CN112996184B - Solid-state light source dimming control circuit and projector applying same - Google Patents
Solid-state light source dimming control circuit and projector applying same Download PDFInfo
- Publication number
- CN112996184B CN112996184B CN201911293378.4A CN201911293378A CN112996184B CN 112996184 B CN112996184 B CN 112996184B CN 201911293378 A CN201911293378 A CN 201911293378A CN 112996184 B CN112996184 B CN 112996184B
- Authority
- CN
- China
- Prior art keywords
- light source
- state light
- solid
- control circuit
- dimming control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 12
- 230000005669 field effect Effects 0.000 claims description 27
- 239000007787 solid Substances 0.000 claims description 15
- 239000003990 capacitor Substances 0.000 claims description 10
- 230000000630 rising effect Effects 0.000 abstract description 10
- 238000010586 diagram Methods 0.000 description 7
- 230000002159 abnormal effect Effects 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The invention provides a solid-state light source dimming control circuit and a projector using the same. The dimming control circuit comprises a pulse width modulation controller connected with the positive end and the negative end of the solid-state light source, a shunt switch arranged between the positive end and the negative end of the solid-state light source, and a voltage stabilizing circuit used for providing preset reference voltage for the pulse width modulation controller. The pulse width modulation controller is provided with an output voltage pin for outputting voltage feedback and a reference voltage pin for providing reference voltage for the pulse width modulation controller, and the output voltage pin is electrically connected to the positive terminal of the solid-state light source. The voltage stabilizing circuit is arranged between the output voltage pin and the reference voltage pin; when the shunt switch is switched on, the positive end and the negative end of the solid-state light source are in short circuit, and the voltage stabilizing circuit provides preset reference voltage for the output voltage pin, so that the pulse width modulation controller cannot enter a protection mode. The invention can shorten the rising and falling time of the pulse edge of the pulse width modulation signal and reduce the distortion in the light modulation control.
Description
Technical Field
The invention relates to the field of light source driving circuits, in particular to a solid-state light source dimming control circuit and a projector using the same.
Background
At present, solid-state light source projectors adopting an LED light source or a laser light source generally adjust light of the light source in a duty cycle (duty cycle) adjusting manner. A conventional adjustment method is to control the solid-state light source to be turned on or off by a Pulse Width Modulation (PWM) signal, for example, the PWM signal is a periodic signal with a certain duty ratio, and when the PWM signal is at a high level, the dimming control circuit outputs a constant current; when the pulse width modulation signal is at a low level, the dimming control circuit turns off the current output.
As such dimming methods are applied to large-size and high-resolution display systems more and more, the requirements on the light source driving circuit are higher and higher, wherein in order to ensure a stable display picture, the response speed of the driving circuit is required to be increased, for example, the rising time and the falling time of a pulse edge are required to be less than 20 microseconds. If the rising/falling speed of the output current of the dimming control circuit is slow, i.e. the rising time and the falling time of the pulse edge are long, a certain error exists between the duty ratio of the current output of the dimming control circuit and the duty ratio of the original pulse width modulation signal, which causes the distortion of the dimming control.
Disclosure of Invention
In view of the above technical problems, the present invention provides a solid-state light source dimming control circuit capable of shortening the rise time and the fall time of a pulse edge, and a projector using the same.
The invention relates to a solid-state light source dimming control circuit, which comprises:
the pulse width modulation controller is connected with the positive end and the negative end of the solid-state light source and is provided with an output voltage pin for outputting voltage feedback and a reference voltage pin for providing reference voltage for the pulse width modulation controller, and the output voltage pin is electrically connected with the positive end of the solid-state light source;
the shunt switch is arranged between the positive end and the negative end of the solid-state light source; and
the voltage stabilizing circuit is used for providing preset reference voltage for the pulse width modulation controller and is arranged between the output voltage pin and the reference voltage pin;
when the shunt switch is switched on, the positive end and the negative end of the solid-state light source are short-circuited, and the voltage stabilizing circuit provides a preset reference voltage for the output voltage pin so that the pulse width modulation controller cannot enter a protection mode due to the fact that the pulse width modulation controller is switched off.
Preferably, the voltage regulator circuit includes a first diode, an anode of the first diode is coupled to the reference voltage pin, and a cathode of the first diode is coupled to the output voltage pin. Furthermore, the voltage stabilizing circuit also comprises a first resistor which is connected in series with the first diode.
Preferably, the shunt switch comprises a first field effect transistor and a second field effect transistor connected in parallel.
Further, the pwm controller further has a dimming output pin for controlling the shunt switch, the dimming output pin is coupled to the gate of the first field effect transistor and the gate of the second field effect transistor, the drain of the first field effect transistor and the drain of the second field effect transistor are both coupled to the positive terminal of the solid state light source, and the source of the first field effect transistor and the source of the second field effect transistor are both coupled to the negative terminal of the solid state light source.
Or further, the first field effect transistor and the second field effect transistor are N-type metal-oxide semiconductor field effect transistors respectively.
Preferably, the pwm controller is a constant current output, and the oscillator frequency of the pwm controller is in the range of 120Hz to 1000 Hz.
Preferably, the output voltage pin is grounded through a first capacitor, and the reference voltage pin is grounded through a second capacitor.
Preferably, the solid-state light source is a red light emitting diode, a green light emitting diode or a blue light emitting diode.
The invention also provides a projector which comprises the solid-state light source and the solid-state light source dimming control circuit used for driving the solid-state light source.
Compared with the prior art, the solid-state light source dimming control circuit and the projector using the same can shorten the rising time and the falling time of the pulse edge of the pulse width modulation signal with a certain duty ratio, reduce the distortion phenomenon in dimming control and further improve the display quality of a projection system.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a system block diagram of a solid-state light source dimming control circuit according to an embodiment of the invention.
Fig. 2 is a circuit diagram of a solid-state light source dimming control circuit according to an embodiment of the invention.
Fig. 3 is a schematic diagram illustrating an application of a dimming control circuit for a solid-state light source according to an embodiment of the invention.
Detailed Description
In order to further understand the objects, structures, features and functions of the present invention, the following embodiments are described in detail.
Referring to fig. 1, fig. 1 is a system block diagram of a dimming control circuit of a solid-state light source according to an embodiment of the invention. The solid state light source dimming control circuit 100 includes a pulse width modulation controller 101, a shunt switch 102, and a voltage stabilizing circuit 103.
The pwm controller 101 is connected to positive and negative terminals (e.g., the positive terminal 111 and the negative terminal 112) of the solid-state light source, the pwm controller 101 has an output voltage pin VOUT for outputting voltage feedback and a reference voltage pin VREF for providing a reference voltage to the pwm controller 101, and the output voltage pin VOUT is electrically connected to the positive terminal 111 of the solid-state light source.
The shunt switch 102 is disposed between the positive and negative terminals (e.g., positive terminal 111, negative terminal 112) of the solid-state light source.
The regulator 103 is configured to provide a predetermined reference voltage to the pwm controller 101, and the regulator 103 is disposed between the output voltage pin VOUT and the reference voltage pin VREF.
When the shunt switch 102 is turned on, the positive and negative terminals (e.g., the positive terminal 111 and the negative terminal 112) of the solid-state light source are shorted, and the voltage regulator circuit 103 provides a predetermined reference voltage to the output voltage pin VOUT, so that the pwm controller 101 cannot enter the protection mode due to being turned off.
Referring to fig. 2, fig. 2 is a circuit schematic diagram of a solid-state light source dimming control circuit according to an embodiment of the invention.
The pulse width modulation controller 101 may be a high voltage, synchronous N-channel field effect transistor (NFET) controller for a buck current regulator, such as the commercially available texas instruments TPS92641 chip. Output current regulation is based on valley current mode operation with on-time controlled architecture. This control approach can simplify the loop compensation design while maintaining the switching frequency at an approximately constant level. The TPS92641 chip includes a high voltage start-up regulator that operates over a wide input range of 7V to 85V. PWM controllers are designed for high speed performance with oscillator frequencies ranging up to 1 MHz. The dead time between the high-side and low-side gate drivers is optimized for efficient operation over a wide input operating voltage and output power range. The TPS92641 chip is capable of receiving analog and PWM input signals and thus provides an excellent dimming control range. A linear response characteristic between the input command and the LED current can be achieved by using a low offset error amplifier and dedicated PWM dimming logic to achieve true zero LED current. The TPS92641 chip also has the ability to provide a precision reference current for low power microcontroller. The protection features include: cycle-by-cycle current protection, overvoltage protection, and thermal shutdown. The TPS92641 chip contains a shunt FET dimming input and MOSFET driver for high resolution PWM dimming.
The regulator circuit 103 includes a first diode 131, an anode of the first diode 131 is coupled to the reference voltage pin VREF, and a cathode of the first diode 131 is coupled to the output voltage pin VOUT. Preferably, the first diode 131 is a high-speed switching diode. Further, the voltage stabilizing circuit 103 may further include a first resistor 132, and the first resistor 132 is connected in series to the first diode 131. Preferably, the first resistor 132 has a resistance of 15 kilo-ohms.
In one embodiment, the shunt switch 102 includes a first field effect transistor 121 and a second field effect transistor 122 connected in parallel. The first field effect transistor 121 and the second field effect transistor 122 are turned on to short-circuit the positive terminal 111 and the negative terminal 112 of the solid-state light source, so that the pwm signal becomes low level, and at this time, the voltage difference between the positive terminal 111 and the negative terminal 112 of the solid-state light source is almost 0V, and this voltage makes the output voltage pin VOUT of the pwm controller 101 almost 0V through a resistor, thereby making the pwm controller 101 enter the protection mode. Since the pwm controller 101 goes from the protection mode to the normal mode and the pwm signal goes high (i.e. the rising time of the pulse edge goes long), the voltage regulator 103 increases from the reference voltage pin VREF to the output voltage pin VOUT of the pwm controller 101 to maintain the voltage of the output voltage pin VOUT at the predetermined reference voltage (e.g. 0.8V), so that the pwm controller 101 does not enter the protection mode, and the rising time of the pulse edge can be improved, e.g. reduced to 10 μ s. Similarly, the voltage regulator circuit 103 may be used to improve the falling time of the pulse edge of the pwm signal, for example, to 10 μ sec.
With continued reference to fig. 1 and fig. 2, preferably, the pwm controller 101 further has a dimming output pin SDRV for controlling the shunt switch 102, the dimming output pin SDRV is respectively coupled to the gate of the field effect transistor 121 and the gate of the second field effect transistor 122, the drain of the first field effect transistor 121 and the drain of the second field effect transistor 122 are both coupled to the positive terminal 111 of the solid-state light source, and the source of the first field effect transistor 121 and the source of the second field effect transistor 122 are both coupled to the negative terminal 112 of the solid-state light source. Including but not limited to ground, the first field effect transistor 121 and the second field effect transistor 122 are N-type metal-oxide semiconductor field effect transistors, respectively.
In one embodiment, the pwm controller 101 is a constant current output and the oscillator frequency of the pwm controller 101 is in the range of 120Hz to 1000 Hz.
Referring to fig. 2, the output voltage pin VOUT is grounded through the first capacitor 141, and the reference voltage pin VREF is grounded through the second capacitor 142. Preferably, the capacitance values of the first capacitor 141 and the second capacitor 142 are 0.1 microfarads. Other resistor, capacitor and inductor components can be further disposed in the circuit diagram shown in fig. 2 as needed, and the known components in the prior art are not described herein again.
The main technical principle of the invention is as follows: the switch between the positive end and the negative end of the solid-state light source is conducted, the capacitor discharge in the circuit can be accelerated, however, the voltage difference between the positive end and the negative end of the solid-state light source is 0 due to the conduction of the switch, the PWM chip can receive an abnormal signal and can be closed, and therefore a preset reference voltage is provided to the PWM chip, the abnormal pin is judged to be arranged at the preset reference voltage, and therefore when the switch is conducted, the PWM chip cannot be closed, and the rising and falling time of the pulse edge of the PWM signal can be accelerated. In addition, the PWM chip has a constant current output function, and when the output is short-circuited, the PWM chip still can maintain the constant current output and cannot have abnormal conditions; because the originally designed frequency is 5KHz, and when the designed frequency is 120Hz to 1KHz, the waiting time is longer, the PWM chip can enter a protection mode, and the problem that the rising and falling time of the pulse edge of the PWM signal is too long can be solved by adding the voltage stabilizing circuit.
Referring to fig. 3, fig. 3 is a schematic diagram of an application of the dimming control circuit for a solid-state light source according to an embodiment of the invention. The projector according to an embodiment of the present invention includes a solid-state light source 200 and the solid-state light source dimming control circuit 100 according to any of the above embodiments for driving the solid-state light source 200.
In practical applications, the solid-state light source 200 may be a red light emitting diode, a green light emitting diode, or a blue light emitting diode. However, the present invention is not limited thereto, and the solid-state light source 200 may be a laser or other semiconductor light source.
The solid-state light source dimming control circuit and the projector using the same can shorten the rising time and the falling time of the pulse edge of the pulse width modulation signal with a certain duty ratio, reduce the distortion phenomenon in dimming control and further improve the display quality of a projection system.
The present invention has been described in relation to the above embodiments, which are only exemplary of the implementation of the present invention. Furthermore, the technical features mentioned in the different embodiments of the present invention described above may be combined with each other as long as they do not conflict with each other. It should be noted that the disclosed embodiments do not limit the scope of the invention. Rather, it is intended that all such modifications and variations be included within the spirit and scope of this invention.
Claims (10)
1. A solid state light source dimming control circuit, comprising:
the pulse width modulation controller is connected with the positive end and the negative end of the solid-state light source and is provided with an output voltage pin for outputting voltage feedback and a reference voltage pin for providing reference voltage for the pulse width modulation controller, and the output voltage pin is electrically connected with the positive end of the solid-state light source; and
the shunt switch is arranged between the positive end and the negative end of the solid-state light source;
the dimming control circuit is characterized by further comprising a voltage stabilizing circuit used for providing preset reference voltage for the pulse width modulation controller, wherein the voltage stabilizing circuit is arranged between the output voltage pin and the reference voltage pin;
when the shunt switch is switched on, the positive end and the negative end of the solid-state light source are short-circuited, and the voltage stabilizing circuit provides a preset reference voltage for the output voltage pin so that the pulse width modulation controller cannot enter a protection mode due to the fact that the pulse width modulation controller is switched off.
2. The dimming control circuit for a solid state light source of claim 1, wherein the voltage regulator circuit comprises a first diode, an anode of the first diode being coupled to the reference voltage pin, and a cathode of the first diode being coupled to the output voltage pin.
3. The dimming control circuit for a solid state light source of claim 2, wherein the voltage regulator circuit further comprises a first resistor connected in series with the first diode.
4. The solid state light source dimming control circuit of claim 1, wherein the shunt switch comprises a first field effect transistor and a second field effect transistor in parallel.
5. The dimming control circuit for a solid state light source according to claim 4, wherein the PWM controller further has a dimming output pin for controlling the shunt switch, the dimming output pin is coupled to the gate of the first FET and the gate of the second FET, respectively, the drain of the first FET and the drain of the second FET are both coupled to the positive terminal of the solid state light source, and the source of the first FET and the source of the second FET are both coupled to the negative terminal of the solid state light source.
6. The dimming control circuit for a solid state light source of claim 4, wherein the first and second fets are N-type mosfets respectively.
7. The dimming control circuit for a solid state light source of claim 1, wherein the pwm controller is a constant current output and the oscillator frequency of the pwm controller is in the range of 120Hz to 1000 Hz.
8. The solid state light source dimming control circuit of claim 1, wherein the output voltage pin is coupled to ground through a first capacitor, and the reference voltage pin is coupled to ground through a second capacitor.
9. The dimming control circuit for a solid state light source of claim 1, wherein the solid state light source is a red led, a green led or a blue led.
10. A projector comprising a solid-state light source and the solid-state light source dimming control circuit of any one of claims 1 to 9 for driving the solid-state light source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911293378.4A CN112996184B (en) | 2019-12-16 | 2019-12-16 | Solid-state light source dimming control circuit and projector applying same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911293378.4A CN112996184B (en) | 2019-12-16 | 2019-12-16 | Solid-state light source dimming control circuit and projector applying same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112996184A CN112996184A (en) | 2021-06-18 |
| CN112996184B true CN112996184B (en) | 2022-08-23 |
Family
ID=76343231
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911293378.4A Expired - Fee Related CN112996184B (en) | 2019-12-16 | 2019-12-16 | Solid-state light source dimming control circuit and projector applying same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112996184B (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102007004393A1 (en) * | 2007-01-29 | 2008-07-31 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Semiconductor light source i.e. high power LED, control circuit for use in circuit carrier, is provided in circuit carrier, produces pulse with pulse length less than three microseconds, and regulates rated current within pulse |
| CN102420520B (en) * | 2011-12-02 | 2014-02-26 | 电子科技大学 | Current limiting protection circuit and direct current (DC)-DC converter integrated with current limiting protection circuit |
| CN103491664A (en) * | 2012-06-12 | 2014-01-01 | 硕颉科技股份有限公司 | Load actuating device and method for light emitting diode lamp and lighting device with light emitting diode lamp |
| TWI497883B (en) * | 2013-08-14 | 2015-08-21 | Beyond Innovation Tech Co Ltd | Boost apparatus with over-current and over-voltage protection function |
| CN204741426U (en) * | 2015-05-18 | 2015-11-04 | 赖可腾 | Novel steady voltage and protection circuit |
-
2019
- 2019-12-16 CN CN201911293378.4A patent/CN112996184B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN112996184A (en) | 2021-06-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8754587B2 (en) | Low cost power supply circuit and method | |
| US6844760B2 (en) | LED drive circuit | |
| US10140931B2 (en) | Shadow mask assemblies and reusing methods of shadow mask assemblies thereof | |
| US6738272B2 (en) | Charge pump rush current limiting circuit | |
| KR102575945B1 (en) | Switching regulator | |
| US8299766B2 (en) | Switching output circuit | |
| US8198818B2 (en) | Vehicle lighting control device | |
| CN108055737B (en) | Boost DC-DC LED constant current drive circuit | |
| US20120127151A1 (en) | Power supply device, liquid crystal drive device, and liquid crystal display device | |
| US20050007086A1 (en) | Switching regulator control circuit | |
| JP7345326B2 (en) | Light emitting element drive device | |
| CN212628502U (en) | LED backlight driving circuit and control chip for same | |
| US7067988B2 (en) | Inverter circuit for lighting discharge lamps with reduced power consumption | |
| US20210084265A1 (en) | Semiconductor light source driving device and projection image display device | |
| CN112996184B (en) | Solid-state light source dimming control circuit and projector applying same | |
| KR20170054504A (en) | Led backlight source for liquid crystal display device and liquid crystal display device | |
| WO2011013692A1 (en) | Dc-dc converter | |
| CN112996185B (en) | Solid-state light source driving circuit and projector using same | |
| WO2021179769A1 (en) | Driving circuit, power circuit and projection device | |
| US6661117B2 (en) | Load driving system and method thereof | |
| US8198879B2 (en) | Booster circuit and PWM signal generator | |
| CN109757007B (en) | Power supply circuit | |
| KR100303439B1 (en) | Rush Current Reduction Circuit and Switching Mode Power Supply Using It | |
| CN115469703B (en) | Linear voltage stabilizing circuit, working method and electronic equipment | |
| CN212060851U (en) | Portable projector |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20220823 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |