JP2001352675A - Power supply for in-vehicle computing equipment - Google Patents

Abstract

(57) [Problem] To provide a power supply device for an in-vehicle arithmetic device capable of starting and stopping a microprocessor by simplified control. SOLUTION: A first switching element 8 receives power from a battery 1 via a power switch 3 and generates a first voltage to be supplied to an input / output circuit unit 22 of a microprocessor 5, and the like.
The second switching element 12 that receives the first voltage and generates a second voltage to be supplied to the arithmetic unit 24, the storage unit 23, and the like of the microprocessor 5, and receives power from the battery 1 without passing through the power switch 3. And the storage unit 2 of the microprocessor 5
And a third switching element 15 for generating a third voltage lower than the second voltage for maintaining operation such as
When the power supply switch 3 is turned on, the second voltage increases in accordance with the increase in the first voltage, and when the power switch 3 is turned off, the second voltage decreases in accordance with the decrease in the first voltage. It is composed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a first power supply voltage supplied to an input / output unit and a second power supply voltage supplied to a calculation unit and a storage unit, which are used in an arithmetic unit mounted on a vehicle. And a power supply device for an on-vehicle computing device.

[0002]

2. Description of the Related Art Many electronic control systems using a microprocessor are used for controlling an internal combustion engine mounted on a vehicle and for controlling various traveling systems. These electronic control systems include an input / output circuit unit and the like. Operates at a power supply voltage of 5.0 V, for example, and operates at 3.3 V
2. Description of the Related Art A dual-power-supply type microprocessor configured to operate at a power supply voltage of 2.times. These are used to suppress power consumption while increasing the operating frequency. For such a device, there are two types of power supply, such as a power supply supplied to the input / output unit and a power supply supplied to the operation unit. Requires a series of constant voltage power supplies.

On the other hand, in an electronic control system mounted on a vehicle, a power source is an on-vehicle battery, and the voltage of the battery is replaced with a predetermined constant voltage by a constant voltage power supply and supplied to a microprocessor or the like. The electric power from the battery is supplied via the key switch, and when the internal combustion engine is started, the supply is started when the key switch is turned on, and when the internal combustion engine is stopped, the power supply is stopped when the key switch is turned off. In the on-vehicle electronic control system in which the supply and stop of power are repeated as described above, various problems may occur in the microprocessor depending on the transient characteristics of the rise and fall of the voltage supplied to the microprocessor. For example, Japanese Patent Application Laid-Open No. Hei 7-191701 discloses a technique for addressing this problem by controlling the timing of control signals at the time of turning on and off the power, when starting and stopping the microprocessor.

The technique disclosed in this publication does not use the above-described dual-power-supply microprocessor, but supplies power to the RAM for backing up the RAM when the key switch is off and to the microprocessor when the key switch is on. Power supply and power supply to peripheral devices such as sensors are provided in parallel.Three systems of constant-voltage power supplies are provided in parallel, each of which supplies power to each load, and determines the voltage of the power supply supplied to the microprocessor. Means for determining the value of the voltage of the constant voltage power supply when the voltage rises and falls, thereby supplying power in the order of a transmission control terminal, a program execution control terminal, and a RAM write control terminal. When the supply is stopped, the supply is stopped in the reverse order, and the microprocessor operates stably without malfunction. Rutotomoni, eliminating the need to power the like to the internal clock from the power supply for backup, but it is made smaller in the power supply for the backup.

[0005]

In such an electronic control system using a microprocessor, the power supply from the power supply unit is related to the control signal of the microprocessor, and the power supply voltage when the key switch is turned on. During the transition period between rising and falling when the power is off, signal timing control is required from both hardware and software. In the case where the voltage rises or falls in relation to each other, more complicated control is required. Further, in the case of using a dual power supply type microprocessor, when a plurality of power supplies exist in parallel as described above, imbalance may occur in the transient characteristics of the rise and fall of each voltage. In such a case, a latch-up accident of the microprocessor may be caused.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. In a system having a plurality of constant voltage power supplies, when starting up a microprocessor, a start signal is supplied after each control power supply has been reliably started. Supply,
For in-vehicle computing equipment that can be started and stopped by simplified control by detecting the interruption of the switch at the time of stop and setting the microprocessor to sleep mode and leaving a controllable voltage until the sleep is completed It is intended to obtain a power supply device.

