CN2718944Y - Digital code camera flash lamp charging control circuit - Google Patents
Digital code camera flash lamp charging control circuit Download PDFInfo
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- CN2718944Y CN2718944Y CN 200420073119 CN200420073119U CN2718944Y CN 2718944 Y CN2718944 Y CN 2718944Y CN 200420073119 CN200420073119 CN 200420073119 CN 200420073119 U CN200420073119 U CN 200420073119U CN 2718944 Y CN2718944 Y CN 2718944Y
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Abstract
The utility model discloses a digital code camera flash lamp charging control circuit, comprising a drive circuit, a power transformer, a high-voltage energy storage capacitor, a PWM oscillation circuit and discharging detection circuits. The PWM oscillation circuit generates a series of oscillation impulses and the oscillation impulses are input into the drive circuit to control the start-stop state of the drive circuit. The drive circuit is connected with primary coils of the power transformer to input charging current. Secondary coils of the power transformer are connected with the high-voltage energy storage capacitor to charge the high-voltage energy storage capacitor by using self-inverse high-voltage. The discharging detection circuits are respectively connected with the primary coils of the power transformer to test the discharging completion of the secondary coils of the power transformer, to generate PWM oscillation circuit control signals which are output to the PWM oscillation circuit. Compared to the prior art, the utility model has the advantages of simple circuit structure, low cost, high working efficiency, strong controllability, wide applicability, etc.
Description
Technical field
The utility model relates to a kind of charging device that is used for the photoflash lamp of camera, particularly a kind of flash lamp of digital camera charging control circuit.
Technical background
Along with CMOS, the CCD digital camera, the popularizing of Digital Video, the photoflash lamp of taking under the insufficient light situation as secondary light source is each mandatory component of taking product;
Domestic production producer all adopts traditional transformer feedback form to form self-excited oscillator and produces charging control signal now, drives charging transformer again high-voltage capacitance is charged.The photoflash lamp that constitutes with this circuit has following shortcoming:
A, charge efficiency low (generally being lower than 30%);
B, charging interval are long;
C, charging current are big, and electric current cannot be controlled;
D, volume are big; The circuit complexity;
Therefore, if continue to adopt traditional flash control circuit, the digital filming product is extra small requiring, ultra-thin, with two No. 5, or two No. 7 battery powered CMOS, in the CCD digital camera, can't allow photoflash lamp and system operate as normal (normal working voltage requires from 3.3V----1.8V) together;
Now a part of domestic and international famous CMOS, the CCD digital camera, Digital Video manufacturer all adopts central processing unit control (but to require software to cooperate, and efficient can not improve equally, charging interval is long), the charging control integrated circuit that another part adopts U.S. LINER company to provide, this charging control integrated circuit efficient height, charging interval is short, but charging current can not be controlled in low pressure, guarantee that system is normal under the low battery voltages state, can only sacrifice the charging interval under the sufficient cell voltage.Maximum problem is that this integrated circuit buying hour is long, cost an arm and a leg (the similar 20RMB of 2.5USD.), to requiring CMOS cheaply, the CCD digital camera, Digital Video is inadvisable.
The utility model content
The purpose of this utility model is: at the deficiencies in the prior art, provide a kind of simple in structure, high efficiency, flash lamp of digital camera charging control circuit cheaply.
In order to solve the problems of the technologies described above, technical solution adopted in the utility model is: a kind of flash lamp of digital camera charging control circuit, comprise drive circuit, power transformer and high-voltage energy storage capacitor, also comprise PWM oscillating circuit and discharge detection circuit, described PWM oscillating circuit produces a series of oscillating impulses and inputs to drive circuit, start and stop state with control Driver Circuit, described drive circuit connects the primary coil of power transformer, with the input charging current, the secondary coil of described power transformer connects high-voltage energy storage capacitor, self instead swash high pressure high-voltage energy storage capacitor is charged to utilize, described discharge detection circuit connects the primary coil of power transformer respectively, secondary coil discharge with the detection power transformer is finished, and produces PWM oscillating circuit control signal and exports the PWM oscillating circuit to.
Described PWM oscillating circuit is made of comparator, transformer charging circuits for triggering, transformer discharge trigger circuit and transformer discharge holding circuit, the in-phase input end of described comparator connects power supply, its inverting input is divided into three the tunnel, one the tunnel connects transformer charging circuits for triggering, with the charging triggering signal of input high level, and produce high level signal from its output; Another road connects the transformer discharge trigger circuit, with the discharge triggering signal of input low level, and produces low level signal from its output; Third Road connects transformer discharge holding circuit, with the discharge inhibit signal of input low level, and makes its output keep the output low level signal, thereby forms a series of continuous oscillator signal that is made of high-low level.
The beneficial effects of the utility model are: owing to adopt PWM (pulse-width modulation) oscillating circuit and discharge detection circuit, thus can be as required, the mode by pulse-width modulation realizes the adjustment to the charging interval, has the high characteristics of charge efficiency.Secondly,, can adopt common components and parts, therefore, can reduce production costs greatly because circuit structure of the present utility model is quite simple.And simple circuit configuration has also reduced the volume of product greatly, enables to be applicable to the more camera of multi-model.In addition,, thereby reach light control charging current, alleviate the power supply momentary load, guarantee the job stability of circuit because the utility model can receive the current peak control signal from the outside.
Description of drawings
Accompanying drawing 2 is the circuit block diagram of PWM oscillating circuit of the present utility model;
Accompanying drawing 3 is the circuit theory diagrams of a kind of preferred embodiment of the present utility model;
Accompanying drawing 4 is the operating state curve chart of the comparator U2-A in the PWM oscillating circuit of the present utility model.
Embodiment
Below in conjunction with Figure of description and specific embodiment the utility model is described in further detail.
With reference to the accompanying drawings 1, a kind of flash lamp of digital camera charging control circuit is by PWM oscillating circuit, drive circuit, discharge detection circuit, power transformer and high-voltage energy storage capacitor.
Described PWM oscillating circuit is used to produce a series of oscillating impulses and inputs to drive circuit, start and stop state with control Driver Circuit, described drive circuit connects the primary coil of power transformer, with the input charging current, the secondary coil of described power transformer connects high-voltage energy storage capacitor, self instead swash high pressure high-voltage energy storage capacitor is charged to utilize, described discharge detection circuit connects the primary coil of power transformer respectively, secondary coil discharge with the detection power transformer is finished, and produces PWM oscillating circuit control signal and exports the PWM oscillating circuit to.
With reference to the accompanying drawings 2, described PWM oscillating circuit is made of comparator, transformer charging circuits for triggering, transformer discharge trigger circuit and transformer discharge holding circuit, the in-phase input end of described comparator connects power supply, its inverting input is divided into three the tunnel, one the tunnel connects transformer charging circuits for triggering, with the charging triggering signal of input high level, and produce high level signal from its output; Another road connects the transformer discharge trigger circuit, with the discharge triggering signal of input low level, and produces low level signal from its output; Third Road connects transformer discharge holding circuit, with the discharge inhibit signal of input low level, and makes its output keep the output low level signal, thereby forms a series of continuous oscillator signal that is made of high-low level.
Accompanying drawing 3 provides a kind of preferred embodiment circuit theory diagrams of the present utility model.Adopting very general model in the present embodiment is the comparator U2 of LM339.
The in-phase input end of described comparator U2-A passes through resistance R 15 connection+5V power supplys, and by resistance R 9 ground connection.
Described transformer charging circuits for triggering are made of resistance R 31, R10, capacitor C 6, diode and peripheral component, one end ground connection of described capacitor C 6, its other end connects the positive pole of diode by resistance R 10, and connects the inverting input of comparator U2-A successively by this diode and resistance R 31.
Described transformer discharge trigger circuit is made of resistance R 31, R29, capacitor C 6, diode and peripheral component, one end ground connection of described capacitor C 6, its other end is by the negative pole of resistance R 29 connection diodes, and the positive pole of described diode connects the inverting input of comparator U2-A by resistance R 31.
Described transformer discharge holding circuit is made of triode Q7, resistance R 1, R11 and peripheral component, the emitter of described triode Q7 connects 3 pin of the secondary coil of power transformer T1 by resistance R 1, its base earth, its collector electrode connect the inverting input of comparator U2-A by resistance R 11.
Described drive circuit is made of buffer U1, power tube Q1 and peripheral component, the 1 pin input of described buffer U1 is from the oscillating impulse of PWM oscillating circuit, its 2 pin connects the collector electrode of the triode Q4 of grounded emitter on the one hand, the base stage of described triode Q4 is by resistance R 22 input charging current peak value control signals, on the other hand, 2 pin of U1 also connect the negative pole of diode D5, and the positive pole of D5 connects the base stage of triode Q4.The output 4 of described buffer U1 connects the grid of power tube Q1, the source ground of power tube Q1, and its drain electrode connects 1 pin of the primary coil of power transformer T1.
Described discharge detection circuit comprises resistance R 19, R27, R20, comparator U2-B, U2-D and corresponding peripheral component, one end of described resistance R 19 connects 1 pin of the primary coil of described power transformer T1, its other end connects the inverting input of comparator U2-B on the one hand by resistance R 27, connect power supply by diode D2 on the other hand, the inverting input of described comparator U2-B is by resistance R 20 ground connection, its in-phase input end connects power supply by resistance R 24 on the one hand, the inverting input that connects comparator U2-D on the other hand, its output connects the in-phase input end of comparator U2-D, the output of described comparator U2-D connects capacitor C 6, with output PWM oscillating circuit control signal.
With reference to the accompanying drawings 4, operation principle of the present utility model is:
By R31, the RC circuit that R10 and C6 form (being transformer charging circuits for triggering) determined from 0 to the working point 2 T1 discharge time to C6, this moment U2-A 2 pin output low levels, buffer U1 exports high level, power tube Q1 conducting, the power transformer conducting, electric current flows into the charge power transformer from power supply, this time T1 and supply voltage have determined the magnetic field intensity that transformer stores, but magnetic field intensity must not surpass transformer maximum magnetic flux saturation intensity (otherwise transformer meeting supersaturation causes inefficient and big electric current).
In like manner, by R31, the RC circuit (being the transformer discharge trigger circuit) that R29 and C6 form determined from 0 to the working point 1 time T 2, this moment, 2 pin of U2-A were exported high level, buffer U1 output low level, power tube Q1 ends, and power transformer primary and secondary coil produces the anti-high pressure that swashs, and energy stored is charged to high-voltage energy storage capacitor C3 by D6 in the transformer.
Transformer to the C3 charging process in, Q7 flows through conducting because of charging current, 4 pin of U2-A are dragged down, and allow 2 pin of U2-A continue keep high level, up to power transformer energy have been put, Q7 withdraws from conducting state, U2-A enters charging cycle next time.
Can monitor the voltage at C3 two ends by the discharge detection circuit that R19, R27, R20 form, when the voltage at C3 two ends reached the voltage of setting, the U2-B output low level triggered the U2-D output low level simultaneously and allows U2-A quit work, and close Q1, transformer quits work.The U2-C also MCU charging of output low level notice digital camera finishes.
In order to prevent that continuing conduction level makes the current peak that flows through in the power transformer excessive to alleviate the power supply momentary load, the charging pulse control peak current level that Q4 produces by FLASH-ENABLE.The low level of FALSH-ENABLE can the charge closing controller simultaneously.
Claims (8)
1, a kind of flash lamp of digital camera charging control circuit, comprise drive circuit, power transformer and high-voltage energy storage capacitor, it is characterized in that: also comprise PWM oscillating circuit and discharge detection circuit, described PWM oscillating circuit produces a series of oscillating impulses and inputs to drive circuit, start and stop state with control Driver Circuit, described drive circuit connects the primary coil of power transformer, with the input charging current, the secondary coil of described power transformer connects high-voltage energy storage capacitor, self instead swash high pressure high-voltage energy storage capacitor is charged to utilize, described discharge detection circuit connects the primary coil of power transformer respectively, secondary coil discharge with the detection power transformer is finished, and produces PWM oscillating circuit control signal and exports the PWM oscillating circuit to.
2, flash lamp of digital camera charging control circuit according to claim 1, it is characterized in that: described PWM oscillating circuit is made of comparator, transformer charging circuits for triggering, transformer discharge trigger circuit and transformer discharge holding circuit, the in-phase input end of described comparator connects power supply, its inverting input is divided into three the tunnel, one the tunnel connects transformer charging circuits for triggering, with the charging triggering signal of input high level, and produce high level signal from its output; Another road connects the transformer discharge trigger circuit, with the discharge triggering signal of input low level, and produces low level signal from its output; Third Road connects transformer discharge holding circuit, with the discharge inhibit signal of input low level, and makes its output keep the output low level signal, thereby forms a series of continuous oscillator signal that is made of high-low level.
3, as flash lamp of digital camera charging control circuit as described in the claim 2, it is characterized in that: described transformer charging circuits for triggering are made of resistance R 31, R10, capacitor C 6, diode and peripheral component, one end ground connection of described capacitor C 6, its other end connects the positive pole of diode by resistance R 10, and connects the inverting input of comparator U2-A successively by this diode and resistance R 31.
4, as flash lamp of digital camera charging control circuit as described in the claim 2, it is characterized in that: described transformer discharge trigger circuit is made of resistance R 31, R29, capacitor C 6, diode and peripheral component, one end ground connection of described capacitor C 6, its other end is by the negative pole of resistance R 29 connection diodes, and the positive pole of described diode connects the inverting input of comparator U2-A by resistance R 31.
5, as flash lamp of digital camera charging control circuit as described in the claim 2, it is characterized in that: described transformer discharge holding circuit is made of triode Q7, resistance R 1, R11 and peripheral component, the emitter of described triode Q7 connects 3 pin of the secondary coil of power transformer by resistance R 1, its base earth, its collector electrode connect the inverting input of comparator U2-A by resistance R 11.
6, as flash lamp of digital camera charging control circuit as described in the claim 1,2,3,4 or 5, it is characterized in that: described drive circuit is made of buffer U1, power tube Q1 and peripheral component, the 1 pin input of described buffer U1 is from the oscillating impulse of PWM oscillating circuit, its 2 pin input charging current peak value control signal, its output 4 connects the grid of power tube Q1, the source ground of power tube Q1, its drain electrode connects 1 pin of the primary coil of power transformer.
7, as flash lamp of digital camera charging control circuit as described in the claim 6, it is characterized in that: described discharge detection circuit comprises resistance R 19, R27, R20, comparator U2-B, U2-D and corresponding peripheral component, one end of described resistance R 19 connects 1 pin of the primary coil of described power transformer, its other end connects the inverting input of comparator U2-B on the one hand by resistance R 27, connect power supply by diode D2 on the other hand, the inverting input of described comparator U2-B is by resistance R 20 ground connection, its in-phase input end connects power supply by resistance R 24 on the one hand, the inverting input that connects comparator U2-D on the other hand, its output connects the in-phase input end of comparator U2-D, the output of described comparator U2-D connects capacitor C 6, with output PWM oscillating circuit control signal.
8, as flash lamp of digital camera charging control circuit as described in the claim 7, it is characterized in that: 2 pin of described buffer U1 connect the collector electrode of the triode Q4 of grounded emitter on the one hand, the base stage of described triode Q4 is by resistance R 22 input charging current peak value control signals, on the other hand, 2 pin of U1 also connect the negative pole of diode D5, and the positive pole of D5 connects the base stage of triode Q4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420073119 CN2718944Y (en) | 2004-07-06 | 2004-07-06 | Digital code camera flash lamp charging control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420073119 CN2718944Y (en) | 2004-07-06 | 2004-07-06 | Digital code camera flash lamp charging control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2718944Y true CN2718944Y (en) | 2005-08-17 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200420073119 Expired - Fee Related CN2718944Y (en) | 2004-07-06 | 2004-07-06 | Digital code camera flash lamp charging control circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2718944Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103475189A (en) * | 2013-08-28 | 2013-12-25 | 中国航天科技集团公司第九研究院第七七一研究所 | Oscillator of PWM (pulse-width modulation) controller |
| CN109743509A (en) * | 2019-01-15 | 2019-05-10 | 上海曼恒数字技术股份有限公司 | A kind of method and device for camera light filling |
-
2004
- 2004-07-06 CN CN 200420073119 patent/CN2718944Y/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103475189A (en) * | 2013-08-28 | 2013-12-25 | 中国航天科技集团公司第九研究院第七七一研究所 | Oscillator of PWM (pulse-width modulation) controller |
| CN103475189B (en) * | 2013-08-28 | 2015-11-18 | 中国航天科技集团公司第九研究院第七七一研究所 | A kind of oscillator of PWM controller |
| CN109743509A (en) * | 2019-01-15 | 2019-05-10 | 上海曼恒数字技术股份有限公司 | A kind of method and device for camera light filling |
| CN109743509B (en) * | 2019-01-15 | 2021-01-05 | 上海曼恒数字技术股份有限公司 | Method and device for supplementing light for camera |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20050817 |