CN208000466U - A kind of watchdog circuit in car body controller - Google Patents
A kind of watchdog circuit in car body controller Download PDFInfo
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- CN208000466U CN208000466U CN201721928520.4U CN201721928520U CN208000466U CN 208000466 U CN208000466 U CN 208000466U CN 201721928520 U CN201721928520 U CN 201721928520U CN 208000466 U CN208000466 U CN 208000466U
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Abstract
The utility model discloses the watchdog circuits in a kind of car body controller, including the first capacitance, the second capacitance, third capacitance, the 4th capacitance, the 5th capacitance, the 6th electricity, the 7th capacitance, first resistor, second resistance, 3rd resistor, the 4th resistance, the 5th resistance, the 6th resistance, the first triode, the second triode, third transistor, NAND gate chip.The utility model can be realized after microcontroller cisco unity malfunction, reset microcontroller, enable to work normally, and improve the whole performance reliability and stability of structure, and there is simple in structure, lower-cost advantages.
Description
Technical field
The utility model is related to the watchdog circuits in a kind of car body controller.
Background technology
Electronic product often uses microcontroller, if the electric appliance environment that uses of electronic product is relatively more severe or microcontroller matter
Measuring unqualified or microcontroller programming software, there are BUG etc., make microcontroller cisco unity malfunction, when microcontroller cannot normal work
After work occurs, if it is possible to reset microcontroller, absolutely in most cases, microcontroller can return to normal operating conditions.
Utility model content
The purpose of this utility model is to provide the watchdog circuit in a kind of car body controller, when microcontroller cannot normal work
After work, microcontroller can be resetted, enables to work normally, and there is simple in structure, lower-cost advantages.
Technical solution adopted by the utility model to solve its technical problems is:A kind of house dog electricity in car body controller
Road, including the first capacitance, the second capacitance, third capacitance, the 4th capacitance, the 5th capacitance, the 6th capacitance, the 7th capacitance, the first electricity
Resistance, second resistance, 3rd resistor, the 4th resistance, the 5th resistance, the 6th resistance, the first triode, the second triode, the three or three
Pole pipe, NAND gate chip,
One end of first capacitance and microcontroller feeding-dog signal output end connect, and the other end distinguishes one end of the second capacitance, the
The collector of one triode, one end of the 4th capacitance, one end of second resistance, NAND gate chip the second input terminal connect;The
The base stage of the other end of two capacitances and one end of first resistor, the first triode connects;3rd resistor is connected to NOT gate chip
Between output end and the base stage of the second triode;One end of the collector of second diode and the 4th resistance, the 5th capacitance one
End connects respectively;The other end of 5th capacitance and one end of the 5th resistance, one end of the 6th capacitance, third transistor base stage point
Do not connect;One end of the collector of third transistor and the 6th resistance, one end of the 7th capacitance, monolithic processor resetting signal input part
Connect;
The other end of second resistance, one end of third capacitance, the first input end of NAND gate chip, NAND gate chip
Another termination VCC networks of power supply positive input, the emitter of the second triode, the 6th resistance;
The other end of first resistor, the emitter of the first triode, the other end of the 4th capacitance, third capacitance it is another
End, the power supply negative input terminal of NAND gate chip, the other end of the 4th resistance, the other end of the 5th resistance, the 6th capacitance it is another
One end, the 7th capacitance the other end ground connection.
Second capacitance, third capacitance, the 4th capacitance, the 5th capacitance, the 6th capacitance, the 7th capacitance, first resistor, the second electricity
Resistance, 3rd resistor, the 4th resistance, the 5th resistance, the 6th resistance, the first triode, the second triode, third transistor, with it is non-
Door chip.
Further, NAND gate chip is 74HC00 chips.
