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LED control device and control method of LED control device

  • US 10,212,772 B2
  • Filed: 01/30/2017
  • Issued: 02/19/2019
  • Est. Priority Date: 01/30/2017
  • Status: Active Grant
First Claim
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1. An LED control device configured to control LED devices, comprising:

  • a first terminal to which a first electrode of a battery is connected, and a first node of a first LED device and a first node of a second LED device are connected;

    a second terminal to which a second electrode of the battery is connected;

    a first switching element connected between a second node of the first LED device and the second terminal to control a current flowing through the first LED device;

    a first detection resistor through which at least a part of a current flowing through the first switching element flows;

    a first integration circuit configured to output a first reference signal obtained by integrating a first PWM light controlling signal defining a dimming ratio of the first LED device;

    a first control unit configured to control an operation of the first switching element by a first control signal based on a relationship between a first reference value obtained from the first reference signal and a first detection voltage value of the first detection resistor;

    a second switching element connected between a second node of the second LED device and the second terminal, and configured to control a current flowing through the second LED device;

    a second detection resistor through which at least a part of a current flowing through the second switching element flows;

    a second integration circuit configured to integrate a second PWM light controlling signal defining a dimming ratio of the second LED device to output a second reference signal; and

    a second control unit configured to control an operation of the second switching element by a second control signal based on a relationship between a second reference value obtained from the second reference signal and a second detection voltage value at the second detection resistor,whereinthe first integration circuit changes the first reference signal to be different from the second reference signal in one cycle of the first PWM light controlling signal, andthe first control unit controls, in the one cycle of the first PWM light controlling signal, the first switching element by the first control signal at a first operational frequency for turning on and off the first switching element, the first operational frequency being different from a second operational frequency for turning on and off the second switching element.

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