US 12,133,306 B2
Lamp driver with over voltage protection
Tijmen Cornelis Van Bodegraven, Eindhoven (NL); and Reinhold Elferich, Eindhoven (NL)
Assigned to SIGNIFY HOLDING B.V., Eindhoven (NL)
Appl. No. 17/919,544
Filed by SIGNIFY HOLDING B.V., Eindhoven (NL)
PCT Filed Apr. 22, 2021, PCT No. PCT/EP2021/060492
§ 371(c)(1), (2) Date Oct. 18, 2022,
PCT Pub. No. WO2021/219477, PCT Pub. Date Nov. 4, 2021.
Claims priority of application No. 20171738 (EP), filed on Apr. 28, 2020.
Prior Publication US 2023/0164898 A1, May 25, 2023
Int. Cl. H05B 45/30 (2020.01); H05B 45/382 (2020.01); H05B 45/50 (2022.01); H05B 47/24 (2020.01)
CPC H05B 45/50 (2020.01) [H05B 45/382 (2020.01); H05B 47/24 (2020.01)] 20 Claims
OG exemplary drawing
 
1. A lamp driver comprising:
a primary side circuit;
a secondary side circuit isolated from the primary side circuit for delivering an output voltage and output current to an LED lamp load; and
an isolating feedback unit for providing a feedback signal from the secondary side circuit to the primary side circuit;
an isolated driver circuit in the form of a transformer-based switch mode power converter, the isolated driver circuit comprising:
a primary side in the primary side circuit, a secondary side in the secondary side circuit and having a current regulation mode and a voltage regulation mode,
wherein the secondary side circuit comprises:
a current regulating circuit comprising a current sensor for sensing the output current wherein the current regulating circuit is for providing the feedback signal based on the sensed output current;
an overvoltage protection circuit for detecting an overvoltage condition of the output voltage and arranged to adapt the feedback signal to provide voltage control during the overvoltage condition; and
a modulator for modulating the feedback signal during detection of the overvoltage condition,
wherein the primary side circuit comprises:
a controller which is adapted to recognize the overvoltage condition based on a modulation of the output voltage during an overvoltage protection mode,
wherein the overvoltage protection circuit comprises a resistive divider connected to the output voltage and an overvoltage comparator circuit for comparing an output of the resistive divider with a reference voltage representing a maximum output voltage, and
wherein the overvoltage protection circuit comprises a shorting switch for selectively shorting a resistor of the resistive divider, thereby changing an input to the overvoltage comparator circuit, wherein the shorting switch is controlled by the modulator.