CN217788005U - Dimming circuit applied to TV backlight and TV backlight power supply circuit - Google Patents
Dimming circuit applied to TV backlight and TV backlight power supply circuit Download PDFInfo
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- CN217788005U CN217788005U CN202221626721.XU CN202221626721U CN217788005U CN 217788005 U CN217788005 U CN 217788005U CN 202221626721 U CN202221626721 U CN 202221626721U CN 217788005 U CN217788005 U CN 217788005U
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Abstract
The utility model provides a be applied to dimming circuit that TV is shaded relates to dimming circuit technical field. The dimming circuit includes: a triode Q1, the emitting electrode of which is grounded; the resistor R3 is connected with the collector of the triode Q1, and the other end of the resistor R3 is connected with VCC voltage; the resistor R4 is also connected with the collector of the triode Q1, the other end of the resistor R4 is connected with the anode of the diode D1 through the resistor R5, and the other end of the resistor R4 is grounded through the capacitor C2; the base electrode of the triode Q1 is used for inputting a PWM dimming signal; and the cathode of the diode D1 is used for being connected with the FB pin of the backlight driving chip. Through the utility model discloses a TV dimming circuit in a poor light no matter whether compatible dimming function of drive chip in a poor light, whether compatible wide enough the regulation PWM frequency of adjusting luminance can both easily realize TV backlight current's regulation.
Description
Technical Field
The utility model relates to a dimming circuit technical field especially relates to a be applied to dimming circuit and TV power supply circuit in a poor light that TV is shaded.
Background
The TV backlight power source occupies a half-wall river mountain of the TV power source, and is closely related to relevant indexes such as the service life of the whole television, the display stability, the energy consumption level of the television and the like. The functions of brightness, standby and the like of the television screen are realized by controlling the backlight power supply. When the TV backlight is required to realize the dimming function, a corresponding dimming circuit is required on the TV backlight driving power supply.
At present, the kinds of dimmers are various, but PWM dimming has great advantages of digital dimming, and is widely applied. The dimming of the TV backlight power supply is realized by outputting a PWM signal by a main chip, and the PWM signal is not directly acted on a backlight output circuit, but directly acted on a dimming circuit to indirectly realize the adjustment of the backlight.
Although the existing TV backlight driving power supply also realizes the dimming function, the dimming function of the existing TV backlight driving power supply needs to depend on the dimming function of the backlight driving chip, and the dimming PWM frequency range is narrow, so that only the dimming frequency supported by the backlight driving chip can be selected.
SUMMERY OF THE UTILITY MODEL
The utility model provides a following technical scheme, its aim at improves TV drive power supply in a poor light and to the dependence of backlight driver chip function of adjusting luminance, has also improved the narrow problem of traditional dimmer circuit frequency range of adjusting luminance simultaneously.
A dimming circuit for application to TV backlighting, comprising:
a triode Q1, the emitter of which is grounded; the resistor R3 is connected with the collector of the triode Q1, and the other end of the resistor R3 is connected with VCC voltage; the resistor R4 is also connected with the collector of the triode Q1, the other end of the resistor R4 is connected with the anode of the diode D1 through a resistor R5, and the other end of the resistor R4 is also grounded through a capacitor C2;
the base electrode of the triode Q1 is used for inputting a PWM dimming signal; and the cathode of the diode D1 is used for being connected with the FB pin of the backlight driving chip.
Further, the base of the triode Q1 is connected with a resistor R1 and a capacitor C1, respectively, and the other end of the resistor R1 is used for inputting a PWM dimming signal and the other end of the capacitor C1 is grounded.
Furthermore, the base electrode of the triode Q1 is also connected with a resistor R6, and the other end of the resistor R6 is grounded.
Further, the base of the triode Q1 is connected with a main control chip or a PWM dimmer, and the main control chip or the PWM dimmer is used for generating a PWM dimming signal.
Further, when the cathode of the diode D1 is connected with the FB pin of the backlight driving chip,
the FB pin is further connected with a resistor SR15 and a capacitor SC6 respectively, the other end of the resistor SR15 is connected with a reference voltage, and the other end of the capacitor SC6 is grounded.
Further, the other end of the resistor SR15 is further connected to an anode of a diode SD9, a resistor RA1, a resistor RA2, a resistor RA3, a resistor RA4, and a resistor RA5, respectively, and a cathode of the diode SD9, the other end of the resistor RA1, the other end of the resistor RA2, the other end of the resistor RA3, the other end of the resistor RA4, and the other end of the resistor RA5 are all grounded.
Further, the reference voltage takes 0.4V.
A TV backlight power supply circuit comprising: the dimming circuit, a master control chip or a PWM (pulse-width modulation) dimmer connected with the input end of the dimming circuit, and a backlight driving chip and a backlight output circuit connected with the output end of the dimming circuit.
Further, the backlight output circuit includes: the resistor SR15 and the capacitor SC6 are respectively connected with the output end of the dimming circuit; the other end of the resistor SR15 is connected with the reference voltage of 0.4V, and the other end of the capacitor SC6 is grounded.
Further, the backlight output circuit further includes: the anode of the diode SD9, the resistor RA1, the resistor RA2, the resistor RA3, the resistor RA4 and the resistor RA5 are respectively connected with the other end of the resistor SR15, and the cathode of the diode SD9, the other end of the resistor RA1, the other end of the resistor RA2, the other end of the resistor RA3, the other end of the resistor RA4 and the other end of the resistor RA5 are all grounded.
The embodiment of the utility model provides a be applied to dimming circuit that TV is shaded, its beneficial effect as follows:
when the dimming circuit of the utility model is used, the main control chip or the PWM dimmer supplies dimming signals from the PWM dimming signal input end on the left side, and the FB pin connected with the backlight driving chip is output from the upper right corner; through promptly the utility model discloses a TV dimmer circuit in a poor light no matter drive chip whether compatible dimming function in a poor light, whether compatible wide enough the adjusting luminance PWM frequency can both easily realize the regulation of TV backlight current.
Drawings
Fig. 1 is a schematic diagram of a dimming circuit applied to a TV backlight according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a backlight output circuit according to an embodiment of the present invention.
Detailed Description
In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.
Example 1:
referring to fig. 1-2 specifically, an embodiment of the present invention provides a light modulation circuit applied to TV backlight, which specifically includes:
a triode Q1, the emitting electrode of which is grounded; the resistor R3 is connected with the collector of the triode Q1, and the other end of the resistor R3 is connected with VCC voltage; the resistor R4 is also connected with the collector of the triode Q1, the other end of the resistor R4 is connected with the anode of the diode D1 through the resistor R5, and the other end of the resistor R4 is also grounded through the capacitor C2; the base electrode of the triode Q1 is used for inputting a PWM dimming signal; and the cathode of the diode D1 is used for connecting the FB pin of the backlight driving chip.
Preferably, the base of the triode Q1 is connected to a resistor R1 and a capacitor C1, respectively, and the other end of the resistor R1 is used for inputting the PWM dimming signal, and the other end of the capacitor C1 is grounded. Namely, the R1 and the C1 are combined to form RC filtering which is used for filtering noise waves in a PWM light modulator or a light modulation signal, so that the circuit works more stably.
Preferably, the base of the triode Q1 is further connected with a resistor R6, and the other end of the resistor R6 is grounded. Namely, R6 plays a protection role to prevent the PWM input end from being suspended in the air in work and causing Q1 to be damaged.
During actual use, the base of the triode Q1 is connected with a main control chip or a PWM light modulator, and the main control chip or the PWM light modulator is used for generating PWM light modulation signals. That is, referring to fig. 1, the main control chip or PWM dimmer supplies the dimming signal from the left PWM dimming signal input terminal, and outputs the FB pin connected to the backlight driving chip from the upper right corner.
It should be noted that Q1 functions as a switch, when the base is at a high level, the base and the emitter are turned on, and the collector is at a low level; when the base electrode is at a low level, the base electrode and the emitter electrode are cut off, and the collector electrode is at a high level.
Example 2:
based on the same inventive concept, and on the basis of the above light modulation circuit, the utility model also provides a TV backlight power supply circuit, specifically includes: the dimming circuit, the master control chip or the PWM dimmer connected with the input end of the dimming circuit, the backlight driving chip connected with the output end of the dimming circuit and the backlight output circuit.
The backlight output circuit includes: the resistor SR15 and the capacitor SC6 are respectively connected with the output end of the dimming circuit; the other end of the resistor SR15 is connected with the reference voltage of 0.4V, and the other end of the capacitor SC6 is grounded; the backlight output circuit further includes: the other end of the resistor SR15 is connected with the anode of the diode SD9, the resistor RA1, the resistor RA2, the resistor RA3, the resistor RA4 and the resistor RA5, and the cathode of the diode SD9, the other end of the resistor RA1, the other end of the resistor RA2, the other end of the resistor RA3, the other end of the resistor RA4 and the other end of the resistor RA5 are all grounded.
The utility model discloses a theory of operation:
when Q1 is turned off, VCC voltage flows through resistors R3, R4 and R5 and then flows through current detection resistor SR15 in FIG. 2 to ground, and the internal voltage of FB pin of backlight driving chip is constant0.4V; that is, when Q1 is turned off, a current flows through SR15, and a voltage V is generated at the end of SR15 close to the FB pin SR15 The backlight driving chip detects V through FB SR15 And comparing with the internal reference of 0.4V to further adjust the driving duty ratio output by the backlight driving chip so as to achieve the purpose of adjusting the output current.
When the cathode of the diode D1 is connected to the FB pin of the backlight driving chip, the FB pin is further connected to a backlight output circuit, specifically referring to fig. 2, that is, the FB pin is further connected to a resistor SR15 and a capacitor SC6, respectively, the other end of the resistor SR15 is connected to a reference voltage, and the other end of the capacitor SC6 is grounded; the other end of the resistor SR15 is also connected with the anode of the diode SD9, the resistor RA1, the resistor RA2, the resistor RA3, the resistor RA4 and the resistor RA5 respectively, and the cathode of the diode SD9, the other end of the resistor RA1, the other end of the resistor RA2, the other end of the resistor RA3, the other end of the resistor RA4 and the other end of the resistor RA5 are all grounded.
In summary, by using the backlight dimming circuit provided by the present invention, even if the backlight driving chip selects a chip without dimming function, the dimming function can be realized; even if one high frequency compatible with the backlight driving chip and dimming frequency of 5KHZ-50KHZ and the other low frequency compatible with 200HZ-1KHZ are selected, the PWM dimming input frequency is 300HZ, and due to the adoption of the dimming circuit, the dimming function can be easily realized by the two types of circuits.
The above examples only represent some embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (10)
1. A dimming circuit for a TV backlight, comprising:
a triode Q1, the emitting electrode of which is grounded; the resistor R3 is connected with the collector of the triode Q1, and the other end of the resistor R3 is connected with VCC voltage; the resistor R4 is also connected with the collector of the triode Q1, the other end of the resistor R4 is connected with the anode of the diode D1 through a resistor R5, and the other end of the resistor R4 is also grounded through a capacitor C2;
the base electrode of the triode Q1 is used for inputting a PWM dimming signal; and the cathode of the diode D1 is used for being connected with the FB pin of the backlight driving chip.
2. A dimming circuit applied to a TV backlight as claimed in claim 1, wherein a resistor R1 and a capacitor C1 are respectively connected to the base of the transistor Q1, and the other end of the resistor R1 is used for inputting a PWM dimming signal and the other end of the capacitor C1 is grounded.
3. A dimming circuit applied to a TV backlight as claimed in claim 2, wherein a resistor R6 is further connected to the base of the transistor Q1, and the other end of the resistor R6 is grounded.
4. A dimming circuit as claimed in claim 1, 2 or 3, wherein the base of the transistor Q1 is connected to a main control chip or a PWM dimmer, and the main control chip or the PWM dimmer is used for generating a PWM dimming signal.
5. The dimming circuit applied to a TV backlight according to claim 1,
when the cathode of the diode D1 is connected to the FB pin of the backlight driving chip,
the FB pin is further connected with a resistor SR15 and a capacitor SC6 respectively, the other end of the resistor SR15 is connected with a reference voltage, and the other end of the capacitor SC6 is grounded.
6. The dimming circuit applied to a TV backlight according to claim 5, wherein the other end of the resistor SR15 is further connected to an anode of a diode SD9, a resistor RA1, a resistor RA2, a resistor RA3, a resistor RA4, and a resistor RA5, respectively, and a cathode of the diode SD9, the other end of the resistor RA1, the other end of the resistor RA2, the other end of the resistor RA3, the other end of the resistor RA4, and the other end of the resistor RA5 are all grounded.
7. A dimming circuit applied to a TV backlight, according to claim 5 or 6, wherein the reference voltage takes 0.4V.
8. A TV backlight power supply circuit, comprising: the dimming circuit of any one of claims 1-4, a main control chip or PWM dimmer connected to an input of the dimming circuit, a backlight driver chip connected to an output of the dimming circuit, and a backlight output circuit.
9. A TV backlight power supply circuit as claimed in claim 8, wherein the backlight output circuit comprises: the resistor SR15 and the capacitor SC6 are respectively connected with the output end of the dimming circuit; the other end of the resistor SR15 is connected with the reference voltage of 0.4V, and the other end of the capacitor SC6 is grounded.
10. A TV backlight power supply circuit as claimed in claim 9, wherein the backlight output circuit further comprises: the anode of the diode SD9, the resistor RA1, the resistor RA2, the resistor RA3, the resistor RA4 and the resistor RA5 are respectively connected with the other end of the resistor SR15, and the cathode of the diode SD9, the other end of the resistor RA1, the other end of the resistor RA2, the other end of the resistor RA3, the other end of the resistor RA4 and the other end of the resistor RA5 are all grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221626721.XU CN217788005U (en) | 2022-06-27 | 2022-06-27 | Dimming circuit applied to TV backlight and TV backlight power supply circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221626721.XU CN217788005U (en) | 2022-06-27 | 2022-06-27 | Dimming circuit applied to TV backlight and TV backlight power supply circuit |
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| Publication Number | Publication Date |
|---|---|
| CN217788005U true CN217788005U (en) | 2022-11-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221626721.XU Active CN217788005U (en) | 2022-06-27 | 2022-06-27 | Dimming circuit applied to TV backlight and TV backlight power supply circuit |
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| Country | Link |
|---|---|
| CN (1) | CN217788005U (en) |
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- 2022-06-27 CN CN202221626721.XU patent/CN217788005U/en active Active
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