Flashlight color temperature adjustable control circuit based on double-color-temperature LED light source, photographing camera and video camera

Abstract

The utility model discloses a flash lamp color temperature adjustable control circuit based on a double-color-temperature LED light source, a photographing camera and a video camera. The flash lamp color temperature adjustable control circuit based on the double-color-temperature LED light source comprises a high-color-temperature light-emitting diode light source set, a low-color-temperature light-emitting diode light source set, an energy storage capacitor, a high-color-temperature NMOS switch tube, a low-color-temperature NMOS switch tube, a high-color-temperature freewheel diode, a low-color-temperature freewheel diode, a high-color-temperature choke inductor and a low-color-temperature choke inductor. By adjusting corresponding current amplitudes in the high-color-temperature light-emitting diode light source group and the low-color-temperature light-emitting diode light source group, the light-emitting energy proportion of the two light sources is changed, so that the light source color temperature within an ideal range is achieved, and the function of adjusting the interval range from low color temperature to high color temperature is achieved; a double-path simultaneous flashing mode is adopted, in the shutter time of camera exposure, the high-color-temperature LED and the low-color-temperature LED emit light at the same time, it is guaranteed that the light mixing state of the two-color-temperature LED is achieved at each photographing moment, and the ideal color temperature effect is achieved.

Description

Technical Field

[0001] The utility model relates to the field of power electronics, in particular to a color temperature adjustable control circuit for a flash lamp based on a two-color temperature LED light source, a photographing camera and a video camera. Background Art

[0002] At present, most of the mainstream flash lamps on the market use xenon tubes as light sources.

[0003] In the process of implementing the color temperature adjustable control circuit for the flash lamp based on the two-color temperature LED light source in the embodiment of the present utility model, the patent inventor of the present invention has at least found the following technical problems in the prior art:

[0004] For a xenon tube, its emission color temperature is single. Each time a photographer takes a photo, the color temperature can only be fixed, and then the staff needs to use computer software to modify the photo to the desired color temperature range. This situation not only increases the labor cost but also consumes a lot of time. Moreover, such a flash lamp cannot achieve the color temperature adjustment of the light source in an ideal range like a traditional two-color temperature LED constant light, which also restricts its wide use.

[0005] If a small or medium power two-color temperature LED lamp is selected, the fill light effect cannot be achieved when using the high-speed photographing of the camera in a conventional use environment. If a conventional two-color temperature LED lamp with a power increased by 50 - 100 times is selected, while increasing the cost of the fill light device, the ultra-high power lamp in a constant on state causes discomfort and eye damage to photographers, and also requires more power supply costs, which is uneconomical and not environmentally friendly, and is more unsuitable for outdoor shooting.

[0006] In summary, the existing flash lamps cannot meet the actual use requirements. Summary of the Utility Model

[0007] The embodiment of the present utility model provides a color temperature adjustable control circuit for a flash lamp based on a two-color temperature LED light source, a photographing camera and a video camera, which solves the problem that the existing flash lamps cannot meet the actual use requirements.

[0008] An embodiment of the present utility model provides a color temperature adjustable control circuit for a flash lamp based on a two-color temperature LED light source, including: a high color temperature light emitting diode light source group; a low color temperature light emitting diode light source group; an energy storage capacitor, one end of which is electrically connected to the input ends of the high color temperature light emitting diode light source group and the low color temperature light emitting diode light source group, and the other end is grounded; a high color temperature NMOS switch tube, the gate of which is electrically connected to a PWM-C high color temperature control signal, and the source is grounded; a low color temperature NMOS switch tube, the gate of which is electrically connected to a PWM-W low color temperature control signal, and the source is grounded; a high color temperature freewheeling diode, the input end of which is electrically connected to the drain of the high color temperature NMOS switch tube, and the output end is electrically connected to the input end of the high color temperature light emitting diode light source group; a low color temperature freewheeling diode, the input end of which is electrically connected to the drain of the low color temperature NMOS switch tube, and the output end is electrically connected to the input end of the low color temperature light emitting diode light source group; a high color temperature choke inductor, one end of which is electrically connected to the output end of the high color temperature light emitting diode light source group, and the other end is electrically connected to the input end of the high color temperature freewheeling diode and the drain of the high color temperature NMOS switch tube; a low color temperature choke inductor, one end of which is electrically connected to the output end of the low color temperature light emitting diode light source group, and the other end is electrically connected to the input end of the low color temperature freewheeling diode and the drain of the low color temperature NMOS switch tube.

