CN207354678U - Non-isolated low pressure does not flicker LED drive circuit - Google Patents
Non-isolated low pressure does not flicker LED drive circuit Download PDFInfo
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- CN207354678U CN207354678U CN201721333618.5U CN201721333618U CN207354678U CN 207354678 U CN207354678 U CN 207354678U CN 201721333618 U CN201721333618 U CN 201721333618U CN 207354678 U CN207354678 U CN 207354678U
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Abstract
It the utility model is related to a kind of non-isolated low pressure and do not flicker LED drive circuit; it is related to field of LED drive technology, including starts resistance R1, electric capacity of voltage regulation C1, UVLO module, demagnetization time detecting module, system control module, peak detection block, LED open-circuit-protections module, high-voltage MOS pipe M1, high-voltage MOS pipe M2, resistance Rs and LED illumination circuit；Maximum ON time detection module is further included, when it detects that inductance ON time has reached the maximum of inner setting, output trigger signal does shielding processing to LED open-circuit-protection modules during demagnetization.In the case where inputting equal-wattage, the capacitance of busbar input high-voltage capacitance can be reduced, can so reduce cost；In the case where inputting equal-wattage, it is possible to achieve lower inlet highway voltage simultaneously keeps LED light not flicker；In the case where network voltage is unstable, LED light can be kept not flicker.
Description
Technical field
The present invention relates to field of LED drive technology, and in particular to a kind of non-isolated low pressure does not flicker LED drive circuit.
Background technology
The non-isolated driving chip used in the domestic market at present is all the BCM mode activated chips using voltage-dropping type,
And system output LED voltage is all up to 80V between 200V, while electric current, in 200mA to 350mA or so, some is even
420mA is used, like this, input power will be very big.At the same time in the case where input voltage is relatively low, can easily it occur
The situation of LED light flicker.This requires that busbar input capacitance try one's best it is big.Power is bigger, it is desirable to input capacitance it is bigger.
The content of the invention
The skill that LED flickers after being reduced the technical problem to be solved in the present invention is existing LED drive circuit median generatrix voltage
Art problem.
In order to solve the above-mentioned technical problem, the technical solution adopted in the utility model：A kind of non-isolated low pressure does not flicker
LED drive circuit, including start resistance R1, electric capacity of voltage regulation C1, UVLO module, demagnetization time detecting module, system control module,
Peak detection block, LED open-circuit-protections module, high-voltage MOS pipe M1, high-voltage MOS pipe M2, resistance Rs and LED illumination circuit；Institute
Stating lighting circuit includes LED lamp tube, resistance, capacitance and inductance；The UVLO modules be used for set LED illumination circuit open and
The voltage up and down closed, prevents open and close repeatedly；Power supply is charged by starting resistance R1 to electric capacity of voltage regulation C1；Electric capacity of voltage regulation C1
Connect UVLO modules and the grid of high-voltage MOS pipe M2, the source electrode connection lighting circuit of high-voltage MOS pipe M2, when drain electrode connection is demagnetized
Between the source electrode of detection module and high-voltage MOS pipe；The demagnetization time that the demagnetization time detecting module is used to setting inductance comes pair
LED lamp tube carries out overvoltage protection, time detecting module connecting system control module of demagnetizing；The source electrode of resistance Rs connection metal-oxide-semiconductors M1,
The peak detection block connects resistance Rs, for setting the peak point current of LED lamp tube, connects system control module；System control
Molding root tuber controls the break-make of high-voltage MOS pipe M1 according to control signal；The LED open-circuit-protections module is used for LED lamp tube overvoltage and protects
Shield；Maximum ON time detection module is further included, it is defeated when it detects that inductance ON time has reached the maximum of inner setting
Go out trigger signal and shielding processing is done during demagnetization to LED open-circuit-protection modules.
Further, the maximum ON time detection module includes the grid same-phase of the signal and high-voltage MOS pipe sent
DRV drive modules, phase inverter, the NMOS tube of two common gates, PMOS tube, current source I1, hysteresis comparator, rest-set flip-flop with
And reset signal generation module, DRV drive modules connect phase inverter and reset signal generation module respectively, the phase inverter it is defeated
Outlet connects the grid of NMOS tube and PMOS tube, the drain electrode connection current source I1 of PMOS tube, and source electrode connects the drain electrode of NMOS tube,
The source electrode ground connection of NMOS, the drain electrode of connection NMOS tube of the cathode of hysteresis comparator are connected with the source electrode of PMOS tube, anode connection
Reference voltage, output terminal connect the input terminal S of rest-set flip-flop, and reset signal generation module connects the input terminal R, RS of rest-set flip-flop
Trigger connects LED open-circuit-protection modules.
Further, described to further include the internal 5V voltage modules of generation, which is used to produce 5V voltages and reference voltage.
From above-mentioned technical proposal it can be seen that the present invention has the following advantages：When output is 24 string LED light (LED light voltages
About in 76V or so) when, it is possible to achieve full voltage inputs (80V -265V inputs), and LED light does not flicker；In input equal-wattage
In the case of, the capacitance of busbar input high-voltage capacitance can be reduced, can so reduce cost；In the situation of input equal-wattage
Under, it is possible to achieve lower inlet highway voltage simultaneously keeps LED light not flicker；, can be with the case where network voltage is unstable
LED light is kept not flicker.
Brief description of the drawings
Fig. 1 is the circuit diagram of the present invention；
Fig. 2 is the oscillogram of the busbar voltage of the utility model；
Fig. 3 is the circuit diagram of maximum ON time detection module in the present invention；
Fig. 4 is each signal waveforms of the circuit of the present invention in normal work；
Fig. 5 is each signal waveforms of the circuit of the present invention after busbar voltage reduction；
Fig. 6 is the circuit diagram of masked segment in the present invention.
Embodiment
Elaborate below in conjunction with attached drawing to the embodiment of the present invention
As shown in Figure 1, the non-isolated low pressure of the present invention does not flicker LED drive circuit, including start resistance R1, electric capacity of voltage regulation
C1, produce internal 5V voltage modules, UVLO modules, demagnetization time detecting module, system control module, peak detection block, LED
Open-circuit-protection module, high-voltage MOS pipe M1, high-voltage MOS pipe M2, resistance Rs and LED illumination circuit；The lighting circuit includes
LED lamp tube, resistance, capacitance and inductance；Produce internal 5V voltage modules to be used to produce 5V voltages and reference voltage, for system
Each module uses；The UVLO modules are used for the voltage up and down for setting LED illumination circuit to open and close, and prevent from opening pass repeatedly
Close；Power supply is charged by starting resistance R1 to electric capacity of voltage regulation C1；The grid of electric capacity of voltage regulation C1 connection UVLO modules and high-voltage MOS pipe M2
The source electrode of pole, the source electrode connection lighting circuit of high-voltage MOS pipe M2, drain electrode connection demagnetization time detecting module and high-voltage MOS pipe；
The demagnetization time that the demagnetization time detecting module is used to set inductance to carry out LED lamp tube overvoltage protection, the inspection of demagnetization time
Survey module connecting system control module；The source electrode of resistance Rs connection metal-oxide-semiconductors M1, the peak detection block connect resistance Rs, use
In the peak point current for setting LED lamp tube, system control module is connected；System control module controls high-pressure MOS according to control signal
The break-make of pipe M1；The LED open-circuit-protections module is used for LED lamp tube overvoltage protection；Maximum ON time detection module is further included,
When it detects that inductance ON time has reached the maximum of inner setting, output trigger signal exists LED open-circuit-protection modules
Shielding processing is done during demagnetization.
As shown in Figure 1.After system electrification, charged by starting resistance R1 to the capacitance C1 of vdd terminal mouth, when voltage is charged to
Then system starts to start UVLO_ON, and internal NMOSFET, M1 are opened, and electric current flows through LED light at this time, inductance to DN ports,
And the voltage that resistance Rs, Rs are flowed to by internal M1 pipes slowly increases with the increase of electric current, and examined by peak detection block
The voltage of Rs is surveyed, when Rs voltages reach its internal dot peak detection, then system closes M1 pipes, and system enters demagnetization mould at this time
Formula, inductance start to demagnetize, and inductive current forms discharge loop by Schottky diode to LED light and discharges.When the electricity of inductance
When stream is zero, the parasitic capacitance of the NMOSFET of inductance and DN ports starts resonance, and internal demagnetization detection circuit detects at this time
Inductance harmonic wave, then it is assumed that demagnetization terminates, then reopens the NMOSFET pipe M1 of inside, so repeatedly.
System is finally operated in BCM critical conduction modes, while when its LED overvoltage detections are the demagnetizations by detecting LED
Between set.It is less than the minimum demagnetization time of inner setting when the demagnetization time of LED, then system thinks that output voltage exceedes
The maximum of setting, then circuit LED overvoltage protections occur.Busbar voltage be AC signal by diode bridge heap rectification after
Signal, there is ripple voltage such as Fig. 2 thereon, also reduces therewith when input exchange signal reduces then busbar voltage, the load of LED at this time
Voltage is constant, and when voltage reaches " voltage under busbar " as shown in Figure 2, the pressure drop on inductance at this time diminishes, then the charging of inductance
Time is elongated, after the maximum of inner setting has been reached in the charging interval of inductance, if Rs voltages are also not reaching to peak value inspection
The test point of voltage is surveyed, then LED current can taper into, and the calculation formula for time of demagnetizing is as follows：
So when IP (peak point current of inductance) reductions, then mean TOFFTime can slowly reduce therewith, work as TOFFTime
The minimum demagnetization time of inner setting is reduced to, then LED overvoltage protections can occur for system, and LED light is gone out.When busbar voltage reaches
" voltage on busbar ", LED is worked normally again at this time, so repeatedly, then LED light can be caused to dodge, and invention increases maximum to turn on
Time detecting, when detecting that system inductance ON time reached the maximum of inner setting, then it is assumed that system is operated in busbar
Lower voltage status, then can export trigger signal S1, S1 signal and shielding processing is done during demagnetization to LED open-circuit-protection modules, this
LED light would not go out if sample.When the next cycle starts, this signal S1 is resetted, and detected within the cycle.Like this
Each cycle can be detected, and do corresponding processing.LED light would not flicker in this case, while the electricity of LED light
Stream can reduce accordingly.
Maximum ON time detection module is as shown in figure 3, the grid same-phase of signal and high-voltage MOS pipe including sending
DRV drive modules, phase inverter, the NMOS tube of two common gates, PMOS tube, current source I1, hysteresis comparator, rest-set flip-flop and
Reset signal generation module, DRV drive modules connect phase inverter and reset signal generation module, the output of the phase inverter respectively
The grid of end connection NMOS tube and PMOS tube, the drain electrode connection current source I1 of PMOS tube, source electrode connect the drain electrode of NMOS tube, NMOS
Source electrode ground connection, the drain electrode of connection NMOS tube of the cathode of hysteresis comparator connects with the source electrode of PMOS tube, and anode connects benchmark
Voltage, output terminal connect the input terminal S of rest-set flip-flop, input terminal R, the RS triggering of reset signal generation module connection rest-set flip-flop
Device connects LED open-circuit-protection modules.So-called shielding processing, that is, the output signal of LED protection modules is not transmitted out
Go.The S1 for being equivalent to rest-set flip-flop is low potential, then it is always low potential to export OUT, and when S1 is height, then OVP signals can pass
It is defeated to arrive OUT port, as shown in Figure 6.
Its operation principle is as follows：DRV drive modules input DRV signal, are equal to the raster data model letter of high-voltage MOS pipe M1
Number, when DRV is high voltage, then high-voltage MOS pipe M1 is opened, and system enters normal shock state；When DRV is low-voltage, then high-voltage MOS pipe
M1 is closed, and system enters demagnetized state.In figure 3, DRV is height, then VA signals are begun to ramp up from 0V, under normal circumstances, VA
Voltage can be less than VREF always, then S2 is always low potential, and S1 is always high potential, and RST goes to reset RS triggerings in each cycle
Device.LED open-circuit-protection modules are unaffected, and waveform is as shown in Figure 4.After busbar voltage reduces, the induction charging time is elongated at this time,
When DRV signal is high voltage, VA signals are begun to ramp up from 0V, and rise to VREF, (VA signals from 0V rise to VREF when
Between, it is maximum ON time TON_MAX) hysteresis comparator upset at this time, the upset of S2 signals, goes triggering to close shown in Fig. 1
M1 is managed, that is, closes system.Triggering shielding OVP module by signal is gone in the upset of S1 signals.At this time within the time of system demagnetization,
OVP does not work, and LED light does not just flicker, and waveform is as shown in Figure 5.
Claims (3)
1. a kind of non-isolated low pressure does not flicker LED drive circuit, including starts resistance R1, electric capacity of voltage regulation C1, UVLO module, demagnetization
Time detecting module, system control module, peak detection block, LED open-circuit-protections module, high-voltage MOS pipe M1, high-voltage MOS pipe
M2, resistance Rs and LED illumination circuit；
The lighting circuit includes LED lamp tube, resistance, capacitance and inductance；
The UVLO modules are used for the voltage up and down for setting LED illumination circuit to open and close, and prevent open and close repeatedly；
Power supply is charged by starting resistance R1 to electric capacity of voltage regulation C1；
The grid of electric capacity of voltage regulation C1 connection UVLO modules and high-voltage MOS pipe M2, the source electrode connection lighting circuit of high-voltage MOS pipe M2,
The source electrode of drain electrode connection demagnetization time detecting module and high-voltage MOS pipe；
The demagnetization time detecting module is used to set the demagnetization time of inductance to carry out LED lamp tube overvoltage protection, during demagnetization
Between detection module connection system control module；
The source electrode of resistance Rs connection metal-oxide-semiconductors M1, the peak detection block connects resistance Rs, for setting the peak value of LED lamp tube
Electric current, connects system control module；
System control module controls the break-make of high-voltage MOS pipe M1 according to control signal；
The LED open-circuit-protections module is used for LED lamp tube overvoltage protection；
It is characterized in that：Maximum ON time detection module is further included, when it detects that inductance ON time has reached internal and set
Fixed maximum, output trigger signal do shielding processing to LED open-circuit-protection modules during demagnetization.
2. non-isolated low pressure according to claim 1 does not flicker LED drive circuit, it is characterised in that：The maximum conducting
Time detecting module include the DRV drive modules of the grid same-phase of the signal that sends and high-voltage MOS pipe, phase inverter, two altogether
NMOS tube, PMOS tube, current source I1, hysteresis comparator, rest-set flip-flop and the reset signal generation module of grid, DRV drivings
Module connects phase inverter and reset signal generation module, the output terminal connection NMOS tube of the phase inverter and the grid of PMOS tube respectively
Pole, the drain electrode connection current source I1 of PMOS tube, source electrode connect the drain electrode of NMOS tube, and the source electrode of NMOS is grounded, hysteresis comparator
The drain electrode of connection NMOS tube of cathode is connected with the source electrode of PMOS tube, anode connection reference voltage, output terminal connection rest-set flip-flop
Input terminal S, reset signal generation module connect rest-set flip-flop input terminal R, rest-set flip-flop connection LED open-circuit-protection modules.
3. non-isolated low pressure according to claim 2 does not flicker LED drive circuit, it is characterised in that：It is described to further include production
Raw internal 5V voltage modules, the module are used to produce 5V voltages and reference voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721333618.5U CN207354678U (en) | 2017-10-17 | 2017-10-17 | Non-isolated low pressure does not flicker LED drive circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721333618.5U CN207354678U (en) | 2017-10-17 | 2017-10-17 | Non-isolated low pressure does not flicker LED drive circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107690213A (en) * | 2017-10-17 | 2018-02-13 | 无锡恒芯微科技有限公司 | Non-isolated low pressure does not flash LED drive circuit |
| CN114554648A (en) * | 2022-02-28 | 2022-05-27 | 深圳利普芯微电子有限公司 | Control circuit, overvoltage protection circuit, control chip and driving power supply |
| CN114845436A (en) * | 2022-07-04 | 2022-08-02 | 深圳贝特莱电子科技股份有限公司 | LED drive circuit multiplexing to general IO port of touch MCU |
-
2017
- 2017-10-17 CN CN201721333618.5U patent/CN207354678U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107690213A (en) * | 2017-10-17 | 2018-02-13 | 无锡恒芯微科技有限公司 | Non-isolated low pressure does not flash LED drive circuit |
| CN114554648A (en) * | 2022-02-28 | 2022-05-27 | 深圳利普芯微电子有限公司 | Control circuit, overvoltage protection circuit, control chip and driving power supply |
| CN114845436A (en) * | 2022-07-04 | 2022-08-02 | 深圳贝特莱电子科技股份有限公司 | LED drive circuit multiplexing to general IO port of touch MCU |
| CN114845436B (en) * | 2022-07-04 | 2022-10-28 | 深圳贝特莱电子科技股份有限公司 | LED drive circuit multiplexing in general IO port of touch MCU |
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