CN101042212A - Series LED driving control system with output open circuit protecting function - Google Patents

Series LED driving control system with output open circuit protecting function Download PDF

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Publication number
CN101042212A
CN101042212A CNA2007100401473A CN200710040147A CN101042212A CN 101042212 A CN101042212 A CN 101042212A CN A2007100401473 A CNA2007100401473 A CN A2007100401473A CN 200710040147 A CN200710040147 A CN 200710040147A CN 101042212 A CN101042212 A CN 101042212A
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signal
open circuit
output open
voltage
circuit
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CN100494767C (en
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史亚军
孙洪军
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QIPAN MICROELECTRONIC (SHANGHAI) CO Ltd
Chiphomer Microelectronics Shanghai Ltd
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QIPAN MICROELECTRONIC (SHANGHAI) CO Ltd
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Abstract

It relates to a series LED control system with output circuit protection.It comprises standard voltage circuit configured to generate standard voltage signal, error amplifier configured to receive standard voltage signal and outside feedback voltage signal generated amplified error signal outside the system, pulse width adapting generator configured to error amplified signal, power switch configured to generate bar signal, output open circuit protection configured to generate open protection signal, enable circuit configured to generate energy signal, enable signal control standard circuit, error amplifier, pulse width adapting generator working status.

Description

A kind of series LED driving control system with output open circuit protecting function
Technical field
The present invention relates to integrated circuit.In particular, the invention provides a kind of series LED driving control system with output open circuit protecting function.The present invention only is that the mode with example is applied to led driver.But will be appreciated that the present invention has more wide applications.
Background technology
Along with portable equipments such as mobile phone, MP3 more and more use color LCD display, white light LEDs becomes a kind of general backlight.Usually lithium battery of portable equipment employing is the whole system power supply, and lithium battery voltage is generally between 3.6V～4.2V.The white light LEDs driver has two kinds of type of drive basically: a kind of is to adopt the DC/DC boosting inverter principle of inductance to drive, and all LED series connections generally also are the series LED type of drive together; Another kind is to adopt the boosting type charge pump principle to drive, and generally at 5V/4.5V or according to the forward conduction voltage of LED and the voltage that self adaptation is determined, all LED's voltage that is produced are connected in parallel, and generally also are called parallel connection type LED type of drive.The series LED drive circuit, owing to all LED are cascaded, so operating current is identical, the luminosity unanimity, this is the advantage that it is compared with parallel connection LED drive circuit.
Fig. 1 is a kind of traditional series LED drive circuit, comprise series LED driving control system 100, boost inductance L11, Schottky diode D11, white light LEDs (D13 ..., D1n), feedback resistance R11 and input and output electric capacity (C11, C12) forms.Driving control system 100 comprises reference voltage circuit 110, error amplifier 120, pulsewidth modulation (PWM) generator 130 and power switch 140.According to DC/DC boosting inverter principle based on inductance, the operation principle of driving control system 100 is as follows: error amplifier 120 receives respectively the reference voltage signal 112 that produces from reference voltage circuit 110 and from the feedback voltage signal 114 of driving control system 100 outsides, and producing a error amplification signal 122 based on these two signal voltage differences, the duty of the pulse-width signal 132 that error amplification signal 122 control pwm generators 130 produce is recently controlled the ON time length of power switch 140.When feedback voltage signal 114 is lower than reference voltage signal 112, error amplification signal 122 increases, the dutycycle of the pulse width signal 132 that pwm generator 130 produces increases, thereby power switch 140 ON times are longer, so more input power is transformed into output VOUT by inductance L 11, and output voltage VO UT and feedback voltage signal 114 rise; Feedback voltage signal 114 is during near reference voltage signal 112, and error amplification signal 122 reduces, and the dutycycle of the pulse-width signal 132 that impulse modulation generator 130 produces stops to increase, and output voltage VO UT is stable.In DC/DC voltage up converting circuit based on inductance, work as input voltage VIN, after output voltage VO UT determines, the ideally available formula of the relation between the dutycycle D three of input voltage VIN, output voltage VO UT and pulse-width signal 132 (1) expression:
V OUT = V IN 1 - D - - - ( 1 )
As the dutycycle D of input voltage VIN, output voltage VO UT and pulse-width signal 132 all fixedly the time, the voltage waveform of output square-wave signal 142 of power switch 140 (being the voltage waveform of SW pin) and output voltage VO UT as shown in Figure 2.
In this traditional series LED drive circuit, when certain white light LEDs (D13 ..., D1n) disconnect or when other open faults take place, the feedback voltage signal 114 that is input to driving control system 100 will be 0V always, power switch 140 will tend to carry out switching manipulation with maximum duty cycle, cause the crest voltage and the output voltage VO UT of the square-wave signal 142 of SW pin to continue to raise.When being elevated to the power switch 140 or the peripheral components that to a certain degree might cause driving control system 100 inside, the crest voltage of the square-wave signal 242 of SW pin and output voltage VO UT under high pressure burnt out.So general series LED drive circuit can increase the ceiling voltage that the output open circuit holding circuit limits output, thereby the guarantee circuit safety is worked reliably.
A kind of common series LED drive circuit with output open circuit protecting function as shown in Figure 3; the output open circuit protecting function of this series LED drive circuit is on the basis of Fig. 1, holds an external Zener diode D12 to realize at output voltage VO UT end and feedback voltage signal 114 input FB.When certain white light LEDs (D13 ..., D1n) disconnect or when other open faults took place, the breakdown voltage that output voltage VO UT is restricted to Zener diode D12 added feedback voltage, thereby realized the function of output open circuit protection.But sort circuit need increase a Zener diode D12 outside, has increased complexity and the totle drilling cost used, and can still need to provide certain operating current to the series LED drive circuit by power supply after the output open circuit protection, produces unnecessary power consumption.
Therefore, in order to overcome above-mentioned shortcoming, driving control system is improved with regard to being necessary very much.
Summary of the invention
Purpose of the present invention is to overcome the existing deficiency of above-mentioned existing led drive circuit, thereby a kind of series LED driving control system with output open circuit protecting function is provided.The present invention only is that the mode with example is applied to led driver.But will be appreciated that the present invention has more wide applications.
According to one embodiment of present invention, provide a kind of series LED driving control system with output open circuit protecting function.Described system comprises reference voltage circuit, is configured to the voltage signal of receiving system outside at least and produces reference voltage signal; Error amplifier is configured to receive the feedback voltage signal of described reference voltage signal and system outside at least and produce error amplification signal; Pwm generator is configured to receive at least described error amplification signal and produces pulse-width signal; Power switch is configured to receive described pulse-width signal and produces square-wave signal; The output open circuit holding circuit is configured to receive at least described square-wave signal and whether decision produces the output open circuit guard signal; Enable circuits is configured to the control signal and the described output open circuit guard signal of receiving system outside and produces enable signal.
Whether described reference voltage circuit also can be configured to receive described enable signal and control described reference voltage circuit by described enable signal and work.
Whether described error amplifier also can be configured to receive described enable signal and control described error amplifier by described enable signal and work.
Whether described pwm generator also can be configured to receive described enable signal and be worked by described enable signal control pwm generator.
The crest voltage of described square-wave signal produces described output open circuit guard signal when being higher than the threshold voltage of output open circuit holding circuit.Wherein said threshold voltage is a fixed voltage of output open circuit holding circuit internal preset, but this voltage can according to circumstances be adjusted.
Described output open circuit holding circuit described output open circuit holding circuit when producing the output open circuit guard signal is in locking state, and keeps the output open circuit guard signal of generation constant.
The locking state of described output open circuit holding circuit is that the regenerative feedback loop by described output open circuit holding circuit inside realizes.
Whether described output open circuit holding circuit also is configured to receive the control signal of described system outside and control described output open circuit holding circuit by described control signal and work.
After described output open circuit holding circuit was in described locking state, the state that the cancelling of described locking state is based on described control signal changes to be realized.
According to another embodiment of the invention, provide a kind of output open circuit protection system, described system comprises SW pin peak voltage detector, is configured to receive described square-wave signal and produces peak detection signal; The guard signal generator is configured to receive described peak detection signal and produces the output open circuit guard signal.
