CN214046075U - Direct current low-voltage discrete LED constant current circuit - Google Patents
Direct current low-voltage discrete LED constant current circuit Download PDFInfo
- Publication number
- CN214046075U CN214046075U CN202120286145.8U CN202120286145U CN214046075U CN 214046075 U CN214046075 U CN 214046075U CN 202120286145 U CN202120286145 U CN 202120286145U CN 214046075 U CN214046075 U CN 214046075U
- Authority
- CN
- China
- Prior art keywords
- resistor
- led
- current
- triode
- switch tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The utility model relates to a direct current low voltage discrete LED constant current circuit, which comprises a direct current clamping constant voltage source, a switch tube Q3 and an energy storage inductor L6; the switch tube Q3 is an MOS tube, the control circuit is connected with the grid of the switch tube Q3, the positive pole of the direct current power supply is connected with the output from the D pole (drain) to the S pole (source) of the switch tube Q3, and the energy storage inductor L6 is connected with the LED in sequence; the control circuit of the switch tube Q3 is also included, the switch tube Q3 is controlled to be opened when the current of the LED is larger than a set value, and the switch tube Q3 is controlled to be closed when the current of the LED is smaller than the set value. The utility model discloses a few discrete device is constituteed, does benefit to the PCB overall arrangement, and the commonality of material is easily purchased, can use the more suitable cost control of selection according to the power size in a flexible way, superior switch frequency spectrum effect to it is convenient to tremble to bring in the switching technology in EMC radiation authentication series frequently.
Description
Technical Field
The utility model relates to a direct current power supply field, especially a direct current low-voltage discrete LED constant current circuit.
Background
At present, the integrated constant current chip in the market mainly carries out precise constant current at high frequency (switching frequency above 1 MHZ), and due to high frequency, easy crosstalk and superposition, the noise is large during EMC radiation authentication, so that the chip cannot be rectified and modified, and in addition, the package of the oversize integrated constant current chip is inconvenient for the layout of the special-shaped PCB.
And the integrated constant current chip is too dependent on a wafer chip, so that the cost is uncontrollable.
For the reasons, the current LED constant current circuit based on the integrated constant current chip cannot meet the requirements of users.
SUMMERY OF THE UTILITY MODEL
The utility model discloses to the not enough that present LED constant current circuit based on integrated form constant current chip can not satisfy the user demand, this application compensaties and provides direct current low-voltage discrete LED constant current circuit, and this circuit output is less than or equal to 350mA drive current and provides low switching frequency with the constant current work for the LED lamp.
The technical scheme of the utility model is that: the power supply comprises a direct-current clamping constant-voltage source, a switching tube Q3 and an energy storage inductor L6; the switching tube Q3 is an MOS tube, the grid of the switching tube Q3 is also connected with a control circuit, the positive pole of a direct current power supply is connected with the output from the D pole (drain) to the S pole (source) of the switching tube Q3, and an energy storage inductor L6 and an LED are sequentially connected; in the control circuit, when the current of the LED is larger than a set value, the switch tube Q3 is controlled to be opened, and when the current of the LED is smaller than the set value, the switch tube Q3 is controlled to be closed.
Further, in the above-mentioned direct current low voltage discrete LED constant current circuit: the control circuit comprises a resistor R15 for detecting the current of the LED, a triode Q1 and a triode Q4, wherein the resistor R15 is arranged between the cathode of the LED and the ground, the base electrode of the triode Q4 is connected with the common end of the resistor R15 connected with the LED, the emitting electrode is connected with the base electrode of the triode Q1 and an enabling signal LED-EN, and the emitting electrode is grounded; the collector of the transistor Q1 is connected with the grid of the switch tube Q3 and also connected with the DC power supply through the resistor R5, and the emitter of the transistor Q1 is grounded through the resistor R3.
Further, in the above-mentioned direct current low voltage discrete LED constant current circuit: a resistor R14 is also arranged between the base of the triode Q4 and the common end of the resistor R15 connected with the LED, and a resistor R25 is arranged between the base of the triode Q4 and the ground.
Further, in the above-mentioned direct current low voltage discrete LED constant current circuit: a resistor R9 and a resistor R3 are respectively arranged between the base electrode and the emitter electrode of the triode Q1 and the ground; a current limiting resistor R10 is also provided between the base of the transistor Q1 and the collector of the transistor Q4 and the enable signal LED-EN.
