CN111093304A - LED lamp control circuit capable of cutting off output current and achieving rapid shutdown - Google Patents
LED lamp control circuit capable of cutting off output current and achieving rapid shutdown Download PDFInfo
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- CN111093304A CN111093304A CN201911326996.4A CN201911326996A CN111093304A CN 111093304 A CN111093304 A CN 111093304A CN 201911326996 A CN201911326996 A CN 201911326996A CN 111093304 A CN111093304 A CN 111093304A
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Abstract
The invention provides a rapid shutdown LED lamp control circuit for cutting off output current, which comprises a sampling circuit and a control circuit, wherein the sampling circuit is connected with the control circuit; the sampling circuit is connected with a control module, the control module is connected with a switch module, and the switch module is connected with an LED load; the sampling circuit receives a level signal and sends the level signal to the control module, and the control module controls the switch module to be switched on or switched off, so that the LED load is controlled to be powered on or powered off; the two ends of the LED load are respectively connected with the switch module and the control module, and the switch module is connected with the LED drive control device. By applying the technical scheme, the quick shutdown function of the LED lamp control circuit can be realized.
Description
Technical Field
The invention relates to the field of LED illumination, in particular to a rapid-shutdown LED lamp control circuit for cutting off output current.
Background
In the LED lighting industry, there is often a time requirement for the turn-off and turn-off process of an LED lamp, and the turn-off and turn-off time requirement in some special application places is more strict. At present, the conventional scheme is adopted, and the effect of quickly extinguishing the lamp when the circuit is shut down is difficult to realize by connecting the continuous discharge resistor at the output end of the circuit in parallel. In practical applications, in order to reduce the stroboscopic effect, a relatively large capacitor is usually connected in parallel to the output terminal of the circuit, and the capacitor discharges to the LED after shutdown, which may cause that the LED cannot be turned off immediately after shutdown. The current common method is to connect a discharge resistor in parallel at two ends of an output capacitor, or to connect the resistors after shutdown to accelerate discharge. However, the output capacitor cannot discharge electricity immediately, and needs a certain time, so that the quick shutdown cannot be extinguished, and the quick shutdown effect cannot be achieved.
Disclosure of Invention
The invention aims to provide a rapid shutdown LED lamp control circuit for cutting off output current, which realizes rapid shutdown of the LED lamp control circuit.
In order to solve the technical problem, the invention provides a rapid shutdown LED lamp control circuit for cutting off output current, which comprises a sampling circuit and a control circuit, wherein the sampling circuit is connected with the control circuit; the sampling circuit is connected with a control module, the control module is connected with a switch module, and the switch module is connected with an LED load; the sampling circuit receives a level signal and sends the level signal to the control module, and the control module controls the switch module to be switched on or switched off, so that the LED load is controlled to be powered on or powered off; the two ends of the LED load are respectively connected with the switch module and the control module, and the switch module is connected with the LED drive control device.
In a preferred embodiment, the control module comprises a first control device, a second control device and a third control device; the sampling circuit is connected with the first control device, the first control device is connected with the second control device, the second control device is connected with the third control device, and the third control device is connected with the switch module.
In a preferred embodiment, the device further comprises a discharge circuit; one end of the discharge circuit is connected with the LED drive control device and the control device, and the other end of the discharge circuit is connected with the LED load.
In a preferred embodiment, the first control device includes a first switch tube, a voltage regulator diode and a first resistor; the second control device comprises a second switching tube, a second resistor and a third resistor; the third control device comprises a third switching tube, a fourth resistor and a fifth resistor; the switch module comprises a fourth switch tube and a sixth resistor.
In a preferred embodiment, the gate of the first switch tube is connected to the sampling circuit, the source of the first switch tube is grounded, the drain of the first switch tube is connected to one end of the first resistor, and the other end of the first resistor is connected to the gate of the second switch tube and one end of the second resistor;
the grid electrode of the second switching tube is connected with one end of the second resistor connected with the first resistor, and the other end of the second resistor is connected with the anode of the discharge circuit; the drain electrode of the second switching tube is connected with the negative electrode of the LED load, the source electrode of the second switching tube is connected with one end of the third resistor, and the other end of the third resistor is connected with the grid electrode of the fourth switching tube;
the grid electrode of the third switching tube is connected with the source electrode of the second switching tube and one end of the fourth resistor, and the other end of the fourth resistor is connected with the anode of the discharge circuit; the source electrode of the third switching tube is connected with one end of the fifth resistor, and the other end of the fifth resistor is connected with the cathode of the LED load; and the drain electrode of the third switching tube is connected with the anode of the discharge circuit.