[0007]

According to the present invention, there is provided a power supply device for an on-vehicle arithmetic device, which receives power from a battery via a power switch and generates a first voltage to be supplied to an input / output circuit of a microprocessor. A first constant voltage power supply, and a second constant voltage power supply connected in series with a first constant voltage power supply that receives the first voltage and generates a second voltage to be supplied to an arithmetic unit, a storage unit, and the like of the microprocessor. A voltage power supply, wherein the second voltage increases as the first voltage increases when the power switch is turned on, and the second voltage decreases as the first voltage decreases when the power switch is turned off. It is what was constituted.

A first constant-voltage power supply for receiving a power from a battery via a power switch and generating a first voltage to be supplied to an input / output circuit of the microprocessor; and receiving the first voltage; A second constant-voltage power supply connected in series with a first constant-voltage power supply that generates a second voltage to be supplied to an arithmetic unit, a storage unit, and the like of the microprocessor, and a power supply that detects whether a power switch is turned on and off. Determining means, command signal generating means for outputting a start or standby command of the microprocessor in response to the determination by the power-on determining means, and provided on at least one of the input side and the output side of the first constant voltage power supply; The command signal generating means issues a start command after the first voltage and the second voltage are established when the power is turned on, and operates the voltage holding capacitor when the power is turned off. In which the standby processing is configured to complete during the remaining period of possible voltages.

Further, a third constant-voltage power supply is provided which receives power from the battery without passing through a power switch, and generates a third voltage lower than the second voltage for maintaining operation of a storage unit or the like of the microprocessor. Each of the first to third constant-voltage power supplies has a switching element for controlling and outputting a voltage, and the first to third constant-voltage power supplies are limited to a case where the first voltage value is equal to or higher than the third voltage value. The switching element of the second constant voltage power supply is configured to be operable. Furthermore, an overcurrent suppression circuit is added to the first constant voltage power supply. Further, the determination by the power-on determination means is performed by comparing a battery voltage not via the power switch with a battery voltage via the power switch. Further, the judgment by the power-on judging means is made by comparing the battery voltage with the output voltage of the reference voltage generating means.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 1 to 4
1 illustrates a power supply device for an on-vehicle computing device according to a first embodiment of the present invention. FIG. 1 is a block diagram showing the configuration thereof, and FIGS. 2 to 4 are circuit diagrams of respective conduction control circuits.
In the figure, reference numeral 1 denotes an on-vehicle battery having a negative terminal connected to the vehicle body 2, 3 a power switch such as a key switch for connecting the battery 1 to a load, and 4 a power supply for supplying a predetermined constant voltage to the microprocessor 5. The battery 1 is charged from a charging generator (not shown) mounted on the vehicle, and the power supply device 4 receives the voltage VS0a from the battery 1 via the power switch 3 and the voltage VS0b directly from the battery 1. And a terminal 7 to be connected.

In the power supply device 4, the power supply device 8 receives the voltage VS 0 a from the terminal 6 via the capacitor 9, generates a first power supply voltage VS 1 under the control of the first energization control circuit 10, and charges the capacitor 11. One switching element,
These constitute a first constant voltage power supply, and the generated voltage VS1 is set to, for example, DC 5.0V. A second switching element 12 receives the voltage of the first constant voltage power supply charged in the capacitor 11, generates a second power supply voltage VS <b> 2 under the control of the second power supply control circuit 13, and charges the capacitor 14. These constitute a second constant voltage power supply, and the generated voltage VS2 is set to, for example, DC 3.3V.

