CN105430794B - Driving chip, LED constant current drive control circuit and LED driving methods - Google Patents
Driving chip, LED constant current drive control circuit and LED driving methods Download PDFInfo
- Publication number
- CN105430794B CN105430794B CN201510893776.5A CN201510893776A CN105430794B CN 105430794 B CN105430794 B CN 105430794B CN 201510893776 A CN201510893776 A CN 201510893776A CN 105430794 B CN105430794 B CN 105430794B
- Authority
- CN
- China
- Prior art keywords
- driving chip
- oxide
- semiconductor
- metal
- voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
Abstract
The present invention provides a kind of driving chip, LED constant current drive control circuit and LED driving methods, and the driving chip includes：One voltage control module, an a reference source, a sampling hold circuit, a comparator, a control logic module and a zero passage detection module.The driving chip can effectively save a pin of chip, and the CS pins of the driving chip play sampling and function relatively, so as to reduce the cost of the driving chip.
Description
Technical field
The present invention relates to electronic technology field, more particularly to a kind of driving chip, LED constant current drive control circuit and LED
Driving method.
Background technology
Fig. 1 is a kind of traditional LED drive circuit, wherein, the alternating current that rectifier bridge 103 will be inputted from alternating current source 101
Repoussage stream is filtered into DC voltage, and is stored in electric capacity C1, and electric capacity C2 is as a kind of electric capacity for control voltage voltage stabilizing,
The VCC pin of chip U1 shown in Fig. 1 receives input voltage VCC, to supply power to chip U1.The chip U1 passes through the chip
U1 DRAIN pins are electrically connected to an inductance L1, and the inductance L1 is connected between the DRAIN ends shown in Fig. 1 and VOUT ends, institute
Inductance L1 is stated to be filtered the electric current for flowing to the chip U1 from the DRAIN pins of the chip U1.It is multiple shown in Fig. 1
LED is in series connection, and in parallel with electric capacity C3 and sustained diode 1, the multiple LED be connected to VBUS ends and VOUT ends it
Between.Chip U1 described in Fig. 1 is BUCK frameworks, and the resistance R2 electrically connected with the chip U1 can be used as sampling resistor, described
Chip U1 CS pins collection flows through resistance R2 electric current and obtains corresponding voltage signal.
Fig. 2 is the internal frame diagram of the chip U1, and the VCC pin of the chip U1 is the energization pins of the chip U1,
To supply power to the chip U1 by the VCC pin.The DRAIN pins of the chip U1 are connected to the high pressure inside one
Metal-oxide-semiconductor, the high-voltage MOS pipe are managed for a kind of LDMOS.The CS pins of the chip U1 are the sampling pin of the chip U1, to
Collection flows through the electric current of the high-voltage MOS pipe.The GND pin of the chip U1 is the grounding pin of the chip.The CS draws
Pin is electrically connected to the first input end of a comparator, will input to the CS sampled signals of the first input end of the comparator
Compared with the reference voltage that the second input of the comparator is received.When the voltage of the CS sampled signals of input is more than
During the reference voltage, then comparator output one cut-off signals a to control logic module, the control logic module exist
After receiving the cut-off signals, a control signal is sent to turn off the high-voltage MOS pipe.Because inductance L1 electric current can not wink
Between saltus step, therefore, the electric current in the inductance L1 progressively reduces, until be decreased to zero, the now zero passage detection of the chip U1
Module detects that the electric current in the inductance L1 is zero, then sends a zero passage detection signal to the control logic module so that
The control logic module resets, and then the control logic module sends a control signal to the high-voltage MOS pipe, with
Again the high-voltage MOS pipe is turned on.That is, when the electric current of the inductance L1 is charged to a predetermined threshold value, the core
Piece U1 turns off the high-voltage MOS pipe, and when the current discharge of the inductance L1 is to zero, the chip U1 turns on the high-pressure MOS
Manage, in this way repetitive cycling.Therefore, the high-voltage MOS pipe inside the chip U1 switches repeatedly between on off state,
To cause the chip U1 to be operated under critical conduction mode.
Fig. 3 is the working waveform figure of the chip U1.As shown in figure 3, the height inside 0~t1 moment, the chip U1
Metal-oxide-semiconductor conducting is pressed, the voltage of DRAIN leads ends is approximately equal to the voltage of CS leads ends, and during this period, the inductance L1, which enters, to be filled
Electricity condition, the voltage difference at the both ends of the inductance L1 is VOUT-DRAIN, is approximately equal to VOUT, and therefore, the inductance L1's fills
Electric slope isNow, flow through the electric current for the resistance R2 being electrically connected with the CS leads ends and flow through the inductance L1's
Electric current is equal.When the voltage of the CS leads ends gradually increases, until when reaching pre-set threshold value (being, for example, 600mV=0.6V),
The chip U1 turns off the high-voltage MOS pipe by the control logic module.Flow through peak point current of the CS leads ends etc.
In the peak point current for flowing through the inductance L1, it is(ampere), and charging intervalWhen the high pressure
Metal-oxide-semiconductor is after the t1 moment turns off, because the electric current in the inductance L1 can not instantaneous abrupt change so that the voltage of DRAIN leads ends
It is charged to the diode drop of the forward conduction more than VBUS ends, that is to say, that the voltage of the DRAIN leads ends is near
The voltage at approximately equal to described VBUS ends, the inductance L1 both ends generate the pressure drop in the same direction with inductance L1 chargings direction, should
Pressure drop is VOUT-VBUS, and the electric discharge slope of the inductance L1 isDischarge time isAfter the current discharge in the inductance L1 is to zero, the zero passage detection module detects
When electric current in the inductance L1 is zero, a zero passage detection signal is sent to the control logic module so that the control is patrolled
Collecting module controls the high-voltage MOS pipe to turn on again, and then the inductance L1 is recharged, and then starts new one week
Phase.
Therefore chip U1 described above CS pins and GND pin each serves as sampling and the effect of ground connection.So
And as chip internal circuits structure of the prior art is increasingly complicated, idle chip pin gradually decreases, and chip needs
Completion is more multi-functional, therefore, for the technical staff of chip design, it is crucial as one how to effectively utilize chip pin
Problem.
The content of the invention
In order to solve the above problems, the present invention provides a kind of driving chip, LED constant current drive control circuit and LED drivings
Method, the driving chip can effectively save a pin of chip, and the CS pins of the driving chip play sampling and
Function relatively, so as to reduce the cost of the driving chip.
According to an aspect of of the present present invention, the present invention provides a kind of driving chip, and it includes：One voltage control module, a base
Quasi- source, a sampling hold circuit, a comparator, a control logic module and a zero passage detection module, wherein, the voltage control
Module is electrically connected to the VCC pin of the driving chip, for producing VCC voltages；The a reference source is respectively electrically connected to described
The VCC pin of driving chip and the voltage control module, for producing a base relative to the CS pins of the driving chip
Quasi- voltage, wherein the current potential of the CS pins of the driving chip is arranged to the potential minimum of the driving chip；The sampling
Holding circuit is electrically connected to the first output end of the control logic module and the output end of a reference source, and the sampling is kept
Circuit is used to export a constant voltage；The first input end of the comparator is electrically connected to the output of the sampling hold circuit
End, the second input of the comparator are electrically connected to the source electrode of a metal-oxide-semiconductor, and the output end of the comparator is electrically connected to described
The first input end of control logic module；Second input of the control logic module is electrically connected to the zero passage detection module
Output end, the second output end of the control logic module is electrically connected to the grid of the metal-oxide-semiconductor；The zero passage detection module
Input be respectively electrically connected to the driving chip DRAIN pins and the metal-oxide-semiconductor drain electrode；The source electrode of the metal-oxide-semiconductor
It is electrically connected to the CS pins of the driving chip；The VCC pin of the driving chip passes through one second capacity earth, the driving
For the VCC pin of chip to be powered to the driving chip, the capacitance for being provided with second electric capacity is more than one first threshold
Value；The CS pins of the driving chip are grounded by a sampling resistor, and the CS pins of the driving chip flow through institute to gather
The electric current of metal-oxide-semiconductor is stated, and plays a part of the driving chip relatively.
In an embodiment of the present invention, the sampling hold circuit includes：One switch, one first electric capacity, a reference voltage
Input and a sampling keep output end；Reference voltage of the reference voltage input received from a reference source；It is described
One end of switch is electrically connected to the reference voltage input, and the control terminal of the switch is electrically connected to the control logic module
The first output end；The other end of the switch is respectively electrically connected to the sampling and keeps the one of output end and first electric capacity
End, the other end of first electric capacity are respectively electrically connected to the VCC pin of the voltage control module and the chip.
In an embodiment of the present invention, when the VCC pin of the driving chip electrically connects an external power source, the control
Logic module sends Continuity signal to the metal-oxide-semiconductor and cut-off signals to the switch so that the metal-oxide-semiconductor conducting, it is described to open
Shut-off is opened.
In an embodiment of the present invention, it is described when switching off when the MOS is turned on, the first input of the comparator
End and a reference source open circuit, the voltage of the VCC pin of the driving chip keep constant, the first input end of the comparator
To the driving chip VCC pin voltage keep it is constant so that the comparator first input end current potential relative to
Current potential utterly keeps constant.
In an embodiment of the present invention, when the voltage of the second input of the comparator is more than or equal to one second threshold
During value, the comparator sends energizing signal to the control logic module, the control logic module and sends a cut-off signals
Extremely switched to the metal-oxide-semiconductor and a Continuity signal so that the metal-oxide-semiconductor cut-off, the switch closure.
In an embodiment of the present invention, when the metal-oxide-semiconductor ends, and the switch closes, the CS of the driving chip draws
The current potential of pin is equal to current potential utterly, and the voltage of the first input end of the comparator is equal to electricity caused by a reference source
Pressure.
In an embodiment of the present invention, the zero passage detection module detects and the DRAIN pins of driving chip electricity
For current discharge in one external inductors of connection to after zero, the zero passage detection module sends a zero passage detection signal to the control
Logic module processed so that the control logic module resets；The control logic module sends a Continuity signal to described
Metal-oxide-semiconductor and a cut-off signals turn on the metal-oxide-semiconductor again to the switch, back off the switch.
In an embodiment of the present invention, the metal-oxide-semiconductor of the driving chip between the on off state repeatedly switched conductive/
Turn off to realize that the constant current using the circuit of the chip drives.
In an embodiment of the present invention, when the metal-oxide-semiconductor turns on, the current potential of the CS pins of the driving chip with definitely
The electric current that potential difference between the current potential on ground is equal in external inductors flows through pressure drop caused by external sampling resistance.
In an embodiment of the present invention, when the metal-oxide-semiconductor ends, the current potential of the CS pins of the driving chip with definitely
Potential difference between the current potential on ground is equal to zero.
According to another aspect of the present invention, the present invention provides a kind of LED constant current drive control circuit, including：One rectifier bridge,
One the 3rd electric capacity, a fly-wheel diode, one the 4th electric capacity, multiple LED, an inductance, a sampling resistor and above-mentioned driving core
Piece；Wherein, the input of the rectifier bridge is electrically connected to an AC power, and it is direct current that the rectifier bridge, which is used for AC rectification,
Electricity；The both ends of 3rd electric capacity are respectively electrically connected to the in parallel two rectification branch road of the rectifier bridge, the 3rd electric capacity
For being filtered to direct current；Multiple LED of the fly-wheel diode, the 4th electric capacity and series connection are connected in parallel to each other；Institute
The VCC pin for stating driving chip is electrically connected to one end of second electric capacity, and the DRAIN pins of the driving chip are electrically connected to
One end of the inductance, the CS pins of the driving chip are electrically connected to one end of the sampling resistor；Second electric capacity
The other end of the other end and the sampling resistor is grounded；The other end of the inductance is electrically connected to the fly-wheel diode, institute
State the 4th electric capacity and multiple LED of series connection points of common connection.
According to another aspect of the present invention, the present invention provides a kind of LED driving methods, using above-mentioned driving chip, institute
The method of stating comprises the following steps：1) when the VCC pin of driving chip electrically connects an external power source, control logic module sends and led
For messenger to metal-oxide-semiconductor, control logic module sends cut-off signals to switching, and to cause metal-oxide-semiconductor to turn on, switches off；2) when than
When voltage compared with the second input of device is more than the voltage of first input end, the comparator sends an energizing signal to control and patrolled
Volume module, the control logic module send cut-off signals to metal-oxide-semiconductor, and the control logic module sends Continuity signal to opening
Close, to cause metal-oxide-semiconductor to end, switch conduction；3) when zero passage detection module detects and the DRAIN pins of driving chip electricity
For current discharge in one external inductors of connection to after zero, the zero passage detection module sends a zero passage detection signal to the control
Logic module processed so that the control logic module sends a Continuity signal to metal-oxide-semiconductor and sends a cut-off signals extremely after resetting
Switch, to cause metal-oxide-semiconductor to turn on, is switched off；4) repeat step 2) and 3), with realization using the circuit of the driving chip
Constant current drives.
In one embodiment of this invention, it is described when switching off when the metal-oxide-semiconductor turns on, the first of the comparator
Input and a reference source open circuit, the voltage of the VCC pin of the driving chip keep constant, and the first of the comparator is defeated
Enter end to the voltage of the VCC pin of the driving chip and keep constant, so that the current potential phase of the first input end of the comparator
Keep constant for current potential utterly.
In one embodiment of this invention, when the metal-oxide-semiconductor ends, and the switch closes, the CS of the driving chip
The current potential of pin is equal to current potential utterly, and the voltage of the first input end of the comparator is equal to caused by a reference source
Voltage.
In one embodiment of this invention, when the metal-oxide-semiconductor turns on, the current potential of the CS pins of the driving chip with absolutely
The electric current that the potential difference between current potential over the ground is equal in external inductors flows through pressure drop caused by external sampling resistance；When described
When metal-oxide-semiconductor ends, the potential difference between the current potential of the CS pins of the driving chip and current potential utterly is equal to zero.
It is an advantage of the current invention that the driving chip of the present invention and the LED constant current drive control electricity using the driving chip
Road is so designed that, compared with the chip of prior art, so that it can be effectively saved a pin, and the driving chip
CS pins play sampling and function relatively simultaneously, so as to reduce the cost of the driving chip.
Brief description of the drawings
Fig. 1 is a kind of circuit connection diagram of traditional LED drive circuit；
Fig. 2 is the internal frame diagram of the chip U1 shown in Fig. 1；
Fig. 3 is the work wave schematic diagram of the chip U1 shown in Fig. 1；
Fig. 4 illustrates a kind of internal frame diagram of driving chip according to an embodiment of the invention；
Fig. 5 illustrates a kind of connection diagram of LED constant current drive control circuit according to an embodiment of the invention；
Fig. 6 illustrates the work wave schematic diagram of the LED constant current drive control circuit.
Embodiment
Below in conjunction with the accompanying drawings to driving chip provided by the invention, LED constant current drive control circuit and LED driving methods
Embodiment elaborates.
It is shown in Figure 4, there is provided a kind of driving chip U400 includes：One voltage control module 410, an a reference source 420, one
Sampling hold circuit 430, a comparator 440, a control logic module 450 and a zero passage detection module 460.Wherein,
The voltage control module 410 is electrically connected to the VCC pin of the driving chip U400, for producing VCC voltages.
The a reference source 420 is respectively electrically connected to the VCC pin of the driving chip U400 and the voltage control module
410, for producing a reference voltage relative to the CS pins of the driving chip U400, wherein the driving chip U400
The current potential of CS pins is arranged to the potential minimum of the driving chip U400.In the present embodiment, a reference source 420 produces
Voltage be 0.6V (i.e. 600mV).
The sampling hold circuit 430 is electrically connected to the first output end of the control logic module 450 and the benchmark
The output end in source 420, the sampling hold circuit 430 are used to export a constant voltage.In the present embodiment, the sampling is kept
Circuit 430 includes a switch S1, one first electric capacity C1, a reference voltage input and a sampling and keeps output end；The base
Reference voltage of the quasi- voltage input end received from a reference source 420；One end of the switch S1 is electrically connected to the benchmark electricity
Input is pressed, the control terminal of the switch S1 is electrically connected to the first output end of the control logic module 450.The switch S1
The other end be respectively electrically connected to one end that the sampling keeps output end and the first electric capacity C1, the first electric capacity C1's
The other end is respectively electrically connected to the voltage control module 410 and the driving chip U400 VCC pin.In the present embodiment
In, because the VCC pin of the driving chip U400 is grounded (reference can be made to shown in Fig. 5) by the second electric capacity C2 outside one, and
And the capacitance of the second electric capacity C2 is set to be more than a first threshold, that is to say, that the second electric capacity C2 capacitance is set
For a higher value (such as 1uF or bigger), so that the current potential of the VCC pin of the driving chip U400 is relative to utterly
GND is highly stable, and then plays a part of voltage stabilizing holding.In addition, the voltage control module 410 can also play voltage stabilizing
The effect of holding.
The first input end of the comparator 440 is electrically connected to the output end of the sampling hold circuit, the comparator
440 the second input is electrically connected to the source electrode of a metal-oxide-semiconductor M1, and the output end of the comparator 440 is electrically connected to the control
The first input end of logic module 450.
Second input of the control logic module 450 is electrically connected to the output end of the zero passage detection module 460, institute
The second output end for stating control logic module 450 is electrically connected to the grid of the metal-oxide-semiconductor M1.Further, when the driving chip
When U400 VCC pin electrically connects an external power source, the control logic module 450 sends a Continuity signal to the metal-oxide-semiconductor
M1 and a cut-off signals are to the switch S1 so that the metal-oxide-semiconductor M1 conductings and switch S1 disconnections.
The input of the zero passage detection module 460 be respectively electrically connected to the driving chip U400 DRAIN pins and
The drain electrode of the metal-oxide-semiconductor M1.The zero passage detection module 460 is detecting in the DRAIN pins with the driving chip U400
Whether the electric current in one external inductors L1 (shown in Figure 5) of electrical connection has been discharged to zero, so that send zero passage detection letter
Number to the control logic module 450.
The source electrode of the metal-oxide-semiconductor M1 is electrically connected to the CS pins of the driving chip U400.The drain electrode electricity of the metal-oxide-semiconductor M1
It is connected to the input of the zero passage detection module 460.The grid of the metal-oxide-semiconductor M1 is electrically connected to the control logic module
450 the second output end.In the present embodiment, the type of the metal-oxide-semiconductor M1 can be that LDMOS is managed.But the metal-oxide-semiconductor M1
Type is not limited thereto.
The VCC pin of the driving chip U400 to give the driving chip U400 power supply；The driving chip U400
CS pins (shown in Figure 5) is grounded by the sampling resistor Rcs outside one, the CS pins of the driving chip U400 to
The electric current of the metal-oxide-semiconductor M1 is flowed through in collection, and further converts that current to relevant voltage and sampled with obtaining corresponding CS
Signal and the second input for being sent to the comparator 440, with the first input end of the comparator 440 received by from
The sampling of the sampling hold circuit 430 keeps the voltage of output end output to be compared.Moreover, the driving chip U400
CS pins play a part of the driving chip U400 relatively.
Furthermore, when the metal-oxide-semiconductor ends, and the switch S1 is closed, because no current flows through the sampling electricity
Hinder Rcs, therefore the current potential of the CS pins of the driving chip U400 is equal to utterly GND current potential, the of the comparator 440
The voltage of one input is equal to voltage caused by a reference source 420, for example, in the present embodiment, the comparator 440
The voltage of first input end is equal to 0.6V, is due to that voltage caused by a reference source 420 is 0.6V.
And when the metal-oxide-semiconductor M1 is turned on, during switch S1 disconnection, the first input end of the comparator 440 with it is described
The open circuit of a reference source 420.Because the VCC pin of the driving chip U400 is grounded by the second larger electric capacity C2 of capacitance, from
And make it that the voltage of the VCC pin of the driving chip U400 keeps constant, furthermore, the first input end of the comparator 440
Voltage to the VCC pin of the driving chip U400 keeps constant, so that, the electricity of the first input end of the comparator 440
Position keeps constant relative to utterly GND current potential.
Furthermore the current discharge in the external inductors L1 electrically connected with the DRAIN pins of the driving chip U400 is extremely
After zero, the zero passage detection module 460 of the driving chip U400 sends a zero passage detection signal to the control logic module
450 so that the control logic module 450 resets, and is believed with sending a Continuity signal value to the shut-offs of the metal-oxide-semiconductor M1 and one
Number to the switch S1, and then the metal-oxide-semiconductor M1 is turned on again and backs off the switch S1.The driving chip afterwards
The current potential of U400 CS pins gradually increases relative to utterly GND current potential.Now, the CS pins of the driving chip U400
Current potential and utterly the potential difference between GND current potential be equal to external inductors L1 in electric current flow through external sampling resistance Rcs
Caused pressure drop.
Hold, when the voltage of the second input of the comparator 440 gradually increases, until being more than or equal to one second threshold
(in the present embodiment, Second Threshold is equal to reference voltage caused by a reference source, such as 0.6V to value, and Second Threshold is not yet
It is limited to this) when, upset (sending energizing signal to the control logic module 450), institute occur for the output of the comparator 440
State control logic module 450 and send a cut-off signals to the metal-oxide-semiconductor M1 and a Continuity signal to the switch S1 so that be described
Metal-oxide-semiconductor M1 ends, the switch S1 closures.Now, the electricity of the current potential of the CS pins of the driving chip U400 and utterly GND
Potential difference between position is equal to zero.Then, the current discharge in the external inductors L1, until after being discharged to zero, the driving
Chip U400 turns on the metal-oxide-semiconductor M1 and backs off the switch S1 again again, hence into a recirculation mode.Cause
This, switched conductive/shut-off uses institute to the metal-oxide-semiconductor M1 of the driving chip U400 to realize repeatedly between the switch S1 states
State the constant current driving of the circuit of chip.
Shown in Figure 5, according to a kind of LED constant current drive control circuit provided in one embodiment of the invention, it is wrapped
Include：One rectifier bridge 510, one the 3rd electric capacity C3, a sustained diode 1, one the 4th electric capacity C4, multiple LED, an inductance L1, one adopt
Sample resistance Rcs and above-mentioned driving chip U400；Wherein,
The input of the rectifier bridge 510 is electrically connected to AC power 501, and the rectifier bridge 510 is used for alternating current is whole
Flow for direct current；The both ends of the 3rd electric capacity C3 are respectively electrically connected to the in parallel two rectification branch road of the rectifier bridge 510,
The 3rd electric capacity C3 is used to be filtered direct current；The sustained diode 1, the 4th electric capacity C4 and series connection
Multiple LED are connected in parallel to each other；The VCC pin of the driving chip U400 is electrically connected to one end of the second electric capacity C2, the drive
Dynamic chip U400 DRAIN pins are electrically connected to one end of the inductance L1, the CS pins electrical connection of the driving chip U400
To one end of the sampling resistor Rcs；The other end of the second electric capacity C2 and the other end of the sampling resistor Rcs connect
Ground；The other end of the inductance L1 is electrically connected to multiple LED of the sustained diode 1, the 4th electric capacity C4 and series connection
Points of common connection.
In the present embodiment, the electric current in the inductance L1 electrically connected with the DRAIN pins of the driving chip U400 is put
For electricity to after zero, the zero passage detection module 460 of the driving chip U400 sends a zero passage detection signal to the control logic mould
Block 450 so that the control logic module 450 resets.The control logic module 450 sends a Continuity signal to described
Metal-oxide-semiconductor M1 and a cut-off signals turn on the metal-oxide-semiconductor M1 again to the switch S1, back off the switch S1.It
The current potential of the CS pins of the driving chip U400 gradually increases relative to utterly GND current potential afterwards.Now, the driving core
The electric current that potential difference between the current potential of piece U400 CS pins and utterly GND current potential is equal in inductance L1 flows through sampling electricity
Hinder pressure drop caused by Rcs.
When the voltage of the second input of the comparator 440 gradually increases, until when being more than or equal to a Second Threshold,
Upset (sending energizing signal to the control logic module 450), the control logic occur for the output of the comparator 440
Module 450 sends a cut-off signals to the metal-oxide-semiconductor M1 and a Continuity signal to the switch S1 so that the metal-oxide-semiconductor M1 is cut
Only, the switch S1 closures.Now, the current potential of the CS pins of the driving chip U400 and utterly between GND current potential
Potential difference is equal to zero.Then, the current discharge in the external inductors L1, until after being discharged to zero, the driving chip U400
Turn on the metal-oxide-semiconductor M1 again again and back off the switch S1, hence into a recirculation mode.Therefore, it is described
Switched conductive/shut-off uses the chip to driving chip U400 metal-oxide-semiconductor M1 to realize repeatedly between the switch S1 states
LED constant current drive control circuit current constant control.
Optionally, when the driving chip U400 in the present invention is applied to LED constant current drive control circuit, the driving chip
U400 may further include one or more in protection module and constant-current control module, and LED constant current is driven with realizing
The constant current driving of control circuit (or system).The constant-current control module by the method for critical current mode continuous control with
Ensure that circuit is operated in constant current mode；The protection module is mainly whether to judge system by the output voltage of sample circuit
Into protected mode, if it is determined that into protected mode, system will restart；Simultaneity factor constantly detects load condition, if therefore
Barrier releases, and system can restart normal work.
With reference to reference to shown in figure 6 and Fig. 3, driving chip U400 of the present invention CS pins serve not only as current sample
End, and, it is different from the utterly GND of reality. as the driving chip U400 relatively.When the metal-oxide-semiconductor M1 is turned on
When, the CS pins of the driving chip U400 have pressure drop relative to utterly GND, and the pressure drop is equal to the electric current stream in inductance L1
Pressure drop caused by sampled resistance Rcs.When the metal-oxide-semiconductor M1 ends, the current potential of the CS pins of the driving chip U400
Utterly GND current potential can be approximately equal to.
As shown in fig. 6, the metal-oxide-semiconductor M1 conductings inside 0~t1 moment, the driving chip U400, the inductance L1 enter
Entering charged state, the voltage difference at the both ends of the inductance L1 is VOUT-DRAIN, is approximately equal to VOUT, therefore, the inductance L1
Charging ramp beNow, the electric current for flowing through the sampling resistor Rcs is equal with the electric current for flowing through the inductance L1.
When the current potential of the CS pins of the driving chip U400 gradually increases relative to utterly GND current potential, until reaching default
During the second threshold values when (being, for example, 600mV), the driving chip U400 turns off the MOS by the control logic module 450
Pipe M1.The peak point current for flowing through the CS pins is equal to the peak point current for flowing through the inductance L1, is(ampere), and fill
The electric time
After the metal-oxide-semiconductor M1 is being turned off at the t1 moment, because the electric current in the inductance L1 can not instantaneous abrupt change so that
The voltage of DRAIN leads ends is charged to the diode drop of the forward conduction more than VBUS ends, that is to say, that described
The voltage of DRAIN leads ends is approximately equal to the voltage at the VBUS ends, and the inductance L1 both ends generate to be filled with the inductance L1
The pressure drop in the same direction of electric direction, the pressure drop are VOUT-VBUS, and the electric discharge slope of the inductance L1 isDuring electric discharge
Between beAfter the current discharge in the inductance L1 is to zero, the zero passage detection module
When 460 electric currents for detecting on the inductance L1 are zero, a zero passage detection signal is sent to the control logic module 450, is made
Obtaining the control logic module 450 controls the metal-oxide-semiconductor M1 to turn on again, and then the inductance L1 is recharged, then
Start a new cycle.
In addition, the present invention also provides a kind of LED driving methods, it uses above-mentioned driving chip U400, and methods described includes
Following steps：
1) when the VCC pin of driving chip electrically connects an external power source, control logic module sends Continuity signal to MOS
Pipe, control logic module send cut-off signals to switching, to cause metal-oxide-semiconductor to turn on, switched off.
2) when the voltage of the second input of comparator is more than the voltage of first input end, the comparator sends one and turned over
To control logic module, the control logic module sends cut-off signals to metal-oxide-semiconductor, the control logic module and sent rotaring signal
Continuity signal is to switching, to cause metal-oxide-semiconductor to end, switch conduction.
3) when zero passage detection module is detected in the external inductors electrically connected with the DRAIN pins of the driving chip
For current discharge to after zero, the zero passage detection module sends a zero passage detection signal to the control logic module so that described
Control logic module sends a Continuity signal to metal-oxide-semiconductor and sends a cut-off signals to switching after resetting, to cause metal-oxide-semiconductor to lead
It is logical, switch off.
4) repeat step 2) and 3), to realize that the constant current using the circuit of the driving chip drives.
In one embodiment of this invention, it is described when switching off when the metal-oxide-semiconductor turns on, the first of the comparator
Input and a reference source open circuit, the voltage of the VCC pin of the driving chip keep constant, and the first of the comparator is defeated
Enter end to the voltage of the VCC pin of the driving chip and keep constant, so that the current potential phase of the first input end of the comparator
Keep constant for current potential utterly.
In one embodiment of this invention, when the metal-oxide-semiconductor ends, and the switch closes, the CS of the driving chip
The current potential of pin is equal to current potential utterly, and the voltage of the first input end of the comparator is equal to caused by a reference source
Voltage.
In one embodiment of this invention, when the metal-oxide-semiconductor turns on, the current potential of the CS pins of the driving chip with absolutely
The electric current that the potential difference between current potential over the ground is equal in external inductors flows through pressure drop caused by external sampling resistance；When described
When metal-oxide-semiconductor ends, the potential difference between the current potential of the CS pins of the driving chip and current potential utterly is equal to zero.
Driving chip of the present invention and it is so designed that using the LED constant current drive control circuit of the driving chip, it is and existing
The chip for having technology is compared, so that it can be effectively saved a pin, and the CS pins of the driving chip play simultaneously
Sampling and function relatively, so as to reduce the cost of the driving chip.
Described above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
Member, under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be regarded as
Protection scope of the present invention.
Claims (15)
- A kind of 1. driving chip, it is characterised in that including：One voltage control module, an a reference source, a sampling hold circuit, one Comparator, a control logic module and a zero passage detection module, wherein,The voltage control module is electrically connected to the VCC pin of the driving chip, for producing VCC voltages；The a reference source is respectively electrically connected to the VCC pin of the driving chip and the voltage control module, for producing one Relative to the reference voltage of the CS pins of the driving chip, wherein the current potential of the CS pins of the driving chip is arranged to institute State the potential minimum of driving chip；The sampling hold circuit is electrically connected to the first output end of the control logic module and the output end of a reference source, The sampling hold circuit is used to export a constant voltage；The first input end of the comparator is electrically connected to the output end of the sampling hold circuit, and the second of the comparator is defeated Enter end and be electrically connected to the source electrode of a metal-oxide-semiconductor, it is first defeated to be electrically connected to the control logic module for the output end of the comparator Enter end；Second input of the control logic module is electrically connected to the output end of the zero passage detection module, and the control is patrolled The second output end for collecting module is electrically connected to the grid of the metal-oxide-semiconductor；The input of the zero passage detection module is respectively electrically connected to the DRAIN pins of the driving chip and the metal-oxide-semiconductor Drain electrode；The source electrode of the metal-oxide-semiconductor is electrically connected to the CS pins of the driving chip；The VCC pin of the driving chip is by one second capacity earth, and the VCC pin of the driving chip is to the drive Dynamic chip power supply, the capacitance for being provided with second electric capacity are more than a first threshold；The CS pins of the driving chip are grounded by a sampling resistor, and the CS pins of the driving chip flow through institute to gather The electric current of metal-oxide-semiconductor is stated, and plays a part of the driving chip relatively.
- 2. driving chip according to claim 1, it is characterised in that the sampling hold circuit includes a switch, one the One electric capacity, a reference voltage input and a sampling keep output end；The reference voltage input is received from the benchmark The reference voltage in source；One end of the switch is electrically connected to the reference voltage input, the control terminal electrical connection of the switch To the first output end of the control logic module；The other end of the switch is respectively electrically connected to the sampling and keeps output end With one end of first electric capacity, the other end of first electric capacity is respectively electrically connected to the voltage control module and the core The VCC pin of piece；
- 3. driving chip according to claim 2, it is characterised in that when the VCC pin of the driving chip electrically connects one During external power source, the control logic module sends a Continuity signal to the metal-oxide-semiconductor and a cut-off signals to the switch, makes The metal-oxide-semiconductor conducting is obtained, it is described to switch off.
- 4. driving chip according to claim 3, it is characterised in that it is described when switching off when the metal-oxide-semiconductor turns on, The first input end of the comparator and a reference source open circuit, the voltage of the VCC pin of the driving chip keep constant, institute The voltage for stating the first input end of comparator to the VCC pin of the driving chip keeps constant, so that the of the comparator The current potential of one input keeps constant relative to current potential utterly.
- 5. the driving chip according to claim 1 or 3, it is characterised in that when the electricity of the second input of the comparator When pressure is more than or equal to a Second Threshold, the comparator sends energizing signal to the control logic module, the control Logic module sends a cut-off signals to the metal-oxide-semiconductor and a Continuity signal and extremely switched so that the metal-oxide-semiconductor cut-off, it is described to open Close and close.
- 6. driving chip according to claim 5, it is characterised in that when the metal-oxide-semiconductor ends, and the switch closes, The current potential of the CS pins of the driving chip is equal to current potential utterly, and the voltage of the first input end of the comparator is equal to institute State voltage caused by a reference source.
- 7. driving chip according to claim 5, it is characterised in that the zero passage detection module detects and the driving For current discharge in one external inductors of the DRAIN pins electrical connection of chip to after zero, the zero passage detection module sends a mistake Zero detection signal is to the control logic module so that the control logic module resets；The control logic module hair A Continuity signal is sent to the metal-oxide-semiconductor and a cut-off signals to the switch, and then turns on the metal-oxide-semiconductor again, is backed off The switch.
- 8. driving chip according to claim 5, it is characterised in that the metal-oxide-semiconductor of the driving chip is in the switch shape Between state repeatedly switched conductive/shut-off with realize using the chip circuit constant current drive.
- 9. the driving chip according to claim 3 or 7, it is characterised in that when the metal-oxide-semiconductor turns on, the driving core The electric current that potential difference between the current potential of the CS pins of piece and current potential utterly is equal in external inductors flows through external sampling electricity Pressure drop caused by resistance.
- 10. driving chip according to claim 6, it is characterised in that when the metal-oxide-semiconductor ends, the driving chip CS pins current potential and current potential utterly between potential difference be equal to zero.
- A kind of 11. LED constant current drive control circuit, it is characterised in that including：One rectifier bridge, one the 3rd electric capacity, the pole of an afterflow two Driving described in any one of pipe, one the 4th electric capacity, multiple LED, an inductance, a sampling resistor and claim 1-10 items Chip；Wherein,The input of the rectifier bridge is electrically connected to an AC power, and it is direct current that the rectifier bridge, which is used for AC rectification,；The both ends of 3rd electric capacity are respectively electrically connected to the in parallel two rectification branch road of the rectifier bridge, the 3rd electric capacity For being filtered to direct current；Multiple LED of the fly-wheel diode, the 4th electric capacity and series connection are connected in parallel to each other；The VCC pin of the driving chip is electrically connected to one end of second electric capacity, the DRAIN pins electricity of the driving chip One end of the inductance is connected to, the CS pins of the driving chip are electrically connected to one end of the sampling resistor；The other end of second electric capacity and the other end of the sampling resistor are grounded；The other end of the inductance is electrically connected to multiple LED of the fly-wheel diode, the 4th electric capacity and series connection public affairs Tie point altogether.
- A kind of 12. LED driving methods, using the driving chip described in claim 2, it is characterised in that comprise the following steps：1) when the VCC pin of driving chip electrically connects an external power source, control logic module transmission Continuity signal to metal-oxide-semiconductor, Control logic module sends cut-off signals to switching, and to cause metal-oxide-semiconductor to turn on, switches off；2) when the voltage of the second input of comparator is more than the voltage of first input end, the comparator sends a upset letter Number to control logic module, the control logic module sends cut-off signals to metal-oxide-semiconductor, the control logic module and sends conducting Signal is to switching, to cause metal-oxide-semiconductor to end, switch conduction；3) when zero passage detection module detects the electric current in the external inductors electrically connected with the DRAIN pins of the driving chip After being discharged to zero, the zero passage detection module sends a zero passage detection signal to the control logic module so that the control Logic module sends a Continuity signal to metal-oxide-semiconductor and sends a cut-off signals to switching after resetting, to cause metal-oxide-semiconductor to turn on, open Shut-off is opened；4) repeat step 2) and 3), to realize that the constant current using the circuit of the driving chip drives.
- 13. driving method according to claim 12, it is characterised in that described to switch off when metal-oxide-semiconductor conducting When, the first input end of the comparator and a reference source open circuit, the voltage of the VCC pin of the driving chip are kept not Becoming, the voltage of the VCC pin of the first input end of the comparator to the driving chip keeps constant, so that the comparator First input end current potential relative to utterly current potential keep it is constant.
- 14. driving method according to claim 12, it is characterised in that when the metal-oxide-semiconductor ends, the switch closes When, the current potential of the CS pins of the driving chip is equal to current potential, the voltage of the first input end of the comparator etc. utterly In voltage caused by a reference source.
- 15. driving method according to claim 12, it is characterised in that when the metal-oxide-semiconductor turns on, the driving chip CS pins current potential and current potential utterly between the electric current that is equal in external inductors of potential difference flow through external sampling resistance Caused pressure drop；When the metal-oxide-semiconductor ends, between the current potential of the CS pins of the driving chip and current potential utterly Potential difference is equal to zero.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510893776.5A CN105430794B (en) | 2015-12-04 | 2015-12-04 | Driving chip, LED constant current drive control circuit and LED driving methods |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510893776.5A CN105430794B (en) | 2015-12-04 | 2015-12-04 | Driving chip, LED constant current drive control circuit and LED driving methods |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105430794A CN105430794A (en) | 2016-03-23 |
| CN105430794B true CN105430794B (en) | 2018-03-16 |
Family
ID=55508650
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510893776.5A Active CN105430794B (en) | 2015-12-04 | 2015-12-04 | Driving chip, LED constant current drive control circuit and LED driving methods |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105430794B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104467373A (en) * | 2014-12-30 | 2015-03-25 | 杭州士兰微电子股份有限公司 | LED drive circuit and switching power controller thereof |
| CN204497985U (en) * | 2015-04-13 | 2015-07-22 | 杭州士兰微电子股份有限公司 | LED drive circuit and switch power controller thereof |
| CN205160837U (en) * | 2015-12-04 | 2016-04-13 | 上海晶丰明源半导体有限公司 | Driver chip and LED constant current drive control circuit |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL2004458C2 (en) * | 2010-03-25 | 2011-09-27 | Eldolab Holding Bv | Led driver operating in boundary condition mode. |
-
2015
- 2015-12-04 CN CN201510893776.5A patent/CN105430794B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104467373A (en) * | 2014-12-30 | 2015-03-25 | 杭州士兰微电子股份有限公司 | LED drive circuit and switching power controller thereof |
| CN204497985U (en) * | 2015-04-13 | 2015-07-22 | 杭州士兰微电子股份有限公司 | LED drive circuit and switch power controller thereof |
| CN205160837U (en) * | 2015-12-04 | 2016-04-13 | 上海晶丰明源半导体有限公司 | Driver chip and LED constant current drive control circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105430794A (en) | 2016-03-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106664021A (en) | Controlling a power supply voltage for a high-side gate driver | |
| CN110337784A (en) | Semiconductor device and power conversion system | |
| CN205248774U (en) | Reverse -connection protective circuit is prevented in input | |
| CN106786396A (en) | One kind amendment ripple inverter intelligent type protective switch of the short circuit circuit | |
| CN102777666A (en) | Electromagnetic valve control circuit and electromagnetic valve closing self-checking method thereof | |
| CN103580461A (en) | Power output discharging circuit | |
| CN108512409A (en) | A kind of highpowerpulse load power source soft starting device and start method | |
| CN205249037U (en) | Switch triode from supply circuit , LED drive module and integrated circuit | |
| CN106602532A (en) | Current limiting circuit, driving method thereof, PMIC protection system and display device protection system | |
| CN205160837U (en) | Driver chip and LED constant current drive control circuit | |
| CN105207457B (en) | Circuit of synchronous rectification and LLC resonant converter with it | |
| CN105430794B (en) | Driving chip, LED constant current drive control circuit and LED driving methods | |
| CN101771338B (en) | Switching power supply module with high reliability and low power consumption | |
| CN105356564A (en) | Wireless energy receiving system | |
| CN107172733A (en) | A kind of electromagnetic heating system and its method of work | |
| CN1815867A (en) | Switch power-supply device | |
| CN208581162U (en) | A kind of current-limiting protection circuit and switching power circuit | |
| CN108964459A (en) | A kind of DC-DC booster circuit and control method | |
| CN213817234U (en) | Protection circuit for AC220V equipment connected to AC380V | |
| CN105406714B (en) | A kind of DC-DC converter integrated circuit and its application circuit | |
| CN108802630A (en) | A kind of initiative alarming circuit of bus power source | |
| CN201260128Y (en) | Power-on shock protection circuit for AC/DC switch power supply | |
| CN105098705B (en) | A kind of earth leakage protective device | |
| CN106226681A (en) | A kind of power circuit failure detector circuit and electronic equipment | |
| CN203119762U (en) | Micro-control unit power supply circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information | ||
| CB02 | Change of applicant information |
Address after: 201204 China (Shanghai) free trade zone Zhang Heng Road, Lane 666, No. 5, room 504-511, room 2 Applicant after: Shanghai semiconducto Limited by Share Ltd Address before: 201204 Zhang Heng road Shanghai, Pudong New Area Zhangjiang hi tech Park Lane 666 No. 2 floor 504-511 room 5 Applicant before: Shanghai Bright Power Semiconductor Co.,Ltd. |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |