CN109121256A - A kind of the pwm signal control circuit and automobile reading lamp LED drive chip of driving chip - Google Patents
A kind of the pwm signal control circuit and automobile reading lamp LED drive chip of driving chip Download PDFInfo
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- CN109121256A CN109121256A CN201811178135.1A CN201811178135A CN109121256A CN 109121256 A CN109121256 A CN 109121256A CN 201811178135 A CN201811178135 A CN 201811178135A CN 109121256 A CN109121256 A CN 109121256A
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- 230000002159 abnormal effect Effects 0.000 claims description 13
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- 238000005562 fading Methods 0.000 claims description 10
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- 238000005286 illumination Methods 0.000 abstract description 4
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- 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]
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- 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]
- H05B45/10—Controlling the intensity of the light
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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Abstract
The present invention relates to a kind of pwm signal control circuit of driving chip and automobile reading lamp LED drive chips, it is compatible with existing car room lighting solutions, that is the method that the pwm signal control LED that MCU is sent out is opened or closed, simultaneously, the pwm signal automatically generated inside a kind of driving chip is provided, gradually become dark state from secretly gradually becoming bright state, or from bright state for controlling LED illumination.When work is in internal pwm signal control model, the average current of LED, i.e., the duty ratio of pwm signal, is changed in the way of GAMMA curve in the pwm pattern of inside, and the bright variation that the eyes of people can be made to see is soft, linear.When driving chip is in internal pwm pattern, the pwm control signal that LED light is read in control is generated by internal pwm control circuit module, is carried out operation without MCU and is accelerated the operational efficiency of MCU to reduce the burden of MCU.
Description
Technical field
The present invention relates to LED drive chip fields, and in particular to a kind of the pwm signal control circuit and vapour of driving chip
Vehicle reading lamp LED drive chip.
Background technique
LED a little, is more and more widely used in automobile lighting system with its energy conservation, high efficiency etc..But low and middle-grade
And the reading lamp at the front row and heel row in vehicle compartment generally still makees the incandescent lamp bulb of electric light source using tungsten wire.
The brightness of incandescent lamp by its current value by being determined, by the point tumor of incandescent lamp current by incandescent lamp both ends electricity
Pressure is determined divided by equivalent resistances such as holdings.Due to incandescent lamp light emitting source tungsten wire resistivity can broken temperature increase and increase, cause
Incandescent lamp varies with temperature.The shake of cell voltage can be such that incandescent lamp voltage difference of the two ends shakes, incandescent lamp is caused to dodge
It is bright.
For this purpose, the applicant proposed January 13 in 2016, publication No. is CN105578650A, date of publication is 2016 5
Patent applications in months 11 days, as shown in Figure 1, the patent application disclose for a kind of automobile reading lamp LED drive chip, automobile is read
It reads lamp and replaces incandescent lamp using LED, LED efficiency is higher than incandescent lamp bulb, saves electric energy；The LED drive chip is in control LED light
When opening and closing, it is necessary to generate the square-wave signal of a change in duty cycle by MCU, which is signally attached to LED driving
The PWM pin of chip, chip receive the opening and closing for being used to synchronously control LED after pwm signal.This also means that,
MCU must be born by the change in duty cycle operation of load, thus generate cumbersome pwm control signal.
Summary of the invention
In view of this, the present invention is in view of the existing deficiencies of the prior art, main purpose is to provide a kind of driving chip
Pwm signal control circuit and automobile reading lamp LED drive chip, the burden of MCU can be reduced.
To achieve the above object, the technical solution adopted by the present invention is that:
A kind of pwm signal control circuit of driving chip comprising gradually bright to fade off time control circuit module, internal pwm signal
Control circuit module and second selector,
The TSET_UP pin and TSET_DN of the gradually bright input terminal connection driving chip for fading off time control circuit module draw
Foot, output end connect internal pwm signal control circuit module；
The internal pwm signal control circuit includes synchronized sampling unit, counter, Gamma data look-up table, DFF caching list
Member, pwm signal generator, the input terminal connection PWM pin of driving chip of the synchronized sampling unit, reference clock CLK with
And the gradually bright output end for fading off time control module, synchronized sampling unit export CLK_UP_SYN signal, CLK_DN_SYN signal,
PWM_PIN_SYN signal to counter input terminal, meanwhile, the PWM_PIN_SYN signal of synchronized sampling unit output is as outer
Portion's pwm signal is input to an input terminal of second selector；The input of the output end connection Gamma data look-up table of counter
End, and the output end of Gamma data look-up table is connected to the input terminal of pwm signal generator via DFF cache unit, meanwhile,
Reference clock CLK is connected to the input terminal of pwm signal generator after negating；And in the output end output of pwm signal generator
Portion's pwm signal to second selector another input terminal；
The MODE1 pin of the control terminal connection driving chip of the second selector, the output end of second selector exports internal
Pwm signal or external PWM signal.
When the control terminal input high level of the second selector, the output end of second selector exports external PWM signal,
When the output end input low level of the second selector, the output end of second selector exports internal pwm signal.
It is described gradually it is bright fade off time control circuit include the first oscillator and the second oscillator, first oscillator it is defeated
Enter end connection driving chip TSET_UP pin, the output end of the first oscillator exports clock signal clk _ UP to inside pwm signal
Control circuit module；The TSET_DN pin of the input terminal connection driving chip of second oscillator, the output of the second oscillator
End exports clock signal clk _ DN to inside pwm signal control circuit module.
A kind of automobile reading lamp LED drive chip comprising driving chip includes filtering detection circuit module, logic control
Circuit module, the first current source module, the second current source module, first choice is arranged in circuit module, OUT1, OUT2 reference current
Device and above-mentioned pwm signal control circuit,
EN1 pin, the EN2 pin of the input terminal connection driving chip of the filtering detection circuit module, control terminal connection driving
The MODE2 pin of chip, and the output end output EN1 pin of detection circuit module and the operating mode of EN2 pin are filtered to patrolling
Collect control circuit module；When MODE2 pin input high level, EN1 pin and EN2 pin work are in Impulsive control mode；When
When MODE2 pin input low level, EN1 pin and the work of EN2 pin are in level control model；
The input terminal of the synchronized sampling unit of the pwm signal control circuit connects the PWM of driving chip via first selector
Pin, specifically, an input terminal of the PWM pin connection first selector of the driving chip, PWM pin is by negating fortune
Another input terminal of calculation device connection first selector, the control terminal of the POL pin connection first selector of driving chip, and first
The input terminal of the output end connection synchronized sampling unit of selector；When POL pin input high level, first selector output
Pwm signal；When POL pin input low level, first selector output PWM's negates signal；
The output end and pwm signal control electricity of the input terminal connection filtering detection circuit module of the logic control circuit modules
The output end of the second selector on road and the gradually bright output end for fading off time control circuit, the logic control circuit modules
Output end is respectively connected to the input terminal of the first current source module and the input terminal of the second current source module；
The ISET1 pin and ISET2 of the input terminal connection driving chip of OUT1, OUT2 reference current setting circuit module draw
Foot, and the output end of OUT1, OUT2 reference current setting circuit module connects the input terminal and the second electricity of the first current source module
Flow the input terminal of source module, the OUT1 pin of the output end connection driving chip of first current source module, the second current source
The OUT2 pin of the output end connection driving chip of module.
The driving chip further includes OUT3 reference current setting circuit module and OUT3 current source module, the OUT3 base
The ISET3 pin and EN3 pin of the input terminal connection driving chip of quasi- current setting circuit module, and OUT3 reference current is arranged
The output end of circuit module is connected to the input terminal of third current source module, and the output end of third current source module connects OUT3
Pin.
The driving chip further includes abnormal detection circuit module, and the abnormal detection circuit module connection FAULTB draws
Foot comprising voltage detecting circuit, thermal-shutdown circuit and output short-circuit detection circuit, the abnormal detection circuit module is for examining
Whether normal and driving chip is led to by no appearance short circuit when occurring abnormal operating voltage, the operating temperature for surveying driving chip
FAULTB pin is crossed to external circuit output abnormal state information.
After adopting the above scheme, the compatible existing car room lighting solutions of the present invention, the i.e. PWM that MCU is sent out
The method that opens or closes of signal control LED, meanwhile, the pwm signal automatically generated inside a kind of driving chip is provided, for controlling
LED illumination processed gradually becomes dark state from secretly gradually becoming bright state, or from bright state.When work is in internal PWM
When control pattern signal, the average current of LED, i.e., the duty ratio of pwm signal, is according to GAMMA song in the pwm pattern of inside
What the mode of line changed, the bright variation that the eyes of people can be made to see is soft, linear.When driving chip is in inside
When pwm pattern, the pwm control signal that LED light is read in control is generated by internal pwm control circuit module, without MCU
It carries out operation and accelerates the operational efficiency of MCU to reduce the burden of MCU.
In addition, the control model of EN1 pin and EN2 pin can also be set as according to the actual demand of user in the present invention
Impulsive control mode or level control model can be such that the compatible touch switch of driving chip applies and mechanical switch application in this way, mention
The flexibility of high driving chip application.If touch switch, selection is set as Impulsive control mode, if mechanical switch, selection
Level control model.
In addition, light on and off of the present invention in the basic function i.e. sedan car door opening and shutdown action control lamp that meet car reading lamp
State；Interior people can be either manually or by touching the button or toggle switch control lamp is constantly in bright state or control lamp and is in
Outside extinguishing, an indicator light is also added, provides instruction for user, to improve user experience.
Detailed description of the invention
Fig. 1 is the LED drive chip structure chart of the prior art；
Fig. 2 is the LED drive chip application drawing of embodiments of the present invention；
Fig. 3 is the structure chart of the LED drive chip of embodiments of the present invention；
Fig. 4 is the structure chart of the pwm signal control circuit module of embodiments of the present invention；
Fig. 5 is the output signal schematic diagram of the pwm signal control circuit module of the embodiment of invention.
Label declaration:
1, filter detection circuit module 2, first selector 3, second selector 4, internal pwm signal control circuit module 5,
It is gradually bright to fade off time control circuit module 6, logic control circuit modules 7, OUT1, OUT2 reference current setting circuit module
8, circuit module 11, third current source mould is arranged in the first current source module 9, the second current source module 10, OUT3 reference current
Block 12, abnormal detection circuit module.
Specific embodiment
As shown in Fig. 2, present invention discloses a kind of automobile reading lamp LED drive chip, there are 20 pins, 20
Pin is respectively shown in table 1:
| Pin | Definition | Pin | Definition | Pin | Definition |
| 1 | OUT3 | 11 | POL | 15 | TSET_UP |
| 2 | EN3 | 12 | ISET1 | 16 | TSET_DN |
| 3 | EN2 | 13 | IEST2 | 17 | GND |
| 4 | EN1 | 14 | ISET3 | 18 | VCC |
| 5 | PWM | 8 | VIO | 19 | OUT1 |
| 6 | GND | 9 | MODE1 | 20 | OUT2 |
| 7 | FAULTB | 10 | MODE2 |
Table 1
Wherein, VCC pin provides power supply for driving chip, and the operating voltage range of driving chip is 5-40V, GND pin
Pin is accessed for the power ground of driving chip.
PWM pin is pwm signal input pin, and POL is PWM polarity control signal input pin, and the input of MODE1 pin is patrolled
Signal is collected, for the working method of PWM to be arranged.
EN1 pin, EN2 pin, EN3 pin are respectively OUT1 pin, OUT2 pin, OUT3 pin output current switch letter
Number input pin；MODE2 pin input logic signal, for controlling the working method of EN1 pin and EN2 pin.
ISET1, ISET2, ISET3 pin are respectively the setting of OUT1 pin, OUT2 pin, OUT3 pin output current value
Pin.
TSET_UP pin is that gradually the bright time controls pin to LED, which connects a resistance to GND.The resistance of the resistance
The time span that value control LED brightens gradually.TSET_UP pin is that gradually the dark time controls pin to LED, which connects an electricity
Hinder GND.The resistance value control LED of the resistance becomes the time span gone out gradually.
OUT1 pin, OUT2 pin and OUT3 pin are that the output pin of driving chip is separately connected automobile reading LED light
As load.FAULTB pin is open-drain output pin, is exported for abnormal state information.VIO pin is that 5V voltage output is drawn
Foot.
The internal structure of the driving chip is as shown in figure 3, driving chip includes filtering detection circuit module 1, logic control
Circuit module 6, gradually bright fades off time control circuit module 5, the first current source at OUT1, OUT2 reference current setting circuit module 7
Module 8, the second current source module 9, third current source module 11, OUT3 reference current setting circuit module 10, abnormality detection electricity
Road module 12, first selector 2, second selector 3, internal pwm signal control circuit module 4.
Wherein, the EN1 pin of driving chip, EN2 pin are connected to the input terminal of filtering detection circuit module 1, and MODE2 draws
Foot is connected to the control terminal of filtering detection circuit module 1, and filters the output end connection logic control circuit of detection circuit module 1
Module 6.Filtering detection circuit module 1 judges the work side of EN1 pin and EN2 pin according to the logical signal that MODE2 is inputted
Formula, i.e., when MODE2 pin input high level, EN1 pin and the work of EN2 pin are in Impulsive control mode；When MODE2 pin is defeated
When entering low level, EN1 pin and the work of EN2 pin are in level control model.
PWM pin connects an input terminal of first selector 2, and PWM pin connects first choice by negating arithmetic unit
Another input terminal of device 2, POL pin connects the control terminal of first selector 2, and the connection of the output end of first selector 2 is internal
One input terminal of pwm signal control circuit module 4.When POL pin input high level, the pwm signal of PWM pin input is height
Level is effective, and the enabled output electric current of PWM pin input high level, PWM pin input low level closes output electric current.When POL draws
When foot input low level, the pwm signal low level of PWM pin input, pwm signal low level is effective, PWM pin input low level
Enabled output electric current, PWM pin input high level close output electric current.
The TSET_UP pin and TSET_DN pin of driving chip is separately connected the gradually bright time control circuit module 5 that fades off
Two input terminals, and gradually the bright output end output clock signal clk _ UP and clock signal clk for fading off time control circuit module 5 _
DN, wherein clock signal clk _ UP frequency determines the bright speed gradually to brighten of LED light, clock signal clk _ DN frequency
Determine the bright gradually dimmed speed of LED light.Gradually the bright output end for fading off time control circuit module 5 is connected to logic control for this
Circuit module 6, while it being additionally coupled to internal pwm signal control circuit module 4, for controlling the change in duty cycle speed of pwm signal
Degree.It is explained further as gradually a cycle of the clock signal of the bright output for fading off time control circuit module 5 is the time, is
The every single order duty ratio of pwm signal constantly time.Internal pwm signal does 62 rank duty ratios and gradually becomes larger, or gradually becomes smaller.
The output end of the input terminal connection first selector of internal pwm signal control circuit module 4 and gradually bright fade off the time
The output end of control circuit module, and two output ends of internal pwm signal control circuit module are separately connected second selector
Two input terminals, the control terminal of second selector connects MODE1 pin, and the output end of second selector is connected to logic control electricity
Road module.One output end of internal pwm signal control circuit module 4 export it is synchronized after external PWM signal, another is defeated
Outlet exports internal pwm signal.According to the input condition of MODE1 pin, the output end of second selector can selectively export outer
Portion's pwm signal can internal pwm signal.I.e. MODE1 pin is used for input logic signal, the control mode of control PWM is arranged；When
It is external PWM mode when MODE1 pin input high level, is internal PWM mode when input low level.
If MODE1 pin input high level, LED current works in external PWM signal control model: the input of PWM pin is high
LED current is opened in level control；LED current is closed in the control of PWM pin input low level.
If MODE1 pin input low level, LED current works in internal pwm signal control model: the input of PWM pin is
High level, LED current is with some cycles open and close, and the frequency FPWM of open and close, the duty ratio for opening LED current is D, accounts for
Sky ratio D is increased with the frequency of FUP, and the eyes of people can see LED and gradually brighten.The input of PWM pin is low level, LED current
With some cycles open and close, the frequency FPWM of open and close, the duty ratio for opening LED current is D, and duty ratio D is with FDOWN's
Frequency is less, and it is gradually dimmed that the eyes of people can see LED.
The ISET1 pin of driving chip connects the defeated of OUT1, OUT2 reference current setting circuit module 7 with ISET2 pin
Enter end, and OUT1, OUT2 reference current setting circuit module 7 are connected to the first current source module 8 and the second current source module 9,
First current source module 8 connects OUT1 pin, and the second current source module 9 connects OUT2 pin.The setting of OUT1, OUT2 reference current
Circuit module 7 exports two reference current IBIAS1, IBIAS2, wherein IBIAS1=VREF/RISET1, IBIAS2=VREF/RISET2, VREFFor core
Piece internal reference voltage is about 1.2V.RISET1、RISET2For ISET1, ISET2The resistance value of the resistance of pin connection.First current source
Module, it is I that the second current source module, which distinguishes output current value,OUT1、IOUT2, wherein IOUT1=IBIAS1*1000, IOUT2=IBIAS2*
1000。
The input terminal of logic control circuit modules 6 connects the output end, second selector 3 for filtering detection circuit module 1
Output end, the gradually bright output end for fading off time control circuit module 5, the output end connection the of logic control circuit modules 6
The input terminal of one current source module 8, another output end of logic control circuit modules 6 connect the input of the second current source module 9
The output end at end, and the short link OUT1 pin of the output of the first current source module 8, the second current source module 9 connects OUT2 pin.
What logic control circuit modules 6 executed is a Mealy type state machine.Output signal is by current state and all input signal shapes
State determines that the signal of output is high level or low level digital signal.
The ISET3 pin and EN3 pin of driving chip are all connected with the input terminal of OUT3 reference current setting circuit module 10,
And the output end of OUT3 reference current setting circuit module 10 is connected to the input terminal of third current source module 11, and third electric current
The output end of source module 11 connects OUT3 pin.10 outputting reference electric current I of circuit module is arranged in OUT3 reference currentBIAS3,, IBIAS3
=VREF/RISET3, VREFIt is about 1.2V for chip interior reference voltage.Third current source output current value is IOUT3, IOUT3=IBIAS3*
1000。
Abnormal detection circuit module 12 connects FAULTB pin comprising voltage detecting circuit, thermal-shutdown circuit and defeated
Short-circuit detecting circuit out, whether normal and driving chip is by no for the operating voltage for being used to detect driving chip, operating temperature
There is short circuit, when occurring abnormal, by FAULTB pin to external circuit output abnormal state information.
Fig. 3 is the pwm signal control circuit block diagram of driving chip, as shown in Figure 3 and as shown in connection with fig. 5, pwm signal control
Circuit fades off time control circuit module 5, internal pwm signal control circuit module 4 and second selector 3 including gradually bright.
Wherein, gradually it is bright fade off time time control circuit module 5 include the first oscillator 51 and the second oscillator 52, first
The input terminal of oscillator connects TSET_UP pin, and the output end of the first oscillator 51 exports clock signal clk _ UP, which determine
The speed that LED light gradually brightens is read, which is input in internal pwm signal control circuit module 4.And the
The input terminal of two oscillators 52 connects TSET_DN pin, and the output end of the second oscillator 52 exports clock signal clk _ DN, determines
Determine to read LED light gradually dimmed speed, which is input in internal pwm signal control circuit module 4.
The resistance value for the resistance that TSET_UP pin, TSET_DN pin are connected, for controlling the first oscillator 51, the second oscillator 52
Export the clock cycle of clock.Gradually bright fade off is realized by the variation for controlling 62 ranks of LED current to LED.
Gradually bright and electric current gradually becomes larger process, and the residence time of intermediate every single order electric current is that the first oscillator 51 exports clock
Period, the resistance value of resistance that the clock cycle length of the first oscillator output clock is connected by TSET_UP pin determines.Institute
To pass through the resistance value for changing the resistance of TSET_UP pin connection, so that it may control LED gradually bright time.Similarly, fade off and
Electric current gradually becomes smaller process, and the residence time of intermediate every single order electric current is the period that the second oscillator exports clock, the second oscillation
The resistance value for the resistance that the clock cycle length of device output clock is connected by TSET_DN pin determines.So passing through change
The resistance value of the resistance of TSET_DN pin connection, so that it may control the time that LED is faded off.
Internal pwm signal control circuit module 4 includes synchronized sampling unit, counter, Gamma data look-up table, 12 ratios
Special DFF cache unit, pwm signal generator, synchronized sampling unit unit connect PWM pin, the vibration of reference clock CLK and first
Device output clock CLK_UP and the second oscillator output clock CLK_DN are swung, synchronized sampling unit is risen using reference clock CLK
Along synchronized sampling CLK_UP signal, CLK_DN signal and pwm signal, synchronous sampling signal CLK_UP_SYN, CLK_DN_ are exported
SYN, PWM_PIN_SYN are into counter, wherein synchronous sampling signal signal PWM_PIN_SYN is connected as external PWM signal
To an input terminal of second selector.
Specifically, synchronous sampling signal CLK_UP_SYN is input to the CNT_UP_CLK pin of counter, synchronized sampling letter
Number CLK_DN_SYN incoming call is to the CNT_DN_CLK pin of counter, and synchronous sampling signal PWM_PIN_SYN is input to counting
The UPDN pin of device.The count value of counter can increase or decrease, when count value increases, UPDN=1, and counting clock
Use CNT_UP_CLK；When for when reducing, UPDN=0, counting clock to use CNT_DN_CLK.Counter exports the ground of 8 bits
Location is used to control the address of Gamma data look-up table.
Gamma data look-up table exports 12 bit datas, in input value pwm signal generator, for controlling pwm signal
Duty ratio, pwm signal generator clocks be CLKB, clock CLKB be benchmark clock CLK obtained after negating arithmetic unit.This
In the DFF buffers of 12 bits is set, for caching 12 bit datas of Gamma data look-up table output, clock is
CLK_UPDATA is synchronous with CLK failing edge, because of Gamma data look-up table output data and CLK rising edge synch.So this
Sample setting clock is the competition and venture in order to avoid digital signal.
Pwm signal generator, generation duty ratio are that the square-like clock signal of D<11:0>is internal pwm signal.Each interior
At the beginning of portion's pwm signal period, duty cycle data is updated, when a update duty cycle data is arranged in pwm signal generator
Clock signal CLK_UPDATA, and the clock signal clk _ UPDATA is input in 12 bit DFF buffers.
The inside pwm signal of pwm signal generator output is connected to another input terminal of second selector, and second selects
The control terminal of device connects MODE1 pin, and according to MODE1 pin input high level or low level, second selector exports external PWM
Signal or internal pwm signal are to logic control circuit modules.Specifically as shown in figure 4, when MODE1 pin input high level, the
Two selectors export external PWM signal to logic control circuit modules；When MODE1 pin input low level, second selector 3
Internal pwm signal is exported to logic control circuit modules 6.
With continued reference to shown in Fig. 2, VCC pin connects power supply V by a zener diodeBattery, power supply VBatteryConnection two
The anode of pole pipe, the cathode of VCC pin connection connection diode, meanwhile, the cathode of diode is through 10F capacity earth.Pressure stabilizing two
Pole pipe and 10F capacitor form voltage regulator circuit, shield.Diode current flow in a flash, not will receive high current, high voltage
Impact, provide the DC voltage of a pressure stabilizing, and lower load shock electric current.GND pin is the power ground of driving chip
Access pin.
OUT1 pin, OUT2 pin are separately connected reading lighting lamp LED1 and LED2, and OUT3 pin connects indication LED lamp
LED3.Car gate signal control LED1 and LED2 light on and off, enabling LED1 and LED2 is gradually light, shutdown LED1 and LED2 by
Step is gone out, and gate-control signal accesses pwm signal.So pwm signal needs to control OUT1, OUT2.And OUT3 is indicator light, is used
In label knob position, light on and off state and gate controlled switch are unrelated, so OUT3 is not controlled by pwm signal.
PWM pin via a 10k resistance RpwmAccess the level signal of a certain range limitation, resistance RpwmConnection
One end of PWM pin is simultaneously also via the capacity earth of 3.3nF.Herein, resistance RpwmRC low pass filtered is constituted with the capacitor of 3.3nF
Wave filters out high-frequency signal.
EN1 pin and EN2 pin are grounded via a touch switch (Momentary Contact) respectively, and EN3 pin connects
Entering high level or low level logical signal, the electric current for controlling OUT3 pin exports, EN3 pin input high level,
The output electric current of OUT3 pin is opened, EN3 pin input low level, and the output electric current of OUT3 pin is closed.
ISET1 pin via resistance RISET1 be grounded, ISET2 pin via resistance RISET2 be grounded, ISET3 pin via
Resistance RISET3 ground connection.
MODE1 pin, MODE2 pin, POL pin are connected to VIO pin, and VIO pin exports the voltage of 5V, institute
To be equivalent to MODE1 pin, MODE2 pin, POL pin and access high level.
TSET_UP pin, TSET_DN pin are grounded via resistance RTSET_UP and resistance RTSET_DN respectively, resistance
The speed that gradually brightens of LED light is read in the resistance value control of RTSET_UP, and the control of the resistance value of resistance RTSET_DN read LED light by
The dark speed of gradual change.LED illumination gradually brightens or gradually dimmed speed, can pass through RTSET_UP resistance and RTSET_DN
The resistance value of resistance is set separately.For the different demand of client, resistance can be simply replaced to meet.
This is using in example, because MODE1 pin, MODE2 pin access high level, which is in outside
Under pwm pattern, EN1 pin and the work of EN2 pin are under Impulsive control mode, and manpower presses a touch switch, then in EN1
Pin and EN2 pin input a low pulse, when EN1 pin and EN2 pin receive a low pulse, then current OUT1
Pin and OUT2 pin output electric current can invert once.
If OUT1 pin and OUT2 pin are current at the time of EN1 pin and EN2 pin receive a low pulse
To there is electric current output state, then OUT1 pin and OUT2 pin output electric current can be gradually reduced in the next time, and LED is gradually
It is dimmed.If OUT1 pin and OUT2 pin are currently nothing at the time of EN1 pin and EN2 pin receive a low pulse
Electric current output state, then OUT1 pin and OUT2 pin output electric current can be incrementally increased in the next time, and LED gradually becomes
It is bright.
In conclusion of the invention focuses on, and the compatible existing car room lighting solutions of the present invention, i.e. MCU hair
The method that opens or closes of pwm signal control LED sent out, meanwhile, the PWM automatically generated inside a kind of driving chip is provided
Signal gradually becomes dark state from secretly gradually becoming bright state, or from bright state for controlling LED illumination.Work as work
Make in internal pwm signal control model, the average current of LED, i.e., the duty ratio of pwm signal in internal pwm pattern is
Change in the way of GAMMA curve, the bright variation that the eyes of people can be made to see is soft, linear.Work as driving
When chip is in internal pwm pattern, the pwm control signal that LED light is read in control is produced by internal pwm control circuit module
It is raw, operation, which is carried out, without MCU accelerates the operational efficiency of MCU to reduce the burden of MCU.
In addition, the control model of EN1 pin and EN2 pin can also be set as according to the actual demand of user in the present invention
Impulsive control mode or level control model can be such that the compatible touch switch of chip applies in this way and drive with mechanical switch application, raising
The flexibility of dynamic chip application.If touch switch, selection is set as Impulsive control mode, if mechanical switch, selects level
Control model.
The above is only the embodiment of the present invention, is not intended to limit the scope of the present invention, therefore all
Any subtle modifications, equivalent variations and modifications to the above embodiments according to the technical essence of the invention still fall within this
In the range of inventive technique scheme.
Claims (6)
1. a kind of pwm signal control circuit of driving chip, it is characterised in that: including gradually it is bright fade off time control circuit module,
Internal pwm signal control circuit module and second selector,
The TSET_UP pin and TSET_DN of the gradually bright input terminal connection driving chip for fading off time control circuit module draw
Foot, output end connect internal pwm signal control circuit module；
The internal pwm signal control circuit includes synchronized sampling unit, counter, Gamma data look-up table, DFF caching list
Member, pwm signal generator, the input terminal connection PWM pin of driving chip of the synchronized sampling unit, reference clock CLK with
And the gradually bright output end for fading off time control module, synchronized sampling unit export CLK_UP_SYN signal, CLK_DN_SYN signal,
PWM_PIN_SYN signal to counter input terminal, meanwhile, the PWM_PIN_SYN signal of synchronized sampling unit output is as outer
Portion's pwm signal is input to an input terminal of second selector；The input of the output end connection Gamma data look-up table of counter
End, and the output end of Gamma data look-up table is connected to the input terminal of pwm signal generator via DFF cache unit, meanwhile,
Reference clock CLK is connected to the input terminal of pwm signal generator after negating；And in the output end output of pwm signal generator
Portion's pwm signal to second selector another input terminal；
The MODE1 pin of the control terminal connection driving chip of the second selector, the output end of second selector exports internal
Pwm signal or external PWM signal.
2. a kind of pwm signal control circuit of driving chip according to claim 1, it is characterised in that: second choosing
When selecting the control terminal input high level of device, the output end of second selector exports external PWM signal, the second selector it is defeated
When outlet input low level, the output end of second selector exports internal pwm signal.
3. a kind of pwm signal control circuit of driving chip according to claim 1, it is characterised in that: it is described gradually it is bright gradually
The time control circuit that goes out includes the first oscillator and the second oscillator, and the input terminal of first oscillator connects driving chip
TSET_UP pin, the output end of the first oscillator export clock signal clk _ UP to inside pwm signal control circuit module；Institute
The TSET_DN pin of the input terminal connection driving chip of the second oscillator is stated, the output end of the second oscillator exports clock signal
CLK_DN is to inside pwm signal control circuit module.
4. a kind of automobile reading lamp LED drive chip, it is characterised in that: including driving chip include filtering detection circuit module,
Logic control circuit modules, OUT1, OUT2 reference current setting circuit module, the first current source module, the second current source module,
First selector and pwm signal control circuit a method according to any one of claims 1-3,
EN1 pin, the EN2 pin of the input terminal connection driving chip of the filtering detection circuit module, control terminal connection driving
The MODE2 pin of chip, and the output end output EN1 pin of detection circuit module and the operating mode of EN2 pin are filtered to patrolling
Collect control circuit module；When MODE2 pin input high level, EN1 pin and the work of EN2 pin are in Impulsive control mode；When
When MODE2 pin input low level, EN1 pin and the work of EN2 pin are in level control model；
The input terminal of the synchronized sampling unit of the pwm signal control circuit connects the PWM of driving chip via first selector
Pin, specifically, an input terminal of the PWM pin connection first selector of the driving chip, PWM pin is by negating fortune
Another input terminal of calculation device connection first selector, the control terminal of the POL pin connection first selector of driving chip, and first
The input terminal of the output end connection synchronized sampling unit of selector；When POL pin input high level, first selector output
Pwm signal；When POL pin input low level, first selector output PWM's negates signal；
The output end and pwm signal control electricity of the input terminal connection filtering detection circuit module of the logic control circuit modules
The output end of the second selector on road and the gradually bright output end for fading off time control circuit, the logic control circuit modules
Output end is respectively connected to the input terminal of the first current source module and the input terminal of the second current source module；
The ISET1 pin and ISET2 of the input terminal connection driving chip of OUT1, OUT2 reference current setting circuit module draw
Foot, and the output end of OUT1, OUT2 reference current setting circuit module connects the input terminal and the second electricity of the first current source module
Flow the input terminal of source module, the OUT1 pin of the output end connection driving chip of first current source module, the second current source
The OUT2 pin of the output end connection driving chip of module.
5. a kind of automobile reading lamp LED drive chip according to claim 4, it is characterised in that: the driving chip is also
Circuit module and OUT3 current source module are set including OUT3 reference current, the defeated of circuit module is arranged in the OUT3 reference current
Enter the ISET3 pin and EN3 pin of end connection driving chip, and the output end of OUT3 reference current setting circuit module is connected to
The input terminal of third current source module, and the output end of third current source module connects OUT3 pin.
6. a kind of automobile reading lamp LED drive chip according to claim 4, it is characterised in that: the driving chip is also
Including abnormal detection circuit module, the abnormal detection circuit module connects FAULTB pin comprising voltage detecting circuit, mistake
Temperature protection circuit and output short-circuit detection circuit, the abnormal detection circuit module are used to detect operating voltage, the work of driving chip
Make whether temperature is normal and driving chip is by no appearances short circuit, when there is exception, by FAULTB pin to external circuit
Output abnormality status information.
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| CN201811178135.1A CN109121256B (en) | 2018-10-10 | 2018-10-10 | PWM signal control circuit of driving chip and LED driving chip of automobile reading lamp |
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| CN201811178135.1A CN109121256B (en) | 2018-10-10 | 2018-10-10 | PWM signal control circuit of driving chip and LED driving chip of automobile reading lamp |
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| CN109121256B (en) | 2023-12-05 |
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