The duplicate supply switching circuit
Technical field
This novel duplicate supply switching circuit that relates to particularly about having the duplicate supply switching circuit of the product of USB device, can link the USB port of personal computer.
Background technology
The product that generally has the USB device can link personal computer by the USB port (USB PORT) by personal computer, for example the power supply switched system and the method for the externally-connected optical drive that discloses of No. the 200609743rd, TaiWan, China publication, be application hardware circuit and tough body technique, externally-connected optical drive except can receive domestic power supply, the power supply that can also receiving computer main frame (via USB) be provided.
Existing notes type personal computer and some desktop PCs (Desktop PC), its USB port will can not obtain power supply under shutdown or resting state, and the product that has duplicate supply USB device this moment can switch to its inner battery supply by USB port with supplying with its required power supply.But in this process, because the USB port of computer is long discharge time, cause power supply to switch having one section zona incerta producing, allow product in using that replacement (RESET) is arranged or take place when the phenomenon of machine (Lock), cause user's data to run off and use and go up inconvenience.
For the duplicate supply switching circuit that makes electronic product can clearly reach Switching power fast, avoid electronic product that the phenomenon of machine takes place to reset or work as in the Switching power process, and propose originally novel.
The utility model content
The main purpose that this is novel, provide a kind of duplicate supply switching circuit, the electronic product that uses duplicate supply can not allow electronic product in using take place to reset because of the time of switching is oversize or when the phenomenon of machine in the process of Switching power, causes user's data to run off and uses and go up inconvenience.
Another purpose that this is novel provides a kind of duplicate supply switching circuit, can promote the stability of the electronic product of use duplicate supply at Switching power, and then promote the quality of electronic product and user's satisfaction.
The duplicate supply switching circuit that this is novel is the person between a computer system and a peripheral device of boundary, comprising:
One power output end, in order to output power to this electronic product;
One first power input end is in order to import electric power to this power output end;
One second power input end is in order to import electric power to this power output end;
Whether one detecting unit is lower than a switching value that presets and makes the output transition in order to the voltage status that detects this first power input end;
One power supply switching circuit is the output according to this detecting unit, switch this second power input end and electrically connect this power output end, with transferring electric power to this electronic product;
Wherein, this first power input end is under this computer system dormancy or shutdown back continuous discharge state, when its voltage status is lower than the switching value of this detecting unit, this power supply switching circuit promptly switches this second power input end and supplies power to this electronic product, can avoid electronic product in the process of Switching power, to produce the phenomenon of resetting or working as machine, can promote the stability of duplicate supply switched system.
The beneficial effects of the utility model are to make the duplicate supply switching circuit of electronic product can clearly reach Switching power fast, avoid electronic product to take place to reset or work as the phenomenon of machine in the Switching power process.
Other purpose, effect that this is novel see also graphic and embodiment, are described in detail as follows.
Description of drawings
Fig. 1 is the functional structure block schematic diagram of this novel duplicate-power switching circuit;
Fig. 2 is the circuit structure embodiment schematic diagram of this novel duplicate-power switching circuit.
[primary clustering symbol description]
1 power output end, 2 first power input ends
21 earth resistances, 3 second power input ends
4 detecting units, 5 power supply switching circuits
51 the first transistors, 52 transistor secondses
53 first resistance, 54 second resistance
6 batteries
Embodiment
See also Fig. 1, shown in Figure 2.Duplicate supply switching circuit of the present invention is to have the stable person of the electronic product of duplicate supply at Switching power in order to lifting, comprising:
One power output end 1, in order to output power to electronic product;
One first power input end 2 is to electrically connect power output end 1 and an earth resistance 21 ground connection respectively; First power input end 2 can be the USB port of personal computer;
One second power input end 3 is to be electrically connected to power supply switching circuit 5, and to power output end, second power input end 3 can electrically connect a battery 6, provides electrical power to this electronic product by battery 6 in order to input electric power;
One detecting unit 4, it is the voltage status that detects first power output end 2, and export corresponding signal person, it includes first, second and third end, the first end ground connection wherein, second end is electrically connected to that power supply switching circuit 5, the three ends electrically connect first power input end 2 and by by earth resistance 21 ground connection;
One power supply switching circuit 5 electrically connects power output end 1, second power input end 3 and detecting unit 4 respectively, and the signal in order to 4 outputs of foundation detecting unit switches second power input end 3 and whether electrically connects power output end 1, and transferring electric power is to electronic product; Power supply switching circuit 5 comprises the first transistor 51 and transistor seconds 52; The first transistor 51 and transistor seconds 52 have first and second and three ends respectively; First end of the first transistor 51 is second ends that electrically connect detecting unit 4 simultaneously, and electrically connects second power input end 3 through first resistance 53, its second end ground connection, and its 3rd end electrically connects second power input end 3 through second resistance 54; First end of transistor seconds 52 electrically connects the 3rd end of the first transistor 51 and electrically connects second power output end 3 through second resistance 54, and its second end electrically connects second power input end 3, and its 3rd end electrically connects power output end 1.
As shown in Figure 2.When personal computer during at open state, first power input end, 2 one side transferring electric powers are to power output end 1 supplies electrons product required electric power, make the 3rd terminal potential of detecting unit 4 be higher than the switching value that presets on the other hand, make the second end ground connection and export a switching signal not, and then first end that makes the first transistor 51 is at electronegative potential, cause second of the first transistor 51, three ends are the state of not conducting, first end of transistor seconds 52 makes second of transistor seconds 52 at high potential simultaneously, three ends are the state of not conducting, cause can't transferring to power output end 1 via second power input end 3 by the electric power of battery 6 output, and the supplies electrons product electric power.Should default definite value be the stable operating voltage value (about 3~4V) of this electronic product.
When personal computer during at the shutdown or the state of dormancy, first power input end 2 is incited somebody to action step-down gradually and can't be provided electronic product to keep the electric power of normal operation, and cause the 3rd terminal potential of detecting unit 4 to be lower than switching value, its first and second i.e. not conducting of end, and second end is to electrically connect second power input ends 3 and be the state of high potential and export transition through first resistance 53, make its output one switch signal, and then make the earth-free state that is high potential of first end of the first transistor 51; Because first end of the first transistor 51 in the pass of high potential is, cause its second and third end conducting, making its 3rd end is electronegative potential; At this moment, because the first end ground connection of transistor seconds 52, cause its second and third end to be the state of conducting, make the electric power of battery 6 can transfer to electronic product via second power input end 3, transistor seconds 52 and power output end 1, supplies electrons product required electric power.
Suppose personal computer when open state, the current potential that can make first power input end 2 is 5V (volt), and when the shutdown or the state of dormancy, the current potential of the input 2 of first electricity will be reduced to 0V gradually.This is novel selects special detecting unit 4 for use, and when the current potential of its three end during for example less than 4V, its second end is exported a signal to power supply switching circuit 5, makes power supply switching circuit 5 conductings, second power input end 3 and power output end 1, and transferring electric power is to electronic product; Therefore can provide power supply switching circuit 5 to reach the time point of stable Switching power clearly, fast, and not can as the duplicate supply switching circuit, the current potential that needs to wait for first power input end 2 drops to the operation of just carrying out Switching power when being lower than system works voltage, having one section long zona incerta produces, and allow electronic product in using take place to reset or when the phenomenon of machine, cause user's data to run off and use and go up inconvenience.
This novel measuring ability that utilizes detecting unit, when the voltage of first power input end is discharged to the voltage quasi position of the Switching power that sets, detecting unit can provide stable and clear and definite voltage quasi position, the duplicate supply switching circuit is moved, make electronic product use the electric power of its internal cell, avoid electronic product when Switching power, to produce the phenomenon of resetting or working as machine, can promote the stability of electronic product, and then promote the quality of electronic product and user's satisfaction at Switching power.This novel duplicate-power switching circuit can effectively overcome in the power supply handoff procedure to produce resets or when the phenomenon of machine, is applicable to the electronic product with duplicate supply that is switched by hardware-in-the-loop control power supply.
The above record only for utilizing the embodiment of this new technique content, anyly is familiar with this skill person and used a novel modification of doing, variation, all belongs to the claim of this novel opinion, and is not limited to those disclosed embodiments.