CN1834850A - Protection circuit - Google Patents
Protection circuit Download PDFInfo
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- CN1834850A CN1834850A CN 200510033510 CN200510033510A CN1834850A CN 1834850 A CN1834850 A CN 1834850A CN 200510033510 CN200510033510 CN 200510033510 CN 200510033510 A CN200510033510 A CN 200510033510A CN 1834850 A CN1834850 A CN 1834850A
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- 230000001681 protective effect Effects 0.000 claims abstract 4
- 238000006243 chemical reaction Methods 0.000 claims description 33
- 238000009434 installation Methods 0.000 claims description 21
- 230000005669 field effect Effects 0.000 claims description 8
- 238000010586 diagram Methods 0.000 description 4
- 230000002093 peripheral effect Effects 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 229910018095 Ni-MH Inorganic materials 0.000 description 1
- 229910018477 Ni—MH Inorganic materials 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- RFHAOTPXVQNOHP-UHFFFAOYSA-N fluconazole Chemical compound C1=NC=NN1CC(C=1C(=CC(F)=CC=1)F)(O)CN1C=NC=N1 RFHAOTPXVQNOHP-UHFFFAOYSA-N 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
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- Charge And Discharge Circuits For Batteries Or The Like (AREA)
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Abstract
The invention is a protective circuit, applied to electric system of an electronic device, used to preventing a host computer being power-off at once if main battery is removed when the electronic device is in ON state to protect in-system load components from damage because of stable voltage, and having data security. Therefore, it uses plural switch transistors and microprocessor reset circuit to cut off power supply of the microprocessor and makes voltage of an AC converting power supply unable to be supplied to the load components after the main battery is removed, so as to achieve the system cutting-off purpose.
Description
[Ji Intraoperative field]
The invention relates to a kind of holding circuit, and particularly relevant for a kind of holding circuit that is applied to the battery electric power system.
[Bei Jing Ji Intraoperative]
The electric system of general electronic installation, its main power supply comprises AC power supplies and DC power supply.AC power supplies is provided (for example source power supply of voltage 110V or 220V) by external power company, and AC power supplies converts lower DC voltage (for example 3.7V or 5V) to via a-c transducer (AC Adapter), uses for the required electric power of system load element.In addition, the DC power supply is provided (for example 3.6V or 5V) or outside DC voltage to be provided by intrasystem main battery, and the DC power supply also can convert the required electric power of system load element to via direct current transducer (DC Converter), is suitable for the fixed voltage (for example 5V or 3.3V) of system load element running with arrival.With the mobile phone is example, its inner microprocessor, storer, display, and perhaps peripherals all can be considered the some of system load element.
Fig. 1 is the block scheme of the electric system of existing a kind of electronic installation.Please refer to Fig. 1, this electronic installation 100 for example is mobile phone, notebook computer, PDA, palm PC or the like.Have a microprocessor 110 in the host computer system of electronic installation 100, in order to computing and drive peripheral load elements, and the power source of microprocessor 110 comprises the DC voltage of an a-c transducer 120 and the direct supply of a main battery 130.When microprocessor 110 either-ors received the DC voltage of the DC voltage of a-c transducer 120 or main battery 130, the voltage in the host computer system is in steady state (SS) and microprocessor 110 can be operated under the normal boot-strap state.In addition, when the undertension of main battery 130, a-c transducer 120 is inserted in the electronic installations 100, the then action that will charge to main battery 130 of a-c transducer 120 is till the electric weight of main battery 130 is saturated.
It should be noted that, under the state of start, if a-c transducer 120 is inserted in the electronic installations 100, and with main battery 130 when pulling out in the electronic installation 100, because the voltage of host computer system acutely descends, cause the spread of voltage of host computer system easily and cause the system load component wear.In addition, the microprocessor 110 of some host computer system has independent reserve battery (not shown) power supply, under the state of start, if with main battery 130 by pulling out in the electronic installation 100 when putting back to again after the several seconds, because microprocessor 110 also has the voltage of reserve battery, therefore microprocessor 110 also is under the open state, causes the system load component wear but the voltage of host computer system is still unstable.For example the SIM card of mobile phone is damaged under the situation of spread of voltage easily, and the data of can't doing is maintained secrecy with shortcomings such as identification users.
