# US 2013/0278157 A1 · Device and method for controlling current to solid state lighting circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0278157 A1 - Document ID: US20130278157A1 - Status: Published application - Kind: A1 - Application number: 13/995,981 - Filed: 2011-12-16 - Published: 2013-10-24 - Earliest claimed: 2010-12-21 - Assignees: Koninklijke Philips Electronics N.V. - Inventors: Harald Josef Günther Radermacher - Web page: https://patentgrep.com/patent/US20130278157A1 ## CPC - H05B 45/397: Current mirror circuits - H05B 45/355: Power factor correction [PFC]; Reactive power compensation - H05B 45/50: responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits - H05B 45/59: for reducing or suppressing flicker or glow effects - Y02B 20/30: Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED] - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A device for controlling current to a solid state lighting load includes a capacitor (241, 341) and a current source (245, 345). The capacitor is connected in a parallel arrangement with the solid state lighting load (260, 360). The current source is connected in series with the parallel arrangement of the capacitor and the solid state lighting load. The current source is configured to modulate dynamically an amplitude of an input current provided to the parallel arrangement of the capacitor and the solid state lighting load based on an input voltage. ## Claims ### Claim 1 A device for controlling current to a solid state lighting load, the device comprising: a capacitor connected in a parallel arrangement with the solid state lighting load; and a current source connected in series with the parallel arrangement of the capacitor and the solid state lighting load, the current source being configured to modulate dynamically an amplitude of an input current provided to the parallel arrangement of the capacitor and the solid state lighting load based on an input voltage. ### Claim 2 (depends on 1) The device of claim 1, wherein the solid state lighting load comprises at least one light-emitting diode (LED) connected in series. ### Claim 3 (depends on 2) The device of claim 2, wherein the modulated amplitude of the input current maximizes operational efficiency of the solid state lighting load and increases a power factor (PF) of the solid state lighting load to at least a minimum PF requirement. ### Claim 4 (depends on 2) The device of claim 2, wherein the modulated amplitude of the input current reduces peak power dissipation in the current source. ### Claim 5 (depends on 1) The device of claim 1, further comprising: a diode providing surge protection of the current source, connected in parallel with the current source. ### Claim 6 (depends on 5) The device of claim 5, wherein the diode comprises a Zener diode. ### Claim 7 (depends on 1) The device of claim 1, wherein the current source comprises a metal oxide semiconductor field effect transistor (MOSFET). ### Claim 8 (depends on 1) The device of claim 1, wherein the current source comprises a bipolar junction transistor (BJT). ### Claim 9 (depends on 1) The device of claim 1, wherein the input voltage is provided by a rectifier supplied from an AC source. ### Claim 10 (depends on 9) The device of claim 9, wherein the rectifier is a bridge rectifier and the AC source is a mains voltage source. ### Claim 11 A device for controlling current to a light emitting diode (LED) load, the device comprising: a capacitor connected in parallel with the LED load; a transistor connected in series between the capacitor and a bridge rectifier circuit providing a rectified input voltage; and a modulation control circuit connected in parallel with the capacitor and the transistor and configured to receive the rectified input voltage from the bridge rectifier circuit, the modulation control circuit comprising a current mirror connected to a gate of the transistor, the current mirror being selectively activated and deactivated to downward and upward modulate an amplitude of a current through the capacitor based on an input voltage from the bridge rectifier circuit. ### Claim 12 (depends on 11) The device of claim 11, wherein the current mirror comprises a plurality of current mirror transistors. ### Claim 13 (depends on 12) The device of claim 12, wherein the modulation control circuit further comprises: a first resistor and a diode connected in series between the bridge rectifier circuit and a first node; a first path connected between the first node and ground, the first path comprising a second resistor and the current mirror; and a second path connected between the first node and ground, the second path comprising a third resistor and one of the current mirror transistors of the current mirror, wherein selection of the first path causes downward modulation of the current through the capacitor, and selection of the second path causes upward modulation of the current through the capacitor. ### Claim 14 (depends on 13) The device of claim 13, wherein the modulation control circuit further comprises: a diode connected in series between the first resistor and the first node, wherein the current through the capacitor is modulated upward or downward when the input voltage exceeds a voltage threshold defined by the diode. ### Claim 15 (depends on 12) The device of claim 12, wherein the transistor comprises a MOSFET. ### Claim 16 (depends on 15) The device of claim 15, wherein each of the current mirror transistors comprises a bipolar junction transistor (BJT). ### Claim 17 (depends on 15) The device of claim 15, wherein the modulation control circuit further comprises a current shunt resistor connected in series between the transistor and ground, a gate-source-voltage of the transistor and the current shunt resistor determining an upper limit of a current through the transistor. ### Claim 18 (depends on 11) The device of claim 11, further comprising: at least one capacitor selectively connectable to the bridge rectifier circuit to alter the input voltage. ### Claim 19 A method for controlling current to a solid state lighting load, the method comprising: receiving an input voltage (Urect) having a waveform; and adjusting an amplitude modulation of a capacitor current of a capacitor connected in parallel with the solid state lighting load, in response to at least one of the waveform of the received input voltage and a time delay in the waveform of the received input voltage, wherein adjusting the amplitude modulation of the capacitor current changes at least one of a power factor and operation efficiency of the solid state lighting load. ### Claim 20 (depends on 20) The method of claim 20, wherein the input voltage comprises a rectified voltage received from a bridge rectifier circuit.