JPS58112116A - Composite device for microcomputer system - Google Patents

Abstract

PURPOSE:To reduce the number of component parts and the packing area and to facilitate the system design, by forming a feed power supply control circuit and a reset pulse generating circuit for prevention of malfunction on the same silicon chip substrate. CONSTITUTION:A reset pulse generating circuit part 10 is actuated by the output stabilizing voltage of a feed power supply control circuit part 9 and produces the signal which is supplied to an LSI for CPU. A fault deciding circuit part 11 of the part 10 monitors the program run signal (P-RUN) which is supplied from an LSI14 to discriminate a fault (program runaway) of a microcomputer and produces the output signal which is supplied to a changeover switch circuit 12. The circuit 12 delivers a pulse when the working of the LSI14 is faulty. Then a reset pulse generation oscillating circuit part 13 produces a reset pulse in response to the reset signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a system in which a supply stabilizing power supply control circuit used in various microcomputer control systems and a reset pulse generation circuit for preventing malfunction of microcomputers are integrated into the same chip using a single-chip IO technology. The present invention relates to a device having multiple functions formed on a silicon chip substrate.

In recent years, control systems using microcomputers have been applied to various fields. This microcomputer control system has
A power supply control circuit is essential. In addition, from the point of view of system safety and reliability, especially in in-vehicle electronic equipment where safety is the most important, reset pulse generation circuits are required to prevent or minimize malfunctions and accidents caused by runaway microcontrollers. It has become essential.

FIG. 1 shows a block diagram of the hardware configuration of various conventional microcomputer control systems. This microcomputer control system is for OPU L8I2. L813° RAM4 for I10 interface. ROM! 5th class L
It consists of 107 components such as SI, analog signal IC, digital signal component 0, and discrete components. Microcomputer control systems use these electronic components selectively depending on the control purpose. Circuits such as the supply voltage control unit 1) which is essential for microcomputer control and the reset pulse generation circuit 6 for preventing malfunction of the microcomputer are not composed of III, but are composed of simple or discrete components.

However, this microcomputer control system has drawbacks such as a large number of parts other than LSI components (high cost, large mounting area on a printed circuit board, etc., and difficulty in system design.
Also, due to the large number of parts connected via printed circuit boards, etc., it does not have sufficiently high reliability. follower,
This microcomputer control system is not necessarily suitable for applications that require high reliability, such as the above-mentioned in-vehicle electronic equipment.

Therefore, an object of the present invention is to form a power supply control circuit used in various microcomputer control systems and a reset pulse generation circuit for preventing malfunctions on the same silicon chip substrate using one-chip C technology. Increasing number of parts in discrete component configuration, high cost,
Solving problems such as increased mounting area and difficulty in system design,
Furthermore, it is possible to provide a highly secure system.

In this way, in the microcomputer control system, the above-mentioned power supply control circuit section, reset pulse generation circuit section, and V-
It is important to consider this as a single subsystem when designing a total system that pursues safety.

From the perspective of the hardware configuration of the microcomputer control system,
In order to reduce the number of parts, reduce cost, reduce mounting area, and facilitate mounting, the subsystem that combines the power supply control circuit section and the reset pulse generation circuit section is integrated into a single chip IO, and various types of Incorporating it into a microcomputer control system will make the total system more compact, lower in price, easier to implement, and will widely provide a safety thinking system.

Hereinafter, the present invention will be explained in detail together with examples.

FIG. 2 is a block diagram of the hardware configuration of the microcomputer control system of the embodiment. In this embodiment, the supply power control circuit section and the reset pulse generation circuit section are divided into five parts as shown in the figure.
It is configured as one IO.

The power supply control circuit section receives power input from a power source such as a battery, thereby controlling the OPU LSI 2. I1
0 interface LSI3.1 (AM4.ROM5
It also outputs a stabilized output voltage to be supplied to the peripheral circuit 7 and to the reset pulse generation circuit section.

The reset pulse generation circuit section is operated by the output stabilizing voltage of the power supply control circuit section, and is operated by the OPU L
Outputs a signal to be supplied to SI.

FIG. 3 is a detailed block diagram of the IO8 in FIG. 2 above.

In the figure, 9 is a supply voltage control circuit diagram that outputs a stabilized output voltage by receiving power input. The output stabilization voltage of this supply voltage control section 9 is I! Although not limited to #, it is considered to be the power supply voltage for the entire microcomputer control system.

10 is a reset pulse generation circuit section, and an abnormality determination circuit section 11. It is composed of a changeover switch circuit s12 and a reset pulse generation oscillation circuit section 13.

