CN210053619U - Low-temperature starting device of LED driver - Google Patents
Low-temperature starting device of LED driver Download PDFInfo
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- CN210053619U CN210053619U CN201920558416.3U CN201920558416U CN210053619U CN 210053619 U CN210053619 U CN 210053619U CN 201920558416 U CN201920558416 U CN 201920558416U CN 210053619 U CN210053619 U CN 210053619U
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Abstract
The utility model relates to a LED driver low temperature starting drive, including power VCC, control opto-coupler, current-limiting resistor, operational amplifier and LED controller output current control circuit, control opto-coupler one end pass through current-limiting resistor and be connected with the power VCC, the control opto-coupler other end be connected with operational amplifier's output, operational amplifier's input and LED controller output current control circuit be connected. Compared with the prior art, the utility model has the advantages of small, low price, strong operability, etc.
Description
Technical Field
The utility model relates to a LED driver starting drive especially relates to a device that LED driver low temperature starts.
Background
For applications in extremely cold regions, it is often necessary for LED drivers to start up at-60 degrees celsius, such as russia. This is a great challenge for LED drivers, such as the electrolytic capacitor used in LED drivers, because the electrolyte of the electrolytic capacitor is almost frozen at low temperature, causing the capacity of the electrolytic capacitor to drop sharply and the internal resistance to rise. Generally, the electrolytic capacitor plays a role in filtering and energy storage in a circuit, and the effect of capacity reduction and internal resistance increase on the electrolytic capacitor is fatal. Eventually leading to LED drivers that do not start well at low temperatures, manifested as large output ripple or protective restart, etc. The common solution is to use a capacitor with a larger capacity and select a more special low-temperature capacitor. First, the cost and capacity of electrolytic capacitors are directly proportional, with higher capacity implying higher cost; secondly, the lowest temperature that the low-temperature electrolytic capacitor can bear is minus 40 ℃, and the starting is more difficult at lower temperature, so that only expensive thin-film capacitors can be selected at lower temperature, and the cost is more expensive.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a LED driver low temperature starting drive who is small, low price, strong operability just in order to overcome the defect that above-mentioned prior art exists.
The purpose of the utility model can be realized through the following technical scheme:
the utility model provides a LED driver low temperature starting drive, includes power VCC, is used for realizing the control opto-coupler of constant current, current-limiting resistor, operational amplifier and LED controller output current control circuit, control opto-coupler one end pass through current-limiting resistor and be connected with power VCC, the control opto-coupler other end be connected with operational amplifier's output, operational amplifier's input and LED controller output current control circuit be connected.
Preferably, the LED controller output current control circuit includes a triode Q1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, and a capacitor C1, a base of the triode Q1 is respectively connected to one end of a resistor R1, one end of a resistor R2, and one end of a capacitor C1, the other end of the resistor R1 is connected to a power source VCC, an emitter of the triode Q1 is connected to one end of the resistor R3, the other end of the resistor R3 is connected between the resistor R4 and the resistor R5, the resistor R4, the resistor R5, and the resistor R6 are sequentially connected in series, a positive input terminal of the operational amplifier is connected between the resistor R5 and the resistor R6, and a negative input terminal of the operational amplifier is an output current detection terminal of the LED driver; the other end of the resistor R2, the other end of the capacitor C1, the collector of the triode Q1 and the other end of the resistor R6 are respectively grounded.
Preferably, the resistor R1 is an NTC thermistor.
Preferably, the LED controller output current control circuit includes a triode Q2, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15 and a capacitor C2, a base of the triode Q2 is respectively connected to one end of the resistor R14, one end of the resistor R15 and one end of the capacitor C2, an emitter of the triode Q2 is connected to one end of the resistor R13, the other end of the resistor R13 and the other end of the resistor R14 are respectively connected to a power VCC, a collector of the triode Q2 is respectively connected to a negative input terminal of the operational amplifier and one end of the resistor R12, the other end of the resistor R12 is respectively connected to an output current detection terminal of the LED driver and one end of the resistor R11, and the other end of the resistor R11, the other end of the resistor R15 and the other end of the capacitor C2 are respectively grounded.
Preferably, the resistor R14 is an NTC thermistor.
Compared with the prior art, the utility model has the advantages of it is following:
1) the volume is small, only a common electrolytic capacitor is needed, and the volume is smaller compared with that of a film capacitor.
2) The price is low, and the electrolytic capacitor, the crystal triode and the optical coupler used in the utility model are all cheap devices.
