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EP-4742836-A1 - MULTI-COLOR LED MIXED COLOR BALANCE CALIBRATION CIRCUIT

EP4742836A1EP 4742836 A1EP4742836 A1EP 4742836A1EP-4742836-A1

Abstract

The disclosure relates to a circuit for multi-color LED mixed color balance calibration, the circuit including: an LED loop including one or more LED channels with different colors, each of the one or more LED channels with different colors includes one or more LEDs with a same color and an LED switch; an LED junction configured to be connected to the one or more LED channels with different colors; a voltage divider resistor configured to be connected between the LED junction and a color calibration switch; the color calibration switch configured to enable or disable color calibration based on a received color calibration enable signal; and a microprocessor configured to: generate a color calibration enable signal, measure a first voltage, based on the generated color calibration enable signal, and adjust a mixed color output by the LED loop based on the measured first voltage.

Inventors

  • FEI, WEIHE

Assignees

  • SCHNEIDER ELECTRIC INDUSTRIES SAS

Dates

Publication Date
20260513
Application Date
20251105

Claims (11)

  1. A circuit for multi-color light-emitting diode (LED) mixed color balance calibration (100), the circuit comprising: an LED loop (101) comprising one or more LED channels with different colors, each of the one or more LED channels with different colors comprises one or more LEDs with a same color and an LED switch; an LED junction (102) configured to be connected to the one or more LED channels with different colors; a voltage divider resistor (103) configured to be connected between the LED junction (102) and a color calibration switch (104); the color calibration switch (104) configured to enable or disable color calibration based on a received color calibration enable signal; and a microprocessor (105) configured to: generate a color calibration enable signal, measure, based on the generated color calibration enable signal, a first voltage at the LED junction (102) when each of the one or more LED channels with different colors is individually turned on, and adjust a mixed color output by the LED loop (101) based on the measured first voltage.
  2. The circuit (100) according to claim 1, wherein, the microprocessor (105) is configured to, send a turn-on signal for the LED switch corresponding to the one or more LED channels with different colors to the LED loop (101), based on the color calibration enable signal.
  3. The circuit (100) according to claim 1, wherein, the microprocessor (105) is configured to adjust, based on the measured first voltage when each of the one or more LED channels with different colors is individually turned on, a turn-on pulse width of a turn-on signal for the LED switch corresponding to the one or more LED channels with different colors.
  4. The circuit (100) according to claim 1, wherein, when the received color calibration enable signal is at a high level, the color calibration switch (104) enables color calibration.
  5. The circuit (100) according to claim 1, wherein, the microprocessor (105) is further configured to determine, according to the color calibration enable signal, whether an LED short-circuit occurs in each of the one or more LED channels with different colors, based on the first voltage at the LED junction (102) when each of the one or more LED channels with different colors is individually turned on, to turn off the LED switch corresponding to the LED channel determined to have an LED short circuit.
  6. The circuit (100) according to claim 1, wherein, the LED loop (101) comprises N LED channels with different colors, wherein N is an integer greater than or equal to 2.
  7. The circuit (100) according to claim 1, wherein, each of the one or more LED channels with different colors further comprises one or more LED series resistors connected to a corresponding one of one or more LED with different colors.
  8. The circuit (100) according to claim 1, wherein, the LED switch corresponding to the one or more LED channels with different colors is a metal oxide semiconductor field effect transistor (MOSFET), and a gate of a corresponding LED switch receives a turn-on signal for the LED switch corresponding to the one or more LED channels with different colors from the microprocessor (105).
  9. The circuit (100) according to claim 1, wherein the circuit further comprises: an LED short-circuit protection switch configured to be connected to the LED junction (102), and an LED short-circuit detection module configured to be connected to the LED junction (102) and the LED short-circuit protection switch, measure a second voltage at the LED junction (102) based on the received color calibration enable signal, and determine whether an LED short-circuit occurs to turn off or turn on the LED short-circuit protection switch based on the measured second voltage.
  10. The circuit (100) according to claim 9, wherein, the LED short-circuit protection switch is configured to be turned on when the received color calibration enable signal is at a low level, and the LED short-circuit detection module measures the second voltage at the LED junction (102).
  11. An electronic device comprising: a regulated power supply module, and a circuit (100) according to any one of the preceding claims, which is configured to be connected to the regulated power supply module.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based on and claims priority to Chinese Patent Application No. 202411585421.5, filed on November 7, 2024 in the Chinese Patent Office, the contents of which being herein incorporated by reference in its entirety. TECHNICAL FIELD The disclosure relates to multi-color LED color mixing technology, in particular to a circuit for multi-color LED mixed color balance calibration. BACKGROUND Light-emitting diode (LED) is a light source with high energy efficiency, high brightness and small volume, which is widely used in electrical equipment, displays and lighting systems. In the application scenario where LED is used as the backlight of the display, multi-color LED such as RGB can be used as the light source, and the backlight can show various color effects through mixed color driving to achieve color indication with specific meaning. In the design of multi-color backlight LED of display, in order to keep the mixed colors consistent between each display backlight, it is necessary to consider the color balance compensation in the backlight driving design. In addition, how to use LED safely is an important topic of LED driving technology. Short-circuit fault sometimes occurs in the production and use of LED leads, therefore, it is necessary to effectively protect the fault of short-circuit of the LED in the design of LED drive to avoid the burning of LED drive power supply and even the collapse of the whole equipment power supply system. SUMMARY The disclosure provides a circuit for multi-color light-emitting diode (LED) mixed color balance calibration, the circuit comprising: an LED loop comprising one or more LED channels with different colors, each of the one or more LED channels with different colors comprises one or more LEDs with a same color and an LED switch; an LED junction configured to be connected to the one or more LED channels with different colors; a voltage divider resistor configured to be connected between the LED junction and a color calibration switch; the color calibration switch configured to enable or disable color calibration based on a received color calibration enable signal; and a microprocessor configured to: generate a color calibration enable signal, measure, based on the generated color calibration enable signal, a first voltage at the LED junction when each of the one or more LED channels with different colors is individually turned on, and adjust a mixed color output by the LED loop based on the measured first voltage. According to an embodiment of the disclosure, the microprocessor is configured to send a turn-on signal for the LED switch corresponding to the one or more LED channels with different colors to the LED loop based on the color calibration enable signal. According to an embodiment of the disclosure, the microprocessor is configured to adjust, based on the measured first voltage when each of the one or more LED channels with different colors is individually turned on, a turn-on pulse width of the turn-on signal for the LED switch corresponding to the one or more LED channels with different colors. According to an embodiment of the disclosure, when the received color calibration enable signal is at a high level, the color calibration switch enables color calibration. According to the embodiment of the disclosure, the microprocessor is further configured to determine, according to the color calibration enable signal, whether an LED short-circuit occurs in each of the one or more LED channels with different colors, based on the first voltage at the LED junction when each of the one or more LED channels with different colors is individually turned on, to turn off the LED switch corresponding to the LED channel determined to have an LED short circuit. According to the embodiment of the disclosure, the LED loop comprises N LED channels with different colors, wherein N is an integer greater than or equal to 2. According to an embodiment of the disclosure, each of the one or more LED channels with different colors further comprises one or more LED series resistors connected to a corresponding one of one or more LED with different colors. According to an embodiment of the disclosure, the LED switch corresponding to the one or more LED channels with different colors is a metal oxide semiconductor field effect transistor (MOSFET), and a gate of a corresponding LED switch receives a turn-on signal for the LED switch corresponding to the one or more LED channels with different colors from the microprocessor. According to an embodiment of the disclosure, the circuit further comprises an LED short-circuit protection switch configured to be connected to the LED junction, and an LED short-circuit detection module configured to be connected to the LED junction and the LED short-circuit protection switch, measure a second voltage at the LED junction based on the received color calibration enable signal, and determine whether an LED