In a preferred embodiment, one end of the sixth resistor is connected to the gate of the fourth switching tube, and the other end of the sixth resistor is connected to the source of the fourth switching tube and the anode of the discharge circuit; and the drain electrode of the fourth switching tube is connected with the anode of the LED load.
In a preferred embodiment, the sampling circuit further comprises a rectifying circuit and an isolating device, the rectifying circuit is connected with the isolating device, and one end of the sampling circuit is connected between the rectifying circuit and the isolating device.
In a preferred embodiment, the sampling circuit includes a seventh resistor, an eighth resistor and a first capacitor; one end of the seventh resistor is connected between the rectifying circuit and the isolating device, the other end of the seventh resistor is connected with one end of the eighth resistor, the other end of the eighth resistor is grounded, one end of the first capacitor is connected between the seventh resistor and the eighth resistor, the other end of the first capacitor is grounded, and the voltage stabilizing diode is connected in parallel with two ends of the first capacitor; the discharge circuit is specifically an output capacitor with polarity.
In a preferred embodiment, in a normal working state, the power input outputs high level after passing through the rectifying circuit and is added to the upper end of the first capacitor through a seventh resistor for voltage reduction, the first capacitor enables the voltage of the first capacitor to become smooth, then the grid voltage of the first switching tube is added to enable the first switching tube to be conducted, then the grid voltage of the second switching tube is reduced to enable the second switching tube to be conducted, then the third switching tube is turned off, and because the third switching tube is in a turned-off state, the output capacitor cannot discharge through the third switching tube; the fourth switch tube is also conducted because the second switch tube is conducted; therefore, normal output is realized, and the work of the LED load is not influenced.
In a preferred embodiment, the power-off transient state: the rectification circuit does not output, the isolation device has an isolation function, the grid electrode of the first switch tube is in a low level through the seventh resistor, the first switch tube enters a turn-off state, then the grid electrode voltage of the second switch tube is increased to turn off the second switch tube, then the grid electrode voltage of the third switch tube is increased, the third switch tube is conducted, the output capacitor discharges through the third switch tube at the moment, during the discharging period of the output capacitor, the grid electrode voltage of the fourth switch tube is increased due to the turn-off of the second switch tube, the fourth switch tube is also turned off, and the LED load is turned off.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
the invention provides a rapid shutdown LED lamp control circuit for cutting off output current, which directly controls the electrification of an LED load by arranging a fourth switching tube; the second switching tube directly controls the switch of the fourth switching tube, so that the fourth switching tube directly controls the switch of the fourth switching tube according to whether the circuit is electrified or not; the discharging circuit is not directly connected with the LED load, the current of the LED load can be cut off no matter whether the energy of the output capacitor is discharged or not when the LED lamp is turned off, and the LED load does not need to wait for the discharging circuit to discharge and then turn off the LED lamp. Therefore, the LED lamp can be rapidly turned off, and the rapid shutdown function is realized. The invention has wide applicability and good compatibility with the LED drive circuit.
Drawings
Fig. 1 is a schematic circuit diagram of a fast-shutdown LED lamp control circuit for cutting off output current in a preferred embodiment of the present invention.
Detailed Description
The invention is further described with reference to the following figures and detailed description.
A fast shutdown LED lamp control circuit for cutting off output current, referring to fig. 1, comprises a rectification circuit BD1, an isolation device, and a sampling circuit; the rectifier circuit BD1 is connected with the isolation device, one end of the sampling circuit is arranged between the rectifier circuit BD1 and the isolation device, the other end of the sampling circuit is connected with a control module, the control module is connected with a switch module, and the switch module is connected with an LED load; the sampling circuit receives a level signal and sends the level signal to the control module, and the control module controls the switch module to be switched on or switched off, so that the LED load is controlled to be powered on or powered off. The two ends of the LED load are respectively connected with the switch module and the control module, and the switch module is connected with the LED drive control device.