The beneficial effects of the utility model:Watchdog circuit in this car body controller can be realized when microcontroller cannot be just
Often after work, microcontroller can be resetted, enables to work normally, improves integrally-built performance reliability and stability,
And there is simple in structure, lower-cost advantages.When microcontroller works normally, the output feeding-dog signal that can continue (feeds dog letter
Number:It is exported outward by microcontroller, period 20ms, low level 0V, high level is the square wave of 5V;), will not be triggered conducting one
Secondary, monolithic processor resetting signal will not be effective, and microcontroller will not reset;When microcontroller is abnormal situation, what is exported outward feeds dog
Lasting export is that high either lasting output is low or lasting export is to change in high-impedance state or period by signal, when hello dog
Signal by lasting output be high either lasting output to be low or lasting output be high-impedance state when, the conducting that can be triggered is primary, list
Piece machine reset signal is effective, and microcontroller can reset once, is that product is withdrawn from endless loop;Avoid product dead because software enters
Cycle, desired function used failure, caused by product repairing expense.
Below with reference to drawings and examples, the utility model is described in detail.
Description of the drawings
Fig. 1 is the circuit diagram of the utility model.
Specific implementation mode
Embodiment, the as shown in Figure 1 watchdog circuit in a kind of car body controller, including the first capacitance C1, the second capacitance
C2, third capacitance C3, the 4th capacitance C4, the 5th capacitance C5, the 6th capacitance C6, the 7th capacitance C7, first resistor R1, second resistance
R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the first triode Q1, the second triode Q2, third
Triode Q3, NAND gate chip U3A,
One end of first capacitance C1 and microcontroller feeding-dog signal output end connect, and the other end distinguishes the one of the second capacitance C2
End, the collector of the first triode Q1, one end of the 4th capacitance C4, one end of second resistance R1, NAND gate chip it is second defeated
Enter end 2 to connect;The base stage of the other end of the second capacitance C2 and one end of first resistor R1, the first triode Q1 connects;Third electricity
Resistance R3 is connected between the output end 3 of NOT gate chip U3A and the base stage of the second triode Q2;The collector of second diode Q2 and
One end of 4th resistance R4, one end of the 5th capacitance C5 connect respectively;The other end of 5th capacitance C5 and the one of the 5th resistance R5
End, one end of the 6th capacitance C6, third transistor Q3 base stage connect respectively;The collector of third transistor Q3 and the 6th resistance
One end of R6, one end of the 7th capacitance C7, monolithic processor resetting signal input part connect;
The other end of second resistance R2, one end of the C3 of third capacitance, NAND gate chip U3A first input end 1, with it is non-
Another termination VCC networks of the power supply positive input 14 of door chip U3A, the emitter of the second triode Q2, the 6th resistance R6;
The other end of first resistor R1, the emitter of the first triode Q1, the other end of the 4th capacitance C4, third capacitance C3
The other end, the power supply negative input terminal 7 of NAND gate chip U3A, the other end of the 4th resistance R4, the 5th resistance R5 it is another
End, the other end of the 6th capacitance C6, the 7th capacitance C7 the other end ground connection.
Second capacitance C2, third capacitance C3, the 4th capacitance C4, the 5th capacitance C5, the 6th capacitance C6, the 7th capacitance C7,
One resistance R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the first triode Q1,
Second triode Q2, third transistor Q3, NAND gate chip U3A.
Microcontroller work normally when, can continue output feeding-dog signal feeding-dog signal:It is exported outward by microcontroller, the period is
20ms, low level 0V, high level are the square wave of 5V;, Q3 will not be triggered, and conducting is primary, and monolithic processor resetting signal does not have
Effect, microcontroller will not reset;
When microcontroller is abnormal situation, lasting output is high by the feeding-dog signal exported outward or lasting export is low
Either lasting output is that either the period changes when lasting output is height by feeding-dog signal or lasting output is low high-impedance state
Or lasting output, when being high-impedance state, Q3 can be triggered, and conducting is primary, and monolithic processor resetting signal is effective, and microcontroller can reset one
It is secondary;
When changing in the feeding-dog signal period, if the period becomes smaller, Q3 will not be triggered conducting once, monolithic processor resetting
Signal will not be effective, and microcontroller will not reset;If the period becomes larger, and it is big to a certain extent when, Q3 can be triggered conducting one
Secondary, monolithic processor resetting signal is effective, and microcontroller can reset once.
