LED lighting systems and methods for constant current control in various operation modes

• US 10,548,195 B2
• Filed: 03/20/2019
• Issued: 01/28/2020
• Est. Priority Date: 11/15/2011
• Status: Active Grant

• Current Assignee: On-Bright Electronics (Shanghai) Co., Ltd. (Orthosie Investment Holdings Ltd.)
• Original Assignee: On-Bright Electronics (Shanghai) Co., Ltd. (Orthosie Investment Holdings Ltd.)
• Inventors: Fang, Lieyi, Zhou, Jun
• Primary Examiner(s): A, Minh D
• Assistant Examiner(s): Cho, James H
• Application Number:
  US16/359,912
• Publication Number:
  US 20190327811A1
• Time in Patent Office: 314 Days
• Field of Search: None
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

System and method for providing at least an output current to one or more light emitting diodes. The system includes a control component configured to receive at least a demagnetization signal, a sensed signal and a reference signal and to generate a control signal based on at least information associated with the demagnetization signal, the sensed signal and the reference signal, and a logic and driving component configured to receive at least the control signal and output a drive signal to a switch based on at least information associated with the control signal. The switch is connected to a first diode terminal of a diode and a first inductor terminal of an inductor. The diode further includes a second diode terminal, and the inductor further includes a second inductor terminal.

Claims

1. A system for providing at least an output current to one or more light emitting diodes, the system comprising:

a transconductance amplifier configured to receive a sensed signal and also receive a predetermined voltage signal through a first switch, the sensed signal being associated with an inductor current flowing through an inductor coupled to a second switch, the transconductance amplifier being further configured to generate a current signal;

a capacitor coupled to the transconductance amplifier and configured to generate a voltage signal;

a comparator configured to process information associated with the voltage signal and the sensed signal and generate a comparison signal based on at least information associated with the voltage signal and the sensed signal;

a modulation-signal generator configured to receive at least the comparison signal and generate a modulation signal; and

a gate driver configured to receive the modulation signal and output a drive signal to the second switch;

wherein;

the drive signal is associated with at least one or more switching periods, each of the one or more switching periods including at least an on-time period for the second switch;

the transconductance amplifier is further configured to, for each of the one or more switching periods, receive at least a predetermined voltage signal only during the on-time period; and

the current signal is configured to charge or discharge the capacitor.

2. The system of claim 1 wherein:

the transconductance amplifier, the comparator, the modulation-signal generator, and the gate driver are located on a chip; and

the capacitor is located off the chip.

3. The system of claim 1 is configured to regulate an output current at a predetermined constant level in a continuous conduction mode and a critical conduction mode.

4. The system of claim 1 is configured to regulate an output current at a predetermined constant level in a continuous conduction mode.

5. The system of claim 1 is configured to regulate an output current at a predetermined constant level in a critical conduction mode.

6. A method for providing at least an output current to one or more light emitting diodes, the method comprising:

receiving at least a sensed signal, the sensed signal being associated with an inductor current flowing through an inductor coupled to a switch;

processing information associated with the sensed signal and a predetermined voltage signal;

generating a current signal based on at least information associated with the sensed signal and the predetermined voltage signal;

processing information associated with the current signal;

generating a voltage signal, by at least a capacitor, based on at least information associated with the current signal;

processing information associated with the voltage signal and the sensed signal;

generating a comparison signal based on at least information associated with the voltage signal and the sensed signal;

receiving at least the comparison signal;

generating a modulation signal based on at least information associated with the comparison signal;

receiving the modulation signal; and

outputting a drive signal based on at least information associated with the modulation signal;

wherein;

the drive signal is associated with at least one or more switching periods, each of the one or more switching periods including at least an on-time period; and

the process for receiving at least a sensed signal includes, for each of the one or more switching periods, receiving at least the predetermined voltage signal during only the on-time period;

wherein the process for processing information associated with the current signal includes charging or discharging the capacitor with the current signal.