Whether described SW pin peak voltage detector produces described peak detection signal based on the crest voltage decision of the described square-wave signal that receives.
The crest voltage of described square-wave signal produces described peak detection signal when being higher than the threshold voltage of output open circuit holding circuit.Wherein said threshold voltage is a fixed voltage of output open circuit holding circuit internal preset, but this voltage can according to circumstances be adjusted.
Described peak detection signal is a pulse signal that transient state is a high level.
Described guard signal generator was in locking state when described guard signal generator received described peak detection signal and produces described output open circuit guard signal, and kept the output open circuit guard signal that produces constant.
The locking state of described guard signal generator is that the regenerative feedback loop by described guard signal generator inside realizes.
Whether described guard signal generator also is configured to receive the control signal of described system outside and control described guard signal generator by described control signal and work.
After described guard signal generator was in locking state, the state that is based on described control signal of cancelling of described locking state changed and realizes.
In mode of the present invention, can obtain to surpass the advantage of conventional art.For example, some embodiments of the present invention can be simplified the application of series LED drive circuit.For instance, the series LED drive circuit needs output open circuit protecting function.Some embodiment of the present invention can not be used in any device of the peripheral increase of series LED drive circuit; but realize output open circuit protecting function by the method for direct detection SW pin crest voltage in driving control system inside; simplify the application of series LED drive circuit, and saved the totle drilling cost of series LED drive circuit.
With reference to following detailed description and accompanying drawing, can more fully understand various other purpose of the present invention, feature and advantage.
Description of drawings
Fig. 1 is a kind of traditional series LED drive circuit;
The voltage waveform of SW pin and output VOUT when Fig. 2 is the series LED drive circuit works;
Fig. 3 is a kind of traditional series LED drive circuit with output open circuit protecting function;
Fig. 4 is a kind of series LED drive circuit with output open circuit protection according to the embodiment of the invention;
Fig. 5 is the simplification system according to a kind of output open circuit protection of the embodiment of the invention;
Fig. 6 is a kind of according to another embodiment of the present invention reduced graph of output open circuit protection.
The specific embodiment
Fig. 4 is a kind of series LED drive circuit with output open circuit protecting function according to the embodiment of the invention; comprise driving control system 200, also comprise in addition boost inductance L11, Schottky diode D11, white light LEDs (D13 ..., D1n), feedback resistance R11 and input and output electric capacity (C11, C12).Wherein, driving control system 200 only is an example of the present invention, and it does not answer the requirement of unsuitable restriction right.Those of ordinary skill in the art will recognize many versions, substitute and modification.Driving control system 200 comprises reference voltage circuit 210, error amplifier 220, pwm generator 230, power switch 240, output open circuit protection (OVP) circuit 250 and enable circuits 260.Though used one group of selected parts that driving control system 200 is shown, many substitutes, modification and version can have been arranged.For example, some parts can be expanded and/or be merged.Insert miscellaneous part in the parts that can mention in the above.Depend on embodiment, the arrangement of parts can exchange, and other parts can be replaced.For example the pwm generator 230 other parts that can be expanded replace.The further details of these parts can find in this manual, can describe more specifically below.
Reference voltage circuit 210 is to reference voltage signal 212 of error amplifier 220 outputs.In one example, the voltage signal 204 that reference voltage circuit 210 receives from driving control system 200 outsides, voltage signal 204 provides biasing for reference voltage circuit 210, and produces a fixed reference voltage signal 212 that does not change with temperature and voltage signal 204.In another example, reference voltage circuit 210 can also receive the enable signal 262 from enable circuits 260, and whether enable signal 262 control reference voltage circuits 210 are worked and whether produced reference voltage signal 212.When enable signal 262 was a kind of state, reference voltage circuit 210 work produced reference voltage signal 212; When enable signal 262 was another state, reference voltage circuit 210 was not worked, and did not produce reference voltage signal 212.
Reference voltage signal 212 is received by error amplifier 220.In addition, error amplifier 220 also receives the feedback voltage signal 214 from driving control system 200 outsides.In one example, error amplifier 220 produces error amplification signal 222 based on reference voltage signal 212 and feedback voltage signal 214.In another example, error amplifier 220 can also receive the enable signal 262 from enable circuits 260, and whether enable signal 262 departure amplifiers 220 are worked and whether produced error amplification signal 222.When enable signal 262 was a kind of state, error amplifier 220 work produced error amplification signal 222; When enable signal 262 was another state, error amplifier 220 was not worked, and did not produce error amplification signal 222.
