US 11,930,574 B2
Drive circuit for a light-emitting diode light source
Stuart W. DeJonge, Riegelsville, PA (US); and Robert C. Newman, Jr., Emmaus, PA (US)
Assigned to Lutron Technology Company LLC, Coopersburg, PA (US)
Filed by Lutron Technology Company LLC, Coopersburg, PA (US)
Filed on May 23, 2022, as Appl. No. 17/750,647.
Application 17/750,647 is a continuation of application No. 17/134,945, filed on Dec. 28, 2020, granted, now 11,343,894.
Application 17/134,945 is a continuation of application No. 16/557,179, filed on Aug. 30, 2019, granted, now 10,904,976, issued on Jan. 26, 2021.
Claims priority of provisional application 62/725,467, filed on Aug. 31, 2018.
Prior Publication US 2022/0279637 A1, Sep. 1, 2022
Int. Cl. H05B 33/08 (2020.01); H03K 7/08 (2006.01); H05B 45/40 (2020.01); H05B 47/19 (2020.01); H05B 45/20 (2020.01)
CPC H05B 45/40 (2020.01) [H03K 7/08 (2013.01); H05B 47/19 (2020.01); H05B 45/20 (2020.01)] 23 Claims
OG exemplary drawing
 
1. A drive circuit for a light-emitting diode (LED) light source, comprising:
a controllable impedance circuit configured to conduct a load current through the LED light source;
a first switching device connected in series with the controllable impedance circuit and responsive to a pulse-width modulated (PWM) signal;
a feedback circuit configured to generate a feedback signal indicative of a magnitude of the load current conducted through the LED light source;
a control loop circuit coupled to the feedback circuit and configured to generate a drive signal for controlling the controllable impedance circuit in response to a target-current control signal and the feedback signal, the control loop circuit comprising a second switching device, the second switching device capable of being rendered conductive and non-conductive in response to a switch control signal to control when the feedback signal is used to generate the drive signal, the control loop circuit configured to adjust a peak magnitude of the load current conducted through the LED light source toward a target magnitude based on the target-current control signal;
wherein the first switching device is rendered conductive and non-conductive in response to the PWM signal and a duty cycle of the PWM signal is adjusted to adjust an average magnitude of the load current, and wherein the second switching device is rendered conductive and non-conductive in response to the switch control signal in coordination with the PWM signal.