As shown in Figure 1, the utility model detailed operation principle is as follows:
Microcontroller work normally when, can continue output feeding-dog signal:Period is 20ms, low level 0V, and high level is
The square wave of 5V.
Feeding-dog signal, when feeding-dog signal is switched to 5V by 0V, due to the charging process of C2, can make electricity by capacitance C1
Resistance R1 generates high potential over the ground (with Q1 connected ends), so that triode Q1 is connected, at this point, capacitance C4 is discharged over the ground by Q1.
VCC is charged by R2 to capacitance C4.
During the periodic discharge of Q1 and VCC are charged by R2, the electricity of capacitance C4 (with the 2nd foot connected ends of U3A)
Corrugating is the period:The triangular wave of 20ms, low level 0V, high level are aV (a<0.7*VCC).
When 74HC00 chip input voltages are less than 0.7*VCC, it is believed that the input pin is low level, when input voltage is not small
When 0.7*VCC, it is believed that the input pin is high level.
When feeding-dog signal is normal, the 1st foot voltage of 74HC00 chips is VCC, which is high level, the 2nd foot
Voltage is aV (a<0.7*VCC), the input pin be low level, so the 3rd foot output be high level, triode Q2 by, from
And Q3 is by monolithic processor resetting invalidating signal, microcontroller does not reset.
When the often work of monolithic exception, lasting output is that either persistently output is that low or lasting output is to height by feeding-dog signal
High-impedance state.
Feeding-dog signal can not be by capacitance C1, and triode Q1 base voltages are 0V by R1 connections, and Q1 is by will not
Periodic discharge is carried out to capacitance C4.
As VCC is ceaselessly charged to C4 by R2, the voltage wave of capacitance C4 (with the 2nd foot connected ends of U3A) gradually rises,
When voltage is not less than 0.7*VCC, the 2nd foot input pin of 74HC00 chips is high level;1st foot voltage of 74HC00 chips
For VCC, which is high level, since 74HC00 chips are a NAND gates, so the output of the 3rd foot is low level;
When the output of the 3rd foot of 74HC00 chips is low level, triode Q2 conductings, the collector and emitter that VCC passes through Q2
It charges to capacitance C5, during C5 charges, resistance R5 (end being connected with Q3 base stages) voltage is height, and Q3 is switched on, monolithic
Machine reset signal is pulled low, and reset signal is pulled low.
After capacitance C5 is fully charged, Q2 is by Q3 is by monolithic processor resetting signal is set to height again, while C5 passes through electricity
Hinder R4 electric discharges, when often work abnormal for monolithic next time, feeding-dog signal by lasting output be it is high either persistently export be it is low or
When lasting output is high-impedance state, triggering single-chip microcomputer signal is dragged down by the short time prepares.
When the often work of monolithic exception, when the feeding-dog signal period changes, if the period becomes smaller, operation principle is with 1)) institute
It states equally, monolithic processor resetting signal will not be effective, and microcontroller will not reset;
If the period becomes larger, and disclosure satisfy that during the periodic discharge of Q1 and VCC are charged by R2, capacitance C4
The voltage waveform of (with the 2nd foot connected ends of U3A) is the triangular wave in period, and low level 0V, high level is not less than 0.7*VCC
When, operation principle is for example 2)) it is described, microcontroller can reset once, and otherwise, operation principle is for example 1)) described, microcontroller will not reset.
The utility model relevant parameter explanation:
Feeding-dog signal frequency is higher, better to the discharge effect of capacitance C4, and R2 resistances are bigger, and the charging time is longer,
C4 is bigger, and the electric energy moon of storage is more, so, the corresponding time of the utility model depends primarily on R2, C4 and feeds setting for dog frequency
It sets.