Error amplification signal 222 is received by pwm generator 230.In one example, pwm generator 230 produces a fixed-frequency, the variable pulse-width signal 232 of dutycycle based on the amplitude of error amplification signal 222.In one embodiment, pwm generator 230 comprises oscillator, produces the oscillator signal of a fixed-frequency, decides the frequency of oscillation of the pulse-width signal 232 of output.In another example, pwm generator 230 can also receive the enable signal 262 from enable circuits 260, and whether enable signal 262 control pwm generators 230 are worked and whether produced pulse-width signal 232.When enable signal 262 was a kind of state, pwm generator 230 work produced pulse-width signal 232; When enable signal 262 was another state, pwm generator 230 was not worked, and did not produce pulse-width signal 232.
Pulse-width signal 232 is received by power switch 240.Power switch 240 just determines conducting based on the level of pulse-width signal 232 or ends, thereby produces a square-wave signal 242 at the SW pin.During power switch 240 conductings, the SW pin voltage is dragged down near 0V, and square-wave signal 242 is a low-voltage, and this moment, the inductance L 11 of driving control system 200 outsides was recharged; When power switch 240 ended, the inductance L 11 of driving control system 200 outsides was to load and output capacitance discharge, and this moment, the SW pin voltage equaled the forward conduction voltage that output voltage VO UT adds Schottky diode D11, the i.e. crest voltage of square-wave signal 242.In one embodiment, power switch 240 conductings when pulse-width signal 232 is high level, power switch 240 ended when pulse-width signal 232 was low level.In one embodiment, power switch 240 conductings when pulse-width signal 232 is low level, power switch 240 ended when pulse-width signal 232 was high level.In one example, power switch 240 is metal-oxide-semiconductors, and in another example, power switch 240 is triodes.
Square-wave signal 242 is received by output open circuit holding circuit 250.Output open circuit holding circuit 250 also receives the voltage signal 204 from driving control system 200 outsides in addition.Voltage signal 204 provides biasing for output open circuit holding circuit 250.Output open circuit holding circuit 250 detects the crest voltage of the square-wave signal 242 that receives, and reaches the threshold value protection voltage (V of output open circuit holding circuit 250 when the crest voltage of square-wave signal 242 OVP) time, output open circuit holding circuit 250 produces an output open circuit guard signal 252, and output open circuit holding circuit 250 is in locking state simultaneously.After state is locked no matter the crest voltage of square-wave signal 242 how to change, output open circuit holding circuit 250 all keeps the output open circuit guard signal 252 that produces constant all the time.Output open circuit holding circuit 250 also receives the control signal 202 from driving control system 200 outsides in addition.Whether control signal 202 control output open circuit holding circuits 250 are worked and whether are produced output open circuit guard signal 252.When control signal 202 is a kind of state, 250 work of output open circuit holding circuit, the threshold value that reaches output open circuit holding circuit 250 when the crest voltage that detects square-wave signal 242 is protected voltage (V OVP) after, output open circuit holding circuit 250 produces an output open circuit guard signal 252 and locked, and output open circuit guard signal 252 remains unchanged simultaneously.When control signal 202 was another kind of state, output open circuit holding circuit 250 was not worked, and did not produce 252 outputs of output open circuit guard signal.Control signal 202 also can be used for cancelling output open circuit guard signal 252, recovers locked output open circuit holding circuit 250 and reworks.When control signal 202 by the state that output open circuit holding circuit 250 idle states is switched to make 250 work of output open circuit holding circuit, can cancel output open circuit guard signal 252, recover locked output open circuit holding circuit 250 and rework.
Output open circuit guard signal 252 is received by enable circuits 260.In addition, enable circuits 260 also receives the control signal 202 from driving control system 200 outsides.Enable circuits 260 produces enable signal 262 based on output open circuit guard signal 252 and outside control signal 202.In one embodiment, enable circuits comprises with XOR (NOR) door.For example; in a kind of example; when enable circuits 260 receives control signal 202 and output open circuit guard signal 252 when all being high level; the enable signal 262 of output is a low level, reference voltage circuit 210, error amplifier 220, pwm generator 230, power switch 240 and output open circuit holding circuit 250 operate as normal.When the control signal 202 that receives driving control system 200 outsides is high level for low level output open circuit guard signal 252; the enable signal 262 of enable circuits 260 outputs is a high level; reference voltage circuit 210, error amplifier 220 and pwm generator 230 are not worked; no pulsewidth modulated output signal 232, power switch also is in cut-off state.Control signal 202 is a low level in addition, and output open circuit holding circuit 250 is not worked yet, and whole driving control system 200 is in off-mode.The control signal 202 that receives when enable circuits 260 is for high level output open circuit guard signal 252 during for low level; the enable signal 262 of output is a high level; reference circuit 210, error amplifier 220, pwm generator 230 and power switch 240 are not worked, and output open circuit holding circuit 250 is worked and is in locking state.At this moment driving control system 200 is in the output open circuit guard mode.Because most of module of output open circuit protection rear drive control system 200 all is closed, current sinking reduces during than operate as normal greatly, so the quiescent dissipation after the output open circuit protection reduces greatly.
Fig. 5 is the simplification system according to a kind of output open circuit protection of the embodiment of the invention.This figure only is an example, and it does not answer the scope of unsuitable restriction claim.Those of ordinary skill in the art will recognize many versions, substitute and modification.System 300 comprises SW pin peak voltage detector 310 and guard signal generator 320.Though used one group of selected parts that system 300 is shown, many substitutes, modification and version can have been arranged.For example, some parts can be expanded and/or merge.Insert miscellaneous part in the parts that can mention in the above.Depend on embodiment, the arrangement of parts can exchange, and other parts can be replaced.For example between SW pin peak voltage detector 310 and guard signal generator 320, can increase filter circuit.The further details of these parts can find in this manual, has below more specifically to describe.
The square-wave signal 242 that SW pin peak voltage detector 310 receives from power switch 240.In one example, whether SW pin peak voltage detector 310 exports a peak detection signal 312 based on the crest voltage size decision of the square-wave signal 242 of power switch 240 outputs.For example, the threshold value protection voltage (V that is higher than SW pin peak voltage detector 310 when the crest voltage of square-wave signal 242 OVP) time, the peak detection signal 312 of a high level of SW pin peak voltage detector 310 outputs, otherwise peak detection signal 312 is a low level.Because square-wave signal 242 is the signals that voltage changes at any time, so the peak detection signal 312 of peak detection circuit 310 outputs also is that a transient state is high-tension pulse signal.
Peak detection signal 312 is received by guard signal generator 320.In addition, guard signal generator 320 also receives voltage signal 204 and the control signal 202 from driving control system 200 outsides.Voltage signal 204 provides biasing for guard signal generator 320.Whether control signal 202 control guard signal generators 320 work.For example, when control signal 202 was a kind of state, guard signal generator 320 was not worked.When control signal 202 was another kind of state, guard signal generator 320 can be worked when receiving peak detection signal 312, and exported an output open circuit guard signal 252.Because peak detection signal 312 is that a transient state is high-tension pulse signal; guard signal generator 320 this high impulse behind the high level pulse that receives peak detection signal 312 may just be cancelled at once; so guard signal generator 320 need can oneself be kept work after the high impulse work that receives peak detection signal 312, and the output open circuit guard signal 252 of locked generation.Unless control signal 202 is given 320 1 idle status signals of guard signal generator, guard signal generator 320 is not worked, just output open circuit guard signal 252 can be cancelled.In one example, guard signal generator 320 is the systems with regenerative feedback loop, guaranteeing the work of the system that after receiving peak detection signal 312, can keep by regenerative feedback loop, and the output open circuit guard signal 252 of locked generation.