The abnormality determination circuit section 11 is an L8114 consisting of L8l for microcomputer OPU or L8I for I10 interface.
By monitoring the program run signal (P-UN) supplied from the microcomputer, an abnormality (program runaway) in the microcomputer is determined, and an output signal to be supplied to the changeover switch circuit 12 is formed. This output signal of the abnormality determination circuit @11 is set to a level depending on whether the microcomputer operation is normal or abnormal.

When the operation of the L8I 14 is determined to be abnormal by the abnormality determination circuit s11, the changeover switch circuit section 12 outputs a pulse for operating the reset pulse generation oscillation circuit [13] in response.

The reset pulse generation oscillation circuit section 13 generates the LS according to the pulse notes supplied from the changeover switch circuit section 12.
611Ii forming a signal for supplying a reset input terminal of 114.

Reset pulse generation oscillation circuit: The section 13 includes a power-on reset circuit section (not shown) configured to detect the rise of the power supply voltage supplied from the supply power supply 1 and the control circuit section 9. Therefore, reset pulse generation oscillation circuit section 1
3 outputs a reset pulse to be supplied to the L8114 not only when an abnormal operation of the kL8114 is detected as described above, but also when the power is turned on.

By setting the power supply control circuit section 9 and the reset pulse generation circuit section 10 to 1 chip, it is possible to supply a reset pulse to L8114 when the microcomputer malfunctions (runaway) or when the power is turned on, thereby controlling the microcomputer. This will help prevent system malfunctions and ensure safety. Moreover, it becomes possible to supply a stabilized power supply to the entire microcomputer system.

FIG. 4 is a circuit diagram of another embodiment.

In the figure, reference numeral 9 denotes a stabilized power supply control circuit section, which itself has the same configuration as a known stabilized power supply control circuit. That is, the stabilized power supply control circuit section 9 includes a reference voltage generation circuit section VRF and a resistor R.

and R1, a voltage divider circuit and a differential amplifier circuit section OP.

It consists of a transistor Q and a control transistor Q1. The circuit section VRF, OP, resistor, R, and transistor Q are the reset pulse generation circuit 1s1.
0 and 1 using known monolithic IO technology.
Chippue is considered to be 0. Although not particularly limited, the control transistor Q is configured as an external component of the IC, considering that the amount of control power in the control transistor Q is relatively large.
It is coupled to external terminals P, P, of O. Voltage supplied from the stabilized power supply circuit to the microcomputer system
t can be arbitrarily set in degrees Celsius by appropriately setting the voltage division ratio determined by the reference voltage, resistance L, R, and K.

In the reset pulse generation circuit section 10, 11 operates a digital pulse filter 11111 to discriminate the program run signal (P4UN) from the microcomputer, and outputs an rHJ level signal when the microcomputer is normal, and outputs an rHJ level signal when the microcomputer is abnormal. This is an abnormality determination circuit that outputs an rLJ level signal.

12 is a switch circuit made up of a resistor R1 and a transistor Q.

13 is a capacitor 03, a constant current source 11 for charging this capacitor 01, a diode D, a resistor R3゜, R3
1. A constant current discharge circuit consisting of a transistor Q for discharging the capacitor O and a constant current source, a Shishimamitsu trigger comparator consisting of resistors R, R, )L, and an operational amplifier 2. The circuit includes a resistor R, , ) transistor Q, and a constant current source1. This is a reset pulse signal generation oscillation circuit composed of a switch circuit composed of resistors n, , R, , ) and a reset pulse output circuit composed of transistors Q6.

Above capacitor 0. is configured as an external component of the IO, and is connected between the external terminal P6 of the IC and the ground point of the circuit, although it is not limited to %, considering that it is made to have a relatively large capacitance value. .

FIG. 5 is a time chart of the circuit section of the present invention. FIGS. 5A and 5B show the input voltage V and the output voltage V of the stabilized power supply control circuit section 90. Figure 0 shows the waveform of the program/transmission 4P-RUN signal output from the L8114 (see Figure 3). The fifth diagram shows the waveform of the reset output signal Rgsg'r of the reset pulse generation oscillation circuit IO.

If the L8114 operates normally, the program run signal P-RUN is inverted in level, for example, every time a program is executed.

A rectangular wave signal with a relatively regular cycle corresponding to the program execution cycle is generated. On the other hand, if the microcomputer starts abnormal operation such as boogram runaway, the one program run signal P-RUN is set as a signal with a frequency or duty cycle below or above the regulation.

The operation of the illustrated circuit is as follows.

When the voltage +1Vin is turned on as shown in FIG. , are output as shown in FIG. 5B.

Immediately after turning on the power, the capacitor is 0. The photoelectric voltage of is zero, so the output of the Schmitt trigger comparator circuit is the regulated voltage V. It is set at a high level that is equivalent to ut. The high level output of the Schmitt trigger comparator circuit turns on the transistor Q, and the reset pulse signal tE8ET outputted to the terminal P is set at a low level equal to the ground potential. LS114 is reset by this reset pulse signal. That is, the reset pulse signal 4RESET is regarded as a system power-on reset signal.

