Method and apparatus for determining a target light intensity from a phase-control signal
AssigneeLutron Technology Company LLC
InventorDonald F. Hausman, Jr.
Life of this patent
Estimating the term…
Abstract
A dimmable ballast circuit for a compact fluorescent lamp controls the intensity of a lamp tube in response to a phase-control voltage received from a dimmer switch. The ballast circuit comprises a phase-control-to-DC converter circuit that receives the phase-control voltage, which is characterized by a duty cycle defining a target intensity of the lamp tube, and generates a DC voltage representative of the duty cycle of the phase-control voltage. Changes in the duty cycle of the phase-control voltage that are below a threshold amount are filtered out by the converter circuit, while intentional changes in the duty cycle of the phase-control voltage are reflected in changes in the target intensity level and thereby the intensity level of the lamp tube.
Claims15
A lamp controller comprising:
- a control circuit to:
- receive phase-controlled AC voltage (VPC-IN) from an electrical load control device;
- generate, via phase-control-to-DC converter circuitry, a target voltage (VTRGT) using the received phase-controlled AC voltage (VPC-IN);
- amplify the determined target voltage to provide an amplified target voltage (VA-TRGT);
- receive a lamp current control signal (VILAMP) from a lamp current sense circuit operatively coupled to a lamp;
- amplify the received lamp current control signal to provide an amplified lamp current signal (VA-ILAMP);
- and
- combine the amplified target voltage and the amplified lamp current signal to provide a drive signal to adjust one or more operating parameters of a driver circuit operatively coupled to the lamp.
A lamp control method comprising:
- receiving, by a lamp control circuit, phase-controlled AC voltage (VPC-IN) from an electrical load control device;
- generating, by the lamp control circuit via phase-control-to-DC converter circuitry, a target voltage (VTRGT) using the received phase-controlled AC voltage (VPC-IN);
- amplifying, by the lamp control circuit, the determined target voltage to provide an amplified target voltage (VA-TRGT);
- receiving, by the lamp control circuit, a lamp current control signal (VILAMP) from a lamp current sense circuit operatively coupled to a lamp;
- amplifying, by the lamp control circuit, the received lamp current control signal to provide an amplified lamp current signal (VA-ILAMP);
- and
- combining, by the lamp control circuit, the amplified target voltage with the amplified lamp current signal to provide a drive signal to adjust one or more operating parameters of a driver circuit operatively coupled to the lamp.
A non-transitory, machine-readable, storage device that includes instructions that, when executed by a lamp control circuit, causes the lamp control circuit to:
- receive a phase-controlled AC voltage (VPC-IN) from an electrical load control device;
- generate, via phase-control-to-DC converter circuitry, a target voltage (VTRGT) using the received phase-controlled AC voltage (VPC-IN);
- amplify the determined target voltage to provide an amplified target voltage (VA-TRGT);
- receive a lamp current control signal (VILAMP) from a lamp current sense circuit operatively coupled to a lamp;
- amplify the received lamp current control signal to provide an amplified lamp current signal (VA-ILAMP);
- and
- combine the amplified target voltage with the amplified lamp current signal to provide a drive signal to adjust one or more operating parameters of a driver circuit operatively coupled to the lamp.
Dependencies are inferred from the claim text.