Fig. 6 is the reduced graph of output open circuit protection according to another embodiment of the present invention.This figure only is an example, and it does not answer the scope of unsuitable restriction claim.Those of ordinary skill in the art will recognize many versions, substitute and modification.System 400 comprises start-up circuit 422, resistance R 41, R42, R43, R44, R45, NPN triode Q41, Q45, PNP triode Q42, Q43, Q44 and capacitor C41.Though used one group of selected parts that system 400 is shown, many substitutes, modification and version can have been arranged.For example, some parts can be expanded and/or be merged.Insert miscellaneous part in the parts that can mention in the above.Depend on embodiment, the arrangement of parts can exchange, and other parts can be replaced.The further details of these parts can find in this manual, can describe more specifically below.
Voltage signal 204 and control signal 202 that start-up circuit 422 receives from Drive and Control Circuit 200 outsides produce a voltage signal (VP) 243, and VP provides bias voltage for other module.Wherein resistance R 41 and R42 form a potential-divider network, detect the crest voltage of the square-wave signal 242 of SW pin, reach the threshold voltage (V of output open circuit protection when crest voltage OVP) and kept certain pulse width; at this moment the part electric current I on the resistance R 41 1 is by 41 chargings of 43 pairs of capacitor C of resistance R; when the voltage rising at capacitor C 41 two ends reaches a BE knot conducting voltage; NPN triode Q41; PNP triode Q43 conducting; produce electric current I 2 on the resistance R 44; via the proportional current mirror (by PNP triode Q42; Q43 and Q44 form) behind the mirror image Q42 produce one with resistance R 44 on the proportional electric current I 3 of electric current I2; electric current I 3 flow to the voltage that can keep capacitor C 41 two ends behind resistance R 42 and the R43; even like this voltage of the square-wave signal 242 of SW pin by the crest voltage step-down after this system 400 with regenerative feedback loop also can keep work, thereby guaranteed that high level pulse that the output open circuit protection starts back square-wave signal 242 cancels system 400 and also can keep work.The electric current I 2 that resistance R 44 is flowed through PNP triode Q44 behind proportional current mirror mirror image also produces a proportional electric current I 4; electric current I 4 resistance R 45 back of flowing through produces the voltage that can make NPN triode Q45 conducting, low level output open circuit guard signals 252 of output after the NPN triode Q45 conducting.The size of adjusting resistance R 43 and capacitor C 41 can be adjusted the pulse width that causes that high level voltage that system 400 produces the SW pin square-wave signal 242 of output open circuit guard signals 252 is kept, to prevent to cause from the high level narrow pulse width interfering signal of system 200 outsides the false triggering of output open circuit protection system 400.The proportionate relationship of adjusting resistance R 41 and R42 in addition can be adjusted the threshold voltage (V of output open circuit protection OVP), the threshold voltage (V of output open circuit protection OVP) (2) estimation by formula:
V OVP = ( R 41 + R 42 ) × V BE R 42 - - - ( 2 )
Wherein the fundamental current I1 of current mirror can pass through formula (3) calculating:
I 1 = V P - V BE R 44 - - - ( 3 )
The resistance that suitably reduces voltage VP or increase resistance R 44 can obtain littler operating current after the output open circuit protection, to prolong the service life of battery in the lithium battery power supply occasion.
The present invention has many advantages.Some embodiments of the present invention can be simplified the application of series LED drive circuit.For instance, the series LED drive circuit needs output open circuit protecting function.Some embodiment of the present invention can not be used in any device of the peripheral increase of series LED drive circuit; but realize output open circuit protecting function by the method for direct detection SW pin crest voltage in driving control system inside; simplified the application of series LED drive circuit; reduce the power consumption under the output open circuit state, and saved the totle drilling cost of series LED drive circuit.
Though described specific embodiments of the invention, it will be apparent to one skilled in the art that to have other embodiment that are equal to the embodiment that describes.Therefore, the present invention should not be understood that the embodiment that only limits to specifically illustrate.The present invention is limited by the scope of claim.

Claims (18)

1, a kind of series LED driving control system with output open circuit protecting function is characterized in that, described system comprises:
Reference voltage circuit is configured to the voltage signal of receiving system outside at least and produces reference voltage signal;
Error amplifier is configured to receive the feedback voltage signal of described reference voltage signal and system outside at least and produce error amplification signal;
Pwm generator is configured to receive at least described error amplification signal and produces pulse-width signal;
Power switch is configured to receive described pulse-width signal and produces square-wave signal;
The output open circuit holding circuit is configured to receive at least described square-wave signal and whether decision produces the output open circuit guard signal;
Enable circuits, the control signal and the described output open circuit guard signal that are configured to the receiving system outside produce enable signal.