Specifically, the control module comprises a first control device, a second control device and a third control device; the sampling circuit is connected with the first control device, the first control device is connected with the second control device, the second control device is connected with the third control device, and the third control device is connected with the switch module. Also includes a discharge circuit; one end of the discharge circuit is connected with the LED drive control device and the control device, and the other end of the discharge circuit is connected with the LED load.
The circuit schematic of this patent is described below in conjunction with specific circuit elements:
the first control device comprises a first switching tube Q1, a voltage stabilizing diode Z1 and a first resistor R6; the second control device comprises a second switching tube Q2, a second resistor R3 and a third resistor R10; the third control device comprises a third switching tube Q3, a fourth resistor R2 and a fifth resistor R8; the switch module comprises a fourth switch tube Q4 and a sixth resistor R9. In this embodiment, the first switch transistor Q1 and the third switch transistor Q3 are specifically NMOS transistors, and the second switch transistor Q2 and the fourth switch transistor Q4 are specifically PMOS transistors. Other switch tubes, such as a relay, a photocoupler, etc., may be used, and the scope of the present invention is not limited thereto.
The gate of the first switch tube Q1 is connected to the sampling circuit, the source of the first switch tube Q1 is grounded, the drain of the first switch tube Q1 is connected to one end of the first resistor R6, and the other end of the first resistor R6 is connected to the gate of the second switch tube Q2 and one end of the second resistor R3;
the grid of the second switch tube Q2 is connected with one end of the second resistor R3 connected with the first resistor R6, and the other end of the second resistor R3 is connected with the anode of the discharge circuit; the drain of the second switching tube Q2 is connected to the cathode of the LED load, the source of the second switching tube Q2 is connected to one end of the third resistor R10, and the other end of the third resistor R10 is connected to the gate of the fourth switching tube Q4;
the grid electrode of the third switching tube Q3 is connected with the source electrode of the second switching tube Q2 and one end of the fourth resistor R2, and the other end of the fourth resistor R2 is connected with the anode of the discharge circuit; the source electrode of the third switching tube Q3 is connected with one end of the fifth resistor R8, and the other end of the fifth resistor R8 is connected with the cathode of the LED load; the drain of the third switching tube Q3 is connected to the positive electrode of the discharge circuit.
One end of the sixth resistor R9 is connected to the gate of the fourth switching tube Q4, and the other end of the sixth resistor R9 is connected to the source of the fourth switching tube Q4 and the anode of the discharge circuit; the drain electrode of the fourth switching tube Q4 is connected with the anode of the LED load.
The sampling circuit comprises a seventh resistor R4, an eighth resistor R5 and a first capacitor C1; one end of the seventh resistor R4 is connected between the rectifier circuit BD1 and the isolation device, the other end of the seventh resistor R4 is connected to one end of the eighth resistor R5, the other end of the eighth resistor R5 is grounded, one end of the first capacitor C1 is connected between the seventh resistor R4 and the eighth resistor R5, the other end of the first capacitor C1 is grounded, and the zener diode Z1 is connected in parallel to two ends of the first capacitor C1; the discharge circuit is embodied as a polarized output capacitor E1.
Specifically, the rectifier circuit BD1 is specifically a rectifier bridge, the isolation device is specifically a diode D1, the anode of the diode D1 is connected to the rectifier bridge, the cathode of the diode D1 is connected to a filter circuit, the other end of the filter circuit is connected to the LED drive control device, the LED drive control device has an anode output interface LED + and a cathode output interface LED-, the anode output interface LED + is connected to the anode of the output capacitor E1, the cathode output interface LED-is connected to the cathode of the output capacitor E1, the anode of the output capacitor E1 is connected to the source of the fourth switch tube Q4, and the cathode of the output capacitor E1 is connected to the cathode of the LED load. For convenience of description, a sampling point B + is taken between the rectifier circuit BD1 and the isolation device. Other positions can be set as the sampling point B +, the position behind the rectifier bridge is set as the sampling point B + in this embodiment, the position in front of the rectifier bridge can be set as the sampling point B +, other positions can be set, and the protection scope of the present invention cannot be limited thereby.
The working principle of the patent is described in the following with reference to a schematic circuit diagram:
in a normal working state, a power supply input outputs a high level after passing through a rectifier circuit BD1, the high level of a sampling point B + is stepped down by a seventh resistor R4 and is added to the upper end of a first capacitor C1, the voltage of the first capacitor C1 is smoothed and then is added to the gate of a first switch tube Q1, the gate of the first switch tube Q1 receives the high level and is switched on, the voltage of the first resistor R6 is pulled down, so that the gate voltage of a second switch tube Q2 is lowered, the second switch tube Q2 receives the low level and is switched on, so that the gate level of a third switch tube Q3 is pulled down, the third switch tube Q3 is switched off, and the output capacitor E1 cannot discharge through the third switch tube Q3 at this time because the third switch tube Q3 is switched off; the second switch tube Q2 is turned on, and the fourth switch tube Q4 is also turned on; therefore, normal output is realized, and the work of the LED load is not influenced.
The power-off instant state: the rectifier circuit BD1 has no output, the isolation device has isolation function, the low level of the sampling point B + makes the grid of the first switch tube Q1 be low level through the seventh resistor R4, the grid of the first switch tube Q1 receives the low level and enters into the off state, then the gate voltage of the second switch tube Q2 is increased to turn off the second switch tube Q2, then the gate voltage of the third switch tube Q3 is increased to turn on the third switch tube Q3, at this time, the output capacitor E1 discharges through the third switch tube Q3, the discharge of the output capacitor E1 requires a certain time, therefore, during the discharging period of the output capacitor E1, no matter whether the discharging of the output capacitor E1 is finished, since the second switching tube Q2 is turned off, the voltage of the gate of the fourth switching tube Q4 rises, the gate of the fourth switching tube Q4 is also turned off after receiving a high level, the LED load is disconnected, the LED lamp is immediately turned off, and the rapid shutdown function of the whole driving circuit is realized.
The invention provides a rapid-shutdown LED lamp control circuit for cutting off output current, which directly controls the electrification of an LED load by arranging a fourth switching tube Q4; the second switching tube Q2 directly controls the switching of the fourth switching tube Q4, so that the fourth switching tube Q4 directly controls the switching of the fourth switching tube Q4 according to whether the circuit is powered on or not; the discharging circuit is not directly connected with the LED load, the current of the LED load can be cut off no matter whether the energy of the output capacitor E1 is discharged or not when the LED lamp is turned off, and the LED load does not need to wait for the discharging circuit to discharge and then turn off the LED lamp. Therefore, the LED lamp can be rapidly turned off, and the rapid shutdown function is realized. The invention has wide applicability and good compatibility with the LED drive circuit.
The above description is only a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any person skilled in the art can make insubstantial changes in the technical scope of the present invention within the technical scope of the present invention, and the actions infringe the protection scope of the present invention are included in the present invention.
Claims (10)
1. A fast shutdown LED lamp control circuit for cutting off output current is characterized by comprising a sampling circuit and a control module; the sampling circuit is connected with a control module, the control module is connected with a switch module, and the switch module is connected with an LED load; the sampling circuit receives a level signal and sends the level signal to the control module, and the control module controls the switch module to be switched on or switched off, so that the LED load is controlled to be powered on or powered off; the two ends of the LED load are respectively connected with the switch module and the control module, and the switch module is connected with the LED drive control device.
2. The fast shutdown LED lamp control circuit for shutting off an output current according to claim 1, wherein the control module comprises a first control device, a second control device and a third control device; the sampling circuit is connected with the first control device, the first control device is connected with the second control device, the second control device is connected with the third control device, and the third control device is connected with the switch module.
3. The fast shutdown LED lamp control circuit to shut off output current of claim 2, further comprising a discharge circuit; one end of the discharge circuit is connected with the LED drive control device and the control device, and the other end of the discharge circuit is connected with the LED load.
4. The fast shutdown LED lamp control circuit for shutting off an output current according to claim 3, wherein the first control means includes a first switching tube, a zener diode, and a first resistor; the second control device comprises a second switching tube, a second resistor and a third resistor; the third control device comprises a third switching tube, a fourth resistor and a fifth resistor; the switch module comprises a fourth switch tube and a sixth resistor.
5. The fast shutdown LED lamp control circuit for cutting off output current according to claim 4, wherein a gate of the first switch tube is connected to the sampling circuit, a source of the first switch tube is grounded, a drain of the first switch tube is connected to one end of the first resistor, and another end of the first resistor is connected to a gate of the second switch tube and one end of the second resistor;
the grid electrode of the second switching tube is connected with one end of the second resistor connected with the first resistor, and the other end of the second resistor is connected with the anode of the discharge circuit; the drain electrode of the second switching tube is connected with the negative electrode of the LED load, the source electrode of the second switching tube is connected with one end of the third resistor, and the other end of the third resistor is connected with the grid electrode of the fourth switching tube;
the grid electrode of the third switching tube is connected with the source electrode of the second switching tube and one end of the fourth resistor, and the other end of the fourth resistor is connected with the anode of the discharge circuit; the source electrode of the third switching tube is connected with one end of the fifth resistor, and the other end of the fifth resistor is connected with the cathode of the LED load; and the drain electrode of the third switching tube is connected with the anode of the discharge circuit.
6. The fast turn-off LED lamp control circuit for cutting off output current according to claim 5, wherein one end of the sixth resistor is connected to the gate of the fourth switching tube, and the other end of the sixth resistor is connected to the source of the fourth switching tube and the anode of the discharge circuit; and the drain electrode of the fourth switching tube is connected with the anode of the LED load.
7. The fast shutdown LED lamp control circuit for cutting off output current according to claim 6, further comprising a rectifying circuit and an isolating device, wherein the rectifying circuit is connected to the isolating device, and one end of the sampling circuit is connected between the rectifying circuit and the isolating device.
8. The fast shutdown LED lamp control circuit for shutting off an output current according to claim 7, wherein the sampling circuit includes a seventh resistor, an eighth resistor and a first capacitor; one end of the seventh resistor is connected between the rectifying circuit and the isolating device, the other end of the seventh resistor is connected with one end of the eighth resistor, the other end of the eighth resistor is grounded, one end of the first capacitor is connected between the seventh resistor and the eighth resistor, the other end of the first capacitor is grounded, and the voltage stabilizing diode is connected in parallel with two ends of the first capacitor; the discharge circuit is specifically an output capacitor with polarity.
9. The circuit of claim 8, wherein in a normal operation state, the power input outputs a high level after passing through the rectifying circuit and is stepped down by the seventh resistor to the upper end of the first capacitor, the voltage of the first capacitor is smoothed and then applied to the gate of the first switch tube to turn on the first capacitor, then the voltage of the gate of the second switch tube is decreased to turn on the second switch tube, and then the third switch tube is turned off, so that the output capacitor does not discharge through the third switch tube due to the off state of the third switch tube; the fourth switch tube is also conducted because the second switch tube is conducted; therefore, normal output is realized, and the work of the LED load is not influenced.
10. The fast shutdown LED lamp control circuit to shut down the output current of claim 8, wherein the shutdown transient state: the rectification circuit does not output, the isolation device has an isolation function, the grid electrode of the first switch tube is in a low level through the seventh resistor, the first switch tube enters a turn-off state, then the grid electrode voltage of the second switch tube is increased to turn off the second switch tube, then the grid electrode voltage of the third switch tube is increased, the third switch tube is conducted, the output capacitor discharges through the third switch tube at the moment, during the discharging period of the output capacitor, the grid electrode voltage of the fourth switch tube is increased due to the turn-off of the second switch tube, the fourth switch tube is also turned off, and the LED load is turned off.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911326996.4A CN111093304A (en) | 2019-12-20 | 2019-12-20 | LED lamp control circuit capable of cutting off output current and achieving rapid shutdown |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911326996.4A CN111093304A (en) | 2019-12-20 | 2019-12-20 | LED lamp control circuit capable of cutting off output current and achieving rapid shutdown |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111093304A true CN111093304A (en) | 2020-05-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911326996.4A Pending CN111093304A (en) | 2019-12-20 | 2019-12-20 | LED lamp control circuit capable of cutting off output current and achieving rapid shutdown |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111093304A (en) |
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2019
- 2019-12-20 CN CN201911326996.4A patent/CN111093304A/en active Pending
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