CN102593946B - Dual-power-supply automatic switching circuit based on power MOSFET application - Google Patents
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Abstract
The invention relates to a dual-power automatic switching circuit based on power MOSFET application, which consists of a voltage detector, three triodes, two P-channel power MOSFETs, two diodes, two light-emitting diodes and a plurality of resistance elements. VIN1 and VIN2 are input ends of two groups of working power supplies, wherein VIN1 is connected with a main power supply, and VIN2 is connected with a standby power supply; VOUT is the output end of the power supply switching circuit and is connected with load equipment; GND is ground. In the working state, the main power supply and the standby power supply are powered on simultaneously, and VIN1= VIN 2. A voltage dividing resistor is added at the detection end of the voltage detector, so that the detected voltage is close to the detection threshold value as much as possible. When the voltage of the main power supply drops, the voltage detector can be driven at the first time to finish the automatic switching work of the power supply. The invention combines the working characteristics of the power MOSFET, cooperates with the voltage detector, adopts the power MOSFET as a change-over switch, and can automatically switch the standby power supply when the voltage of the main power supply is reduced below the threshold voltage set by the power detector or the power is cut off.
Description
Technical field
The present invention relates to a kind of power supply automatic switchover circuit, specifically a kind of double supply automatic switch-over circuit based on power MOSFET application.
Background technology
Conventionally the application of some key equipments need to arrange stand-by power supply, when main power source is undesired or during power-off, stand-by power supply will automatically switch incessantly, to guarantee the normal operation of equipment.The most frequently used way is relay switch and diodes in parallel switching mode, but these two kinds of switching modes all exist drawback.First be problem switching time, conventionally the reaction time of relay is all ms level, this just need to be equipped with enough jumbo storage capacitors at power end restarts in electrical source exchange process to prevent equipment, and obviously this is unpractical in the larger occasion of equipment applied current; Next is problem of pressure drop, diodes in parallel mode all brings problem can to two passages of primary and secondary, the tube voltage drop of diode can cause the too low unit exception that causes of supply power voltage, particularly at some low voltage operating occasions (as 5V, 3.3V), so typical diode pressure drop (0.7V) can make Power supply brownout, memory IC tolerance limit problem to low-tension supply power supply is more serious, even if use Schottky diode (0.2V～0.5V) and so on the lower diode of pressure drop, also just make to a certain extent situation make moderate progress, can't resolve root problem.
Summary of the invention
Technical problem to be solved by this invention is, overcome above prior art and mention two technical problems, a kind of double supply automatic switch-over circuit based on power MOSFET application is provided, operating characteristic in conjunction with power MOSFET, coordinate voltage detector, adopt power MOSFET to do diverter switch, below main power voltage drops to the threshold voltage that Power supply detector sets or during power-off, stand-by power supply can automatically switch.
The technical scheme that the present invention solves above technical problem is:
Double supply automatic switch-over circuit based on power MOSFET application, the input VIN1 and the VIN2 that comprise two working powers, a voltage detector U1, three triode T1, T2 and T3, two P channel power MOS FETQ2 and Q4, two diode Q1 and Q3 and resistance, working power input VIN1 connects the output of main electricity, and working power input VIN2 connects the output of stand-by power supply power supply, working power input VIN1 is by resistance R 1 earth connection GND, resistance R 1 plays the effect of repid discharge, guarantee in electrical source exchange, thereby the input terminal voltage of voltage detector U1 can drop to the level translation of drive output below threshold values within the shortest time, complete electrical source exchange work, working power input VIN2 is by resistance R 2 earth connection GND, and working power input VIN2 passes through resistance R 5 and R6 earth connection GND, simultaneously the base stage of the connection termination triode T3 of resistance R 5 and resistance R 6, working power input VIN1 is by resistance R 9 and R10 earth connection GND, the 2 pin inputs of the connection termination voltage detector U1 of while resistance R 9 and resistance R 10, the effect of resistance R 9 and resistance R 10 is dividing potential drops, the 2 pin input terminal voltages of voltage detector U1 are adjusted to as far as possible close threshold values, guarantee to complete level translation within the shortest time, the 3 pin earth connection GND of voltage detector U1, the base stage of 1 pin output termination triode T1, also by pull-up resistor R3, meet working power input VIN1 simultaneously, and by pull down resistor R4 earth connection GND, wherein the effect of resistance R 3 is to guarantee that voltage detector U1 is in idle situation, output keeps high level (because voltage detector is out to leak output, so this pull-up resistor is necessary), and resistance R 4 plays the effect of dividing potential drop and electric discharge, working power input VIN1 finally receives the drain electrode of positive pole and the power MOSFET Q2 of diode Q1, the collector electrode of triode T1 connects the grid of power MOSFET Q2, by resistance R 7, connect the source electrode of power MOSFET Q2 and the negative pole of diode Q1 is also the output VOUT of whole circuit simultaneously simultaneously, wherein diode Q1 and power MOSFET Q2 parallel connection shield, and resistance R 7 is to guarantee that the grid of power MOSFET Q2 when triode T1 ends and source electrode keep equipotential cut-off state, the emitter of triode T1 connects the base stage of triode T2, the grounded emitter line GND of triode T2, the base stage of the collector connecting transistor T3 of triode T2, the grid that the collector electrode of triode T3 meets power MOSFET Q4 simultaneously also by resistance R 8, connects the source electrode of power MOSFET Q4 and the negative pole of diode Q3 is also the output VOUT of whole circuit simultaneously, these three triode T1, T2 and T3 coupled in series are for Guarantee Status interlock, in the time of triode T1 conducting, also conducting of triode T2, triode T3 cut-off, drag down the grid level of power MOSFET Q2 simultaneously, the grid level of raising power MOSFET Q4 makes power MOSFET Q2 conducting power MOSFET Q4 cut-off, equipment is powered by working power input VIN1, working power input VIN2 stops power supply, it is contrary when voltage detector U1 detects low level, triode T1 cut-off, triode T2 also ends, triode T3 conducting, at this moment the grid of power MOSFET Q2 and the cut-off of source electrode equipotential, and the grid level of power MOSFET Q4 is drawn as low level, power MOSFET Q4 conducting completes electrical source exchange, equipment is powered by working power input VIN2, and working power input VIN1 stops power supply.
The Main Function of two diodes in parallel with power MOSFET has two, is first to play standby effect, and the in the situation that of power MOSFET damage or cisco unity malfunction, power supply can directly be powered to equipment by diode, the not power-off of assurance equipment; Next is to play a protective role, and when power supply is directly powered to power consumption equipment by diode, utilizes diode reverse cut-off characteristics effectively to prevent that the electric current between duplicate supply from pouring in down a chimney damage power supply.
Like this, when the voltage detecting when voltage detector U1 test side is greater than its detection threshold voltage, its output cut-off, by pull-up resistor R3 output high level, this high level makes triode T1 saturation conduction, thereby make also saturation conduction of triode T2, finally making the grid of power MOSFET Q2 and the base stage of triode T3 is all low level, triode T3 cut-off, the grid of power MOSFET Q4 and the cut-off of source electrode equipotential, source current flows to the source electrode of power MOSFET Q4 by heavy-duty diode, the source voltage that the source voltage of power MOSFET Q2 equals power MOSFET Q4 approximates the pressure drop that main electricity voltage deducts diode, because the grid of power MOSFET Q2 is low level, power MOSFET Q2 saturation conduction, because power MOSFET Q4 cut-off, the conducting resistance of power MOSFET Q2 is very little, its tube voltage drop is much smaller more than the pressure drop of diode in parallel, so main power source is powered to load equipment by power MOSFET Q2,
When main power voltage declines the voltage cause voltage detector U1 test side to detect when being less than it and detecting threshold voltage, the conducting of voltage detector U1 output, output low level, this low level makes triode T1 cut-off, thereby triode T2 is also ended, finally making the grid of power MOSFET Q2 and the base stage of triode T3 is all high level, the grid of power MOSFET Q2 and the cut-off of source electrode equipotential, triode T3 saturation conduction, the grid that makes power MOSFET Q4 is low level, stand-by power supply electric current flows to the source electrode of power MOSFET Q4 by diode, so equaling the source voltage of power MOSFET Q2, the source voltage of power MOSFET Q4 approximates the pressure drop that backup power source voltage deducts diode, and because the grid of power MOSFET Q4 is low level, power MOSFET Q4 saturation conduction, because power MOSFET Q2 cut-off, the conducting resistance of power MOSFET Q4 is very little, its tube voltage drop is much smaller more than the pressure drop of diode in parallel, so stand-by power supply is powered to load equipment by power MOSFET Q2,
When primary power source de-energizes, voltage detector test side is without input voltage, and output is forced to low level by pull down resistor, and triode T1 ends equally, and the situation of its working condition and voltage drop is above basically identical.
The technical scheme that the present invention further limits is:
The aforesaid double supply automatic switch-over circuit based on power MOSFET application, the threshold values of voltage detector U1 is selected lower than power supply nominal output voltage values 0.5V.Consider the possibility that may exist output voltage slightly to decline after power supply access load, also to consider the reasonable domain of walker of voltage detector detection threshold, so general selection of the threshold values of voltage detector U1 is advisable lower than power supply nominal output voltage values 0.5V left and right simultaneously.Due to generally, after power supply access load, magnitude of voltage all can have the decline of certain amplitude, so must consider this point when selecting voltage detection device, if thereby selected the too high detection means of detection threshold likely to cause main power source just to start to switch on output that magnitude of voltage just drops to the following driving voltage detector of detection threshold is always in low level state, so main electricity is just in off state, equipment can only be powered by stand-by power supply, and commutation circuit is ineffective.
The aforesaid double supply automatic switch-over circuit based on power MOSFET application, voltage detector U1 selects HT7044, and detection threshold voltage is 4.4V.
The aforesaid double supply automatic switch-over circuit based on power MOSFET application, working power input VIN1 is through the positive pole of current-limiting resistance R11 sending and receiving optical diode L1, the minus earth line GND of light-emitting diode L1, resistance R 11, for limiting the size of current that flows through light-emitting diode L1, guarantees that light-emitting diode L1 is operated within the scope of safe current; Working power input VIN2 is through the positive pole of current-limiting resistance R12 sending and receiving optical diode L2, the minus earth line GND of light-emitting diode L2, resistance R 12, for limiting the size of current that flows through light-emitting diode L2, guarantees that light-emitting diode L2 is operated within the scope of safe current; Two light-emitting diodes have been used for indicative function, and under normal operation, two light-emitting diodes are all lighted, when any road power supply wherein occurs when abnormal, corresponding that light-emitting diode extinguish prompting on-call maintenance or replacement.
The invention has the beneficial effects as follows: the present invention is in conjunction with the operating characteristic of power MOSFET, adopt power MOSFET to do diverter switch, coordinate voltage detector, below main power voltage drops to the threshold voltage that Power supply detector sets or during power-off, stand-by power supply can automatically switch, and can solve two problems of mentioning above simultaneously.First, the switching frequency of MOSFET very fast (ns level), can accomplish that equipment work uninterruptedly automatically switches completely; Secondly, the tube voltage drop of MOSFET is extremely low, substantially can be controlled in 0.1V, and part of devices even can be accomplished in 50mV, substantially can accomplish the harmless switching of supply voltage.When powering on for the first time, power consumption equipment powered by main power source, once in the equipment course of work main electricity occur extremely to fall or power-off in, can under working impregnable situation, maintenance equipment automatically switch to stand-by power supply power supply, equally after main electricity recovers normally, can by stand-by power supply, uninterruptedly automatically switch to main power source again and power, in handoff procedure, can guarantee not power down of power supply unit, not restart.
Accompanying drawing explanation
Fig. 1 is circuit diagram of the present invention.
Embodiment
Embodiment 1
The present embodiment provides a kind of double supply automatic switch-over circuit based on power MOSFET application, circuit as shown in Figure 1, the input VIN1 and the VIN2 that comprise two working powers, a voltage detector U1, three triode T1, T2 and T3, two P channel power MOS FETQ2 and Q4, two diode Q1 and Q3 and resistance, working power input VIN1 connects the output of main electricity, and working power input VIN2 connects the output of stand-by power supply power supply, working power input VIN1 is through the positive pole of current-limiting resistance R11 sending and receiving optical diode L1, the minus earth line GND of light-emitting diode L1, resistance R 11, for limiting the size of current that flows through light-emitting diode L1, guarantees that light-emitting diode L1 is operated within the scope of safe current, working power input VIN2 is through the positive pole of current-limiting resistance R12 sending and receiving optical diode L2, the minus earth line GND of light-emitting diode L2, resistance R 12, for limiting the size of current that flows through light-emitting diode L2, guarantees that light-emitting diode L2 is operated within the scope of safe current, two light-emitting diodes have been used for indicative function, and under normal operation, two light-emitting diodes are all lighted, when any road power supply wherein occurs when abnormal, corresponding that light-emitting diode extinguish prompting on-call maintenance or replacement, working power input VIN1 is by resistance R 1 earth connection GND, resistance R 1 plays the effect of repid discharge, guarantee in electrical source exchange, thereby the input terminal voltage of voltage detector U1 can drop to the level translation of drive output below threshold values within the shortest time, complete electrical source exchange work, working power input VIN2 is by resistance R 2 earth connection GND, and working power input VIN2 passes through resistance R 5 and R6 earth connection GND, simultaneously the base stage of the connection termination triode T3 of resistance R 5 and resistance R 6, working power input VIN1 is by resistance R 9 and R10 earth connection GND, the 2 pin inputs of the connection termination voltage detector U1 of while resistance R 9 and resistance R 10, the effect of resistance R 9 and resistance R 10 is dividing potential drops, the 2 pin input terminal voltages of voltage detector U1 are adjusted to as far as possible close threshold values, guarantee to complete level translation within the shortest time, the 3 pin earth connection GND of voltage detector U1, the base stage of 1 pin output termination triode T1, also by pull-up resistor R3, meet working power input VIN1 simultaneously, and by pull down resistor R4 earth connection GND, wherein the effect of resistance R 3 is to guarantee that voltage detector U1 is in idle situation, output keeps high level (because voltage detector is out to leak output, so this pull-up resistor is necessary), and resistance R 4 plays the effect of dividing potential drop and electric discharge, working power input VIN1 finally receives the drain electrode of positive pole and the power MOSFET Q2 of diode Q1, the collector electrode of triode T1 connects the grid of power MOSFET Q2, by resistance R 7, connect the source electrode of power MOSFET Q2 and the negative pole of diode Q1 is also the output VOUT of whole circuit simultaneously simultaneously, wherein diode Q1 and power MOSFET Q2 parallel connection shield, and resistance R 7 is to guarantee that the grid of power MOSFET Q2 when triode T1 ends and source electrode keep equipotential cut-off state, the emitter of triode T1 connects the base stage of triode T2, the grounded emitter line GND of triode T2, the base stage of the collector connecting transistor T3 of triode T2, the grid that the collector electrode of triode T3 meets power MOSFET Q4 simultaneously also by resistance R 8, connects the source electrode of power MOSFET Q4 and the negative pole of diode Q3 is also the output VOUT of whole circuit simultaneously, these three triode T1, T2 and T3 coupled in series are for Guarantee Status interlock, in the time of triode T1 conducting, also conducting of triode T2, triode T3 cut-off, drag down the grid level of power MOSFET Q2 simultaneously, the grid level of raising power MOSFET Q4 makes power MOSFET Q2 conducting power MOSFET Q4 cut-off, equipment is powered by working power input VIN1, working power input VIN2 stops power supply, it is contrary when voltage detector U1 detects low level, triode T1 cut-off, triode T2 also ends, triode T3 conducting, at this moment the grid of power MOSFET Q2 and the cut-off of source electrode equipotential, and the grid level of power MOSFET Q4 is drawn as low level, power MOSFET Q4 conducting completes electrical source exchange, equipment is powered by working power input VIN2, and working power input VIN1 stops power supply.The Main Function of two diodes in parallel with power MOSFET has two, is first to play standby effect, and the in the situation that of power MOSFET damage or cisco unity malfunction, power supply can directly be powered to equipment by diode, the not power-off of assurance equipment; Next is to play a protective role, and when power supply is directly powered to power consumption equipment by diode, utilizes diode reverse cut-off characteristics effectively to prevent that the electric current between duplicate supply from pouring in down a chimney damage power supply.
Consider the possibility that may exist output voltage slightly to decline after power supply access load, also to consider the reasonable domain of walker of voltage detector detection threshold, so general selection of the threshold values of voltage detector U1 is advisable lower than power supply nominal output voltage values 0.5V left and right simultaneously.Press detector U1 to select HT7044, detection threshold voltage is 4.4V.Due to generally, after power supply access load, magnitude of voltage all can have the decline of certain amplitude, so must consider this point when selecting voltage detection device, if thereby selected the too high detection means of detection threshold likely to cause main power source just to start to switch on output that magnitude of voltage just drops to the following driving voltage detector of detection threshold is always in low level state, so main electricity is just in off state, equipment can only be powered by stand-by power supply, and commutation circuit is ineffective.
Main power voltage normal (VIN1=5V):
The voltage of working power input VIN1 makes light-emitting diode L1 light (indicate this road power supply normal), and the voltage of working power input VIN2 makes light-emitting diode L2 light (indicate this road power supply normal).Voltage detector U1 is that CMOS type is driven Lou output device (low effectively), resistance R 3 is pull-up resistor, the detection threshold voltage of voltage detector U1 is 4.4V, when the voltage detecting when its test side (2 pin) is greater than 4.4V, the inner metal-oxide-semiconductor cut-off of its output (1 pin), by pull-up resistor R3 output high level, this high level makes triode T1 saturation conduction, the emitter of triode T1 is connected with the base stage of triode T2, thereby make also saturation conduction of triode T2, finally making the grid of power MOSFET Q2 and the base stage of triode T3 is all low level.Triode T3 cut-off, the grid of power MOSFET Q4 and the cut-off of source electrode equipotential; Source current flows to the source electrode of power MOSFET Q4 by heavy-duty diode, so the source voltage of power MOSFET Q2 equals the source voltage of power MOSFET Q4, approximate the pressure drop (5V-0.7V=4.3V) that main power voltage (or backup power source voltage) deducts heavy-duty diode.And because the grid of power MOSFET Q2 is low level, so-VGS-≈ 4.3V, power MOSFET Q2 saturation conduction, because power MOSFET Q4 cut-off, the conducting resistance of power MOSFET Q2 is very little, its tube voltage drop is much smaller more than the pressure drop of heavy-duty diode in parallel, so main power source is powered to load equipment by power MOSFET Q2.
Main power voltage declines or power-off:
When the main power voltage voltage cause voltage detector U1 test side (2 pin) the to detect inner metal-oxide-semiconductor conducting of voltage detector U1 output (1 pin) when being less than 4.4V that declines, output low level.This low level makes triode T1 cut-off, and the emitter of triode T1 is connected with the base stage of triode T2, thereby triode T2 is also ended, and finally making the grid of power MOSFET Q2 and the base stage of triode T3 is all high level.The grid of power MOSFET Q2 and the cut-off of source electrode equipotential, triode T3 saturation conduction, the grid that makes power MOSFET Q4 is low level, stand-by power supply electric current flows to the source electrode of power MOSFET Q4 by diode, so the source voltage of power MOSFET Q4 equals the source voltage of power MOSFET Q2, approximate the pressure drop (5V-0.7V=4.3V) that backup power source voltage deducts diode.And because the grid of power MOSFET Q4 is low level, so-VGS ≈ 4.3V, power MOSFET Q4 saturation conduction, because power MOSFET Q2 cut-off, the conducting resistance of power MOSFET Q4 is very little, its tube voltage drop is much smaller more than the pressure drop of diode in parallel, so stand-by power supply is powered to load equipment by power MOSFET Q2.
When primary power source de-energizes, light-emitting diode L1 extinguishes, and voltage detector test side is without input voltage, and output is forced to low level by pull down resistor, and triode T1 ends equally, and the situation of its working condition and voltage drop is above basically identical.
In addition to the implementation, the present invention can also have other execution modes.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection range of requirement of the present invention.
Claims (4)
1. the double supply automatic switch-over circuit of applying based on power MOSFET, it is characterized in that: comprise input VIN1 and the VIN2 of two working powers, a voltage detector U1, three triode T1, T2 and T3, two P channel power MOS FETQ2 and Q4, two diode Q1 and Q3 and resistance, described working power input VIN1 connects the output of main electricity, and working power input VIN2 connects the output of stand-by power supply power supply, described working power input VIN1 is by resistance R 1 earth connection GND, resistance R 1 plays the effect of repid discharge, guarantee in electrical source exchange, thereby the input terminal voltage of voltage detector U1 can drop to the level translation of drive output below threshold values within the shortest time, complete electrical source exchange work, described working power input VIN2 is by resistance R 2 earth connection GND, and described working power input VIN2 passes through resistance R 5 and R6 earth connection GND, simultaneously the base stage of the connection termination triode T3 of resistance R 5 and resistance R 6, described working power input VIN1 is by resistance R 9 and R10 earth connection GND, the 2 pin inputs of the connection termination voltage detector U1 of while resistance R 9 and resistance R 10, the effect of resistance R 9 and resistance R 10 is dividing potential drops, the 2 pin input terminal voltages of voltage detector U1 are adjusted to as far as possible close threshold values, guarantee to complete level translation within the shortest time, the 3 pin earth connection GND of voltage detector U1, the base stage of 1 pin output termination triode T1, also by pull-up resistor R3, meet working power input VIN1 simultaneously, and by pull down resistor R4 earth connection GND, wherein the effect of resistance R 3 is to guarantee that voltage detector U1 is in idle situation, output keeps high level, and resistance R 4 plays the effect of dividing potential drop and electric discharge, working power input VIN1 finally receives the drain electrode of positive pole and the power MOSFET Q2 of diode Q1, the collector electrode of triode T1 connects the grid of power MOSFET Q2, by resistance R 7, connect the source electrode of power MOSFET Q2 and the negative pole of diode Q1 is also the output VOUT of whole circuit simultaneously simultaneously, wherein diode Q1 and power MOSFET Q2 parallel connection shield, and resistance R 7 is to guarantee that the grid of power MOSFET Q2 when triode T1 ends and source electrode keep equipotential cut-off state, the emitter of triode T1 connects the base stage of triode T2, the grounded emitter line GND of triode T2, the base stage of the collector connecting transistor T3 of triode T2, the grid that the collector electrode of triode T3 meets power MOSFET Q4 simultaneously also by resistance R 8, connects the source electrode of power MOSFET Q4 and the negative pole of diode Q3 is also the output VOUT of whole circuit simultaneously, these three triode T1, T2 and T3 coupled in series are for Guarantee Status interlock, in the time of triode T1 conducting, also conducting of triode T2, triode T3 cut-off, drag down the grid level of power MOSFET Q2 simultaneously, the grid level of raising power MOSFET Q4 makes power MOSFET Q2 conducting power MOSFET Q4 cut-off, equipment is powered by working power input VIN1, working power input VIN2 stops power supply, it is contrary when voltage detector U1 detects low level, triode T1 cut-off, triode T2 also ends, triode T3 conducting, at this moment the grid of power MOSFET Q2 and the cut-off of source electrode equipotential, and the grid level of power MOSFET Q4 is drawn as low level, power MOSFET Q4 conducting completes electrical source exchange, equipment is powered by working power input VIN2, and working power input VIN1 stops power supply.
2. the double supply automatic switch-over circuit based on power MOSFET application as claimed in claim 1, is characterized in that: the threshold values of described voltage detector U1 is selected lower than power supply nominal output voltage values 0.5V.
3. the double supply automatic switch-over circuit based on power MOSFET application as claimed in claim 2, is characterized in that: described voltage detector U1 selects HT7044, and detection threshold voltage is 4.4V.
4. the double supply automatic switch-over circuit based on power MOSFET application as claimed in claim 1, it is characterized in that: described working power input VIN1 is through the positive pole of current-limiting resistance R11 sending and receiving optical diode L1, the minus earth line GND of light-emitting diode L1, resistance R 11, for limiting the size of current that flows through light-emitting diode L1, guarantees that light-emitting diode L1 is operated within the scope of safe current; Described working power input VIN2 is through the positive pole of current-limiting resistance R12 sending and receiving optical diode L2, the minus earth line GND of light-emitting diode L2, resistance R 12, for limiting the size of current that flows through light-emitting diode L2, guarantees that light-emitting diode L2 is operated within the scope of safe current; Two light-emitting diodes have been used for indicative function, and under normal operation, two light-emitting diodes are all lighted, when any road power supply wherein occurs when abnormal, corresponding that light-emitting diode extinguish prompting on-call maintenance or replacement.
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| CN115085336B (en) * | 2022-07-22 | 2022-12-06 | 深圳市创芯微微电子有限公司 | Dynamic load circuit for charging equipment, dynamic load adjusting method and charging equipment |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1627593A (en) * | 2003-12-11 | 2005-06-15 | 上海贝尔阿尔卡特股份有限公司 | Switching circuit for low voltage power supply in master-slave power supply mode |
| CN202014132U (en) * | 2011-03-25 | 2011-10-19 | 鸟取三洋电机（广州）有限公司 | Power source switching circuit |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101841183A (en) * | 2009-03-16 | 2010-09-22 | 鸿富锦精密工业（深圳）有限公司 | Power supply switching circuit |
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2012
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1627593A (en) * | 2003-12-11 | 2005-06-15 | 上海贝尔阿尔卡特股份有限公司 | Switching circuit for low voltage power supply in master-slave power supply mode |
| CN202014132U (en) * | 2011-03-25 | 2011-10-19 | 鸟取三洋电机（广州）有限公司 | Power source switching circuit |
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| CN102593946A (en) | 2012-07-18 |
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