US 11,991,797 B2
LED power supply with bi-level dimming and bi-level dimming method
Ching-Ho Chou, Taoyuan (TW); and Yung-Chuan Lu, Taoyuan (TW)
Assigned to DELTA ELECTRONICS, INC., Taoyuan (TW)
Filed by DELTA ELECTRONICS, INC., Taoyuan (TW)
Filed on Jan. 17, 2023, as Appl. No. 18/155,509.
Claims priority of application No. 202211247783.4 (CN), filed on Oct. 12, 2022.
Prior Publication US 2024/0130014 A1, Apr. 18, 2024
Int. Cl. H05B 45/10 (2020.01); H05B 45/3725 (2020.01)
CPC H05B 45/10 (2020.01) [H05B 45/3725 (2020.01)] 9 Claims
OG exemplary drawing
 
1. An LED power supply with bi-level dimming, configured to receive an input voltage to supply power to an LED lamp, and adjust the brightness of the LED lamp according to whether an external detection switch is triggered to be turned on, the LED power supply comprising:
a conversion circuit, configured to convert the input voltage into an output voltage, and provide the output voltage to supply power to the LED lamp through a bus positive end and a bus negative end so as to control the LED lamp to provide a first brightness,
a switch, coupled to the bus positive end or the bus negative end, and
an oscillation circuit, comprising a dimming end and a control end, wherein the control end is coupled to the switch, and the dimming end is coupled to the external detection switch, wherein the oscillation circuit comprises: a first charging/discharging circuit, coupled to the dimming end, a second charging/discharging circuit, coupled to the dimming end and the bus positive end, a first transistor, comprising a first end, a second end, and a control end, the first end of the first transistor coupled to the first charging/discharging circuit, the control end of the first transistor coupled to the second charging/discharging circuit, and the second end of the first transistor coupled to the bus negative end, a second transistor, comprising a first end, a second end, and a control end, the first end of the second transistor coupled to the second charging/discharging circuit and the control end of the oscillation circuit, the control end of the second transistor coupled to the first charging/discharging circuit, and the second end of the second transistor coupled to the bus negative end, and a voltage diving resistor, coupled to the second charging/discharging circuit and the bus negative end,
wherein the oscillation circuit is coupled to the other of the bus positive end and the bus negative end through the dimming end when the external detection switch is turned on so as to provide a dimming signal with a fixed frequency and a duty cycle to the switch through the control end; the switch correspondingly adjusts the output voltage according to the dimming signal to control the LED lamp to provide a second brightness and wherein the external detection switch is triggered to be turned off, the switch is turned on by a divided voltage generated between the second charging/discharging circuit and the voltage dividing resistor according to the output voltage.