When the power is turned on, the high level output of the Schmitt trigger comparator circuit also turns on transistor Q, so transistor Q4 is turned off. Therefore, the above capacitor 0. is charged via a constant current source I.

When a predetermined period of time has passed since the power was turned on, the capacitor 0. The charging voltage exceeds the high threshold voltage of the Schmitt trigger comparator circuit, causing the output of the Schmitt trigger comparator circuit to change from the high level to the low level. Since the operating state of the Schmitt trigger comparator circuit is reversed, its threshold voltage is changed to the low level side IIK.

The output of the Schmitt trigger comparator circuit is brought to a low level as described above.
-Q@ is turned off-state 1lIVC. The off-state 11 of the transistor Qs causes the reset output signal agsg
'r) is changed to 1 level, and as a result, the power-on reset state of the microcomputer is released.

Transistor Q is turned on if the microcomputer is operating normally. Therefore, transistor Q
, even if it is turned off as described above, the transistor Q
4 is the transistor Q mentioned above.

The off-state 1IVc is maintained by 1IVc. Above capacitor 0
, are maintained in a charged state by keeping the transistor Q4 in an off state. The output of the Schmitt trigger comparator circuit is accordingly set to low level Km.
held.

If the microcomputer is abnormal, the programmer ym number P-RU
The period of N or the duty cycle is out of the permissible range, and as a result, the output of the abnormality determination circuit 11 is set to a low level, and the transistor Q is turned off. The off-state of transistor Q causes transistor Q4 to have a constant current source 1. at its base. via ノ(
The Iasumi flow is now flowing and is turned on.

By turning on transistor Q4.

The charge in capacitor 01 begins to be discharged.

Due to an abnormality in the microcomputer, transistor Q is turned off.
continues, the capacitor 0. The photoelectric voltage is the low level side threshold 1 of the Schmitt trigger comparator circuit.
− voltage is lower than the field voltage. As a result, the output of the Schmitt trigger comparator circuit is set to -low level, and the reset pulse output signal Rg8BT is set to low level as shown in Figure 5. The above signal RIJ
L8114 etc. are reset by BT. When the operating state of the Schmitt trigger comparator circuit is reversed, the Schmitt trigger comparator circuit starts waiting for the high-level threshold voltage again.

Transistor Q is turned off in response to the output of the output trigger comparator circuit being brought to a high level.
lk will be given. Capacitor Oj begins to charge again as transistor Q4 is turned off. When the charging voltage of capacitor 010 exceeds the high level side threshold voltage of the Schmict trigger comparator circuit,
The output of this Shemite trigger comparator circuit is set to low level.

As a result, the microcomputer is automatically released from its reset state and starts operating again.

According to the present invention, the stabilized power supply control section and the glue set circuit section for preventing malfunction of the conventional microcomputer control system! 0
In contrast, these components are considered as essential subsystems for various microcomputer control systems, and can be integrated into a single chip IO, making the total microcomputer control system more compact, lower in price, and
This has the effect of facilitating implementation, simplifying system design, and providing a wide range of highly secure systems.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional microcomputer system hardware configuration, Fig. 2 is a block diagram of a microcomputer system hardware configuration using the present invention, and Fig. 3 is a block diagram of a specific embodiment. The figure is a circuit diagram of another embodiment.
The figure is a time chart explaining another embodiment. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A control circuit for stabilizing power supply to various electronic components in a microcomputer control system, a power-on reset pulse for initializing the microcomputer when the power is turned on, and detecting program runaway of the microcomputer. By doing this, you can minimize runaway programs and prevent system malfunctions.
A composite device for a microcomputer system, characterized in that an auto-reset pulse for ensuring safety and a reset pulse generation circuit section for generating the reset pulse are integrated into a single chip IO on the same silicon chip substrate. 2. The above microcomputer control system is an automotive microcomputer 7fl.
IJ? The microcomputer system composite device according to claim 8, characterized in that it is composed of an Il system. 3. As a means for generating an auto-reset pulse, a digital filter control circuit unit that monitors the program signal output from the microcontroller abnormality (runaway) VT icon, and a rectangular wave rooting circuit for generating the reset pulse. and a selector switch circuit section which has a predetermined output level when the microcomputer is normal or abnormal, and which stops the generation of reset pulses when the microcomputer is normal, and continues the rectangular wave failure operation and generates the reset pulse when the microcomputer is abnormal. Claims 1 and 11 are characterized in that:
A composite device for a microcomputer system according to item 2. 4. A composite device for a microcomputer system according to claims 1 and 2, characterized in that the device is provided with at least one output terminal of normal phase and negative phase as a reset output of the reset pulse generation circuit section. .