[summary of the invention]
The object of the present invention is to provide a kind of holding circuit, in order to preventing electronic installation under open state, if when main battery pulled out, host computer system will be cut off the power supply immediately, can be to guarantee the system load element because of spread of voltage does not damage, and with data security.
For reaching above-mentioned purpose of the present invention, the present invention proposes a kind of holding circuit, is applicable in the electric system of an electronic installation, and the electric system of this electronic installation has a main battery and and exchanges conversion electric power.Described holding circuit comprises a unidirectional breakover element, an on-off circuit and a microprocessor at least; wherein the input end of unidirectional breakover element is connected in the voltage output end of main battery, and the output terminal of unidirectional breakover element is connected in the voltage output end that exchanges conversion electric power.In addition, on-off circuit has one first switching transistor, a second switch transistor and a resistance, and the grid of first switching transistor couples mutually with the voltage output end of main battery, and resistance connects the drain electrode and the voltage output end that exchanges conversion electric power of first switching transistor.In addition, the transistorized grid of second switch couples mutually with the drain electrode of first switching transistor, and the second switch transistor drain couples mutually with a reset circuit of microprocessor, and the voltage of reset circuit is logic low during reset (reset).Moreover the transistorized source electrode of second switch couples mutually with a system power supply control end of microprocessor, and the system power supply control end couples mutually with the voltage output end that exchanges conversion electric power, and the voltage of setting system power supply control end when driving is logic low.
Compared to prior art, the present invention is because of adopting the reset circuit of microprocessor, with the dump of microprocessor, to reach the purpose of outage.Therefore, under usual off-mode, pull out main battery, can not have any impact for microprocessor, if under open state, pull out main battery, host computer system will be cut off the power supply immediately, can be to guarantee the system load assembly because of spread of voltage does not damage, and with data security.
[description of drawings]
Fig. 1 is the block scheme of the electric system of existing a kind of electronic installation.
Fig. 2 is the circuit diagram of a kind of holding circuit of a preferred embodiment of the present invention.
Fig. 3 is the synoptic diagram of the another kind of unidirectional breakover element of the present invention.
[embodiment]
Please refer to Fig. 2, the circuit diagram for a kind of holding circuit of a preferred embodiment of the present invention is applicable in the electric system of an electronic installation.The electric system of this electronic installation 200 comprises that a main battery 210 and exchanges conversion electric power 220, main battery 210 for example is chargeable secondary cell, and main battery 210 can provide the DC voltage (load elements to the host computer system of 3.6V ~ 5V) for example, and load elements can be operated under the voltage steady state (SS).Main battery 210 is Ni-MH battery, lithium battery or the like for example.In addition, exchange conversion electric power 220 for example will be connected to outside source power supply (for example 110V or 220V) via an AC converter alternating voltage, after overcommutation/filtering, be converted to DC voltage (for example 3.6V ~ 5V) output.Wherein, the voltage output end 212 of main battery 210 couples mutually with the voltage output end (DC_IN) 222 that exchanges conversion electric power 220, and exchange conversion electric power 220 except can charging to main battery 210, more can be used as the voltage source of host computer system, the voltage input end of host computer system as shown in Figure 2 (Vcc_IN).
In Fig. 2, for avoiding under the state of start, if with main battery 210 when pulling out in the electronic installation 200, cause the spread of voltage of host computer system easily and cause the system load component wear.In the present embodiment, design a holding circuit, when guaranteeing that electronic installation 200 pulls out main battery 210 under open state, host computer system will be cut off the power supply immediately.This holding circuit comprises a diode 232, an on-off circuit 230 and a microprocessor 240.Wherein, diode 232 has an input end and an output terminal, and the input end of diode 232 is connected in the voltage output end 212 of main battery 210, and the output terminal of diode 232 is connected in the voltage output end 222 that exchanges conversion electric power 220.In addition, on-off circuit 230 has one first switching transistor Q1, a second switch transistor Q2 and a resistance 234, and the grid of the first switching transistor Q1 couples mutually with the voltage output end 212 of main battery 210, and resistance 234 (for example 100K ohm) connects the drain electrode and the voltage output end 222 that exchanges conversion electric power 220 of the first switching transistor Q1, and the source electrode of the first switching transistor Q1 can be considered an earth terminal, its voltage is 0V for example, and is under the state of logic low.Wherein, the first switching transistor Q1 and second switch transistor Q2 for example are N slot field-effect transistor (FET), and the first switching transistor Q1 can be subjected to the Dc bias of main battery 210 and start, and second switch transistor Q2 then is subjected to the Dc bias of drain electrode of the first switching transistor Q1 and start, and the flowing mode of doing of the relevant first switching transistor Q1, second switch transistor Q2 will be in follow-up detailed description.