Reference numeral 15 receives the voltage VS0b from the terminal 7 via the capacitor 16 and the current limiting resistor 17, generates a third power supply voltage VS3 under the control of the third conduction control circuit 18, and charges the capacitor 19. A third switching element,
These constitute a third constant voltage power supply, and the generated voltage VS3 is set to, for example, 2.7 VDC. Reference numeral 20 denotes a comparator, in which the voltage VS0b from the terminal 7 is divided by the voltage dividing resistors R2 and R3 and applied to one of the input terminals.
Is applied to the other input terminal by dividing the voltage VS0a from the input to the other input terminal, thereby functioning as power-on determination means for detecting the on / off of the power switch 3, and its signal is a command signal generation circuit. 21. The command signal generation circuit 21 receives this signal and outputs various control signals SGn to the microprocessor 5 as described later.

The microprocessor 5 includes an input / output circuit unit 22
And a RAM unit 23 constituting an input / output memory and an arithmetic memory
, An operation unit 24, a ROM unit 25 constituting a system memory, and a control unit 26 for controlling the start and stop of the microprocessor 5 by a control signal SGn. The input / output circuit unit 22, the control unit 26 Is supplied with the voltage VS1 from the power supply 4, and the RAM 23, the arithmetic unit 24 and the ROM
The voltage VS2 is supplied to the unit 25 from the power supply device 4.
The voltage VS3 is also supplied from the power supply device 4 to the RAM unit 23. When the power switch 3 is turned on, the RAM unit 23
Is operated by the voltage VS2, and the memory is held by the voltage VS3 when the power switch 3 is off. In addition,
When it is necessary to maintain the operation in the low power consumption mode even when the power switch 3 is turned off, such as when the microprocessor 5 has a calendar clock function, the arithmetic unit 24 and the ROM unit 2
5 is also supplied with the voltage VS3.

As shown in FIG. 2, the first energization control circuit 10 for controlling the first switching element 8 of the power supply device 4 is connected to the first switching element 8 via the base resistor R6 and the emitter resistor R7 of the first switching element 8. A transistor 27 for driving one switching element 8, a transistor 28 receiving the voltage VS0a from the terminal 6 via the collector resistor R8, and driving the transistor 27;
A constant current circuit 29 that receives the voltage VS0a and supplies a base current to the transistor 28, and a voltage across the emitter resistor R7 of the transistor 27 is input via a base resistor R9 to increase the base current of the first switching element 8. Accordingly, the base current of the transistor 28 is divided, and the first switching element 8
, The collector current is controlled indirectly to prevent the overcurrent of the first switching element 8, and the base current of the transistor 28 is reduced when the output voltage VS1 becomes excessive. Transistor 31
And an output voltage of a known reference voltage generation circuit 32 that receives the output voltage VS1 and generates a reference voltage, and resistors R10 and R11.
And an operational amplifier 33 that inputs the divided voltage of the voltage VS1 and drives the transistor 31. Note that R12 is a stable resistor of the transistor 27.

As shown in FIG. 3, a second energization control circuit 13 for controlling the second switching element 12
A transistor 34 for driving the second switching element 12 via the base resistor R14 and the emitter resistor R15, an output voltage of a known reference voltage generating circuit 35 for receiving the voltage VS1 and generating a reference voltage, and resistors R16 and R17. And the operational amplifier 36 for reducing the base current of the transistor 34 when the voltage VS2 becomes excessive, and generating a reference voltage by receiving the voltage VS1. A comparator 38 which receives the output voltage of the reference voltage generating circuit 37 and the divided voltage of the voltage VS1 divided by the resistors R18 and R19, and receives the output of the comparator 38, and the voltage VS1 is smaller than a predetermined value. Sometimes, the transistor 39 interrupts the base current of the transistor 34 and stops the operation of the second switching element 12. The predetermined value of VS1 for disabling the second switching element 12 is at least the third power supply voltage VS as described later.
It is set to a value higher than 3.

