Lighting assembly

Patent metadata

Field	Value
Publication number	US-12520402-B2
Application number	US-202218714288-A
Country	US
Kind code	B2
Filing date	Dec 1, 2022
Priority date	Dec 7, 2021
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

A lighting assembly comprises a first lighting arrangement with a first lighting unit board and a first switched mode driving unit and a second lighting arrangement with a second lighting unit board and a second switched mode driving unit. A parasitic capacitance is present between the first and second lighting unit boards. The switched mode driving units switches voltages on the lighting arrangements and said voltages generates a differential voltage across the parasitic capacitance and leads to a leakage current. A blocking arrangement is in a path between the first and second lighting arrangements and it blocks the leakage current flowing at least from one of the first and second lighting arrangements to the other of the first and second lighting arrangements via the parasitic capacitance due to the differential voltage between the driving units. In this way, disturbances to the current regulation function in one of the driving units, caused by a parasitic current flow from the other driving unit, is prevented.

First claim

The invention claimed is:

1 . A lighting assembly comprising:
a first lighting arrangement comprising a first lighting unit board for mounting first lighting units, a first switched mode driving unit for driving the first lighting units, and a first point, wherein the first switched mode driving unit is adapted to switch, at a particular moment, a first voltage potential to the first point; a second lighting arrangement comprising a second lighting unit board for mounting second lighting units, a second switched mode driving unit, different from the first switched mode driving unit, for driving the second lighting units and a second point coupled with the second switched mode driving unit, wherein the second switched mode driving unit is adapted to switch, at the particular moment, a second voltage potential lower than the first voltage potential, by a differential voltage, to the second point, a parasitic capacitance present between the first point and the second point; and a blocking arrangement coupled in a path between the first point and the second point wherein the blocking arrangement is configured for blocking a current flowing from the first point of the first lighting arrangement to the second point of the second lighting arrangement via the parasitic capacitance which current is due to the differential voltage.

2 . The lighting assembly of claim 1 , wherein the blocking arrangement is configured for blocking a current flowing from the first lighting unit board to the second switched mode driving unit,
the capacitance of the parasitic capacitance is between 1 nF and 100 nF, the blocking arrangement is configured for blocking the current flowing from the first point of the first lighting arrangement into the second switched mode driving unit via the parasitic capacitance, wherein the current is in a current loop different from a current loop flowing from a power input to the second switched mode driving unit, or is not monitored by the second switched mode driving unit.

3 . The lighting assembly of claim 1 , wherein switching of the first and second switched mode driving units is asynchronized in switching different voltages on the first point and the second point at the same particular moment.

4 . The lighting assembly of claim 3 , wherein the first point is coupled to an anode position of the parasitic capacitance, and the second point is coupled to a cathode position of the parasitic capacitance.

5 . The lighting assembly of claim 4 , wherein the first switched mode driving unit comprises a first shunt switch in parallel with the first lighting units and adapted to switch an input voltage to a cathode of the first lighting units when the first shunt switch shunts the first lighting unit, and
the second switched mode driving unit comprises a second shunt switch in parallel with the second lighting units and adapted to switch an input voltage to a cathode of the second lighting units when the second shunt switch shunts the second lighting unit.

6 . The lighting assembly of claim 5 , wherein the first switched mode driving unit comprises a first converter including a first power switching component adapted to couple a ground voltage to a point in the first converter, and the second switched mode driving unit comprises a second converter including a second power switching component adapted to couple a ground voltage to a point in the second converter.

7 . The lighting assembly of claim 6 , wherein at the particular moment the first shunt switch is adapted to conduct and the power switching component of the second converter is adapted to conduct thereby coupling the input voltage onto the first lighting units and coupling the ground voltage onto the second converter, the input voltage and the ground voltage are across the parasitic capacitance but are isolated from each other by the a reverse biasing of the blocking arrangement.

8 . The lighting assembly of claim 6 , wherein the first converter comprises a buck converter and the second converter comprises a buck converter.

9 . The lighting assembly of claim 5 , wherein the blocking arrangement comprises a first blocking element which is adapted to block current from the first shunt switch to the cathode of the first lighting units; or block current from the anode of the first lighting units to the first shunt switch.

10 . The lighting assembly of claim 9 , wherein the lighting assembly comprises a first board carrying the first switched mode driving unit, and
the first blocking element is amounted on the first lighting unit board or on the first board carrying the first switched mode driving unit.

11 . The lighting assembly of claim 9 , wherein the blocking arrangement further comprises a second blocking element which is adapted to block current from the second shunt switch to the cathode of the second lighting units; or block current the anode of the second lighting units to the second shunt switch.

12 . The lighting assembly of claim 11 , wherein the lighting assembly comprises a second board carrying the second switched mode driving unit, and
the second blocking element is amounted on the second lighting unit board or on the second board carrying the second switched mode driving unit.

13 . The lighting assembly of claim 9 , wherein the, or each, blocking element comprises a diode forward biased from the cathode of the lighting units to a current out terminal of the shunt switch, or
a diode configured forward biased from a current in terminal of the shunt switch to an anode of the lighting unit.

14 . The lighting assembly of claim 1 , comprising a first metal housing for the first lighting arrangement and a second metal housing for the second lighting arrangement, which housings electrically contact each other, wherein the parasitic capacitance is formed between each lighting unit board and its respective metal housing.

15 . The lighting assembly of claim 14 , wherein the lighting unit board comprises a pad, and the parasitic capacitance is formed between:
the pad of the lighting unit board and a metal substrate of the lighting unit board which is electrically contacting the metal housing; or the pad of the lighting unit board and the metal housing.

Assignees

• Signify Holding Bv

Inventors

• Zhou Liwen
• Feng Ye

Classifications

• H02M1/008

  Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators · CPC title

• H05B45/375

  using buck topology · CPC title

• H05B45/10

  Controlling the intensity of the light · CPC title

• H05B45/325

  Pulse-width modulation [PWM] · CPC title

• H05B47/155

  Coordinated control of two or more light sources · CPC title