2, system according to claim 1 is characterized in that, whether described reference voltage circuit also can be configured to receive described enable signal and control described reference voltage circuit by described enable signal and work.
3, system according to claim 1 is characterized in that, whether described error amplifier also can be configured to receive described enable signal and control described error amplifier by described enable signal and work.
4, system according to claim 1 is characterized in that, whether described pwm generator also can be configured to receive described enable signal and be worked by described enable signal control pwm generator.
5, system according to claim 1 is characterized in that, whether described pwm generator also can be configured to receive described enable signal and be worked by described enable signal control pwm generator.
6, system according to claim 1; it is characterized in that; the crest voltage of described square-wave signal produces described output open circuit guard signal when being higher than the threshold voltage of output open circuit holding circuit, and described threshold voltage is an adjustable fixed voltage of output open circuit holding circuit internal preset.
7, system according to claim 6 is characterized in that, described output open circuit holding circuit described output open circuit holding circuit when producing the output open circuit guard signal is in locking state, and keeps the output open circuit guard signal of generation constant.
8, system according to claim 7 is characterized in that, the locking state of described output open circuit holding circuit is that the regenerative feedback loop by described output open circuit holding circuit inside realizes.
9, system according to claim 1 is characterized in that, whether described output open circuit holding circuit also is configured to receive the control signal of described system outside and control described output open circuit holding circuit by described control signal and work.
According to claim 7 or 9 described systems, it is characterized in that 10, after described output open circuit holding circuit was in described locking state, the state that the cancelling of described locking state is based on described control signal changes to be realized.
11, a kind of output open circuit protection system is characterized in that, described system comprises:
SW pin peak voltage detector is configured to receive described square-wave signal and produces peak detection signal;
The guard signal generator is configured to receive described peak detection signal and produces the output open circuit guard signal.
12, system according to claim 11 is characterized in that, whether described SW pin peak voltage detector produces described peak detection signal based on the crest voltage decision of the described square-wave signal that receives.
13, system according to claim 12; it is characterized in that; the crest voltage of described square-wave signal produces described peak detection signal when being higher than the threshold voltage of output open circuit holding circuit, and described threshold voltage is an adjustable fixed voltage of output open circuit holding circuit internal preset.
14, system according to claim 13 is characterized in that, described peak detection signal is a pulse signal that transient state is a high level.
15, system according to claim 11; it is characterized in that; described guard signal generator was in locking state when described guard signal generator received described peak detection signal and produces described output open circuit guard signal, and kept the output open circuit guard signal that produces constant.
16, system according to claim 15 is characterized in that, the locking state of described guard signal generator is that the regenerative feedback loop by described guard signal generator inside realizes.
17, system according to claim 11 is characterized in that, whether described guard signal generator also is configured to receive the control signal of described system outside and control described guard signal generator by described control signal and work.
According to claim 15 or 17 described systems, it is characterized in that 18, after described guard signal generator was in locking state, the state that is based on described control signal of cancelling of described locking state changed and realizes.
CNB2007100401473A 2007-04-27 2007-04-27 Series LED driving control system with output open circuit protecting function Expired - Fee Related CN100494767C (en)

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WO2013097211A1 (en) * 2011-12-31 2013-07-04 大洋电机新动力科技有限公司 Narrow pulse filter circuit with automatic compensation and motor controller applying same
CN103428970A (en) * 2013-07-23 2013-12-04 美芯晟科技（北京）有限公司 Non-isolated LED (light-emitting diode) driving circuit and control method
US8836241B2 (en) 2009-08-24 2014-09-16 Green Solution Technology Co., Ltd. LED driving circuit and driving controller for controlling the same
CN106793363A (en) * 2015-11-20 2017-05-31 华润矽威科技（上海）有限公司 LED drive circuit and its open-circuit-protection method
CN107979895A (en) * 2017-12-25 2018-05-01 上海灿瑞科技股份有限公司 A kind of output overvoltage protection circuit based on floating ground BUCK frameworks
CN115296259A (en) * 2022-09-27 2022-11-04 深圳利普芯微电子有限公司 Overvoltage protection circuit and LED drive power supply
CN117423559A (en) * 2023-12-18 2024-01-19 西安西电高压开关有限责任公司 Quick switch electromagnetic repulsion mechanism

Cited By (23)

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Publication number Priority date Publication date Assignee Title
CN101600281B (en) * 2009-07-24 2012-06-27 上海艾为电子技术有限公司 Light modulation control drive control device, system and method
CN101616520B (en) * 2009-08-03 2012-10-10 上海晶丰明源半导体有限公司 LED open circuit guard circuit featuring low cost and high reliability
US8836241B2 (en) 2009-08-24 2014-09-16 Green Solution Technology Co., Ltd. LED driving circuit and driving controller for controlling the same
CN101835311A (en) * 2010-05-11 2010-09-15 重庆美硅微电子有限公司 Light load frequency expanding method of LED drive system
CN102300376B (en) * 2010-06-25 2014-04-09 上海新进半导体制造有限公司 LED (light emitting diode) short circuit detection and protection method and device of LED (light emitting diode) driving chip
CN102300376A (en) * 2010-06-25 2011-12-28 上海新进半导体制造有限公司 LED (light emitting diode) short circuit detection and protection method and device of LED (light emitting diode) driving chip
CN102222461A (en) * 2010-07-30 2011-10-19 惠州Tcl移动通信有限公司 LED drive circuit of mobile terminal
CN102487242A (en) * 2010-12-06 2012-06-06 上海华虹Nec电子有限公司 Charge pump feedback system with time sequence control function
CN102098843A (en) * 2011-01-13 2011-06-15 浙江大学 LED driving circuit with high accuracy and low power consumption
CN102143640A (en) * 2011-04-20 2011-08-03 杭州士兰微电子股份有限公司 LED (light-emitting diode) drive control circuit
CN102143640B (en) * 2011-04-20 2013-11-27 杭州士兰微电子股份有限公司 LED (light-emitting diode) drive control circuit
CN103444063B (en) * 2011-12-31 2015-11-25 大洋电机新动力科技有限公司 A kind of with the burst pulse filtering circuit of auto-compensation and the electric machine controller of application thereof
CN103444063A (en) * 2011-12-31 2013-12-11 大洋电机新动力科技有限公司 Narrow pulse filter circuit with automatic compensation and motor controller applying same
WO2013097211A1 (en) * 2011-12-31 2013-07-04 大洋电机新动力科技有限公司 Narrow pulse filter circuit with automatic compensation and motor controller applying same
CN103428970A (en) * 2013-07-23 2013-12-04 美芯晟科技（北京）有限公司 Non-isolated LED (light-emitting diode) driving circuit and control method
CN103428970B (en) * 2013-07-23 2015-06-24 美芯晟科技（北京）有限公司 Non-isolated LED (light-emitting diode) driving circuit and control method
CN106793363A (en) * 2015-11-20 2017-05-31 华润矽威科技（上海）有限公司 LED drive circuit and its open-circuit-protection method
CN106793363B (en) * 2015-11-20 2019-04-16 华润矽威科技（上海）有限公司 LED drive circuit and its open-circuit-protection method
CN107979895A (en) * 2017-12-25 2018-05-01 上海灿瑞科技股份有限公司 A kind of output overvoltage protection circuit based on floating ground BUCK frameworks
CN107979895B (en) * 2017-12-25 2024-01-05 上海灿瑞科技股份有限公司 Output overvoltage protection circuit based on floating BUCK framework
CN115296259A (en) * 2022-09-27 2022-11-04 深圳利普芯微电子有限公司 Overvoltage protection circuit and LED drive power supply
CN117423559A (en) * 2023-12-18 2024-01-19 西安西电高压开关有限责任公司 Quick switch electromagnetic repulsion mechanism
CN117423559B (en) * 2023-12-18 2024-03-12 西安西电高压开关有限责任公司 Quick switch electromagnetic repulsion mechanism

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