As shown in FIG. 4, the third energization control circuit 18 for controlling the third switching element 15 is connected to the third switching element 15 via a base resistor R20 and an emitter resistor R21. Transistor 40 for driving switching element 15
And a known reference voltage generating circuit 41 which receives the voltage VS0b from the terminal 7 and generates a reference voltage, and outputs the output voltage and the voltage VS3 of the reference voltage generating circuit 41 to the resistors R22 and R23.
And the operational amplifier 42 that drives the transistor 40 by inputting the divided voltage divided by the above and reduces the base current of the transistor 40 when the voltage VS3 is larger than the predetermined value to maintain the voltage VS3 at the predetermined value. It is configured.

In the power supply device for an on-vehicle computing device according to the first embodiment of the present invention, when the power switch 3 is in the open state, that is, when the vehicle is not in the driving state, the battery 1 is connected to the terminal 7. Headwater resistance 17
The voltage VS0b is supplied to the third switching element 15 through the third switching element 15, the third switching element 15 generates the third power supply voltage VS3, and is supplied to the RAM unit 23 of the microprocessor 5,
The storage stored in the RAM unit 23 is held. here,
As described above, the voltage VS3 is set to, for example, 2.7 VDC. In addition, as described above, when it is necessary to maintain the operation of the microprocessor 5 even when the power switch 3 is turned off, such as when the microprocessor 5 has a calendar clock function, as shown by a dotted line in FIG. The voltage VS3 is also supplied to the arithmetic unit 24 and the ROM unit 25 by being connected,
Internal operation is maintained in the low power consumption mode.

When the power switch 3 is open, the voltage applied to the comparator 20 through the dividing resistors R4 and R5 is not applied, so that the command signal is generated by the signal from the comparator 20. The circuit 21 suspends the operation of the control unit 26 of the microprocessor 5 or gives a command of the low power consumption mode operation.

When starting operation of the vehicle, the power switch 3
Is closed, the capacitor 9 is charged, the first energization control circuit 10 is operated by the charging voltage VS0a to control the first switching element 8, and the capacitor 11 is charged by this output. Reaches the power supply voltage VS1. Then, the first energization control circuit 10 applies this voltage V
S1 is maintained, and VS1 is, for example, DC5.
It is set to 0V.

In the second energization control circuit 13 for controlling the second switching element 12, the comparator 38 detects the voltage of the capacitor 11, and outputs a signal when the voltage exceeds a predetermined value, for example, DC 3.0V. By turning off the transistor 39, the transistor 34 is operated, the second switching element 12 is turned on, and the charging operation for the capacitor 14 is started. Then, as the voltage of the capacitor 11 further increases and reaches a predetermined value VS1, the capacitor 1
4 also rises and reaches the second power supply voltage VS2. This voltage is, for example, 3.3 V DC as described above.
And is maintained at a constant value by the operation of the operational amplifier 36 in FIG.

As described above, the second switching element 12 starts conducting after the voltage of the capacitor 11 exceeds a predetermined value, for example, 3.0 V DC, and the judgment voltage of the comparator 38 is at least the first voltage. It is set higher than the third power supply voltage VS3. With this setting, it is possible to prevent the current from flowing from the third switching element 15 to the second switching element 12 when the power supply rises.

On the other hand, when the power switch 3 is turned on, the voltage divided by the voltage dividing resistors R4 and R5 is applied to the comparator 20.
, The voltage VS0a of the terminal 6 is
If the potential is higher than S1, it is possible to establish VS1 and VS2. Therefore, a power-on signal is output from the comparator 20 to the command signal generation circuit 21. After that, various signals SGn are output to the control unit 26 of the microprocessor 5. The predetermined time is set to at least a time required to establish the voltage VS2 after the power is turned on, and various signals SGn include, for example, a clock oscillation start command, a program execution start command,
The commands are issued in the order of the RAM write permission command.

When the operation of the vehicle is completed and the power switch 3 is turned off, the comparator 20 detects the loss of the voltage VS0a from the disappearance of the voltage VS0a. Output various command signals SGn. This command signal SGn is, for example,
The order of the RAM write prohibition command, the program execution stop command, and the clock oscillation stop command is reversed, and is reversed from the order at the time of startup.
With this signal, the microprocessor 5 shifts to a sleep state or a low power consumption mode.

After the power switch 3 is turned off, the voltages of the capacitors 9, 11 and 14 gradually decrease with the discharge, and the operation of the microprocessor 5 can be maintained when the voltage of the capacitor 14 falls below a predetermined value. However, the capacitance of the capacitors 9 and 11 and the discharge time constant with respect to the load are determined by the command signal SGn until the voltage of the capacitor 14 becomes lower than the predetermined value. Is set so that it can be transferred to. Also in this voltage decay process, the comparator 3
8 is set higher than the third power supply voltage VS3, the second switching element 12 is cut off when the voltage VS2 is higher than the voltage VS3, and the third switching element 1
5 prevents the current from flowing back to the second switching element 12.

Embodiment 2 In the power supply device for the on-vehicle arithmetic device according to the first embodiment of the present invention described above, the voltage VS0a of the terminal 6 and the voltage VS0b of the terminal 7 are used for the determination of the comparator 20 in FIG. 1, but in this embodiment. Terminal 7
VS0b, the voltage V of the terminal 6 (not shown)
S0a is supplied via a reference voltage generation circuit. With this configuration, the current flowing from the battery 1 to the fixed resistors R2 and R3 in FIG. 1 is eliminated, and it is possible to reduce the battery drain due to discharge during stopping.

The command signal SGn of the command signal generating circuit 21 described in the first embodiment depends on the type and format of various signals required by the microprocessor 5, and can be changed depending on the type and format. Things. Further, the signal of the comparator 20 can be directly supplied to the microprocessor 5 to generate various command signals inside the microprocessor 5.

[0027]

As described above, according to the power supply device for the on-vehicle arithmetic device of the present invention, the first constant voltage power supply for supplying a voltage to the input / output circuit section of the microprocessor, and the first constant voltage power supply A second constant-voltage power supply is provided to receive the generated voltage of the power supply and supply the voltage to the arithmetic unit, the storage unit, and the like, and when the power switch is turned on and off, the generated voltage of the second constant-voltage power supply is the first Since the increase and decrease are made dependent on the increase and decrease of the voltage of the constant voltage power supply, no imbalance occurs between the first and second voltages, and a latch-up accident of the microprocessor can be prevented.

Further, a third constant voltage power supply for generating a voltage lower than the second constant voltage power supply for holding the operation of the storage unit or the like is provided, and the second constant voltage power supply to the arithmetic unit and the storage unit is provided. Since the operation of the switching element of the power supply is made to operate only when the first power supply voltage is higher than the voltage of the third constant voltage power supply which is the holding power supply of the storage unit, the third constant voltage power supply The backflow to the second constant-voltage power supply can be prevented, the third constant-voltage power supply can be reduced in size by reducing the capacity, and an overcurrent suppression circuit is added to the first constant-voltage power supply. The first constant-voltage power supply and the second constant-voltage power supply that operates in accordance with the first constant-voltage power supply can prevent overcurrent burnout and reduce the size.

Further, a power-on determining means, a command signal generating means for outputting a start or standby command to the microprocessor in response to the determination, and a voltage applied to at least one of the input side and the output side of the first constant voltage power supply. A holding capacitor, wherein the command signal generation means determines whether the power is turned on or off and issues a start command after establishing the voltages of the first and second constant voltage power supplies when the power is turned on, and the voltage holding capacitor when the power is turned off. Since the standby process is completed during the remaining voltage period of the battery, malfunctions can be prevented without performing complicated timing processing in the signal processing. This is done by comparing with the battery voltage that has passed through, so that it is possible to quickly detect power-on and power-off without being affected by battery voltage fluctuations. Can, furthermore, since the determination is performed by comparing the battery voltage with a reference voltage, in which it is possible to obtain a vehicle operation equipment for power supply which is excellent like becomes possible to reduce the dead battery.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a power supply device for an on-vehicle arithmetic device according to Embodiment 1 of the present invention.

FIG. 2 is a circuit diagram of a first conduction control circuit used in the power supply device for the on-vehicle arithmetic device according to the first embodiment of the present invention;

FIG. 3 is a circuit diagram of a second conduction control circuit used in the power supply device for the on-vehicle arithmetic device according to the first embodiment of the present invention;

FIG. 4 is a circuit diagram of a third conduction control circuit used in the power supply device for the on-vehicle arithmetic device according to the first embodiment of the present invention;

[Explanation of symbols]

1 battery, 3 power switch, 4 power supply device, 5
Microprocessor, 8 first switching element, 9, 11,
14, 16, 19 capacitor, 10 first energization control circuit, 12 second switching element, 13 second energization control circuit, 15 third switching element, 17 current limiting resistance, 18 third energization control circuit, Reference Signs List 20 comparator, 21 command signal generation circuit, 22 input / output circuit section, 23 RAM section, 24 operation section, 25 ROM section, 26 control section, 27, 28, 3
0, 31 34, 39, 40 transistors, 29 constant current circuit, 32, 35, 37, 41 Reference voltage generation circuit 3
3, 36, 42 operational amplifier 38 comparator.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G05F 1/56 310 G05F 1/56 310U G06F 1/32 H02J 7/00 302B H02J 7/00 302 G06F 1 / 00 332Z F-term (reference) 5B011 DA06 DA13 DB20 EA10 HH02 LL11 5G003 BA01 CC02 DA02 DA17 GC05 5G065 BA00 EA02 FA01 GA06 GA09 HA05 HA06 JA02 KA02 KA05 LA01 MA09 MA10 NA01 5H430 BB01 BB09 BB11 EE03 FE11 KK03 EE03 EE08

Claims (6)

[Claims] A first constant-voltage power supply that receives power from a battery via a power switch and generates a first voltage to be supplied to an input / output circuit unit of a microprocessor; A second constant-voltage power supply connected in series with a first constant-voltage power supply that generates a second voltage to be supplied to an arithmetic unit, a storage unit, and the like of the microprocessor, wherein the first voltage is applied when the power switch is turned on. The second voltage increases as the power supply switch increases, and the second voltage decreases as the first voltage decreases when the power switch is turned off. Power supply. 2. A first constant-voltage power supply that receives power from a battery via a power switch and generates a first voltage to be supplied to an input / output circuit unit or the like of a microprocessor; A second constant-voltage power supply connected in series with a first constant-voltage power supply that generates a second voltage to be supplied to an arithmetic unit, a storage unit, and the like of the microprocessor; a power supply for detecting whether the power switch is turned on and off; Determining means, command signal generating means for outputting a command to start or wait for the microprocessor in response to the determination of the power-on determining means, provided on at least one of an input side and an output side of the first constant voltage power supply; The command signal generating means issues a start command after the first voltage and the second voltage are established when the power is turned on, and the voltage holding capacitor when the power is turned off. A power supply device for an in-vehicle computing device, wherein a standby process is completed during a remaining period of a voltage operable in a capacitor. 3. A third constant-voltage power supply that receives power from a battery without passing through a power switch and generates a third voltage lower than the second voltage for maintaining operation of a storage unit or the like of a microprocessor. Each of the first to third constant-voltage power supplies has a switching element for controlling and outputting a voltage, and the first to third constant-voltage power supplies are limited to a case where the first voltage value is equal to or higher than the third voltage value. 3. The power supply device for an on-vehicle computing device according to claim 1, wherein the switching device of the second constant voltage power supply is configured to be operable. 4. The on-vehicle computing device power supply device according to claim 1, wherein an overcurrent suppression circuit is added to the first constant voltage power supply. 5. The power supply for an in-vehicle computing device according to claim 2, wherein the determination by the power-on determination means is performed by comparing a battery voltage not via a power switch with a battery voltage via a power switch. apparatus. 6. The power supply device for an on-vehicle arithmetic device according to claim 2, wherein the determination by the power-on determination unit is performed by comparing a battery voltage with an output voltage of the reference voltage generation unit.