CN100365909C - Flashing-lamp charging apparatus - Google Patents
Flashing-lamp charging apparatus Download PDFInfo
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- CN100365909C CN100365909C CNB2005100523363A CN200510052336A CN100365909C CN 100365909 C CN100365909 C CN 100365909C CN B2005100523363 A CNB2005100523363 A CN B2005100523363A CN 200510052336 A CN200510052336 A CN 200510052336A CN 100365909 C CN100365909 C CN 100365909C
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- charging device
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Abstract
The present invention provides a flasher charging device of a digital camera, which comprises a digital signal processor, a charging capacitor, a voltage boost circuit and a charging circuit, wherein the digital signal processor comprises a pulse control unit and an analog digital converting unit; the pulse control unit is used for generating pulse width modulation control signals, and the analog digital converting unit is used for converting analog signals into digital signals; the voltage boost circuit is electrically connected to the digital signal processor, and output induced current under the control of the pulse width modulation control singles; the charging circuit is respectively and electrically connected to the voltage boost circuit and the charging capacitor, and uses the induced current output by the voltage boost circuit to charge the charging capacitor; meanwhile, a feedback signal is fed back to the analog digital converting unit of the digital signal processor for adjusting whether charge is completed. The flasher charging device of the present invention uses a few components, the circuits are simple, and charging efficiency is high; the present invention not only reduces the occupying space of the flasher charging device, but also reduces the cost of the digital camera.
Description
[technical field]
The present invention relates to a kind of photoflash lamp of digital camera, refer to a kind of flasher charging device especially.
[background technology]
Flash unit all is equipped with on traditional optical camera and the at present popular digital camera, can be when insufficient light light filling.Before photoflash lamp work, need charge to it, to provide its operate as normal required voltage.Usually, the flasher charging device of digital camera mainly adopts two kinds of internal circuit forms, and a kind of is the self-excitation mode, announces the 5th, 966 as United States Patent (USP), the flash lamp circuit that is disclosed for No. 552; Another kind is the circuit that comprises a slice dedicated IC chip.The structure of the circuit of above-mentioned first kind of employing self-excitation mode is very complicated, usually need a plurality of field effect transistor, diode, resistance, electric capacity and inductance to form oscillating circuit, filter circuit, booster circuit, rectification circuit, voltage stabilizing circuit and feedback circuit or the like, especially only vibration and filter circuit just need take a large amount of circuit board spaces, be unfavorable for the simplification of charging circuit for flashlamp and the miniaturization of circuit board, and the circuit charge efficiency of this employing self-excitation mode is low, is difficult to satisfy the requirement of digital camera to reaction speed.And the circuit of above-mentioned second kind of employing dedicated IC chip is to utilize the special-purpose integrated circuit (IC) chip of a slice charging that pulse width modulation control (pulsewidth modulation is provided, PWM) signal is with the work of control charging circuit, though this mode can improve charge efficiency and reduce the volume of circuit board to a certain extent, but, thereby make the cost of digital camera promote because of needs increase a slice special chip.
United States Patent (USP) announces the 6th, 714, promptly discloses a kind of flash lamp of digital camera charging device that contains special chip No. 735.This charging device comprises: capacitor of flash lamp; Be electrically connected at the transformation charging circuit of capacitor of flash lamp, be used to provide to the capacitor of flash lamp induced current; And the voltage-type pulse width control circuit that is electrically connected at voltage charging circuit, being used for providing pulse voltage to the transformation charging circuit, this pulse voltage can drive the transformation charging circuit and produce corresponding induced current.Wherein, the voltage-type pulse width control circuit is provided by a slice special chip, and the charging control circuit that also needs to arrange in pairs or groups is controlled the pulse duration of its voltage pulse output.Though this flasher charging device structure is also uncomplicated, special chip and charging control circuit all can make the cost of digital camera improve.
In view of the foregoing, the invention provides a kind of simple in structure, take up room little, and the flasher charging device that cost is low, efficient is high.
[summary of the invention]
Main purpose of the present invention be to provide a kind of simple in structure, take up room little, and the flasher charging device that cost is low, efficient is high.
For achieving the above object, the present invention adopts following technical scheme: the invention provides a kind of flasher charging device, it is applied in the digital camera, comprises a digital signal processor in this digital camera, output pulse width modulation control signal; This flasher charging device comprises booster circuit, and it is electrically connected at digital signal processor, and exports induced current under the control of pulse width modulation control signal; Electric capacity; And charging circuit, the one end is electrically connected at booster circuit, the other end is electrically connected at electric capacity, and utilize the induced current of booster circuit output that electric capacity is charged, this charging circuit comprises at least one feedback circuit, be used to provide and feed back signal to digital signal processor, digital signal processor is output pulse width modulation control signal according to this feedback signal.
Above-mentioned digital signal processor comprises pulse control unit, is used for exporting described pulse width modulation control signal, and analog digital converting unit, is used for receiving feedback signals, and feedback signal is converted to digital signal.
For achieving the above object, the present invention also can adopt following technical scheme: the invention provides a kind of flasher charging device, comprise charging capacitor; Pulse control unit is used for sending the pulse width modulation control signal; Booster circuit is electrically connected at pulse control unit, and exports induced current under the control of pulse width modulation control signal; Charging circuit, the one end is electrically connected at booster circuit, is used to receive induced current, and the other end is electrically connected at charging capacitor, and this charging circuit can provide at least one feedback signal; Analog digital converting unit is used for receiving feedback signals, and converts feedback signal to digital signal; And the microprocessing unit that electrically connects pulse control unit and analog digital converting unit, it can come the signal of control impuls control unit to send according to the feedback signal that converts digital signal to.
In the course of work of flasher charging device, digital signal processor or microprocessor monitor the value of feedback signal all the time by analog digital converting unit, in case find that feedback signal reaches critical voltage, digital signal processor or will stop output pulse width modulation control signal then by the pulse control unit that microprocessor is controlled, thus charging finished.
Compared with prior art, the assembly that flasher charging device of the present invention uses is few, circuit is simple, and the charge efficiency height, has not only reduced the shared space of flasher charging device, and has greatly reduced the cost of digital camera.
[description of drawings]
Fig. 1 is the circuit block diagram of flasher charging device of the present invention.
Fig. 2 is the circuit diagram of flasher charging device first embodiment of the present invention.
Fig. 3 is the circuit diagram of flasher charging device second embodiment of the present invention.
[embodiment]
Please refer to illustrated in figures 1 and 2, according to the first embodiment of the present invention, flasher charging device 1 of the present invention mainly comprises: and digital signal processor (digital signal processor, DSP) 10, booster circuit 20, charging circuit 30, charging capacitor C0 and filter circuit 210.
Pulse width modulation control signal PWM low continuous impulse when high when being a current potential is used to control grid and the source voltage difference VGS of field effect transistor Q1.When pulse width modulation control signal PWM is high potential, field effect transistor Q1 conducting, the elementary electric current I D of the feasible transformer T1 that flows through increases.When pulse width modulation control signal PWM was electronegative potential, field effect transistor Q1 ended, and the elementary electric current I D of transformer T1 that therefore flows through can diminish.The variation of electric current I D can cause the primary coil vibration of step-up transformer T1, thereby produces the electric current and the voltage of vibration in booster circuit 20.Among Fig. 2 among digital signal processor 10 or Fig. 3 microprocessing unit 115 see through control impuls control unit 110 and the pwm signal that produces characteristic frequency to the field effect transistor Q1 of booster circuit 20, and make step-up transformer T1 constantly vibrate by the switch repeatedly of field effect transistor Q1, thereby the secondary generation induced current I1 at step-up transformer T1 inputs to charging circuit 30.
Diode D1 in the charging circuit 30 carries out halfwave rectifier to induced current I1, thereby forms direct current so that charging capacitor C0 is charged.Voltage on the charging capacitor C0 increases gradually, up to reaching setting voltage.Voltage stabilizing didoe D2 in the charging circuit 30 and resistance R 3, capacitor C 3 form an overvoltage crowbar 310, and it is in parallel with charging capacitor C0, is used to protect charging capacitor C0.When the voltage that loads on charging capacitor C0 two ends exceeded the setting voltage of charging capacitor C0, voltage stabilizing didoe D2 can be breakdown, thereby formed big electric current (not shown) in 310 last moments of overvoltage crowbar, makes charging capacitor C0 discharge with this.Charging circuit 30 also comprises feedback circuit 320, is composed in series with R2 by resistance R 1.Resistance R 1 is drawn described feedback signal Uf with R2 is middle, inputs to analog digital converting unit 120.In charging process, digital signal processor 10 (microprocessing unit 115) is always by the value of analog digital converting unit 120 at supervision feedback signal Uf, when the voltage on the charging capacitor C0 reaches setting voltage, the feedback signal Uf of feedback circuit 320 feedbacks also reaches critical voltage simultaneously, this critical voltage is pre-set in the digital signal processor 10 (microprocessing unit 115), its magnitude of voltage is followed according to feedback circuit 320 and is set, and is the magnitude of voltage of equal proportion less than setting voltage.When digital signal processor 10 (microprocessing unit 115) receives feedback signal Uf, and when the voltage on the charging capacitor C0 is equal to or greater than setting voltage, pulse control unit 110 can stop to send pulse width modulation control signal PWM, thereby booster circuit 20 and charging circuit 30 are quit work; Otherwise, when the voltage on the charging capacitor C0 during less than setting voltage, be that feedback signal Uf is when changeing less than critical voltage, digital signal processor 10 (microprocessing unit 115) can control impuls control unit 110 sends pulse width modulation control signal PWM once more according to the value of feedback signal Uf, thereby makes booster circuit 20 and charging circuit 30 start working.
The size of above-described critical voltage is according to the saturation voltage Va of charging capacitor C0 and is decided by the feedback circuit 320 that R1, R2 formed, specify it in conjunction with above-mentioned two embodiment of the present invention, the saturation voltage Va that supposes capacitor C 0 is 300V, the resistance ratio of R1: R2 is 9: 1, then critical voltage is Va* ((R2/ (R1+R2)), be 300* (1/10)=30V, that is to say, when feedback signal Uf reaches 30V, be considered as the C0 charging and finish.
Claims (7)
1. a flasher charging device comprises pulse control unit, is used for output pulse width modulation control signal; Booster circuit, it exports induced current under the control of pulse width modulation control signal; Charging capacitor; And charging circuit, the one end is electrically connected at booster circuit, and the other end is electrically connected at charging capacitor, and utilizes the induced current of booster circuit output that charging capacitor is charged, and this charging circuit comprises at least one feedback circuit, is used to provide feedback signal; It is characterized in that: this flasher charging device also comprises analog digital converting unit, be used for receiving feedback signals, and this feedback signal is converted to digital signal, and described pulse control unit and analog digital converting unit all are integrated in the digital signal processor, this digital signal processor can be according to the value of feedback signal output pulse width modulation control signal, described feedback signal reaches critical voltage, and digital signal processor just stops output pulse width modulation control signal.
2. flasher charging device as claimed in claim 1 is characterized in that: described feedback circuit comprises the resistance of two series connection, and feedback signal is drawn in the middle of two series resistances.
3. flasher charging device as claimed in claim 2 is characterized in that: described charging circuit also comprises the overvoltage crowbar in parallel with charging capacitor.
4. flasher charging device as claimed in claim 3 is characterized in that: described overvoltage crowbar comprises a voltage stabilizing didoe.
5. flasher charging device as claimed in claim 1 is characterized in that: described booster circuit comprises field effect transistor and step-up transformer, and field effect transistor is electrically connected at pulse control unit.
6. flasher charging device as claimed in claim 5 is characterized in that: this flasher charging device also comprises filter circuit, and the one end is connected in step-up transformer, and the other end is connected to a direct current power supply.
7. as claim 1 or 6 described flasher charging devices, it is characterized in that: described induced current need be through just charging to charging capacitor behind the diode rectification.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100523363A CN100365909C (en) | 2005-02-06 | 2005-02-06 | Flashing-lamp charging apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100523363A CN100365909C (en) | 2005-02-06 | 2005-02-06 | Flashing-lamp charging apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1815843A CN1815843A (en) | 2006-08-09 |
| CN100365909C true CN100365909C (en) | 2008-01-30 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100523363A Expired - Fee Related CN100365909C (en) | 2005-02-06 | 2005-02-06 | Flashing-lamp charging apparatus |
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| Country | Link |
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| CN (1) | CN100365909C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7782018B2 (en) * | 2007-09-10 | 2010-08-24 | Maxim Integrated Products, Inc. | Adaptive current limiting for any power source with output equivalent series resistance |
| CN101726964B (en) * | 2008-10-28 | 2012-01-18 | 亚洲光学股份有限公司 | Image acquiring device and method for shifting charging capacitance of flashlamp thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4638236A (en) * | 1984-11-08 | 1987-01-20 | A. G. Busch & Co., Inc. | DC to DC battery charger |
| CN2249996Y (en) * | 1996-06-25 | 1997-03-19 | 霍学义 | Timing switch for remote controlled TV receiver |
| CN2626183Y (en) * | 2003-05-23 | 2004-07-14 | 普立尔科技股份有限公司 | Flashlight capacitor charging unit |
| CN1553757A (en) * | 2003-05-27 | 2004-12-08 | ������ҵ�ɷ�����˾ | Flashing light controller and operatnig method thereof |
-
2005
- 2005-02-06 CN CNB2005100523363A patent/CN100365909C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4638236A (en) * | 1984-11-08 | 1987-01-20 | A. G. Busch & Co., Inc. | DC to DC battery charger |
| CN2249996Y (en) * | 1996-06-25 | 1997-03-19 | 霍学义 | Timing switch for remote controlled TV receiver |
| CN2626183Y (en) * | 2003-05-23 | 2004-07-14 | 普立尔科技股份有限公司 | Flashlight capacitor charging unit |
| CN1553757A (en) * | 2003-05-27 | 2004-12-08 | ������ҵ�ɷ�����˾ | Flashing light controller and operatnig method thereof |
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| Publication number | Publication date |
|---|---|
| CN1815843A (en) | 2006-08-09 |
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Granted publication date: 20080130 Termination date: 20110206 |