Zumtobel Group has been granted a patent for an isolated primary side switched converter for LED drivers. The converter includes a galvanic isolation stage, a rectification circuit, and a decoupling circuit to reduce voltage fluctuations. The driver also features a controller, output current sensing unit, and communications interface. GlobalData’s report on Zumtobel Group gives a 360-degree view of the company including its patenting strategy. Buy the report here.
According to GlobalData’s company profile on Zumtobel Group, Pipeline inspection robots was a key innovation area identified from patents. Zumtobel Group's grant share as of September 2023 was 58%. Grant share is based on the ratio of number of grants to total number of patents.
Isolated primary side switched converter for led driver
A recently granted patent (Publication Number: US11765802B2) describes an LED driver with an isolated primary side switched converter. The converter includes a galvanic isolation stage that separates the primary side and the secondary side of the converter. The secondary side winding of the isolation stage is coupled to a primary side winding and includes a center tap. The LED driver also includes a rectification circuit on the secondary side, which sets the first terminal at a first electrical polarity and the second and third terminals at a second electrical polarity that is different from the first. The third terminal is electrically connected to the center tap.
To reduce voltage fluctuations, the LED driver includes a decoupling circuit comprising two capacitors. The first capacitor is in parallel with the second and third terminals, while the second capacitor is in parallel with the first and third terminals. The first capacitor and the second capacitor are in series with each other and in parallel with the first and second terminals. The voltage between the second and first terminals is larger than the voltage between the third terminal and the first terminal, as well as the voltage between the second terminal and the third terminal.
The LED driver further includes a controller, an output current sensing unit, and a communications interface connected to the controller. The secondary side winding of the isolation stage does not have any further tapping besides the center tap. The first and second capacitors in the decoupling circuit have the same capacitance.
The rectification circuit in the LED driver can be a center tap rectifier, a full wave bridge rectifier, or four diodes or switches. The isolated primary side switched converter in the LED driver can be a resonant half bridge LLC converter.
Overall, this patent describes an LED driver with an isolated primary side switched converter that includes a decoupling circuit to reduce voltage fluctuations. The design allows for efficient and reliable operation of LED loads connected to the secondary side of the converter.