[0009] Optionally, the current amplitude of the high color temperature light emitting diode light source group and the current amplitude of the low color temperature light emitting diode light source group are the same or different.

[0010] Optionally, the high color temperature light emitting diode light source group is specifically a high color temperature light emitting diode light source group of 6500K; or, the low color temperature light emitting diode light source group is specifically a low color temperature light emitting diode light source group of 2700K.

[0011] Optionally, the high color temperature light emitting diode light source group is specifically a high color temperature light emitting diode light source group of 6500K; and, the low color temperature light emitting diode light source group is specifically a low color temperature light emitting diode light source group of 2700K.

[0012] Optionally, the number of groups of the high color temperature light emitting diode light source group and the number of groups of the low color temperature light emitting diode light source group are the same or different.

[0013] Optionally, the number of high color temperature light sources in the high color temperature light emitting diode light source group and the number of low color temperature light sources in the low color temperature light emitting diode light source group are the same or different.

[0014] Optionally, the number of high color temperature light sources in the high color temperature light emitting diode light source group and the number of low color temperature light sources in the low color temperature light emitting diode light source group are 2 or more than 2.

[0015] Optionally, the K values of adjacent high-color-temperature light sources are the same or different, and the K values of adjacent low-color-temperature light sources are the same or different.

[0016] On the other hand, an embodiment of the present invention further provides a photographing camera, including: the flash lamp color temperature adjustable control circuit based on a two-color temperature LED light source described in the foregoing embodiment; a camera body electrically connected to the flash lamp color temperature adjustable control circuit based on the two-color temperature LED light source.

[0017] In a third aspect, an embodiment of the present invention further provides a video camera, including: the flash lamp color temperature adjustable control circuit based on a two-color temperature LED light source described in the foregoing embodiment; a video shooting body electrically connected to the flash lamp color temperature adjustable control circuit based on the two-color temperature LED light source.

[0018] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0019] The present invention mainly realizes using a two-color temperature LED capable of withstanding large pulsed currents as the light source of the flash lamp to replace the traditional xenon light source, achieving the function that the color temperature during the flash process can be adjusted, which cannot be achieved by traditional flash lamps.

[0020] The luminous color temperature of a traditional xenon flash lamp is single and cannot be selected, and it is impossible to meet the requirements of photographers for different fill light color temperatures in different environments. Compared with traditional xenon flash lamps, the flash lamp color temperature adjustable control circuit based on a two-color temperature LED light source in this patent uses a low-color temperature LED light source group and a high-color temperature LED light source group to emit light in a mixed manner. By adjusting the current amplitude of the two light source groups, the proportion of the light emission energy of the two light source groups is changed to achieve the adjustable function in the range from low color temperature to high color temperature. At the same time, the circuit of this patent adopts a dual-channel simultaneous flash mode, that is, within the shutter time of the camera exposure, the two-color temperature LEDs of high color temperature and low color temperature emit light simultaneously, ensuring that the mixed light state of the two-color temperature LEDs of high color temperature and low color temperature exists at each shooting moment, and achieving an ideal color temperature effect.

[0021] Although traditional dual-color temperature LED constant lights can support the function of adjustable color temperature, medium and small power traditional LED lamps are commonly used for normal ambient lighting. In this case, when using a camera to take high-speed photos, traditional LED lighting fixtures cannot achieve an ideal fill light effect; if using ultra-high power strong light LED lamps, it will make the photography staff unable to adapt. Compared with traditional LED light sources, the flash color temperature adjustable control circuit based on dual-color temperature LED light sources in this patent does not emit light when not taking pictures, so the staff will not be exposed to strong light for a long time. Only when the shutter is pressed will it flash and emit strong light with an extremely short exposure time to achieve the fill light effect. Compared with traditional LED constant lights, the circuit in this patent enables an ultra-small volume LED flash to achieve the same photo-taking effect as an LED constant light with a power 50-100 times that of a much larger volume, has extremely high portability, and significantly reduces the cost of photography equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural diagram of the flash color temperature adjustable control circuit based on dual-color temperature LED light sources in an embodiment of the present utility model;

[0023] Figure 2 is Figure 1 The current waveform diagrams of the high-color temperature light-emitting diode light source group and the low-color temperature light-emitting diode light source group corresponding to the PWM-C and PWM-W different duty cycle drive signals in the flash color temperature adjustable control circuit based on dual-color temperature LED light sources described above;

[0024] In the figure:

[0025] LED-C - High-color temperature light-emitting diode light source group;

[0026] LED-W - Low-color temperature light-emitting diode light source group;

[0027] D1-C - High-color temperature freewheeling diode;

[0028] D2-W - Low-color temperature freewheeling diode;

[0029] L1-C - High-color temperature choke inductor;

[0030] L2-W - Low-color temperature choke inductor;

[0031] Q1-C - High-color temperature NMOS switch tube;

[0032] Q2-W - Low-color temperature NMOS switch tube;

[0033] EC1 - Energy storage capacitor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] An embodiment of the present utility model provides a color temperature adjustable control circuit for a flash lamp based on a two-color temperature LED light source, which solves the problem that existing flash lamps cannot meet the actual use requirements.

[0035] First, the terms appearing in the specification will be explained respectively.

[0036] 1. PWM

[0037] PWM (Pulse Width Modulation) is a method of digitally encoding an analog signal level. By using a high-resolution counter, the duty cycle of a square wave is modulated to encode the level of a specific analog signal. The PWM signal is still digital because at any given moment, the full-amplitude DC power supply is either completely on (ON) or completely off (OFF). The voltage or current source is applied to the analog load in a repeating pulse sequence of on (ON) or off (OFF). When it is on, the DC power supply is applied to the load, and when it is off, the power supply is disconnected.

[0038] The main characteristics of PWM pulses include:

[0039] Duty cycle: In a PWM cycle, the ratio of the time the pulse is at a high level (pulse width) to the entire cycle time is called the duty cycle. The size of the duty cycle determines the average voltage or current level of the PWM signal.

[0040] Frequency: The frequency of the PWM signal is the reciprocal of its period. It determines how fast the PWM signal changes.

[0041] Resolution: The resolution of PWM depends on the number of bits of the counter or register used to control the pulse width. The more bits, the higher the resolution and the higher the achievable analog accuracy.

[0042] The PWM signal in this patent is divided into two paths. One path is used to generate a high color temperature control signal, denoted by the symbol PWM-C; the other path is used to generate a low color temperature control signal, denoted by the symbol PWM-W.

[0043] 2. LED

[0044] LED (Light Emitting Diode) is a solid-state semiconductor device that can convert electrical energy into visible light and can directly convert electricity into light.

[0045] The light source group in this patent selects light emitting diodes. This light source group is divided into two types. One is a high color temperature light emitting diode light source group, denoted by the symbol LED-C; the other is a low color temperature light emitting diode light source group, denoted by the symbol LED-W.

[0046] 3. MCU

[0047] MCU (Microcontroller Unit), also known as a single-chip microcomputer or microcontroller, is an integrated circuit chip that contains peripherals such as a processor, memory, timer, and input / output ports.

[0048] 4. Color Temperature

[0049] Color temperature is a physical quantity that describes the color characteristics of the light emitted by a light source. It represents the color components contained in the light and is usually used to define the warm and cool tones of a light source. The unit of color temperature is Kelvin (K).

[0050] Specifically, light sources with lower color temperatures will exhibit warm tones such as red and orange, while light sources with higher color temperatures will exhibit cool tones such as blue and purple. For example, the color temperature of a candle flame is approximately 1800K, presenting a warm tone; while the color temperature of sunlight reflected by a clear blue sky is approximately above 10000K, presenting a cool tone.

[0051] For high color temperatures, the K value is usually above 5000K. The higher the K value, the more the color of the light source tends towards blue.

[0052] For low color temperatures, the K value usually refers to below 3300K. The lower the K value, the more the color of the light source tends towards red.

[0053] In this patent, the symbol C is used to represent high color temperature, and the symbol W is used to represent low color temperature. Attaching the symbol C after an electronic component symbol indicates an electronic component that is used in conjunction with a high color temperature light source group; attaching the symbol W after an electronic component symbol indicates an electronic component that is used in conjunction with a low color temperature light source group. For example: L1-C represents a high color temperature choke inductor, and L1-W represents a low color temperature choke inductor.

[0054] To better understand the above flash color temperature adjustable control circuit based on a dual-color temperature LED light source, the above flash color temperature adjustable control circuit based on a dual-color temperature LED light source will be described in detail below in conjunction with the accompanying drawings of the specification and specific implementation manners. Obviously, the embodiments described in the present utility model are some embodiments of the present utility model, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present utility model without creative efforts fall within the scope of protection of the present utility model.

[0055] (1) Structure of the Flash Color Temperature Adjustable Control Circuit Based on a Dual-Color Temperature LED Light Source

[0056] Please refer to Figure 1 , the flash color temperature adjustable control circuit based on a dual-color temperature LED light source of the present utility model includes:

[0057] High color temperature light-emitting diode light source group LED-C;

[0058] Low color temperature light-emitting diode light source group LED-W;

[0059] Energy storage capacitor EC1, one end is electrically connected to the input ends of the high color temperature light-emitting diode light source group LED-C and the low color temperature light-emitting diode light source group LED-W, and the other end is grounded;

[0060] High color temperature NMOS switch tube Q1-C, the gate is electrically connected to the PWM-C high color temperature control signal, and the source is grounded;

[0061] Low color temperature NMOS switch tube Q2-W, the gate is electrically connected to the PWM-W low color temperature control signal, and the source is grounded;

[0062] High color temperature freewheeling diode D1-C, the input end is electrically connected to the drain of the high color temperature NMOS switch tube Q1-C, and the output end is electrically connected to the input end of the high color temperature light-emitting diode light source group LED-C;

[0063] Low color temperature freewheeling diode D2-W, the input end is electrically connected to the drain of the low color temperature NMOS switch tube Q2-W, and the output end is electrically connected to the input end of the low color temperature light-emitting diode light source group LED-W;

[0064] High color temperature choke inductor L1-C, one end is electrically connected to the output end of the high color temperature light-emitting diode light source group LED-C, and the other end is electrically connected to the input end of the high color temperature freewheeling diode D1-C and the drain of the high color temperature NMOS switch tube Q1-C;

[0065] Low color temperature choke inductor L2-W, one end is electrically connected to the output end of the low color temperature light-emitting diode light source group LED-W, and the other end is electrically connected to the input end of the low color temperature freewheeling diode D2-W and the drain of the low color temperature NMOS switch tube Q2-W.

[0066] Preferably, the high color temperature light-emitting diode light source group, specifically a high color temperature light-emitting diode light source group of 6500K, can achieve an ideal color temperature effect of 6500K.

[0067] Preferably, the low color temperature light-emitting diode light source group with a choke, specifically a low color temperature light-emitting diode light source group of 2700K, can achieve an ideal color temperature effect of 2700K.

[0068] Preferably, by simultaneously using a high color temperature light-emitting diode light source group of 6500K and a low color temperature light-emitting diode light source group of 2700K, a function of adjustable color temperature in the range of 2700K - 6500K can be achieved.

[0069] Among them, the current amplitudes of the high-color-temperature light-emitting diode light source group and the low-color-temperature light-emitting diode light source group can be the same or different, which is not limited in the present utility model. In specific applications, the corresponding current amplitudes in the high-color-temperature light-emitting diode light source group and the low-color-temperature light-emitting diode light source group can be adjusted according to actual needs to change the proportion of the light-emitting energy of the two-way light sources so as to achieve the light source color temperature within an ideal range.

[0070] The number of groups of the high-color-temperature light-emitting diode light source group and the number of groups of the low-color-temperature light-emitting diode light source group can be the same or different, and the specific number of groups is set according to actual usage needs. For example: the number of groups of the high-color-temperature light-emitting diode light source group and the number of groups of the low-color-temperature light-emitting diode light source group can both be set to 4 groups; or the number of groups of the high-color-temperature light-emitting diode light source group can be set to 2 groups, and the number of groups of the low-color-temperature light-emitting diode light source group can be set to 3 groups. In specific applications, the number of groups of the high-color-temperature light-emitting diode light source group and the number of groups of the low-color-temperature light-emitting diode light source group can be adjusted according to actual needs so as to achieve the light source color temperature within an ideal range.

[0071] In the high-color-temperature light-emitting diode light source group and the low-color-temperature light-emitting diode light source group, there is no limit to the corresponding number of light sources. Specifically, the number of corresponding light sources in the high-color-temperature light-emitting diode light source group and the low-color-temperature light-emitting diode light source group is 2 or more, such as 2, 5, 10, etc. In specific applications, the specific number of high-color-temperature light-emitting diodes can be selected according to actual needs, such as 4; the specific number of low-color-temperature light-emitting diodes can be selected, such as 10. In specific applications, the number of corresponding light-emitting diode light sources in the high-color-temperature light-emitting diode light source group and the low-color-temperature light-emitting diode light source group can be adjusted according to actual needs so as to achieve the light source color temperature within an ideal range.

[0072] In the high-color-temperature light-emitting diode light source group and the low-color-temperature light-emitting diode light source group, the number of corresponding light-emitting diode light sources can be the same or different, and can be adjusted according to actual usage needs. For example: the number of high-color-temperature light-emitting diodes and the number of low-color-temperature light-emitting diodes can both be set to 2; or the number of high-color-temperature light-emitting diodes can be set to 3, and the number of low-color-temperature light-emitting diodes can be set to 4. In specific applications, the number of high-color-temperature light-emitting diodes and the number of low-color-temperature light-emitting diodes can be adjusted according to actual needs so as to achieve the light source color temperature within an ideal range.

[0073] In the high-color-temperature light-emitting diode light source group, the K values of adjacent high-color-temperature light sources can be the same or different, and the K value of each high-color-temperature light source can be set according to actual circumstances, which is not limited in the present utility model. In specific applications, the K value of each high-color-temperature light source in the high-color-temperature light-emitting diode light source group can be adjusted according to actual needs so as to achieve the light source color temperature within an ideal range.

[0074] In the low-color-temperature light-emitting diode light source group, the K values of adjacent low-color-temperature light sources can be the same or different, and the K value of each low-color-temperature light source can be set according to the actual situation, which is not limited in the present utility model. In specific applications, the K value of each low-color-temperature light source in the low-color-temperature light-emitting diode light source group can be adjusted according to actual needs to achieve the light source color temperature within the ideal range.

[0075] (2) Functions of electronic components in the flash color temperature adjustable control circuit based on the dual-color-temperature LED light source

[0076] First, the energy storage capacitor EC1 provides the light-emitting energy for the high-color-temperature light-emitting diode light source group LED-C and the low-color-temperature light-emitting diode light source group LED-W respectively;

[0077] Second, the high-color-temperature light source group control module circuit:

[0078] The high-color-temperature light-emitting diode light source group LED-C is a high-color-temperature cold light element, a light source with the ability to withstand large-amplitude pulsed current;

[0079] The high-color-temperature choke inductor L1-C has two functions. One is to limit the current passing through the high-color-temperature light-emitting diode light source group LED-C to ensure that the high-color-temperature light-emitting diode light source group LED-C will not be burned out due to overcurrent. The other is to stabilize the current of the LED-C high-color-temperature light-emitting diode light source group and emit stable high-color-temperature light when a single working PWM-C high-color-temperature control signal pulse group is applied;

[0080] The high-color-temperature NMOS switch tube Q1-C controls the on-time and off-time of the conduction between the high-color-temperature light-emitting diode light source group LED-C and the high-color-temperature high-level conduction branch to GND (i.e., grounding), so as to adjust the current values of the high-color-temperature light-emitting diode light source group LED-C and the high-color-temperature high-level conduction branch;

[0081] The high-color-temperature freewheeling diode D1-C, when the high-color-temperature NMOS switch tube Q1-C is turned off, the current of the high-color-temperature choke inductor L1-C cannot change suddenly, and it continues to flow through the high-color-temperature freewheeling diode D1-C to form a discharge loop to the high-color-temperature light-emitting diode light source group LED-C.

[0082] Third, the low-color-temperature light source group control module circuit:

[0083] The low-color-temperature light-emitting diode light source group LED-W is a low-color-temperature warm light element, a light source with the ability to withstand large-amplitude pulsed current;

[0084] The low-color-temperature choke inductor L2-W has two functions. One is to limit the current passing through the low-color-temperature light-emitting diode light source group LED-W to ensure that the low-color-temperature light-emitting diode light source group LED-W will not be burned out due to overcurrent. The other is to stabilize the current of the low-color-temperature light-emitting diode light source group LED-W and emit stable low-color-temperature light when a single working PWM-W low-color-temperature control signal pulse group is present;

[0085] The low-color-temperature NMOS switch Q2-W controls the on-time and off-time of the conduction between the low-color-temperature light-emitting diode light source group LED-W and the low-color-temperature high-level turn-on branch to GND (i.e., ground), so as to adjust the current value of the low-color-temperature light-emitting diode light source group LED-W and the low-color-temperature high-level turn-on branch;

[0086] The low-color-temperature freewheeling diode D2-W is used when the low-color-temperature NMOS switch Q2-W is turned off. The current of the low-color-temperature choke inductor L2-W cannot change suddenly, and it forms a discharge loop through the low-color-temperature freewheeling diode D2-W and continues to flow to the low-color-temperature light-emitting diode light source group LED-W.

[0087] It should be noted that the color-temperature adjustable control circuit of the dual-color-temperature LED flash has a high-color-temperature high-level turn-on branch, a high-color-temperature low-level turn-off branch, a low-color-temperature high-level turn-on branch, and a low-color-temperature low-level turn-off branch.

[0088] The high-color-temperature high-level turn-on branch refers to the path that the current flows through when the PWM-C high-color-temperature control signal is at a high level and the high-color-temperature NMOS switch Q1-C is turned on. In the high-color-temperature high-level turn-on branch, the current passes through the energy storage capacitor EC1, the high-color-temperature light-emitting diode light source group LED-C, the high-color-temperature choke inductor L1-C, and the high-color-temperature NMOS switch Q1-C in sequence.

[0089] The high-color-temperature low-level turn-off branch refers to the discharge loop that the current flows through when the PWM-C high-color-temperature control signal is at a low level and the high-color-temperature NMOS switch Q1-C is turned off. In the high-color-temperature low-level turn-off branch, the current passes through the high-color-temperature light-emitting diode light source group LED-C, the high-color-temperature choke inductor L1-C, and the high-color-temperature freewheeling diode D1-C in sequence.

[0090] The low-color-temperature high-level turn-on branch refers to the path that the current flows through when the PWM-W low-color-temperature control signal is at a high level and the low-color-temperature NMOS switch Q2-W is turned on. In the low-color-temperature high-level turn-on branch, the current passes through the energy storage capacitor EC1, the low-color-temperature light-emitting diode light source group LED-W, the low-color-temperature choke inductor L2-W, and the low-color-temperature NMOS switch Q2-W in sequence.

[0091] The low-color-temperature low-level turn-off branch refers to the discharge loop through which current flows when the PWM-W low-color-temperature control signal is at a low level and the low-color-temperature NMOS switch Q2-W is turned off. In the low-color-temperature low-level turn-off branch, the current sequentially passes through the low-color-temperature light-emitting diode light source group LED-W, the low-color-temperature choke inductor L2-W, and the low-color-temperature freewheeling diode D2-W.

[0092] (III) Operating conditions of the flash color-temperature adjustable control circuit based on the dual-color-temperature LED light source

[0093] As Figure 2 shown, the C high-color-temperature light duty cycle of the pulse group of the PWM-C high-color-temperature control signal is large, and the current I-C flowing through the high-color-temperature high-level turn-on branch and the high-color-temperature low-level turn-off branch has a large current amplitude.

[0094] The W low-color-temperature light duty cycle of the pulse group of the PWM-W low-color-temperature control signal is small, and the current I-W flowing through the low-color-temperature high-level turn-on branch and the low-color-temperature low-level turn-off branch has a small current amplitude.

[0095] 1) Before the control circuit sends out a light-emitting signal:

[0096] The PWM-C high-color-temperature control signal or the PWM-W low-color-temperature control signal remains at a low level; both groups of light sources do not emit light;

[0097] The energy storage capacitor EC1 is charged by the charging power supply and maintained at the set voltage value.

[0098] 2) When the MCU control circuit simultaneously sends out pulse group control signals with different duty cycles of the PWM-C high-color-temperature control signal or the PWM-W low-color-temperature control signal for the same length of time:

[0099] A) The principle of regulating the current size by the PWM-C high-color-temperature control signal or the PWM-W low-color-temperature control signal in each branch is described as follows:

[0100] a) When the PWM-C high-color-temperature control signal is at a high level (PWM-C-H):

[0101] The high-color-temperature NMOS switch Q1-C is turned on, and the energy storage capacitor EC1 discharges through the high-color-temperature light-emitting diode light source group LED-C, the high-color-temperature choke inductor L1-C, and the high-color-temperature NMOS switch Q1-C. The current of the high-color-temperature light-emitting diode light source group LED-C linearly rises, where the high-color-temperature choke inductor L1-C determines the rising slope.

[0102] b) When the PWM-C high-color-temperature control signal is at a low level (PWM-C-L):

[0103] When the high-color-temperature NMOS switch Q1-C is turned off, the current in the high-color-temperature choke inductor L1-C cannot suddenly change to zero. Instead, it turns to form a discharge loop through the high-color-temperature freewheeling diode D1-C to the high-color-temperature LED light source group LED-C, and the current in the high-color-temperature LED light source group LED-C decreases linearly.

[0104] c) Results of adjusting the duty cycle of the PWM-C high-color-temperature control signal:

[0105] When the duty cycle is increased, the time ratio of the high level PWM-C-H of the high-color-temperature control signal relative to the low level PWM-C-L of the high-color-temperature control signal increases, and the rising ratio of the current in the high-color-temperature choke inductor L1-C increases. The overall current is relatively large, achieving the effect of increasing the current, which is manifested as an increase in the flash energy.

[0106] When the duty cycle is decreased, the time ratio of the high level PWM-C-H of the high-color-temperature control signal relative to the low level PWM-C-L of the high-color-temperature control signal decreases, and the decreasing ratio of the current in the high-color-temperature choke inductor L1-C increases. The overall current is relatively small, achieving the effect of decreasing the current, which is manifested as a decrease in the flash energy.

[0107] Since the control circuit of the high-color-temperature light source group for the high-color-temperature control signal PWM-C and the control circuit of the low-color-temperature light source group for the low-color-temperature control signal PWM-W have similar current regulation principles. For the sake of simplicity in the description of the specification, taking the control circuit of the high-color-temperature light source group for the high-color-temperature control signal PWM-C as an example, the current regulation principle is described, and the current regulation principle of the control circuit of the low-color-temperature light source group for the low-color-temperature control signal PWM-W will not be elaborated further.

[0108] B) By changing the duty cycles of the high-color-temperature control signal PWM-C and the low-color-temperature control signal PWM-W, the respective luminous energies of the high-color-temperature LED light source group and the low-color-temperature LED light source group can be controlled separately. Moreover, the two PWM signals are emitted and cut off simultaneously. When the lights with two different ratios are mixed together, a mixed light effect with different color temperatures is formed.

[0109] An embodiment of the present invention further provides a camera, including: the flash color temperature adjustable control circuit based on the dual-color-temperature LED light source in the foregoing embodiment; a camera body, electrically connected to the flash color temperature adjustable control circuit based on the dual-color-temperature LED light source.

[0110] An embodiment of the present invention further provides a video camera, including: the flash color temperature adjustable control circuit based on the dual-color-temperature LED light source in the foregoing embodiment; a video camera body, electrically connected to the flash color temperature adjustable control circuit based on the dual-color-temperature LED light source.

[0111] Obviously, those skilled in the art can make various modifications and variations to the present utility model without departing from the spirit and scope of the present utility model. Thus, if these modifications and variations of the present utility model fall within the scope of the claims of the present utility model and their equivalent technologies, the present utility model is also intended to include these modifications and variations.

Claims

1. A flash light color temperature adjustable control circuit based on a dual color temperature LED light source, characterized in that: include: High color temperature light emitting diode light source group; Low color temperature light emitting diode light source group; An energy storage capacitor, one end of which is electrically connected to the input ends of the high color temperature LED light source group and the low color temperature LED light source group, and the other end of which is grounded; A high color temperature NMOS switch tube, the gate of which is electrically connected to the PWM-C high color temperature control signal, and the source of which is grounded; A low color temperature NMOS switch tube, the gate of which is electrically connected to the PWM-W low color temperature control signal, and the source of which is grounded; A high color temperature freewheeling diode, whose input end is electrically connected to the drain of the high color temperature NMOS switch tube, and whose output end is electrically connected to the input end of the high color temperature light emitting diode light source group; A low color temperature freewheeling diode, whose input end is electrically connected to the drain of the low color temperature NMOS switch tube, and whose output end is electrically connected to the input end of the low color temperature light emitting diode light source group; A high color temperature choke inductor, one end of which is electrically connected to the output end of the high color temperature light emitting diode light source group, and the other end of which is electrically connected to the input end of the high color temperature freewheeling diode and the drain of the high color temperature NMOS switch tube; A low color temperature choke inductor has one end electrically connected to the output end of the low color temperature light emitting diode light source group, and the other end electrically connected to the input end of the low color temperature freewheeling diode and the drain of the low color temperature NMOS switch tube.

2. The color temperature adjustable control circuit of the flash lamp based on the dual color temperature LED light source as claimed in claim 1, characterized in that: The current amplitude of the high color temperature LED light source group is the same as or different from the current amplitude of the low color temperature LED light source group.

3. The color temperature adjustable control circuit of the flash lamp based on the dual color temperature LED light source as claimed in claim 1, characterized in that: The high color temperature LED light source group is specifically a 6500K high color temperature LED light source group; or, the low color temperature LED light source group is specifically a 2700K low color temperature LED light source group.

4. The color temperature adjustable control circuit of the flash lamp based on the dual color temperature LED light source as claimed in claim 1, characterized in that: The high color temperature LED light source group is specifically a 6500K high color temperature LED light source group; and the low color temperature LED light source group is specifically a 2700K low color temperature LED light source group.

5. The color temperature adjustable control circuit of the flash lamp based on the dual color temperature LED light source as claimed in claim 1, characterized in that: The number of the high color temperature LED light source groups and the number of the low color temperature LED light source groups are the same as or different from each other.

6. The color temperature adjustable control circuit of the flash lamp based on the dual color temperature LED light source as claimed in claim 1, characterized in that: The number of high color temperature light sources in the high color temperature LED light source group is the same as or different from the number of low color temperature light sources in the low color temperature LED light source group.

7. The color temperature adjustable control circuit of the flash lamp based on the dual color temperature LED light source as claimed in claim 1, characterized in that: The number of high color temperature light sources in the high color temperature LED light source group and the number of low color temperature light sources in the low color temperature LED light source group are 2 or more.

8. The color temperature adjustable control circuit of the flash lamp based on the dual color temperature LED light source as claimed in claim 7, characterized in that: The K values ​​of adjacent high color temperature light sources are the same or different, and the K values ​​of adjacent low color temperature light sources are the same or different.

9. A camera, characterized in that: include: The color temperature adjustable control circuit of the flash lamp based on the dual color temperature LED light source as described in any one of claims 1 to 8; The camera body is electrically connected to the flash light color temperature adjustable control circuit based on the dual-color temperature LED light source.

10. A camera, characterized in that: include: The color temperature adjustable control circuit of the flash lamp based on the dual color temperature LED light source as described in any one of claims 1 to 8; The photographic subject is electrically connected to the flash light color temperature adjustable control circuit based on the dual-color temperature LED light source.

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