CN212573037U

CN212573037U - Multi-path load circuit with common anode output

Info

Publication number: CN212573037U
Application number: CN202021370981.6U
Authority: CN
Inventors: 吴涛; 徐立平; 应战标
Original assignee: Shenzhen Zhongkeyuan Electronics Co ltd
Current assignee: Shenzhen Zhongkeyuan Electronics Co ltd
Priority date: 2020-07-14
Filing date: 2020-07-14
Publication date: 2021-02-19
Anticipated expiration: 2030-07-14

Abstract

The utility model relates to a drive power supply load technical field, specifically speaking relates to a multichannel load circuit of anodal output altogether. The LED lamp comprises a Local Dimming power circuit and a lamp bead load circuit, wherein the Local Dimming power circuit is used for adjusting Local backlight of a display screen; the lamp bead load circuit is used for providing a path for detecting output voltage of a Local Dimming power supply before starting for the load of the Local Dimming, and normal starting is ensured. The utility model discloses a design is realized realizing maximum quantity scope lamp pearl continuously adjustable with minimum switch, very big improvement use the flexibility, simultaneously, has effectively avoidd the EMC problem that the electric potential reversal arouses, has ensured the normal work of load.

Description

Multi-path load circuit with common anode output

Technical Field

The utility model relates to a drive power supply load technical field, specifically speaking relates to a multichannel load circuit of anodal output altogether.

Background

With the use of liquid crystal televisions and displays becoming more and more widespread, it is more and more important to reduce the power consumption of the backlight source. Local Dimming (Local backlight adjustment) technology not only improves display contrast, but also has an obvious energy-saving effect, and is a trend of future development. The Local Dimming power supply is greatly different from the conventional power supply in output characteristics, and the load of the Local Dimming power supply is not directly connected between the positive and negative output of the power supply, but is connected in series with a switching tube and then connected to the ground, so that the conventional electronic load and feedback load cannot be applied in the manufacturing aging process, and a novel load must be introduced. The utility model discloses ageing to Local Dimming power provides one kind and uses more nimble, the interference killing feature is stronger, work more steady load.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a be anodal output's multichannel load circuit altogether to solve the problem that proposes among the above-mentioned background art.

In order to achieve the above object, the present invention provides a multi-path load circuit with common positive output, which includes a Local Dimming power circuit and a lamp bead load circuit, wherein the Local Dimming power circuit is used for adjusting the Local backlight of the display screen; the lamp bead load circuit is used for providing a path for a Local Dimming load and detecting output voltage of a Local Dimming power supply before starting, so that normal starting is ensured;

the lamp bead load circuit comprises a plurality of switches K and lamp bead LEDs connected with the switches K in parallel, when a certain lamp bead LED is required to be used as a load, the switch K connected with the certain lamp bead LED in parallel correspondingly is switched off, current flows through the lamp bead LED, when the switch K corresponding to the certain lamp bead LED is not required to be switched on, the current passes through the switch K and bypasses the lamp bead LED;

local Dimming power supply circuit includes controller MCU, controller MCU connects lamp pearl load circuit.

As a further improvement of the technical scheme, the number of the switches K connected with the lamp beads in parallel and the LEDs connected in series is different.

For convenience of explanation, switches K used in the circuit are sequentially named as K1 and K2 … … Kn, lamp bead LEDs are also sequentially named as LED1 and LED2 … … LEDn, and the number of the switches Ki (i is a naming serial number) corresponding to the number of the parallel lamp bead LEDs is 2^(i-1)Corresponding to the serial number of the parallel lamp bead LED naming is from 2^(i-1)To 2⁽ⁱ⁾-1, the circuit uses K1, K2 … … Kn, N switches, and 1+2+ … +2 in total^(n-1)＝2⁽ⁿ⁾Individual lamp pearl LED can realize continuous adjustable: 0 to 2⁽ⁿ⁾And the series connection of any number of lamp bead LEDs in the lamp bead structure greatly improves the application flexibility.

As a further improvement of the technical scheme, the controller MCU is connected to the lamp bead load circuit through a switching tube Q1 working in a linear region, the controller MCU is connected to Vout-through a current sampling resistor R1, when the controller MCU starts working, the number of lamp bead LEDs connected in series by a load is set according to the output voltage Vout of a Local Dimming power supply, and the rated voltage of the lamp bead LEDs subtracted from Vout is controlled within the range of 1-3V.

As a further improvement of the present technical solution, the method for controlling the current of the current sampling resistor R1 by the controller MCU is to adjust the duty ratio driven by the switching transistor Q1 or adjust the level driven by the switching transistor Q1.

As a further improvement of the technical scheme, the controller MCU is controllably connected to Vout +, Vout + passes through the current sampling resistor R1 and then is connected to the lamp bead LED load, and the current sampling resistor R1 is arranged at the position, so that the current sampling circuit can be connected to the MCU without isolation, and meanwhile, no alternating potential exists, the precision of the current sampling circuit is improved, and the normal operation is guaranteed.

Compared with the prior art, the beneficial effects of the utility model are that:

1. in the multi-path load circuit with common anode output, the load which is simulated as Local Dimming through the serially connected LED lamp beads is used, the actual application scene of a Local Dimming power supply is practically reproduced, and the normal work of the power supply after leaving a factory is effectively guaranteed.

2. In the multi-path load circuit with common anode output, voltage regulation is carried out by switching the quantity of lamp beads connected in series in parallel through the switches, innovative application switches correspond to the quantity of the lamp beads connected in parallel, the maximum quantity range of the lamp beads is continuously adjustable by using the minimum switches, and application flexibility is greatly improved.

3. In the multi-path load circuit with the common anode output, the control ground GND of the load is placed at Vout +, so that the EMC problem caused by potential alternation is effectively avoided, and the normal work of the load is guaranteed.

Drawings

Fig. 1 is a lamp bead load circuit working schematic diagram of embodiment 1;

FIG. 2 is a circuit principle of the Local Dimming power supply and the lamp bead load of embodiment 1 in a matching application;

FIG. 3 is an overall circuit operation diagram of embodiment 1;

fig. 4 is an impedance characteristic diagram of the LED lamp bead of embodiment 1.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Example 1

Referring to fig. 1-4, the present embodiment provides a multi-path load circuit with common positive output, which includes a Local Dimming power circuit and a bead load circuit, where the Local Dimming power circuit is used to adjust Local backlight of a display screen; the lamp bead load circuit is used for providing a path for a Local Dimming load and detecting output voltage before starting of a Local Dimming power supply, so that normal starting is ensured;

the lamp bead load circuit comprises a plurality of switches K and lamp bead LEDs connected with the switches K in parallel, when a certain lamp bead LED is required to be loaded, the corresponding switch K connected in parallel is switched off, current flows through the lamp bead LED, when the certain lamp bead LED is not required, the corresponding switch K is switched on, and the current passes through the switch K and bypasses the lamp bead LED;

local Dimming power supply circuit includes controller MCU, and controller MCU connects lamp pearl load circuit.

In the embodiment, the load serving as the Local Dimming is simulated by serially connecting the lamp bead LEDs, so that a path is provided for detecting the output voltage of the Local Dimming power supply before starting, and normal starting is ensured; the quantity of lamp pearl LED series connection is switched through switch K, realizes the Local Dimming power of adaptation different output voltage types.

Specifically, the LED lamp beads have the same impedance characteristic as that of the liquid crystal display screen and the liquid crystal television, as shown in fig. 4, the same impedance characteristic actually reproduces the actual application scene of a Local Dimming power supply, effectively ensures that the power supply after leaving a factory normally works, screens out defective products in the factory in advance, is low in price, and can radiate heat through a surface-mounted aluminum substrate without high investment cost.

For the Local Dimming power supply that same load adapts to different output voltage, this embodiment switches the quantity that lamp pearl LED establishes ties through switch K and carries out voltage control, and the quantity that every switch K connects lamp pearl LED in parallel establishes ties is different.

For convenience of explanation, switches K used in the circuit are sequentially named as K1 and K2 … … Kn, lamp bead LEDs are also sequentially named as LED1 and LED2 … … LEDn, and the number of the switches Ki (i is a naming serial number) corresponding to the number of the parallel lamp bead LEDs is 2^(i-1)Corresponding to the serial number of the parallel lamp bead LED naming is from 2^(i-1)To 2⁽ⁱ⁾1, as shown in fig. 1, the circuit uses K1, K2 … … Kn, N switches, and 1+2+ … +2 in total^(n-1)＝2⁽ⁿ⁾Individual lamp pearl LED can realize continuous adjustable: 0 to 2⁽ⁿ⁾And the series connection of any number of lamp bead LEDs in the lamp bead structure greatly improves the application flexibility.

The circuit principle of the matched application of the Local Dimming power circuit and the lamp bead load circuit is shown in fig. 2, the controller MCU is connected to the lamp bead load circuit through a switching tube Q1 working in a linear region, the controller MCU is connected to Vout-through a current sampling resistor R1, when the work is started, according to the output voltage Vout of the Local Dimming power supply, the number of lamp bead LEDs connected in series by a load is set, and the rated voltage of the lamp bead LEDs subtracted from the Vout is controlled within the range of 1-3V.

Further, the method for controlling the current flowing through the current sampling resistor R1 by the controller MCU is to adjust the duty ratio of the driving of the switching transistor Q1 or adjust the level of the driving of the switching transistor Q1.

Wherein, when the duty ratio driven by the regulating switch tube Q1, the potential of Load-in the circuit is in an alternating state, and when Q1 is switched on, the potential of Load-is approximately zero Vout-.

When Q1 is turned off, the potential of Load-is approximately Vout +, the normal Load is placed on Load-in a controlled manner, EMC problems can be generated, and the Load is abnormal, the Load is placed on Load + in a controlled manner, the potential of the Load is constant at Vout +, and the Load cannot alternate, and the normal work of the Load is guaranteed.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the description in the above embodiments and the description is only preferred examples of the present invention, and is not intended to limit the present invention, and that the present invention can have various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications all fall into the scope of the claimed invention. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A multi-path load circuit with common anode output is characterized by comprising a Local Dimming power circuit and a lamp bead load circuit, wherein the Local Dimming power circuit is used for adjusting Local backlight of a display screen; the lamp bead load circuit is used for providing a path for a Local Dimming load and detecting output voltage of a Local Dimming power supply before starting, so that normal starting is ensured;

the lamp bead load circuit comprises a plurality of switches K and lamp bead LEDs connected with the switches K in parallel;

2. A common positive output multi-load circuit as claimed in claim 1, wherein: and the number of the switch K parallel lamp beads connected in series is different.

3. A common positive output multi-load circuit as claimed in claim 1, wherein: the controller MCU is connected to a lamp bead load circuit through a switching tube Q1 working in a linear region, and the controller MCU is connected to a Vout-through a current sampling resistor R1.

4. A multi-load circuit with common positive output according to claim 3, wherein: the method for controlling the current of the current sampling resistor R1 by the controller MCU is to adjust the duty ratio driven by the switching tube Q1 or adjust the level driven by the switching tube Q1.

5. A common positive output multi-load circuit as claimed in claim 1, wherein: the controller MCU is controllably connected to Vout +, Vout + and connected to the lamp bead load circuit through the current sampling resistor R1.