CN1421761A - Initiate circuit for power supply of peripheral elements - Google Patents
Initiate circuit for power supply of peripheral elements Download PDFInfo
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- CN1421761A CN1421761A CN 01134983 CN01134983A CN1421761A CN 1421761 A CN1421761 A CN 1421761A CN 01134983 CN01134983 CN 01134983 CN 01134983 A CN01134983 A CN 01134983A CN 1421761 A CN1421761 A CN 1421761A
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Abstract
The initiate circuit for power supply of peripheral elements includes one switch controlling circuit for controlling the conduction of P-type or N-type transistor switch. For a P-type transistor switch, the switch controlling circuit includes one lift element, one current source and one current switch. For a N-type transistor switch, the switch controlling circuit includes one pull-down element, one current source and one current switch. By means of the charge of the current source to the capacitor, slowly lowered or lifted output is produced to control the P-type or N-type transistor switch for slow on of the power supply. In an integrated circuit, the constant current source circuit is simple in design and small in covered area, and this is superior to available technology.
Description
(1) technical field:
The present invention relates to a kind of power initiation circuit, particularly a kind of power initiation circuit of computing machine peripheral element, it can reduce the momentary pulse electric current that peripheral element is produced when power initiation.
(2) background technology:
At present, be applied to the peripheral element of computing machine, USB (universal serial bus) for example is via the main control end power supply of USB (universal serial bus).Setting up in the process of line agreement in main control end and member end, is to supply the member end of the electric current of 100mA to USB (universal serial bus) by the main control end of USB (universal serial bus).And after the line agreement was set up, then the member end by USB (universal serial bus) required to increase the electric current supply according to the needed source current of specifications for delivery to the main control end of USB (universal serial bus).But before the line agreement is set up, because the existence of various filter capacitors and stray capacitance, pulse phenomenon appears in source current easily that open the beginning, and the hub that makes responsible monitoring power supply and line agreement set up process can be closed USB system because of takeing for the power supply overload.
For solving above-mentioned misoperation, prior art is to increase a power initiation circuit between the power supply input of USB system and USB (universal serial bus) element, as shown in Figure 1.This power initiation circuit mainly is to utilize resistance 16 and load capacitance 15 to form a RC charge-discharge circuit, to avoid current impulse to produce, and utilize a switch 14, bypass resistance 16 over time, still cause voltage drop to avoid resistance 16 under normal connection state.In addition, this power initiation circuit can comprise a switch 13 and a delay circuit 11 in addition, and switch 13 inserts power supply in order to make this USB (universal serial bus) of time spent conducting at power supply starting signal, and delay circuit 11 is in order to open switch 14 over time.
As shown in Figure 2, it is that the circuit of the circuit diagram of another kind of existing power supply start-up circuit and Fig. 1 is similar, and this power initiation circuit is switch 13,14 and the delay circuit 11 that replaces Fig. 1 with diode 21, second capacitor 23 and PNP transistor 22.In Fig. 2, during when power supply starting signal activation (being reduced to logic low potential gradually by logic high potential) and by diode 21 outputs, the RC path that second capacitor 23 and resistance 16 constitute will make PNP transistor 22 have the effect of slow unlatching.
But, form resistance and quite waste area of chip for integrated circuit.Therefore, above-mentioned power initiation circuit haves much room for improvement.
(3) summary of the invention:
Fundamental purpose of the present invention is to provide a kind of power initiation circuit of avoiding source current at the pulse phenomenon of Qi Shishi.
Second purpose of the present invention is to provide a kind of power initiation circuit that occupies less chip area.
The 3rd purpose of the present invention is to provide a kind of power initiation circuit of power supply starting time more easy to control.
For achieving the above object, the present invention takes following technical measures:
Power initiation circuit of the present invention comprises an ON-OFF control circuit that is used to control P type or N transistor npn npn switch conduction state.For P transistor npn npn switch, this ON-OFF control circuit comprises a lift elements, a current source and an electric current beginning.For N transistor npn npn switch, this ON-OFF control circuit comprises that one drags down element, a current source and a current switch.
Concrete structure of the present invention also can be described below:
The power initiation circuit of a kind of peripheral element of the present invention comprises: the P transistor npn npn switch of a capacitor, a connection capacitor and an ON-OFF control circuit that is used to control P transistor npn npn switch;
ON-OFF control circuit comprises: a current source and a current switch;
Current source is connected to peripheral element power supply and described capacitor respectively;
Current switch is connected between current source and the earth point, and when power initiation, current switch is used to provide a path to make current source be connected to earth terminal;
Utilize current source that capacitor is charged, with slow unlatching P transistor npn npn switch.
Wherein, described ON-OFF control circuit also comprises a lift elements, and it is connected between described current source and the peripheral element power supply;
When power supply did not start, lift elements was electrically connected to power supply with described P transistor npn npn switch.
The power initiation circuit of another kind of peripheral element of the present invention comprises: the N transistor npn npn switch of a capacitor, a connection capacitor and an ON-OFF control circuit that is used to control N transistor npn npn switch;
ON-OFF control circuit comprises: a current source and a current switch;
Current source is connected to peripheral element power supply and described capacitor respectively;
Current switch is connected between current source and the earth point, and when power initiation, current switch is used to provide a path to make current source be connected to earth terminal;
Utilize current source that capacitor is charged, with slow unlatching N transistor npn npn switch.
Wherein, described ON-OFF control circuit comprises that also drags down an element, is connected between described current source and the peripheral element power supply; When power supply did not start, it was electrically connected to earth terminal with described N transistor npn npn switch.
Compared with prior art, the present invention has following effect:
Because the present invention utilizes capacitor that is parallel to transistor switch of an ON-OFF control circuit collocation, the time of may command transistor switch conducting is so that transistor switch has the effect of slow unlatching.In other words, that is utilize transistor switch, reach the function that power supply is slowly opened.And for integrated circuit, the design of constant-current source circuit is comparatively simple, does not also occupy too big area, therefore, can overcome shortcoming of the prior art.
(4) description of drawings:
Fig. 1: the circuit diagram of existing a kind of power initiation circuit;
Fig. 2: the circuit diagram of existing another kind of power initiation circuit;
Fig. 3 A, 3B: the circuit diagram of power initiation circuit embodiments of the present invention;
Fig. 4 A, 4B: the sequential chart of power initiation circuit embodiments of the present invention.
(5) embodiment
Reaching embodiment in conjunction with the accompanying drawings is described in detail as follows architectural feature of the present invention:
Shown in Fig. 3 A and Fig. 3 B, it is for the circuit diagram of power initiation circuit embodiments of the present invention, in Fig. 3 A, an ON-OFF control circuit 32 is used to control the conducting state of P transistor npn npn switch 31, and make slow the falling of voltage of node g with 23 chargings of the 35 pairs of capacitors of current source in the ON-OFF control circuit 32, reach the slow purpose that rises of the voltage that makes node L.ON-OFF control circuit 32 of the present invention comprises a lift elements (a for example weak P transistor npn npn) 33, current sources 35 and current switches (a for example N transistor npn npn) 34.When power supply starting signal is not imported, by lift elements 33 the voltage Vg of node g (the control utmost point of P transistor npn npn switch 31) is promoted to supply voltage, can avoid due to leakage current that the voltage of node g is descended and the P transistor npn npn that misleads.Current source 35 can utilize current mirror symmetry modes such as (current mirror) to set up, and direction of current points to earth terminal.And current switch 34 provides a path, makes the electric current of current source form an electric pathway via earth point.In integrated circuit, the occupied area of current source is much smaller than the shared area of resistance, and current source is subjected to manufacture process or influence of temperature variation less than resistance.Therefore, adopt the method for current source substitutional resistance, make the present invention be better than prior art.In Fig. 3 B, an ON-OFF control circuit 32 is used to control the conducting of N transistor npn npn switch 37, and makes slow liter of voltage of node g with 23 chargings of the 35 pairs of capacitors of current source in the ON-OFF control circuit 32, reaches the slow purpose that rises of the voltage that makes node L.ON-OFF control circuit 32 in the power initiation circuit of the present invention comprises that one drags down element (a for example weak N transistor npn npn) 36, current sources 35 and current switches (a for example P transistor npn npn) 34.When power supply starting signal is not imported, utilize to drag down element 36 the voltage Vg of node g is pulled low to earth terminal voltage, can avoid due to leakage current that the voltage of node g is risen, and the N transistor npn npn that misleads.Current source 35 can utilize modes such as current mirror symmetry to set up, and direction of current also flows to earth terminal.When power supply starting signal was imported, the electric current that current switch 34 provides a path to make current source can form an electric pathway from the USB (universal serial bus) power supply.In addition, P transistor npn npn switch 31 or N transistor npn npn switch 37 can use bipolarity (Bipolar) transistor, metal-oxide semiconductor (MOS) (MOS) transistor, and the present invention does not impose any restrictions this.
Fig. 4 A is the sequential chart of circuit shown in Fig. 3 A, and Fig. 4 B is the sequential chart of circuit shown in Fig. 3 B; In Fig. 4 A, after the power supply starting signal input, the voltage signal Vg of node g will be descended gradually by supply voltage.And relatively, the voltage signal V of node L
LThrough T after a while
0After the delay, rise gradually, and at T
1Time reaches stable voltage output.T
1Time can calculate via following formula:
T
1=C×ΔV/I
S ……(1)
In formula (1), C is the capacitance of second capacitor, and Δ V is the voltage drop of Vg.In Fig. 4 B, after the power supply starting signal input, voltage signal Vg will be risen gradually by ground voltage.And relatively, the voltage signal V of node L
LThrough T after a while
0After the delay, also rise gradually, and at T
1Time reaches stable voltage output.
Foregoing is to utilize embodiment that technical characterictic of the present invention is described, is not to be used to limit protection scope of the present invention, even there is the people to change slightly on the basis of the present invention's design, must belong in protection scope of the present invention.
Claims (8)
1, a kind of power initiation circuit of peripheral element comprises: the P transistor npn npn switch of a capacitor, a connection capacitor and an ON-OFF control circuit that is used to control P transistor npn npn switch;
It is characterized in that ON-OFF control circuit comprises: a current source and a current switch;
Current source is connected to peripheral element power supply and described capacitor respectively;
Current switch is connected between current source and the earth point, and when power initiation, current switch is used to provide a path to make current source be connected to earth terminal;
Utilize current source that capacitor is charged, with slow unlatching P transistor npn npn switch.
2, power initiation circuit according to claim 1 is characterized in that, described P transistor npn npn switch is selected from bipolar transistor and metal oxide semiconductor transistor.
3, power initiation circuit according to claim 1 is characterized in that, described ON-OFF control circuit also comprises a lift elements, and it is connected between described current source and the peripheral element power supply;
When power supply did not start, lift elements was electrically connected to power supply with described P transistor npn npn switch.
4, start-up circuit according to claim 1 is characterized in that, described current switch is a N transistor npn npn.
5, a kind of power initiation circuit of peripheral element comprises: the N transistor npn npn switch of a capacitor, a connection capacitor and an ON-OFF control circuit that is used to control N transistor npn npn switch;
It is characterized in that ON-OFF control circuit comprises: a current source and a current switch;
Current source is connected to peripheral element power supply and described capacitor respectively;
Current switch is connected between current source and the earth point, and when power initiation, current switch is used to provide a path to make current source be connected to earth terminal;
Utilize current source that capacitor is charged, with slow unlatching N transistor npn npn switch.
6, power initiation circuit according to claim 5 is characterized in that, described N transistor npn npn switch is selected from bipolar transistor and metal oxide semiconductor transistor.
7, power initiation circuit according to claim 5 is characterized in that, described ON-OFF control circuit comprises that also drags down an element, is connected between described current source and the peripheral element power supply; When power supply did not start, it was electrically connected to earth terminal with described N transistor npn npn switch.
8, power initiation circuit according to claim 5 is characterized in that, described current switch is a P transistor npn npn.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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CN 01134983 CN1221880C (en) | 2001-11-23 | 2001-11-23 | Initiate circuit for power supply of peripheral elements |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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CN 01134983 CN1221880C (en) | 2001-11-23 | 2001-11-23 | Initiate circuit for power supply of peripheral elements |
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CN1421761A true CN1421761A (en) | 2003-06-04 |
CN1221880C CN1221880C (en) | 2005-10-05 |
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CN 01134983 Expired - Fee Related CN1221880C (en) | 2001-11-23 | 2001-11-23 | Initiate circuit for power supply of peripheral elements |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1333326C (en) * | 2004-03-12 | 2007-08-22 | 凌阳科技股份有限公司 | Illuminant brightness control device for optical mouse |
JP2009201345A (en) * | 2007-12-27 | 2009-09-03 | O2 Micro Inc | Battery cell balancing system using current regulator |
CN1859001B (en) * | 2006-03-01 | 2010-05-12 | 华为技术有限公司 | DC power slow start circuit |
CN102012732B (en) * | 2009-09-08 | 2012-11-21 | 佛山市顺德区顺达电脑厂有限公司 | Electronic device with circuit for preventing contact sparks |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101409457B (en) * | 2007-10-08 | 2010-12-01 | 凹凸科技(中国)有限公司 | Equalization circuit and method for charging battery set |
US7973514B2 (en) | 2007-10-09 | 2011-07-05 | O2Micro, Inc. | Battery cell balancing systems using current regulators |
CN103972930A (en) | 2013-01-24 | 2014-08-06 | 凹凸电子(武汉)有限公司 | Battery management system, method for controlling charging of battery pack and battery pack |
-
2001
- 2001-11-23 CN CN 01134983 patent/CN1221880C/en not_active Expired - Fee Related
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1333326C (en) * | 2004-03-12 | 2007-08-22 | 凌阳科技股份有限公司 | Illuminant brightness control device for optical mouse |
CN1859001B (en) * | 2006-03-01 | 2010-05-12 | 华为技术有限公司 | DC power slow start circuit |
JP2009201345A (en) * | 2007-12-27 | 2009-09-03 | O2 Micro Inc | Battery cell balancing system using current regulator |
CN102012732B (en) * | 2009-09-08 | 2012-11-21 | 佛山市顺德区顺达电脑厂有限公司 | Electronic device with circuit for preventing contact sparks |
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CN1221880C (en) | 2005-10-05 |
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Granted publication date: 20051005 Termination date: 20091223 |