When normally feeding dog, the size of the voltage value of the 2nd foots of NAND gate 74HC00 is mainly determined by R2, C4 and hello dog frequency
Fixed, the NAND gate of the utility model can select the chip of other models to replace, and can refer to the threshold values of NAND gate low and high level,
Setting R2, C4 appropriate and hello dog frequency.
Resistance R4 resistance values are bigger, and the abnormal minimum time interval for feeding dog is bigger twice in succession for identification, and ring is used according to product
The requirements such as border, the value of setting R4 appropriate.
The utility model is exemplarily described above in association with attached drawing.Obviously, the utility model implements not
It is limited by aforesaid way.As long as using the various unsubstantialities of the methodology and technical solution progress of the utility model
Improvement;Or it is not improved, above-mentioned design and technical solution by the utility model directly apply to other occasions, at this
Within the protection domain of utility model.
Claims (2)
1. the watchdog circuit in a kind of car body controller, it is characterised in that:Including the first capacitance C1, the second capacitance C2, third
Capacitance C3, the 4th capacitance C4, the 5th capacitance C5, the 6th capacitance C6, the 7th capacitance C7, first resistor R1, second resistance R2, third
Resistance R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the first triode Q1, the second triode Q2, third transistor
Q3, NAND gate chip U3A,
One end of first capacitance C1 and microcontroller feeding-dog signal output end connect, and the other end distinguishes one end of the second capacitance C2, the
Second input of the collector, one end of the 4th capacitance C4, one end of second resistance R1, NAND gate chip U3A of one triode Q1
End (2) connects;The base stage of the other end of the second capacitance C2 and one end of first resistor R1, the first triode Q1 connects;Third electricity
Resistance R3 is connected between the output end (3) of NOT gate chip U3A and the base stage of the second triode Q2;The collector of second diode Q2
Connect respectively with one end of the 4th resistance R4, one end of the 5th capacitance C5;The other end of 5th capacitance C5 and the 5th resistance R5's
One end, one end of the 6th capacitance C6, third transistor Q3 base stage connect respectively;The collector of third transistor Q3 and the 6th electricity
Resistance one end of R6, one end of the 7th capacitance C7, monolithic processor resetting signal input part connect;
The other end of second resistance R2, one end of the C3 of third capacitance, the first input end (1) of NAND gate chip U3A, NAND gate
Another termination VCC networks of the power supply positive input (14) of chip U3A, the emitter of the second triode Q2, the 6th resistance R6;
The other end of first resistor R1, the emitter of the first triode Q1, the other end of the 4th capacitance C4, third capacitance C3 it is another
One end, the power supply negative input terminal (7) of NAND gate chip U3A, the other end of the 4th resistance R4, the 5th resistance R5 the other end,
The other end of 6th capacitance C6, the other end ground connection of the 7th capacitance C7.
2. the watchdog circuit in car body controller according to claim 1, it is characterised in that:NAND gate chip U3A is
74HC00 chips.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721928520.4U CN208000466U (en) | 2017-12-30 | 2017-12-30 | A kind of watchdog circuit in car body controller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721928520.4U CN208000466U (en) | 2017-12-30 | 2017-12-30 | A kind of watchdog circuit in car body controller |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208000466U true CN208000466U (en) | 2018-10-23 |
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ID=63836597
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721928520.4U Active CN208000466U (en) | 2017-12-30 | 2017-12-30 | A kind of watchdog circuit in car body controller |
Country Status (1)
| Country | Link |
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| CN (1) | CN208000466U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113162602A (en) * | 2021-04-17 | 2021-07-23 | 青岛京先仪表有限公司 | Low-cost watchdog circuit design realized by using gate circuit |
-
2017
- 2017-12-30 CN CN201721928520.4U patent/CN208000466U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113162602A (en) * | 2021-04-17 | 2021-07-23 | 青岛京先仪表有限公司 | Low-cost watchdog circuit design realized by using gate circuit |
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