3) Do not influence normal use, the LED lamp that adopts the LED driver is used under the low temperature condition, all is outdoor basically, the utility model relates to a LED driver low temperature starting drive start-up power in the twinkling of an eye is luminance than normally less a little, but does not influence normal use because the day has not hidden completely when starting.
Drawings
Fig. 1 is a specific implementation circuit of embodiment 1 of the present invention;
fig. 2 is a specific implementation circuit of embodiment 2 of the present invention;
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall fall within the protection scope of the present invention.
The biggest bottleneck of low-temperature starting is an electrolytic capacitor, and the capacity of the electrolytic capacitor is basically selected according to the output power of the LED driver, namely, the high-power electrolytic capacitor is required to have large capacity, and the low-power electrolytic capacitor is required to have relatively small capacity. Meanwhile, the internal impedance of the electrolytic capacitor rapidly decreases with the temperature of the capacitor, and the capacity rapidly increases. When the LED driver is loaded at low temperature, the internal impedance of the electrolytic capacitor is equivalent to that of the electrolytic capacitor connected in series in a high-frequency loop, and the internal impedance of the electrolytic capacitor can be reduced as long as the temperature of the electrolytic capacitor rapidly rises after the power supply is started, which is a virtuous circle. Therefore, as long as the LED driver is enabled to operate for a period of time under the condition of low temperature, the electrolytic capacitor can quickly reach the performance at normal temperature, and the normal working requirement is met. From above thinking, the utility model discloses when letting the LED driver start, output is than lower, and output rises to the normal power of settlement after a period of time. Therefore, the capacity of the electrolytic capacitor required by low-power permission during starting is low, the influence of large internal impedance is limited, after the electrolytic capacitor works for a period of time, the special effect of the electrolytic capacitor is recovered to a normal value along with the temperature rise of the electrolytic capacitor, the output of the LED driver is also increased to normal power, and the starting problem is solved.
Example 1
As shown in fig. 1, a low-temperature starting device of an LED driver includes a power VCC, a control optocoupler for realizing constant current, a current-limiting resistor, an operational amplifier, and an LED controller output current control circuit, wherein one end of the control optocoupler is connected to the power VCC through the current-limiting resistor, the other end of the control optocoupler is connected to an output end of the operational amplifier, and an input end of the operational amplifier is connected to the LED controller output current control circuit;
the LED controller output current control circuit comprises a triode Q1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a capacitor C1, wherein the base electrode of the triode Q1 is respectively connected with one end of a resistor R1, one end of a resistor R2 and one end of a capacitor C1, the other end of the resistor R1 is connected with a power supply VCC, the emitter electrode of the triode Q1 is connected with one end of the resistor R3, the other end of the resistor R3 is connected between a resistor R4 and the resistor R5, the resistor R4, the resistor R5 and the resistor R6 are sequentially connected in series, the positive input end of an operational amplifier is connected between the resistor R5 and the resistor R6, and the negative input end of the operational amplifier is the output current detection end of the LED driver; the other end of the resistor R2, the other end of the capacitor C1, the collector of the triode Q1 and the other end of the resistor R6 are respectively grounded.
The + input terminal of the operational amplifier U1A is the constant current reference setting value of the driver, the setting value is the voltage division of the reference voltage Vref through R4, R5 and R6, and the-input terminal of U1A is the output current detection terminal of the driver. When the LED driver is started, VCC charges C1 through the voltage division of R1 and R2, and the b-level voltage of Q1 is very low when the LED driver is started, namely Q1 is in a saturated conduction state, and R3 is connected with R5 and R6 in parallel, so that the constant current set value of the driver is reduced, the output current of the driver is reduced, and the purpose of reducing power operation of the driver is achieved. The rated current is reduced by a certain amount according to the resistance of R3. Over time, the capacitor C1 will gradually fill up, the Q1 will transition from saturated conduction to the amplification region and finally enter the cut-off region, the R3 will be completely turned off, and the driver output current will return to the original set value. According to the scheme, the output current reference is slowly and smoothly raised along with the voltage on the C1, so that the output current of the LED driver can also slowly and gradually rise, the LED lamp is intuitively felt that the output brightness of the LED lamp slowly becomes bright, and no flicker or step change exists.
If the function of starting power reduction is not needed at normal temperature, the circuit can be optimized, R1 is replaced by an NTC thermistor, the resistance value of R1 is large at low temperature, the time constant of R1C1 is large, and the time of starting power reduction is long. At normal temperature R1 is small, so the power down time is very short.
