourth invention includes a main power supply circuit that is supplied with power from an on-vehicle battery and supplies and cuts off power to on-vehicle peripheral devices such as sensors, and a main power supply circuit that has a smaller output capacity than the main power supply circuit and cannot control the vehicle. A power supply device I comprising a sub-power circuit that constantly supplies power to an in-vehicle arithmetic unit using a MOS type semiconductor device, in which power is supplied from the main power circuit to the in-vehicle peripheral device If so, the gist is that a main power supply maintaining means is provided for maintaining power supply from the main power circuit regardless of the state of the sub power circuit.

[Function] When the power supply control device of the first invention is supplied with power from the vehicle-mounted valve breaker, if the power supply voltage value for supplying power from the auxiliary power supply circuit to the vehicle-mounted arithmetic unit is less than or equal to a preset value, The main power supply prohibition means prohibits the supply of power from the main power circuit to in-vehicle peripheral devices such as sensors, and thereafter, when the power supply voltage value from the sub power circuit to the in-vehicle arithmetic unit exceeds the set value, Supplies power from the power supply circuit to the in-vehicle peripheral circuits. Therefore, when a signal from a vehicle peripheral device is input to the vehicle-mounted arithmetic device, the power supply voltage value of the vehicle-mounted arithmetic device always exceeds the set value.

In the power supply control device of the second invention, when a predetermined period of time has elapsed since the main power supply circuit is not supplied with power from the vehicle battery, and the vehicle peripheral device is in a state where dual power supply can be supplied,
The main power supply starting means causes the main power circuit to supply power to the on-vehicle peripheral device. This power supply from the main power circuit depends, for example, on whether the sub power circuit outputs a voltage higher than a predetermined value to the in-vehicle arithmetic unit, or whether the sub power circuit outputs a signal to interlock the main power circuit. It is executed regardless of whether the Therefore, even if an interlock is performed so that the main power circuit supplies power after the sub power supply circuit operates normally, as in the first invention, for example, an abnormality in the sub power supply circuit may occur. Accordingly, when this state in which the interlock is not released continues for a predetermined period of time, power is supplied from the main power supply circuit to the in-vehicle peripheral device. As a result, the operation of the vehicle-mounted peripheral device is ensured.

In the power supply control device of the third invention, even though power is being supplied from the main power supply circuit to the in-vehicle peripheral device, if the power supply voltage value of the sub power supply circuit has not reached a preset value, The auxiliary power supply prohibiting means prohibits power supply from the auxiliary power supply circuit to the in-vehicle arithmetic unit. Therefore, regardless of the status of the sub power supply circuit, the main power supply circuit is forced to supply power, and if the signal from the in-vehicle peripheral device is input to the in-vehicle arithmetic unit, the power supply voltage is not supplied to the in-vehicle arithmetic unit. is never started.

In the power supply control device of the fourth aspect of the invention, after the main power supply circuit starts supplying power to the in-vehicle peripheral device, the main power supply maintaining means is configured to control the main power supply circuit from the main power supply circuit regardless of the presence or absence of power supply from the sub power supply circuit or a failure. maintains power supply to in-vehicle peripheral devices. Therefore, even if the main power circuit is interlocked to supply power only when the sub power circuit is operating normally, as in the first invention, for example, the main power circuit supplies power. Even if the sub power supply circuit does not function properly, the power supply from the main power supply circuit to the in-vehicle peripheral device is maintained. This ensures the operation of the in-vehicle peripheral device.

[Embodiments] In order to further clarify the configuration and operation of the present invention described above, preferred embodiments of the power supply control device of the present invention will be described below.

FIG. 1 is a schematic configuration diagram of a power supply control device as a first embodiment. The power supply control device 1 includes a reference voltage generation device 3.
Main power control section 5. The sub power supply control section 7 is composed of an ICl3 consisting of a voltage comparison section 9, and a transistor which outputs a constant voltage under the control of the main power supply control section 5.

The input/output terminals of this power supply control device 1 include a BATT terminal that is directly connected to the vehicle battery B, an IG terminal that is connected to the vehicle battery B via the ignition switch IGS, and a terminal that is connected to the collector of the transistor 11. Main power output terminal TM (this output voltage is VM (V)
) and the sub power supply output terminal TS of the sub power supply control section 7
(this output voltage is assumed to be VS (V)), and a base terminal TB and a collector terminal TC, which are connection terminals between the base and collector of the transistor 1 and the main power supply control section 5, respectively. Note that the emitter of the transistor 11 is connected to the load side of the ignition switch IGS.

The reference voltage generator 3 is a circuit that is connected to the BATT terminal and generates a reference voltage VR from the vehicle battery B. This reference voltage VR is output to an operational amplifier 53 of the main power supply control section 5, an operational amplifier 71 of the auxiliary power supply control section 7, and a comparator 91 of the voltage comparison section 9, which will be described later.

The main power control unit 5 has a resistor 51.52 connected to the collector terminal TC.
are grounded in series, and the voltage VM1 of this resistor 52 is input to the negative terminal of an operational amplifier 53 (hereinafter referred to as ○P amplifier 53). The reference voltage VR of the reference voltage generator 3 is inputted to the positive terminal of the P amplifier 53, and its output is given to the base of the transistor 54. The collector of this transistor 54, whose emitter is grounded, is connected to the base terminal TB of the transistor]1. Therefore, based on the difference between voltage VMI and reference voltage VR, ○P
The amplifier 53 controls the base current of the transistor 54,
As a result, the base current of the transistor 11 is controlled, and the output voltage VM of the main power output terminal TM is kept stable.

The sub power supply control section 7 connects a resistor 72.7 to the sub power supply output terminal TS.
3.74 is grounded in series, and operational amplifier 71 (hereinafter referred to as ○
The voltage VS2 of the resistor 74 is taken into the negative terminal of the P amplifier 71, and the reference voltage VR of the reference voltage generator 3 is taken into the positive terminal, and the output thereof is given to the sub power supply output terminal TS. Therefore, the output current of the ○P amplifier 71 is not controlled based on the difference between the voltage VS2 and the reference voltage VR, and the output voltage VS of the sub power supply output terminal TS is kept stable (this stable voltage is defined as vSC ). Furthermore, this OP amplifier 71
In order to suppress consumption of the vehicle battery B, the output current is set to be small.

The voltage comparison section 9 includes a resistor 73.7 provided in the sub power supply control section 7.
4 and the reference voltage VR of the reference voltage generator 3;
and an inverter 92 that inverts the output of. The output of this inverter 92 is connected to the transistor 54 of the main power control section 5.
connected to the base of. Reference voltage VR is voltage VSI
When it is larger than , the output of the comparator 91 becomes high level, the output of the inverter 92 becomes low level,
As a result, transistor 54 remains off. Therefore,
The transistor 11 also remains off, and the main power output terminal T
Output voltage VM is not output to M.

The main power output terminal TM of the power supply control device 1 explained above is
Connect to the power supply terminal TCC (power supply voltage is set to VCC (V)) of peripheral devices X such as various sensors (rotation speed, water temperature, intake air temperature sensor, etc.) (The power supply voltage is VDD (V))
connected to. Output terminal TOU of peripheral device X such as a sensor
Signal from T (output voltage tVOUT (V))
is the input terminal TIN (input voltage VIN(
V). A diode D is provided at the input terminal TIN for internal protection of the microcomputer Y, and for later explanation, the voltage generated across this diode D is expressed as VBE.
shall be.

Next, the operation of the power supply control device 1 when the vehicle battery B is connected while the ignition switch IGS is on will be described. When the vehicle battery B is connected, the reference voltage generator 3 immediately generates the reference voltage VR.
is generated, and this reference voltage VR is applied to the OP amplifiers 53 and 71 and the comparator 9]. ○P amplifier 7] has a small current output capability, so its output voltage vS does not rise instantaneously, but after a predetermined period of time (for example, 1
m seconds), the voltage becomes stable VSC.

At this time, comparator 91. The voltage VSltl, which is input to the negative terminal of , changes from O to VSIC (the voltage across the resistor 74 when stable). Therefore, comparator 9
The output of the inverter 92 becomes a high level during the period of VR)VSI, and the output of the inverter 92 becomes a low level. As a result, regardless of the output of the ○P amplifier 53, the transistor 54
is in the off state, so transistor]1 does not turn on,
Power is not supplied from the main power output terminal TM to peripheral devices X such as sensors.

Next, when the voltage vSl increases and VR<VSI,
The output of the comparator 9 is inverted and becomes low level, that is, the output of the inverter 92 becomes high level, the transistor 54 operates according to the output of the OP amplifier 53, and the output voltage VM is transferred from the main power output terminal TM to the sensor, etc. Output to peripheral device X. In addition, at the time of this output, the output voltage vS of the sub power supply output terminal TS is set to vSl so as to satisfy the condition of the following equation.
is set.

VS > VM -VBE In other words, the power supply voltage VDD of microcomputer Y is equal to the input voltage VIN
The value is set to be larger than the value obtained by subtracting the voltage drop VBE of the protection diode D from the voltage drop VBE of the protection diode D.

The power supply control device 1 of the present embodiment described above compares the voltage VSI, which changes according to the output voltage vS of the sub-power supply output terminal TS, with the reference voltage VR, and compares the voltage VSI, which changes according to the output voltage vS of the sub-power supply output terminal TS, with the reference voltage VR. During the VSI period, output of the output voltage VM from the main power output terminal TM is prohibited, so the signal voltage VIN input to the microcomputer Y is equal to the power supply voltage VD.
D will not exceed VBE. Therefore, microcontroller Y
In this case, the latch-up phenomenon peculiar to MOS type semiconductors does not occur, and the microcomputer Y does not malfunction or break down. Therefore, the reliability of power supply to the microcomputer Y is improved. Also, when replacing vehicle battery B, etc., we do not take the trouble to replace the ignition switch IGS.
There is no need to check and turn it off.

Although the first embodiment of the present invention has been described above, the present invention is not limited to this embodiment in any way. For example, instead of the comparator 91 in the comparing section 9, a transistor 93 and diodes 94, 95 . The configuration may be such that the level of the voltage vS is detected using the resistors 96, 97, and 98, and the inverter 92 is operated.

Next, a second embodiment will be explained. The second embodiment corresponds to the first to third inventions. In the power supply control device 101 of the second embodiment, the ignition switch IGs is turned on.
When the battery B is connected in the above state, similarly to the first embodiment corresponding to the first invention, after the output voltage vS of the sub power supply output terminal TS exceeds a predetermined value, the main power supply output terminal TM is connected.
Power is supplied to the In addition, if there is a failure in any of the parts, each part performs a predetermined operation according to the configuration shown above and below.

FIG. 3 is a schematic configuration diagram of the power supply control device 01 (second embodiment).The power supply control device 101 is composed of an IC 113 and a transistor 11B.1c11
3 includes a reference voltage generator 3B similar to the first embodiment, a main power supply control section 5B, a sub power supply control section 7B, and a voltage comparison section 9.
It is equipped with B. Furthermore, the 1c113 includes a main power supply start section 103 and a sub power supply prohibition section 105.

C113 includes a BATT terminal, an IG terminal, a main power output terminal TM, a sub power supply output terminal TS, a base terminal TB, a rectifier terminal TC, and a ground terminal GND. The BATT terminal is directly connected to the vehicle battery B. The IG terminal is connected to the secondary side of the ignition switch IGs. Collector terminal TC is connected to the collector of transistor 11B. Base terminal T
8 is connected to the base of transistor IIB.

The emitter of the transistor IIB is connected to the secondary side of the ignition switch IGs, and the collector is connected to the main power output terminal TM of the power supply control device 101.

The power supply control device 101 is connected to the vehicle-mounted control device 111 through a main power output terminal TM and a sub-power supply output terminal TS. The vehicle-mounted control device 1 ] 1 is provided with a power terminal TCC that supplies power to a vehicle-mounted peripheral device (not shown) and a power terminal TDD that supplies power to a vehicle-mounted arithmetic unit (not shown). One power supply terminal TCC is connected to the main power supply output terminal TM. The other power supply terminal TDD is connected to the sub-power supply output terminal TS.

Main power supply start section] 03 (upper comparator 121 and
Resistance 938. 123. 125. 127, an electrolytic capacitor 129, and a diode 131.

One ends of the resistors 123 and 127, the cathode side of the diode 131, and the ilG terminal are connected. One end of the resistor 125 and the negative electrode of the electrolytic capacitor 29 are grounded. The positive terminal of the comparator]21 is connected to the connection between the resistor]23 and the resistor]25. comparator]
The negative terminal of the comparator 121 is connected to the other end of the resistor 127 and the positive terminal of the diode 131 and the electrolytic capacitor 129. A power supply voltage is applied to the output terminal of the comparator 121 via a resistor 93B.

As a result, the state of each part of the main power supply starting section 103 changes as shown in FIG. That is, at the time TO when the battery B voltage is supplied via the ignition switch IGS, the voltage at the IG terminal increases from roVJ to the voltage of the vehicle battery B (12VJ). Positive terminal voltage [i1
The voltage at the G terminal is immediately increased to a value obtained by dividing the voltage by the resistors 123 and 125. The voltage at the other negative terminal remains at rOVJ at the current time TO. Therefore, the output terminal of the comparator 121 is at a high level (
"Eye 1"). As time progresses from time TO, the voltage at the positive terminal does not change, but the voltage at the negative terminal changes as the capacitor]29 is charged,
The voltage gradually rises to the IG terminal voltage.

At time T1 when the voltage at the negative terminal becomes the same as the voltage at the positive terminal, the output terminal of the comparator [2] becomes ro.
It drops to VJ.

That is, the main power supply starting unit 103 operates from the time TO when the voltage of the IG terminal increases from roVJ to N2VJ until the time TI after a predetermined time has elapsed (for example, after 10 msec has elapsed).
The output terminal of the comparator 121 is set to high level, and thereafter set to low level. In other words, before time T1 (
The output terminal of inverter 92B is maintained at a high level that does not affect the output thereof, and after time T1, the input terminal of inverter 92B is set to low level, and the output terminal of inverter 92.8 is set to high level.

As a result, when the main power supply starting section 103 reaches the time TI, the main power supply starting section 103 controls the transistor 54B in the main power supply control section 5B.
is turned on, and the transistor IIB driven by this
Turn on. That is, when time point Tit2 is reached, power is supplied to the main power output terminal TM.

As explained above, the main power supply starting unit 103 allows the power supply control device 101 to control the output voltage of the sub power supply output terminal TS even if the sub power supply control unit 7B has a failure and the battery B is connected. If VS does not reach the predetermined value (
When a predetermined period of time has passed since battery B was connected (
For example, 10 m5), power is supplied to the main power output terminal TM. Therefore, the portion of the on-vehicle control device 111 that receives power from the main power output terminal TM operates.

The above functions correspond to the embodiment of the second invention.

Sub-power supply prohibition section 105i1OR circuit 141 and resistor 1
43,145. Resistor 143 and Resistor 145
is connected in series with the ○P amplifier 7 in the sub power supply control section 7.
It is interposed between the positive terminal of 1B and the reference voltage generator 3B. OR circuit 141 has two input terminals, one of which is connected to the input terminal of inverter 92B in voltage comparison section 9B. The other input terminal (connected to the output terminal of the ○P amplifier 71B in the sub power supply control section 7B. The output terminal of the OR circuit 141 is
It is connected to the connection portion between resistor 143 and resistor 145.

As a result, the sub power supply prohibition unit 105 controls the inverter 9
If the input terminal of ○P amplifier 71B is at low level and the output terminal of ○P amplifier 71B is at - level, the output terminal of ○P amplifier 71B is set to low level by setting the positive input terminal of ○P amplifier 71B to low level. level. That is,
The output voltage VS of the sub power supply output terminal TS is set to ro VJ.

As a result, if the input terminals of the sub power supply inhibiting unit 1051 & inverter 92B are at high level, that is, it is guaranteed that no power is supplied to the main power output terminal TM, or the sub power supply output terminal TS If power is being supplied to

Therefore, if the voltage of the auxiliary power supply does not reach a preset value after the main power is supplied, the supply of the auxiliary power is prohibited and the MOS element built in the on-vehicle control device 1] latch-up. can be prevented from occurring.

The above functions correspond to the first embodiment of the third invention.

Next, a third example will be described. The third embodiment corresponds to the first, third, and fourth inventions.

A schematic configuration diagram of a power supply control device 201 as a third embodiment is shown in FIG. In the power supply control device 201 of the third embodiment, parts having the same configuration as the second embodiment are enclosed.
The reference numeral B in FIG. 3 is changed to the reference numeral C. The third example is the first example. The differences from the second embodiment will be described below.

That is, the IC 213 of the power supply control device 201 is newly equipped with a main power supply maintaining section 207, and the main power supply starting section 103 in the second embodiment is omitted.

The main power supply maintaining section 207 includes a comparator 251 and resistors 253 and 255. Resistor 253 and Resistor 2
55 are connected in series, one end of which is connected to the IG terminal, and the other end is grounded. The resistance value of the resistor 253 connected to the IG terminal is set to approximately 19 times the resistance value of the other resistor 255. The comparator 251 is
The negative terminal is connected to the collector terminal TC. Further, the positive terminal (connected to the connection portion between the upper resistor 253 and the resistor 255).

As a result, as shown in FIG. 6, the main power supply maintaining unit 207 sets the output terminal of the comparator 251 to a low level at time T2 when a voltage higher than the predetermined operating voltage is supplied to the collector terminal TC, and compares the voltage. The input terminal of the inverter 92C in the section 9C is set to low level.

As a result, after the main power supply maintaining unit 207 starts supplying power to the main power output terminal TM, the inverter 92C
At time T3 in FIG. 6, the input terminal of
As shown in FIG. 2, this supply state is maintained even if the voltage of the sub power supply output terminal TS decreases. Therefore, regardless of the state of the auxiliary power source, it is possible to ensure the supply of the main power source and ensure the operation of the portions receiving the main power supply. The main power supply maintaining unit 207 continues to maintain the main power supply state until the power supplied via the ignition switch IGSe is turned off.

The above functions correspond to the embodiment of the fourth invention.

The second point explained above. Power supply control device 101 of third embodiment
, 211 reliably supplies power to the portions of the on-vehicle control devices 111 and 211 that receive power from the main power output terminal TM (taking into consideration the operating state of the portions that supply sub-power) at appropriate times.

Furthermore, this is performed only when no failure occurs in any part, taking into consideration the state of power supply 1 to the sub power supply output terminal TM and the power supply to the main power supply output terminal TM.

Therefore, this second book. The third embodiment ensures the operation of specific functions in the on-vehicle control devices 111 and 211, guarantees the minimum running performance of the vehicle, and has an extremely excellent effect of improving the reliability of the vehicle. . Moreover, in-vehicle control devices 111 and 2 due to abnormality in the power supply.
This has the effect of preventing the occurrence of new failures.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented in various embodiments.

Effects of the Invention As detailed above, according to the power supply control device of the first invention, until the power supply voltage value supplied by the auxiliary power supply circuit exceeds a preset value, the main power supply circuit supplies power to the in-vehicle peripheral device. Since power supply to the in-vehicle processing unit is prohibited, when the in-vehicle peripheral device operates and outputs a signal to the in-vehicle arithmetic unit, the
The power supply voltage of the in-vehicle arithmetic unit is higher than the set value.

Therefore, even if a vehicle battery is replaced while the ignition switch is on, for example, the relationship between the signal voltage value from the vehicle peripheral device and the power supply voltage value of the vehicle arithmetic unit will be made appropriate. Therefore, the latch-up phenomenon peculiar to MOS type semiconductors does not occur, and the on-vehicle arithmetic unit does not malfunction or break down. Therefore, the reliability of power supply to the in-vehicle arithmetic unit is improved.

Furthermore, when replacing a vehicle battery, there is no need to take the trouble of checking the ignition switch and turning it off.

According to the power supply control device of the second invention, when a predetermined period of time has elapsed since the main power circuit received power supply from the vehicle battery, the main power circuit controls the vehicle peripheral Start supplying power to the device. Therefore, for example, if the main power supply circuit is configured to start supplying power after the sub power supply circuit operates normally, even if the sub power supply circuit fails and does not start supplying power, the main power supply circuit will not start supplying power. The power supply circuit supplies power to in-vehicle peripheral devices.

As a result, even if the function for protecting the vehicle-mounted arithmetic unit in the power supply control device malfunctions or breaks down, it is possible to start supplying power to the vehicle-mounted peripheral device.

Accordingly, by adding, for example, a minimum function for running the vehicle to the vehicle-mounted peripheral device, running of the vehicle can be ensured.

According to the power supply control device of the third invention, if the main power supply circuit is supplying power to the vehicle-mounted peripheral device, the sub-power supply circuit does not start supplying power to the vehicle-mounted arithmetic unit. Therefore, even if the sub power supply circuit that had stopped supplying power due to a failure recovers and attempts to start supplying power, the sub power supply circuit will not resume power supply, so the latch that is unique to MOS type semiconductors The up phenomenon does not occur, and the in-vehicle arithmetic unit does not fall into a state of malfunction or destruction.

According to the power supply control device of the fourth aspect of the invention, co-supply of power from the main power circuit to the in-vehicle peripheral device is started; f.

Regardless of the state of the auxiliary power supply circuit, the main power supply circuit maintains power supply to the in-vehicle peripheral devices. Therefore, for example, if the configuration is such that the main power supply circuit supplies power only when the sub power supply circuit is operating normally, even if a failure occurs in the sub power supply circuit and the power supply is stopped, Power supply from the main power circuit is maintained. This ensures the operation of the in-vehicle peripheral devices and maintains the minimum functionality necessary for driving the vehicle.

According to the first to fourth inventions described above, it is possible to prevent the occurrence of a failure of the in-vehicle arithmetic unit and to ensure the minimum running performance of the vehicle, which is an extremely excellent effect.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a power supply control device as a first embodiment, FIG. 2 is a circuit diagram showing another part of the configuration of the power supply control device,
3 is a schematic configuration diagram of a power supply control device as a second embodiment, FIG. 4 is an explanatory diagram of its operating state, FIG. 5 is a schematic diagram of a power supply control device as a third embodiment, and FIG. 6 is an explanatory diagram of its operating state, and FIG. 7 is a schematic configuration diagram of a power supply control device as a prior art. 1.101,201...power control device 3, 3B,
3C...Reference voltage generator 5. 5B, 5C・
...Main power supply control section 7, 7B, 7C...Sub power supply control section 9, 9B, 9C...Voltage comparison section 11, II
B, IIC...Transistor x...Peripheral devices such as sensors Y...In-vehicle arithmetic unit 103...Main power supply start section 105.105C...Sub power supply prohibition section 207...
Main power supply maintenance unit 111.211... Vehicle control device

Claims (1)

[Claims] 1. A main power supply circuit that is supplied with power from an on-vehicle battery and supplies and cuts off power to on-vehicle peripheral devices such as sensors, and a MOS that controls the vehicle and has a smaller output capacity than the main power supply circuit.
In a power supply device equipped with a sub-power circuit that constantly supplies power to an in-vehicle arithmetic unit using a type semiconductor device, the above-mentioned power supply voltage value supplied by the sub-power circuit exceeds a preset value. A power supply control device comprising a main power supply inhibiting means for inhibiting power supply from the main power circuit to the vehicle-mounted peripheral device. 2. A main power supply circuit that is supplied with power from the vehicle battery and supplies and cuts off power to vehicle peripheral devices such as sensors, and a MOS that has a smaller output capacity than the main power supply circuit and controls the vehicle.
In a power supply device equipped with a sub-power circuit that constantly supplies power to an in-vehicle arithmetic unit using a type semiconductor device, a predetermined period of time elapses after the main power circuit becomes ready to supply power to an in-vehicle peripheral device. 2. A power supply control device comprising main power supply start means for causing power supply to be supplied from the main power supply circuit to the in-vehicle peripheral device regardless of the state of the auxiliary power supply circuit when the time period has elapsed. 3. A main power circuit that is supplied with power from the vehicle battery and supplies and cuts off power to vehicle peripheral devices such as sensors, and a MOS that has a smaller output capacity than the main power circuit and controls the vehicle.
In a power supply device equipped with a sub-power supply circuit that constantly supplies power to an in-vehicle arithmetic unit using a type semiconductor device, the main power supply circuit supplies power to the in-vehicle peripheral device, and the sub-power supply circuit includes If the power supply voltage value supplied by the power supply circuit does not exceed a preset value, sub-power supply prohibition means is provided to prohibit the supply of power from the sub-power supply circuit to the in-vehicle arithmetic unit. Characteristic power control device. 4. A main power supply circuit that is supplied with power from the vehicle battery and supplies and cuts off power to vehicle peripheral devices such as sensors, and a MOS that has a smaller output capacity than the main power supply circuit and controls the vehicle.
In a power supply device equipped with a sub-power circuit that constantly supplies power to an in-vehicle arithmetic unit using a type semiconductor device, when power is supplied from the main power circuit to the in-vehicle peripheral device, A power supply control device comprising main power supply maintenance means for maintaining power supply from the main power supply circuit regardless of the state of the auxiliary power supply circuit.