In Fig. 2, this holding circuit more comprises one the 3rd switching transistor Q3, and the grid of the 3rd switching transistor Q3 couples mutually with system power supply control end 244, and the source electrode of the 3rd switching transistor Q3 couples mutually with the voltage output end 222 that exchanges conversion electric power 220.In addition, the drain electrode of the 3rd switching transistor Q3 can be considered the direct supply (Vcc_SYS) of system load element, it provides the fixed voltage of system load element running, and (for example 3.3V ~ 5V), for example display, storer or peripherals all can be considered the some of system load element.Wherein, the 3rd switching transistor Q3 for example is the P-channel field-effect transistor (PEFT) transistor, and the 3rd switching transistor Q3 is when the voltage of system power supply control end 244 is logic low and conducting, and the 3rd switching transistor Q3 can conducting when the voltage of system power supply control end 244 is logic high.
By above-mentioned explanation as can be known, under the state that host computer system is being started shooting, when the voltage of the system power supply control end 244 of microprocessor 240 is logic low, the 3rd switching transistor Q3 conducting is so that the DC voltage of main battery 210 or interchange conversion electric power 220 can be passed through the 3rd switching transistor Q3 and the required voltage of supply system load elements.In addition; when main battery 210 in when location; promptly do not pull out before the main battery; the first switching transistor Q1 of holding circuit is subjected to the Dc bias of main battery 210 and conducting; and make the voltage of the drain electrode of the first switching transistor Q1 reduce to logic low; similarly the voltage of the grid of second switch transistor Q2 is also reduced to logic low, and makes not conducting of second switch transistor Q2.At this moment, the reset circuit 242 of microprocessor 240 and keeps its voltage at logic high still under the normal boot-strap state, so the power supply of microprocessor 240 normally and not is affected.
Yet, if under open state, pull out main battery 210, make main battery 210 not in electric system, the first switching transistor Q1 of holding circuit is not subjected to the Dc bias of main battery 210 therefore can conducting.At this moment, the grid of the drain electrode of the first switching transistor Q1 and second switch transistor Q2 is under the voltage of logic high equally, make second switch transistor Q2 thereby conducting, and the reset circuit 242 of microprocessor 240 and system power supply control end 244 are under the voltage of logic low equally.When reset circuit 242 received the signal of logic low, reset circuit 242 was in the power supply that the state that resets is also turned off microprocessor 240 down immediately, damages to guarantee microprocessor 240 can not be subjected to voltage instability.In addition, under the state of shutdown, microprocessor 240 can come timing and preserve individual data by built-in reserve battery (backup battery) 246, and the voltage of system power supply control end 244 returns back to after the initial value, be the voltage of logic high, the voltage of reset circuit 242 also returns back to logic high, and the grid that makes the 3rd switching transistor Q3 also is under the voltage of logic high, therefore the 3rd not conducting of switching transistor Q3, and cut off the primary power of system load element, and reach the purpose of system closedown.
Fig. 3 is the synoptic diagram of the another kind of unidirectional breakover element of the present invention.In Fig. 2,, more can utilize the combination between other element to replace diode except utilizing simple diode 232 as the unidirectional breakover element.Please refer to Fig. 3, the voltage output end 222 that exchanges conversion electric power 220 is connected to the input end of a comparer 250, and the output terminal of comparer 250 is connected to the grid of one the 4th switching transistor Q4.In addition, the drain electrode of the 4th switching transistor Q4 is connected to the voltage output end 212 of main battery 210, and the source electrode of the 3rd switching transistor Q3 couples mutually with the source electrode of the 4th switching transistor Q4.In addition, the output terminal 254 of diode 252 also is connected to the source electrode of the 4th switching transistor Q4, and the input end 256 of diode 252 also is connected to the voltage output end 222 that exchanges conversion electric power 220.
In present embodiment, the reference voltage of comparer 250 is 4V, when the voltage of voltage output end 222 during greater than 4V, the bias voltage signal of comparer 250 outputs is a high level, otherwise when the voltage of voltage output end 222 was not more than 4V, the bias voltage signal of comparer 250 outputs was a low level.When the voltage of voltage output end 222 was 5V, the 4th switching transistor Q4 was subjected to (high level) bias voltage signal of comparer 250 and not conducting, and this moment, system voltage Vcc_SYS was by exchanging conversion electric power 220 power supplies.When if the voltage of voltage output end 222 is lower than 4V, the 4th switching transistor Q4 is subjected to (low level) bias voltage signal of comparer 250 and conducting, and this moment, system voltage Vcc_SYS was by main battery 210 power supplies.Therefore, system voltage Vcc_SYS can remain on a fixing magnitude of voltage.
In sum; holding circuit of the present invention; be applicable in the electric system of an electronic installation; in order to prevent that electronic installation is under open state; if when main battery is pulled out; host computer system will be cut off the power supply immediately, can be to guarantee the system load element because of spread of voltage does not damage, and with data security.Therefore; in holding circuit, utilize the reset circuit of a plurality of switching transistors and microprocessor,, and make main battery after pulling out the dump of microprocessor; the voltage that exchanges conversion electric power is unable to supply to the system load element, to reach the purpose of system cut-off.
Claims (14)
1. a holding circuit is applicable in the electric system of an electronic installation, and the electric system of described electronic installation has a main battery and and exchanges conversion electric power, and it is characterized in that: described holding circuit comprises at least:
One unidirectional breakover element has an input end and an output terminal, and described input end is connected in the voltage output end of described main battery, and described output terminal is connected in the voltage output end of described interchange conversion electric power;
One on-off circuit, has one first switching transistor, a second switch transistor and a resistance, the grid of described first switching transistor couples mutually with the voltage output end of described main battery, and the transistorized grid of described second switch couples mutually with the drain electrode of first switching transistor, and the drain electrode that described resistance connects described first switching transistor couples mutually with the voltage output end of described interchange conversion electric power; And
One microprocessor, have a reset circuit and a system power supply control end, described reset circuit couples mutually with described second switch transistor drain, and the voltage of described reset circuit is logic low during reset, described system power supply control end couples mutually with the transistorized source electrode of described second switch, and described system power supply control end couples mutually with the voltage output end of described interchange conversion electric power, and the voltage of described system power supply control end is logic low when set driving.
2. holding circuit according to claim 1 is characterized in that: described first switching transistor is a N slot field-effect transistor.
3. holding circuit according to claim 1 is characterized in that: described second switch transistor is a N slot field-effect transistor.
4. holding circuit according to claim 1; it is characterized in that: described on-off circuit more comprises one the 3rd switching transistor; and the grid of described the 3rd switching transistor couples mutually with described system power supply control end, and the source electrode of described the 3rd switching transistor couples mutually with the voltage output end of described interchange conversion electric power.
5. holding circuit according to claim 4 is characterized in that: described the 3rd switching transistor is a P-channel field-effect transistor (PEFT) transistor.
6. holding circuit according to claim 1; it is characterized in that: described unidirectional breakover element comprises diode; the input end of diode is connected in the voltage output end of described main battery, and the output terminal of diode is connected in the voltage output end of described interchange conversion electric power.
7. holding circuit according to claim 1; it is characterized in that: described unidirectional breakover element comprises a comparer; the input end of this comparer is connected to the voltage output end that exchanges conversion electric power; the output terminal of this comparer is connected to the grid of the 4th switching transistor; the drain electrode of the 4th switching transistor is connected to the voltage output end of main battery; the source electrode of the 4th switching transistor is connected to the output terminal of a diode, and the input end of this diode is connected to the voltage input end that exchanges conversion electric power.
8. the protective device of an electric power system is applicable in the electric system of an electronic installation, and the protective device of described electric power system comprises that at least a main battery and exchanges conversion electric power, is characterized in that the protective device of described electric power system also comprises:
One unidirectional breakover element has an input end and an output terminal, and described input end is connected in the voltage output end of described main battery, and described output terminal is connected in the voltage output end of described interchange conversion electric power;
One on-off circuit, has one first switching transistor, a second switch transistor and a resistance, the grid of described first switching transistor couples mutually with the voltage output end of described main battery, and the transistorized grid of described second switch couples mutually with the drain electrode of first switching transistor, and described resistance connects the drain electrode and the described voltage output end that exchanges conversion electric power of described first switching transistor; And
One microprocessor, have a reset circuit and a system power supply control end, described reset circuit couples mutually with described second switch transistor drain, and the voltage of described reset circuit is logic low during reset, described system power supply control end couples mutually with the transistorized source electrode of described second switch, and described system power supply control end couples mutually with the voltage output end of described interchange conversion electric power, and the voltage of described system power supply control end is logic low when set driving.
9. holding circuit according to claim 8 is characterized in that: described first switching transistor is a N slot field-effect transistor.
10. holding circuit according to claim 8 is characterized in that: described second switch transistor is a N slot field-effect transistor.
11. holding circuit according to claim 8; it is characterized in that: described on-off circuit more comprises one the 3rd switching transistor; and the grid of described the 3rd switching transistor couples mutually with described system power supply control end, and the source electrode of described the 3rd switching transistor couples mutually with the voltage output end of described interchange conversion electric power.
12. holding circuit according to claim 11 is characterized in that: described the 3rd switching transistor is a P-channel field-effect transistor (PEFT) transistor.
13. holding circuit according to claim 8; it is characterized in that: described unidirectional breakover element comprises diode; the input end of diode is connected in the voltage output end of described main battery, and the output terminal of diode is connected in the voltage output end of described interchange conversion electric power.
14. holding circuit according to claim 8; it is characterized in that: described unidirectional breakover element comprises a comparer; the input end of this comparer is connected to the voltage output end that exchanges conversion electric power; the output terminal of this comparer is connected to the grid of the 4th switching transistor; the drain electrode of the 4th switching transistor is connected to the voltage output end of main battery; the source electrode of the 4th switching transistor is connected to the output terminal of a diode, and the input end of this diode is connected to the voltage input end that exchanges conversion electric power.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200510033510XA CN100362450C (en) | 2005-03-14 | 2005-03-14 | Protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200510033510XA CN100362450C (en) | 2005-03-14 | 2005-03-14 | Protection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1834850A true CN1834850A (en) | 2006-09-20 |
| CN100362450C CN100362450C (en) | 2008-01-16 |
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ID=37002636
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB200510033510XA Expired - Fee Related CN100362450C (en) | 2005-03-14 | 2005-03-14 | Protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100362450C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102063170A (en) * | 2010-11-15 | 2011-05-18 | 深圳市中兴移动通信有限公司 | Circuit for removing shutdown leakage current of electronic products |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3470774B2 (en) * | 1995-03-13 | 2003-11-25 | 日本電信電話株式会社 | DC uninterruptible power supply system |
| KR0148053B1 (en) * | 1995-05-12 | 1998-09-15 | 김광호 | Apparatus and method for driving back light source of liquid crystal display device |
| JPH10191579A (en) * | 1996-12-26 | 1998-07-21 | Nec Gumma Ltd | Uninterruptible power and information processor with uninterruptible power |
| JPH11313443A (en) * | 1998-04-28 | 1999-11-09 | Hitachi Denshi Ltd | Battery charger |
| JP2001238365A (en) * | 2000-02-21 | 2001-08-31 | Matsushita Electric Ind Co Ltd | Secondary battery charge control circuit |
-
2005
- 2005-03-14 CN CNB200510033510XA patent/CN100362450C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102063170A (en) * | 2010-11-15 | 2011-05-18 | 深圳市中兴移动通信有限公司 | Circuit for removing shutdown leakage current of electronic products |
| CN102063170B (en) * | 2010-11-15 | 2016-01-20 | 努比亚技术有限公司 | A kind of circuit solving electronic product shutdown leakage current |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100362450C (en) | 2008-01-16 |
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Granted publication date: 20080116 Termination date: 20160314 |