Example 2
As shown in fig. 2, a low-temperature starting device of an LED driver includes a power VCC, a control optocoupler for realizing constant current, a current-limiting resistor, an operational amplifier, and an LED controller output current control circuit, wherein one end of the control optocoupler is connected to the power VCC through the current-limiting resistor, the other end of the control optocoupler is connected to an output end of the operational amplifier, and an input end of the operational amplifier is connected to the LED controller output current control circuit;
the LED controller output current control circuit comprises a triode Q2, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15 and a capacitor C2, wherein the base of the triode Q2 is respectively connected with one end of the resistor R14, one end of the resistor R15 and one end of the capacitor C2, the emitter of the triode Q2 is connected with one end of the resistor R13, the other end of the resistor R13 and the other end of the resistor R14 are respectively connected with a power supply VCC, the collector of the triode Q2 is respectively connected with the negative input end of an operational amplifier and one end of the resistor R12, the other end of the resistor R12 is respectively connected with the output current detection end of the LED driver and one end of the resistor R11, and the other end of the resistor R11, the other end of the resistor R15 and the other end of the capacitor C2.
The operational amplifier U2A controls the reverse input terminal (-) input voltage to be equal to the forward (+) Iref voltage by controlling the current of the optical coupler. VCC divides voltage through R13 and R12, the voltage is superposed on the output current of the LED driver and is dropped on R11, the superposed voltages of the two parts are equal to the output current of the LED driver to set a reference, and the output current is controlled by controlling the on-state of Q2, so that the aim of controlling power is finally achieved.
VCC charges C2 through R14 by dividing voltage of R14 and R15, the voltage of C2 rises slowly, the voltage of C2 is almost zero when power is on, and Q2 is in a saturated conduction state. As the voltage of C2 rises, the on state of Q2 turns from saturated on, amplifying to final off, so that the LED driver output power starts to be low, the magnitude of the reduction depends on the wallpaper of R13 and R12, and finally the power output of the driver returns to normal when Q2 turns off.
If the function of reducing power at normal temperature is considered, the same as the embodiment 1, the purpose of not reducing power at normal temperature can be achieved by replacing R14 with an NTC thermistor.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope of the present invention, and these modifications or replacements should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (5)
1. The utility model provides a LED driver low temperature starting drive which characterized in that, includes power VCC, is used for realizing the control opto-coupler of constant current, current-limiting resistor, operational amplifier and LED controller output current control circuit, control opto-coupler one end pass through current-limiting resistor and be connected with power VCC, the control opto-coupler other end be connected with operational amplifier's output, operational amplifier's input and LED controller output current control circuit be connected.
2. The device as claimed in claim 1, wherein the LED controller output current control circuit includes a transistor Q1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, and a capacitor C1, a base of the transistor Q1 is connected to one end of a resistor R1, one end of a resistor R2, and one end of a capacitor C1, respectively, the other end of the resistor R1 is connected to a power VCC, an emitter of the transistor Q1 is connected to one end of the resistor R3, the other end of the resistor R3 is connected between the resistor R4 and the resistor R5, the resistor R4, the resistor R5, and the resistor R6 are connected in series, a positive input terminal of the operational amplifier is connected between the resistor R5 and the resistor R6, and a negative input terminal of the operational amplifier is an output current detection terminal of the LED driver; the other end of the resistor R2, the other end of the capacitor C1, the collector of the triode Q1 and the other end of the resistor R6 are respectively grounded.
3. The device as claimed in claim 2, wherein the resistor R1 is an NTC thermistor.
4. The device as claimed in claim 1, wherein the LED controller output current control circuit includes a transistor Q2, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, and a capacitor C2, a base of the transistor Q2 is connected to one end of the resistor R14, one end of the resistor R15, and one end of the capacitor C2, an emitter of the transistor Q2 is connected to one end of the resistor R13, the other ends of the resistor R13 and the resistor R14 are connected to the power source VCC, a collector of the transistor Q2 is connected to a negative input terminal of the operational amplifier and one end of the resistor R12, the other end of the resistor R12 is connected to an output current detection terminal of the LED driver and one end of the resistor R11, and the other ends of the resistor R11, the resistor R15, and the capacitor C2 are grounded.
5. The device as claimed in claim 4, wherein the resistor R14 is an NTC thermistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920558416.3U CN210053619U (en) | 2019-04-23 | 2019-04-23 | Low-temperature starting device of LED driver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920558416.3U CN210053619U (en) | 2019-04-23 | 2019-04-23 | Low-temperature starting device of LED driver |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210053619U true CN210053619U (en) | 2020-02-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920558416.3U Active CN210053619U (en) | 2019-04-23 | 2019-04-23 | Low-temperature starting device of LED driver |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210053619U (en) |
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2019
- 2019-04-23 CN CN201920558416.3U patent/CN210053619U/en active Active
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