CN204258758U - A kind of power down does not produce the reset circuit of reset signal - Google Patents
A kind of power down does not produce the reset circuit of reset signal Download PDFInfo
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- CN204258758U CN204258758U CN201420758594.8U CN201420758594U CN204258758U CN 204258758 U CN204258758 U CN 204258758U CN 201420758594 U CN201420758594 U CN 201420758594U CN 204258758 U CN204258758 U CN 204258758U
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Abstract
The utility model discloses the reset circuit that a kind of power down does not produce reset signal, comprise integrated circuit U391, charging and discharging circuit and reset switch pipe circuit; Described integrated circuit U391 integrates the function of reset, detection of power loss and house dog, and the reset signal output RESET of described integrated circuit U391 connects one end of charging and discharging circuit, and the other end of described charging and discharging circuit connects reset switch pipe circuit.This reset circuit provides reset signal to the single chip circuit having backup battery to power when externally fed powers on the initial stage, all reset signal can not be produced after the power down initial stage and power down of externally fed, thus can guarantee no matter single-chip microcomputer is operated in which kind of power supply state described, can normally work all the time.
Description
Technical field
The utility model relates to a kind of reset circuit, and specifically a kind of power down does not produce the reset circuit of reset signal.
Background technology
Along with the development of society, the intelligence degree of all trades and professions is also more and more higher, and intelligentized key be unable to do without single-chip microcomputer, and people are while utilization single-chip microcomputer, corresponding just along with the reset of single-chip microcomputer single-chip microcomputer.On market, a lot of intelligentized instrument all requires two kinds of supply power modes, one is powered by external power source VDD, two is powered by backup battery after outside power vd D power down, in order to after making instrument power down battery-powered be switched to externally fed time can normally work, this just requires that single-chip microcomputer hardware produces and resets.And existing reset circuit all can be affected after the power down initial stage and power down of externally fed, produce reset signal, thus affect single-chip microcomputer and to reset normally work.
Utility model content
The purpose of this utility model is to provide a kind of power down not produce the reset circuit of reset signal, this reset circuit provides reset signal to the single chip circuit having backup battery to power when externally fed powers on the initial stage, after the power down initial stage and power down of externally fed, all can not produce reset signal.
For achieving the above object, the utility model provides following technical scheme:
Power down does not produce a reset circuit for reset signal, comprises integrated circuit U391, charging and discharging circuit and reset switch pipe circuit; Described integrated circuit U391 integrates the function of reset, detection of power loss and house dog, hand-reset input MR and the WDT output WDO of integrated circuit U391 are interconnected, and the WDT input WDI of integrated circuit U391 is connected with single-chip microcomputer; The voltage input end VCC of described integrated circuit U391 connects external power source VDD and shunt capacitance C391 simultaneously, and the other end of described shunt capacitance C391 connects the earth terminal GND of integrated circuit U391; The inside detection of power loss output PFO of described integrated circuit U391 is also connected with single-chip microcomputer, the inside detection of power loss input PFI of integrated circuit U391 connects shunt capacitance C392, divider resistance R388 and divider resistance R389 simultaneously, the other end of described shunt capacitance C392 and the equal ground connection of the other end of divider resistance R389, the other end of described divider resistance R388 connects backup battery VHH; The reset signal output RESET of described integrated circuit U391 connects one end of charging and discharging circuit, and the other end of described charging and discharging circuit connects reset switch pipe circuit.
As further program of the utility model: described charging and discharging circuit comprises the coupling capacitance C393 and resistance R390 that are connected with reset signal output RESET simultaneously, the resistance R391 be connected with the coupling capacitance C393 other end, and the pull down resistor R392 to be connected with the resistance R390 other end, and this end ground connection of pull down resistor R392, the other end of pull down resistor R392 is connected with resistance R391.
As further program of the utility model: described reset switch pipe circuit comprises triode Q301, and the pull-up resistor R393, decoupling capacitor C394 and the reset output terminal RST that are connected with triode Q301 collector electrode; Described triode Q301 uses as the electronic control switch of reset signal in circuit, its base stage is connected with pull down resistor R392 and resistance R391 simultaneously, the other end of described decoupling capacitor C394 and the emitter of triode Q301 ground connection simultaneously, the other end of described pull-up resistor R393 connects power supply BVCC; Described reset output terminal RST is connected with the input of reset circuit of SCM.
As further program of the utility model: described power supply BVCC is merged by backup battery VHH and external power source VDD and produces.
As further program of the utility model: described integrated circuit U391 sets a threshold voltage, when single-chip microcomputer power powered to external power source VDD by backup battery VHH power switching time, the input voltage of external power source VDD is greater than the threshold voltage of this setting.
As further program of the utility model: the inside detection of power loss input PFI of described integrated circuit U391 is also provided with a threshold values, when being input to the voltage of inner detection of power loss input PFI lower than when setting threshold values, detection of power loss output sends a signal to single-chip microcomputer.
Compared with prior art, the beneficial effects of the utility model are:
This reset circuit provides reset signal to the single chip circuit having backup battery to power when externally fed powers on the initial stage, all reset signal can not be produced after the power down initial stage and power down of externally fed, thus can guarantee no matter single-chip microcomputer is operated in which kind of power supply state described, can normally work all the time.
Accompanying drawing explanation
Fig. 1 is the circuit diagram that power down does not produce the reset circuit of reset signal.
Embodiment
Be described in more detail below in conjunction with the technical scheme of embodiment to this patent.
Refer to Fig. 1, a kind of power down does not produce the reset circuit of reset signal, comprises integrated circuit U391, charging and discharging circuit and reset switch pipe circuit; Described integrated circuit U391 integrates the function of reset, detection of power loss and house dog, hand-reset input MR and the WDT output WDO of integrated circuit U391 are interconnected, and the WDT input WDI of integrated circuit U391 is connected with single-chip microcomputer; The voltage input end VCC of described integrated circuit U391 connects external power source VDD and shunt capacitance C391 simultaneously, and the other end of described shunt capacitance C391 connects the earth terminal GND of integrated circuit U391; The inside detection of power loss output PFO of described integrated circuit U391 is also connected with single-chip microcomputer, detect externally fed whether power down, the inside detection of power loss input PFI of integrated circuit U391 connects shunt capacitance C392, divider resistance R388 and divider resistance R389 simultaneously, the other end of described shunt capacitance C392 and the equal ground connection of the other end of divider resistance R389, the other end of described divider resistance R388 connects backup battery VHH; The reset signal output RESET of described integrated circuit U391 connects one end of charging and discharging circuit, and the other end of described charging and discharging circuit connects reset switch pipe circuit.
Described charging and discharging circuit comprises the coupling capacitance C393 and resistance R390 that are connected with reset signal output RESET simultaneously, the resistance R391 be connected with the coupling capacitance C393 other end, and the pull down resistor R392 to be connected with the resistance R390 other end, and this end ground connection of pull down resistor R392, the other end of pull down resistor R392 is connected with resistance R391.
Described reset switch pipe circuit comprises triode Q301, and the pull-up resistor R393, decoupling capacitor C394 and the reset output terminal RST that are connected with triode Q301 collector electrode; Described triode Q301 uses as the electronic control switch of reset signal in circuit, its base stage is connected with pull down resistor R392 and resistance R391 simultaneously, the other end of described decoupling capacitor C394 and the emitter of triode Q301 ground connection simultaneously, the other end of described pull-up resistor R393 connects power supply BVCC; Described power supply BVCC is merged by backup battery VHH and external power source VDD and produces, and is supplied to the circuit not power-off such as single-chip microcomputer and runs and use; Described reset output terminal RST is connected with the input of reset circuit of SCM, and the reset signal produced by this circuit is supplied to single chip circuit and uses.
Operation principle of the present utility model is:
In the utility model, described single-chip microcomputer has two kinds of supply power modes, and one is powered by external power source VDD, and two is powered by backup battery VHH.Powered by external power source VDD when single-chip microcomputer normally works, external power source VDD powers after power down and is powered by backup battery VHH.The inside detection of power loss input PFI of described integrated circuit U391, voltage input end VCC, the signal output part of reset switch pipe circuit is all connected with electric capacity, its role is to stablize, level and smooth input and output signal.
In the utility model, the reset pin of single-chip microcomputer is that low level resets, single-chip microcomputer powered by external power source VDD and by external power source VDD power switching to when being powered by backup battery VHH, reset circuit does not produce reset signal, single-chip microcomputer guarantees that reset pin is high level all the time, does not produce reset; Single-chip microcomputer is when being powered to external power source VDD by backup battery VHH power switching, and reset circuit produces reset signal, and monolithic processor resetting pin is low level, produces and resets.
When single-chip microcomputer enters endless loop because of certain reason, the WDT input WDI no signal input of integrated circuit U391, after certain hour, WDT output WDO exports a low ordinary mail number and produces a reset signal to hand-reset input MR, integrated circuit U391.When external power source VDD powers power down, single-chip microcomputer is that backup battery VHH powers by external power source VDD power switching, and triode Q301 is because drop-down cut-off, and reset signal is high level by pull-up resistor R393 pull-up, and single-chip microcomputer receives high level, does not produce reset.
Described integrated circuit U391 sets a threshold voltage, when single-chip microcomputer power powered to external power source VDD by backup battery VHH power switching time, the input voltage of external power source VDD is greater than the threshold voltage of this setting, integrated circuit U391 sends a reset signal, coupling capacitance C393 charges, and triode Q301 conducting, drags down signal, single-chip microcomputer receives low flat reset signal, completes hardware reset.And external power source VDD powered can not produce reset signal after power down initial stage and power down, therefore do not affect the normal work of single chip circuit, single-chip microcomputer runs between not, powered to backup battery VHH by external power source VDD power switching.
The inside detection of power loss input PFI of described integrated circuit U391 is also provided with a threshold values, when being input to the voltage of inner detection of power loss input PFI lower than when setting threshold values, detection of power loss output sends a signal to single-chip microcomputer, and single-chip microcomputer carries out corresponding analysis and process.