Further, in the above-mentioned direct current low voltage discrete LED constant current circuit: an operational amplifier U1-A is further arranged between the base electrode of the triode Q4 and the common end of the resistor R15 connected with the LED, the common end of the resistor R15 connected with the LED is connected with the same-phase end of the operational amplifier U1-A through the resistor R2, the out-phase end of the operational amplifier U1-A is grounded through the resistor R25, a resistor R1 is arranged between the out-phase end and the output end of the operational amplifier U1-A, and a resistor R14 is connected between the base electrode of the operational amplifier U1-A and the base electrode of the triode Q4.
Further, in the above-mentioned direct current low voltage discrete LED constant current circuit: the two ends of the energy storage inductor L6 are grounded through a diode D2 and a capacitor C5 respectively, and the anode of the diode D2 is grounded.
The utility model discloses a few discrete device is constituteed, does benefit to the PCB overall arrangement, and the commonality of material is easily purchased, can use the more suitable cost control of selection according to the power size in a flexible way, superior switch frequency spectrum effect to it is convenient to tremble to bring in the switching technology in EMC radiation authentication series frequently.
The present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
Drawings
Fig. 1 is a schematic diagram of a direct-current low-voltage discrete LED constant-current circuit according to embodiment 1 of the present invention.
Fig. 2 is the utility model discloses embodiment 1 direct current low voltage discrete LED constant current circuit is at the direction schematic diagram of positive half cycle current of electric current.
Fig. 3 is the utility model discloses embodiment 1 direct current low voltage discrete LED constant current circuit is at the direction schematic diagram of electric current negative half cycle current.
Fig. 4 is the utility model discloses embodiment 2 direct current low-voltage discrete LED constant current circuit schematic diagram.
Detailed Description
The circuit of this embodiment works as follows:
1. firstly, a direct current power supply IN10-25V is input, and the grid voltage of the switching tube Q3 does not output under the action of the bias resistor R5 through the switching tube Q3(MOS tube), so that no current passes through the energy storage inductor L6, and the output LED current is 0.
2. When the LED-EN enable signal is input to high level, current is generated through the resistor R10 to drive the base electrode of the triode Q1, the C-E electrode of the triode Q1 is conducted, the grid electrode bias voltage of the switch tube Q3 is set to be low, and the drain electrode voltage of the switch tube Q3 flows to the source electrode to be conducted.
3. The current is positive half cycle, the current passes through an L1 inductor, an LED and an inductor R15 to form energy storage, meanwhile, a 0.5-1V voltage drop is generated on a sampling resistor R15, a base electrode of a triode Q4 is driven through a biasing resistor R14, a C-E electrode of a triode Q4 is conducted, an enabling signal input by the base electrode of a triode Q1 is pulled down to enter a disconnected state, a grid biasing resistor R5 of a switching tube Q3 is pulled high, and the switching tube Q3 is disconnected to output. The flow of current is shown in figure 2.
4. In the negative half cycle of current, the charge stored in the inductor L6 flows from left to right and positive direction, and flows through the capacitor C5 for filtering, the LED, the resistor R15 and the freewheeling diode D2 to generate a loop. When the inductor charges are put below 0.5V in the sampling resistor R15, the transistor Q4 is cut off. The base signal of the transistor Q1 is normally input and driven, and the transistor Q1, the transistor C-E, is conducted. The switching tube Q3 continues to conduct, and so on. The output LED gets a constant current. The flow of current is shown in figure 3.
The embodiment adopts few discrete devices to form, is favorable for PCB layout, has easy purchase of the universality of materials, can flexibly apply and select more appropriate cost control and superior switching frequency spectrum effect according to the power, and brings convenience in EMC radiation certification series by a frequency-jittering switching technology.
Claims (6)
1. A direct current low voltage discrete LED constant current circuit which characterized in that: the power supply comprises a direct-current clamping constant-voltage source, a switching tube Q3 and an energy storage inductor L6; the switching tube Q3 is an MOS tube, the grid of the switching tube Q3 is also connected with a control circuit, the positive pole of the direct current power supply is connected with the output from the D pole to the S pole of the switching tube Q3, and the energy storage inductor L6 and the LED are sequentially connected; in the control circuit, when the current of the LED is larger than a set value, the switch tube Q3 is controlled to be opened, and when the current of the LED is smaller than the set value, the switch tube Q3 is controlled to be closed.
2. The direct current low voltage discrete LED constant current circuit of claim 1, wherein: the control circuit comprises a resistor R15 for detecting the current of the LED, a triode Q1 and a triode Q4, wherein the resistor R15 is arranged between the cathode of the LED and the ground, the base electrode of the triode Q4 is connected with the common end of the resistor R15 connected with the LED, the collector electrode is connected with the base electrode of the triode Q1 and an enabling signal LED-EN, and the emitter electrode is grounded; the collector of the transistor Q1 is connected with the grid of the switch tube Q3 and also connected with the DC power supply through the resistor R5, and the emitter of the transistor Q1 is grounded through the resistor R3.
3. The direct current low voltage discrete LED constant current circuit of claim 2, wherein: a resistor R14 is also arranged between the base of the triode Q4 and the common end of the resistor R15 connected with the LED, and a resistor R25 is arranged between the base of the triode Q4 and the ground.
4. The direct current low voltage discrete LED constant current circuit of claim 2, wherein: a resistor R9 and a resistor R3 are respectively arranged between the base electrode and the emitter electrode of the triode Q1 and the ground; a current limiting resistor R10 is also provided between the base of the transistor Q1 and the collector of the transistor Q3 and the enable signal LED-EN.
5. The direct current low voltage discrete LED constant current circuit of claim 2, wherein: an operational amplifier U1-A is further arranged between the base electrode of the triode Q4 and the common end of the resistor R15 connected with the LED, the common end of the resistor R15 connected with the LED is connected with the same-phase end of the operational amplifier U1-A through the resistor R2, the out-phase end of the operational amplifier U1-A is grounded through the resistor R25, a resistor R1 is arranged between the out-phase end and the output end of the operational amplifier U1-A, and a resistor R14 is connected between the base electrode of the operational amplifier U1-A and the base electrode of the triode Q4.
6. The direct-current low-voltage discrete LED constant-current circuit according to any one of claims 1 to 5, characterized in that: the two ends of the energy storage inductor L6 are grounded through a diode D2 and a capacitor C5 respectively, and the anode of the diode D2 is grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120286145.8U CN214046075U (en) | 2021-01-29 | 2021-01-29 | Direct current low-voltage discrete LED constant current circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120286145.8U CN214046075U (en) | 2021-01-29 | 2021-01-29 | Direct current low-voltage discrete LED constant current circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214046075U true CN214046075U (en) | 2021-08-24 |
Family
ID=77347889
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120286145.8U Active CN214046075U (en) | 2021-01-29 | 2021-01-29 | Direct current low-voltage discrete LED constant current circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN214046075U (en) |
-
2021
- 2021-01-29 CN CN202120286145.8U patent/CN214046075U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101720148B (en) | LED driving circuit and LED device | |
| CN107659160B (en) | A kind of DC-DC constant-current circuit | |
| CN104901385B (en) | Generator energy managing device and electricity generation system | |
| CN104427699B (en) | LED signal lamp and its LED drive circuit | |
| CN105338690A (en) | LED dimming power source | |
| CN106170163B (en) | A kind of LED flash power supply | |
| WO2020038156A1 (en) | Drive circuit, and aroma diffuser apparatus | |
| CN105680693B (en) | A kind of bi-directional DC-DC device with stepping functions | |
| CN214046075U (en) | Direct current low-voltage discrete LED constant current circuit | |
| CN110139427B (en) | Device capable of closing emergency function and lamp | |
| CN101749551A (en) | Hand-operated rechargeable lamp | |
| CN208638066U (en) | A kind of charger system | |
| CN205793543U (en) | A kind of LED flash power supply | |
| CN211090045U (en) | Peak-valley current controlled dimming circuit | |
| CN206004528U (en) | A kind of high power booster circuit | |
| CN204046881U (en) | A kind of LED dimming power source | |
| CN100464488C (en) | Power circuit | |
| CN108696267B (en) | Driving device and driving method of field effect transistor and power supply device | |
| CN206923077U (en) | A kind of new regulation LED current circuit | |
| CN205657608U (en) | System for be arranged in in corona discharge ignition system control corona intensity | |
| CN109981005A (en) | A kind of DC fan driving circuit and the DC fan using the driving circuit | |
| CN109546852B (en) | High-power factor switching power supply control circuit | |
| CN104038061A (en) | Input adaptive auto-excitation type Buck converter | |
| CN216390542U (en) | Boost charging circuit and inflator pump | |
| CN109302052A (en) | High-voltage starting circuit and switching power supply |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |