CN204559949U - Possesses the current mode LED drive circuit of start detection function - Google Patents
Possesses the current mode LED drive circuit of start detection function Download PDFInfo
- Publication number
- CN204559949U CN204559949U CN201520178389.9U CN201520178389U CN204559949U CN 204559949 U CN204559949 U CN 204559949U CN 201520178389 U CN201520178389 U CN 201520178389U CN 204559949 U CN204559949 U CN 204559949U
- Authority
- CN
- China
- Prior art keywords
- start detection
- output
- drive circuit
- voltage
- current
- 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.)
- Expired - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Abstract
Possess the current mode LED drive circuit of start detection function, comprise the start detection resistance joined with load LED strip, and to the start detection amplifier that the ohmically pressure drop of start detection detects; The output of error amplifier connects the first input end connection of alternative gating switch, and the second input of described alternative gating switch is connected with high position reference voltage; The described control end of alternative gating switch is connected with the output of trigger, and the output of described alternative gating switch is connected with the input of PWM comparator; Also comprise and being connected with another input of PWM comparator with the current sense resistor of power tube source series and the output of current comparator.The utility model by startup stage with big space rate continuous service, improve the rate of climb of output voltage, shorten start-up time; Adopt current sampling circuit to power tube and Correctional tube current sample, further increase loop response speed.
Description
Technical field
The utility model belongs to integrated circuit (IC) design field, relates to Switching Power Supply, particularly a kind of current mode LED drive circuit possessing start detection function.
Background technology
The one of semiconductor diode, can become luminous energy electric energy conversion.Light-emitting diode is the same with general-purpose diode to be made up of a PN junction, also has unilateral conduction.After adding forward voltage to light-emitting diode, be injected into the hole in N district from P district and be injected into the electronics in P district by N district.
LED can only toward a direction conducting (energising), be called forward bias (forward bias), when the current flows, electronics and hole compound and send monochromatic light within it, this is electroluminescent effect, compare with neon lamp with incandescent lamp bulb, the feature of light-emitting diode is: operating voltage very low (more several volts had); Operating current very little (the only zero point several milliamperes had can be luminous); Shock resistance and anti-seismic performance good, reliability is high, and the life-span is long; Can the power of modulated luminescence easily by modulating that the electric current that passes through is strong and weak.Owing to there being these features, utilizing and emitting ledly carry out illumination and be applied in more and more widely among scope.
In existing single-stage high-power rate factor LED illumination drive scheme, bulky capacitor in parallel (usual hundreds of microfarad) is needed to reduce the ripple of LED at LED output.This electric capacity initial voltage is 0V, needs the operating voltage tens volts of stable states charging to LED.If the soft start not adding chip internal controls, then easily there is output voltage overshoot when startup and cause LED to have startup Transient Currents.And chip internal increases soft start control, then can increase start-up time entirely bright from switch opens to LED, be difficult to needs start-up time meeting <0.5S.
Utility model content
For improving the toggle speed of LED drive circuit, the utility model discloses a kind of current mode LED drive circuit possessing start detection function.
The current mode LED drive circuit possessing start detection function described in the utility model, comprise feedback control loop and power tube, described feedback control loop comprises error amplifier, PWM comparator, logic drive circuit, the output of described logic drive circuit is connected with the control end of power tube, and described error amplifier is for detecting the output voltage of LED drive circuit;
Also comprise the start detection resistance joined with load LED strip, and to the start detection amplifier that the ohmically pressure drop of start detection detects, and for the power on detection circuit that testing circuit powers on, the output of described start detection amplifier and power on detection circuit is connected with the input of trigger and reset terminal respectively;
The output of described error amplifier connects the first input end connection of alternative gating switch, and the second input of described alternative gating switch is connected with high position reference voltage; The described control end of alternative gating switch is connected with the output of trigger, and the output of described alternative gating switch is connected with the input of PWM comparator; The reference voltage value of described high position reference voltage is not less than the supply voltage of error amplifier;
Also comprise the current sense resistor with power tube source series, the two ends of described current sense resistor are connected with two inputs of current comparator respectively, and the output of described current comparator is connected with another input of PWM comparator.
Preferably, described high position reference voltage for described in possess the supply voltage of the current mode LED drive circuit of start detection function.
Preferably, also comprise sample circuit, described sample circuit is the divider resistance string be connected between output voltage terminal and ground, and the divider node of divider resistance string is connected to the input of error amplifier.
Preferably, also building-out capacitor is connected with between described error amplifier and ground.
Preferably, described trigger is rest-set flip-flop.
Preferably, also comprise under-voltage reference voltage, described power on detection circuit is under-voltage comparator, and two inputs of described under-voltage comparator connect supply voltage and under-voltage reference voltage respectively.
Adopt the current mode LED drive circuit possessing start detection function described in the utility model, by detecting the on off state of output voltage control power tube, startup stage with big space rate continuous service until meet the turn-on condition of load LED, improve the rate of climb of output voltage, shorten start-up time.Adopt current sampling circuit to power tube and Correctional tube current sample, further increase loop response speed.
Accompanying drawing explanation
Fig. 1 illustrates a kind of embodiment structural representation of the present utility model.
Embodiment
Below in conjunction with accompanying drawing, embodiment of the present utility model is described in further detail.
The current mode LED drive circuit possessing start detection function described in the utility model, comprise feedback control loop and power tube, described feedback control loop comprises error amplifier, PWM comparator, logic drive circuit, the output of described logic drive circuit is connected with the control end of power tube, and described error amplifier is for detecting the output voltage of LED drive circuit;
It is characterized in that, also comprise the start detection resistance joined with load LED strip, and to the start detection amplifier that the ohmically pressure drop of start detection detects, and for the power on detection circuit that testing circuit powers on, the output of described start detection amplifier and power on detection circuit is connected with the input of trigger and reset terminal respectively;
The output of described error amplifier connects the first input end connection of alternative gating switch, and the second input of described alternative gating switch is connected with high position reference voltage; The described control end of alternative gating switch is connected with the output of trigger, and the output of described alternative gating switch is connected with the input of PWM comparator; The reference voltage value of described high position reference voltage is not less than the supply voltage of error amplifier;
Also comprise the current sense resistor with power tube source series, the two ends of described current sense resistor are connected with two inputs of current comparator respectively, and the output of described current comparator is connected with another input of PWM comparator.
Embodiment as shown in Figure 1, power on detection circuit is under-voltage comparator, two inputs of described under-voltage comparator connect supply voltage and under-voltage reference voltage respectively, when powering on, input capacitance CIN is charged, voltage rises gradually, under-voltage reference voltage is default system brownout threshold voltage, usually about 1.5-2.2V is arranged on, when CIN be charged to be greater than this under-voltage reference voltage time, under-voltage comparator output voltage overturns, trigger is made to export high level signal, trigger can select the simplest rest-set flip-flop formed with door by two, flipflop output signal is to single-pole double-throw switch (SPDT), control single-pole double-throw switch (SPDT) to be connected between PWM input and high position reference voltage.
Startup stage, as shown in Figure 1, two inputs of PWM comparator are connected between high position reference voltage and triangular-wave generator, high position reference voltage, higher than the supply voltage of error amplifier, makes PWM compare the output voltage maximum being necessarily greater than error amplifier by comparative voltage of input.
Another input of PWM comparator is connected with current comparator, in the starting stage, although load LED does not have conducting, but due to power tube MN1 switch, the electric current of generation cycle appearance on the current sense resistor RCS2 connected between power tube source electrode and ground, at the voltage triangles ripple of output generating period after being amplified by current comparator detection, input comparative voltage due to PWM comparator is high position reference voltage, now voltage triangles crest value still may lower than high position reference voltage, and therefore the output waveform of PWM comparator is the maximum square wave of duty ratio.
After logic drive circuit, the square wave driving power pipe MN1 of this maximum duty cycle runs with maximum duty cycle, and output voltage rises fast, and in FIG, high position reference voltage directly can select the supply voltage VIN inputted, and need not redesign internal module.
Startup stage, because output voltage is not enough, the load LED of cascade cannot conducting, start detection resistance RCS1 does not have electric current to flow through, two ends pressure reduction is zero, when output voltage VO UT rises to certain value, such as each load LED conducting needs 3V voltage, then 10 LED strip connection need 30V to get final product conducting, now load LED conducting, generation current on RCS1, RCS two ends produce pressure drop, start detection amplifier output level reverses, flipflop output signal is reset, control alternative gating switch error amplifier output is connected with PWM comparator input terminal, thus realize normal FEEDBACK CONTROL, startup stage big space rate promote output voltage VO UT process and terminate.
When Normal Feedback, when power tube or Correctional tube are closed, current sense resistor RCS2 does not have electric current to flow through, amplifier both end voltage is equal, current detection circuit output low level, when power tube and Correctional tube are opened, electric current produces pressure drop on RCS, current detection circuit exports the pressure drop voltage after being exaggerated, and electric current is larger, RCS two ends pressure reduction is larger, and current detection circuit output voltage is larger, because power tube is periodically opened, current detection circuit is exported as periodicity and comprises the waveform of low and high level.For reducing the power consumption on current sense resistor, the resistance of current sense resistor RCS2 can be arranged within the scope of 0.5-2 ohm.
Also sample circuit is comprised in embodiment shown in Fig. 1, described sample circuit is the divider resistance string be connected between output voltage terminal and ground, the divider node of divider resistance string is connected to the input of error amplifier, such as be made up of R1 and R2 two divider resistances, sample circuit output is divider node.Sampling end voltage in proportion can be reduced to error amplifier by which can in detection range.
Preferably, between the output of described error amplifier and ground, be connected with building-out capacitor C2, a dominant pole can be provided for control loop, the stability that reinforcing feedback controls.Switching Power Supply topology in Fig. 1 is BOOST structure, comprises inductance and rectifier diode, jointly forms BOOST framework with power tube MN1.
Adopt the current mode LED drive circuit possessing start detection function described in the utility model, by detecting the on off state of output voltage control power tube, startup stage with big space rate continuous service until meet the turn-on condition of load LED, improve the rate of climb of output voltage, shorten start-up time.Adopt current sampling circuit to power tube and Correctional tube current sample, further increase loop response speed.
Previously described is each preferred embodiment of the present utility model, preferred implementation in each preferred embodiment is if not obviously contradictory or premised on a certain preferred implementation, each preferred implementation can stack combinations use arbitrarily, design parameter in described embodiment and embodiment is only the utility model proof procedure in order to clear statement utility model people, and be not used to limit scope of patent protection of the present utility model, scope of patent protection of the present utility model is still as the criterion with its claims, the equivalent structure change that every utilization specification of the present utility model and accompanying drawing content are done, in like manner all should be included in protection range of the present utility model.
Claims (6)
1. possesses the current mode LED drive circuit of start detection function, comprise feedback control loop and power tube, described feedback control loop comprises error amplifier, PWM comparator, logic drive circuit, the output of described logic drive circuit is connected with the control end of power tube, and described error amplifier is for detecting the output voltage of LED drive circuit;
It is characterized in that, also comprise the start detection resistance joined with load LED strip, and to the start detection amplifier that the ohmically pressure drop of start detection detects, and for the power on detection circuit that testing circuit powers on, the output of described start detection amplifier and power on detection circuit is connected with the input of trigger and reset terminal respectively;
The output of described error amplifier connects the first input end connection of alternative gating switch, and the second input of described alternative gating switch is connected with high position reference voltage; The described control end of alternative gating switch is connected with the output of trigger, and the output of described alternative gating switch is connected with the input of PWM comparator; The reference voltage value of described high position reference voltage is not less than the supply voltage of error amplifier;
Also comprise the current sense resistor with power tube source series, the two ends of described current sense resistor are connected with two inputs of current comparator respectively, and the output of described current comparator is connected with another input of PWM comparator.
2. possess the current mode LED drive circuit of start detection function as claimed in claim 1, it is characterized in that, described high position reference voltage for described in possess the supply voltage of the current mode LED drive circuit of start detection function.
3. possesses the current mode LED drive circuit of start detection function as claimed in claim 1, it is characterized in that, also comprise sample circuit, described sample circuit is the divider resistance string be connected between output voltage terminal and ground, and the divider node of divider resistance string is connected to the input of error amplifier.
4. possess the current mode LED drive circuit of start detection function as claimed in claim 1, it is characterized in that, between described error amplifier and ground, be also connected with building-out capacitor.
5. possess the current mode LED drive circuit of start detection function as claimed in claim 1, it is characterized in that, described trigger is rest-set flip-flop.
6. possesses the current mode LED drive circuit of start detection function as claimed in claim 1, it is characterized in that, also comprise under-voltage reference voltage, described power on detection circuit is under-voltage comparator, and two inputs of described under-voltage comparator connect supply voltage and under-voltage reference voltage respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520178389.9U CN204559949U (en) | 2015-03-27 | 2015-03-27 | Possesses the current mode LED drive circuit of start detection function |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520178389.9U CN204559949U (en) | 2015-03-27 | 2015-03-27 | Possesses the current mode LED drive circuit of start detection function |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204559949U true CN204559949U (en) | 2015-08-12 |
Family
ID=53835012
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520178389.9U Expired - Fee Related CN204559949U (en) | 2015-03-27 | 2015-03-27 | Possesses the current mode LED drive circuit of start detection function |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204559949U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106992678A (en) * | 2017-03-31 | 2017-07-28 | 上海晶丰明源半导体股份有限公司 | Power supply circuit, method of supplying power to, control chip and power-supply system |
| CN108366457A (en) * | 2018-03-07 | 2018-08-03 | 上海理工大学 | The LED drive circuit of current adjustment |
-
2015
- 2015-03-27 CN CN201520178389.9U patent/CN204559949U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106992678A (en) * | 2017-03-31 | 2017-07-28 | 上海晶丰明源半导体股份有限公司 | Power supply circuit, method of supplying power to, control chip and power-supply system |
| CN108366457A (en) * | 2018-03-07 | 2018-08-03 | 上海理工大学 | The LED drive circuit of current adjustment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103269548B (en) | LED drive circuit system, controller and control method | |
| CN106332390B (en) | A kind of non-isolated LED constant current driving chip, circuit and method | |
| CN101389168B (en) | High-voltage large power LCD constant current driving device | |
| CN101527990B (en) | Light emitting diode driving circuit | |
| CN103702486A (en) | LED driving circuit system, control circuit and control method | |
| CN204559950U (en) | For the current feedback LED constant current controller of cctv surveillance | |
| CN203722871U (en) | LED drive circuit system and LED drive control circuit | |
| CN104470099B (en) | Light emitting diode driving circuit | |
| CN103401428B (en) | Switch power supply control chip and switch power supply control system | |
| CN208656639U (en) | Control circuit and switch converters for switch converters | |
| CN202738176U (en) | An electronic apparatus and a control circuit of the electronic apparatus | |
| CN104427721A (en) | Led drive circuit | |
| CN104470096B (en) | LED driving circuit | |
| CN104768303A (en) | Led drive control circuit | |
| CN204259229U (en) | Exchange the current mode LED fast start circuit driven | |
| CN201854486U (en) | Constant-current LED (light-emitting diode) driving power supply | |
| CN204559949U (en) | Possesses the current mode LED drive circuit of start detection function | |
| CN204259231U (en) | Possesses the LED driving circuit of start detection function | |
| CN203896538U (en) | LED driving power source employing single switch tube and two Buck-Boost circuits in cascade connection | |
| CN204559948U (en) | Apply to the LED alternating-current drive circuit of community intelligent system | |
| CN102711322B (en) | High-efficiency energy-saving LED lighting flow balancing module | |
| CN201116672Y (en) | Equal-current controllable light-emitting diode array circuit | |
| CN204681625U (en) | Input feedforward LED drive circuit | |
| CN102123553B (en) | COT mode LED lighting driving circuit | |
| CN104470095B (en) | Ripple rejection LED drive circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150812 Termination date: 20170327 |