Above the better embodiment of this patent is explained in detail, but this patent is not limited to above-mentioned execution mode, in the ken that those of ordinary skill in the art possesses, can also makes a variety of changes under the prerequisite not departing from this patent aim.
Claims (6)
1. power down does not produce a reset circuit for reset signal, it is characterized in that, comprises integrated circuit U391, charging and discharging circuit and reset switch pipe circuit; Described integrated circuit U391 integrates the function of reset, detection of power loss and house dog, hand-reset input MR and the WDT output WDO of integrated circuit U391 are interconnected, and the WDT input WDI of integrated circuit U391 is connected with single-chip microcomputer; The voltage input end VCC of described integrated circuit U391 connects external power source VDD and shunt capacitance C391 simultaneously, and the other end of described shunt capacitance C391 connects the earth terminal GND of integrated circuit U391; The inside detection of power loss output PFO of described integrated circuit U391 is also connected with single-chip microcomputer, the inside detection of power loss input PFI of integrated circuit U391 connects shunt capacitance C392, divider resistance R388 and divider resistance R389 simultaneously, the other end of described shunt capacitance C392 and the equal ground connection of the other end of divider resistance R389, the other end of described divider resistance R388 connects backup battery VHH; The reset signal output RESET of described integrated circuit U391 connects one end of charging and discharging circuit, and the other end of described charging and discharging circuit connects reset switch pipe circuit.
2. power down according to claim 1 does not produce the reset circuit of reset signal, it is characterized in that, described charging and discharging circuit comprises the coupling capacitance C393 and resistance R390 that are connected with reset signal output RESET simultaneously, the resistance R391 be connected with the coupling capacitance C393 other end, and the pull down resistor R392 to be connected with the resistance R390 other end, and this end ground connection of pull down resistor R392, the other end of pull down resistor R392 is connected with resistance R391.
3. power down according to claim 2 does not produce the reset circuit of reset signal, it is characterized in that, described reset switch pipe circuit comprises triode Q301, and the pull-up resistor R393, decoupling capacitor C394 and the reset output terminal RST that are connected with triode Q301 collector electrode; Described triode Q301 uses as the electronic control switch of reset signal in circuit, its base stage is connected with pull down resistor R392 and resistance R391 simultaneously, the other end of described decoupling capacitor C394 and the emitter of triode Q301 ground connection simultaneously, the other end of described pull-up resistor R393 connects power supply BVCC; Described reset output terminal RST is connected with the input of reset circuit of SCM.
4. power down according to claim 3 does not produce the reset circuit of reset signal, it is characterized in that, described power supply BVCC is merged by backup battery VHH and external power source VDD and produces.
5. the reset circuit of reset signal is not produced according to the power down one of claim 1-4 Suo Shu, it is characterized in that, described integrated circuit U391 sets a threshold voltage, when single-chip microcomputer power powered to external power source VDD by backup battery VHH power switching time, the input voltage of external power source VDD is greater than the threshold voltage of this setting.
6. power down according to claim 5 does not produce the reset circuit of reset signal, it is characterized in that, the inside detection of power loss input PFI of described integrated circuit U391 is also provided with a threshold values, when being input to the voltage of inner detection of power loss input PFI lower than when setting threshold values, detection of power loss output sends a signal to single-chip microcomputer.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420758594.8U CN204258758U (en) | 2014-12-08 | 2014-12-08 | A kind of power down does not produce the reset circuit of reset signal |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420758594.8U CN204258758U (en) | 2014-12-08 | 2014-12-08 | A kind of power down does not produce the reset circuit of reset signal |
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| CN204258758U true CN204258758U (en) | 2015-04-08 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106094808A (en) * | 2016-08-15 | 2016-11-09 | 威胜集团有限公司 | Controller reset circuit and the measuring instrument made with this circuit |
| CN106760993A (en) * | 2016-12-12 | 2017-05-31 | 上海图正信息科技股份有限公司 | A kind of electronic lock |
| CN107707233A (en) * | 2017-11-03 | 2018-02-16 | 中国电子科技集团公司第五十四研究所 | A kind of reset circuit for preventing instant power-down from causing secondary reset |
-
2014
- 2014-12-08 CN CN201420758594.8U patent/CN204258758U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106094808A (en) * | 2016-08-15 | 2016-11-09 | 威胜集团有限公司 | Controller reset circuit and the measuring instrument made with this circuit |
| CN106760993A (en) * | 2016-12-12 | 2017-05-31 | 上海图正信息科技股份有限公司 | A kind of electronic lock |
| CN106760993B (en) * | 2016-12-12 | 2019-08-20 | 上海图正信息科技股份有限公司 | A kind of electronic lock |
| CN107707233A (en) * | 2017-11-03 | 2018-02-16 | 中国电子科技集团公司第五十四研究所 | A kind of reset circuit for preventing instant power-down from causing secondary reset |
| CN107707233B (en) * | 2017-11-03 | 2020-09-01 | 中国电子科技集团公司第五十四研究所 | Reset circuit for preventing instantaneous power failure from causing secondary reset |
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