# US 11,310,878 B2 · Dimming control circuit, driving device and control method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,310,878 B2 - Document ID: US11310878B2 - Status: Granted - Kind: B2 - Application number: 17/155,471 - Filed: 2021-01-22 - Published: 2021-07-22 - Granted: 2022-04-19 - Earliest claimed: 2020-01-22 - Assignees: Shanghai Bright Power Semiconductor Co., Ltd. - Applicants: Shanghai Bright Power Semiconductor Co., Ltd. - Inventors: Wei-Jia Yu; Min-Min Fan - Web page: https://patentgrep.com/patent/US11310878B2 ## CPC - H05B 45/325: Pulse-width modulation [PWM] - H05B 45/14: using electrical feedback from LEDs or from LED modules - H05B 45/395: Linear regulators - 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 dimming control circuit, driving device and control method thereof, the dimming control circuit comprising a dimmer, a driving device coupled to the dimmer and controlling a load on the basis of a dimming level reference of the dimmer, and a bleeder supplying power to the dimmer, the driving device including a power switch coupled to the load, wherein a duty ratio of a driving voltage on the power switch is adjusted in accordance with the dimming level reference to control an operating current of the load. ## Claims ### Claim 1 A driving device utilized in a dimming control circuit for driving a load, the driving device configured to receive an output of a rectifier, the rectifier configured to receive an AC power and to output a rectified DC output voltage to the load, wherein the driving device comprises: a power switch serially coupled to the load, configured to regulate a current flowing through the load; and a power switch control module, configured to generate a pulse width modulation signal to control the power switch on and off, wherein the pulse width modulation signal turns to an on-state state according to a conducting signal, the conducting signal being configured to indicate the rectified output voltage reaching a first reference, and wherein a duty ratio of the pulse width modulation signal is adjusted in accordance with an error between a sensed signal indicating a current flowing through the load and a dimming level reference. ### Claim 2 (depends on 1) The driving device according to claim 1, wherein the power switch control module controls the power switch to regulate the current flowing through the load to a constant first predetermined value during the on-state of the pulse width modulation signal. ### Claim 3 (depends on 1) The driving device according to claim 1, wherein the load and the power switch comprises a driving branch circuit, and wherein the driving device further comprising a bleeder, parallelly coupled to the driving branch circuit. ### Claim 4 (depends on 1) The driving device according to claim 1, comprising: a comparison module, the comparison module comprising a first comparison unit and a second comparison unit, the first comparison unit sensing the output voltage and generating the conduction signal on the basis of a first comparison result between a first reference signal corresponding to the first reference and a sensed output voltage, the second comparison unit generating an off signal to determine the duty ratio of the pulse width modulation signal on the basis of a second comparison result between an integral reference associated with the error and a timing signal; and a pulse width modulation signal generator, receiving the conduction signal and the second comparison result, operable to generate the pulse width modulation signal accordingly. ### Claim 5 (depends on 4) The driving device according to claim 4, wherein the first comparison unit comprises a first comparator receiving the sensed output voltage and the first reference signal and a trigger coupled to the first comparator. ### Claim 6 (depends on 4) The driving device according to claim 4, wherein the second comparison unit comprises a first arithmetic circuit coupled to the pulse width modulation signal generator, the first arithmetic circuit receiving the integral reference and the timing signal, and wherein the second comparison unit outputs the off signal when the integral reference is equal to the timing signal. ### Claim 7 (depends on 6) The driving device according to claim 6, wherein the second comparison unit further comprises: an integrator coupled to the first arithmetic circuit, receiving the error and operable to output the integral reference accordingly; and a second arithmetic circuit, coupled to the integrator, the second arithmetic circuit, receiving the sensed signal and the dimming level reference, operable to output the error. ### Claim 8 (depends on 6) The driving device according to claim 6, wherein the error is a difference between the sensed signal and the dimming level reference. ### Claim 9 (depends on 6) The driving device according to claim 6, wherein the second comparison unit further comprises: a timer coupled to the first arithmetic circuit, operable to output the timing signal to the first arithmetic circuit; and a second comparator coupled to the timer, the second comparator generating a reset signal to reset the timer if the rectified DC output voltage is below a second predetermined value. ### Claim 10 (depends on 6) The driving device according to claim 6, wherein the second comparison unit further comprises: a timer coupled to the first arithmetic circuit, operable to output the timing signal to the first arithmetic circuit; and a second comparator coupled to the timer, the second comparator generating a reset signal to reset the timer if the sensed signal is below a third predetermined value. ### Claim 11 (depends on 4) The driving device according to claim 4, wherein the pulse width modulation signal generator comprises: an amplifier coupled to the power switch, wherein the amplifier receives the sensed signal and a first predetermined value, operable to generate the pulse width modulation signal; and an enabling unit coupled to the amplifier, and wherein the enabling unit determines whether to enable the amplifier according to the conduction signal and the off signal . ### Claim 12 (depends on 1) A dimming control circuit, comprising a dimmer, a driving device according to claim 1 coupled to the dimmer and controlling a load and a bleeder for supplying power to the dimmer on the basis of a dimming signal. ### Claim 13 A dimming control method used for a dimming control circuit, the dimming control circuit comprising a dimmer, a rectifier, a driving device and a bleeder, the rectifier being coupled to the dimmer and configured to receive an AC power and to output a rectified DC output voltage to a load, the driving device comprising a power switch coupled to the load and a pulse width modulation signal generator, the power switch controlling the load on the basis of a dimming signal, the bleeder supplying power to the dimmer, wherein the method comprises the following steps: receiving a conduction signal based on the rectified DC output voltage and a off signal based on the dimming signal by the pulse width modulation signal generator; and outputting a pulse width modulation signal to the power switch on the basis of the conduction signal and the off signal, wherein a duty ratio of the pulse width modulation signal is adjusted in accordance with an error between a sensed signal indicating a current flowing through the load and a dimming level reference. ### Claim 14 (depends on 13) The dimming control method according to claim 13, wherein the conduction signal is generated when the rectified DC output voltage reaches a first reference signal. ### Claim 15 (depends on 13) The dimming control method according to claim 13, wherein a second comparison result between an integral reference associated with the error and a timing signal is obtained to generate the off signal, a first arithmetic circuit receiving the integral reference and the timing signal, the off signal being generated when the integral reference is equal to the timing signal. ### Claim 16 (depends on 15) The dimming control method according to claim 15, wherein the integral reference is based on integrating the error between the sensed signal indicating the current flowing through the load and the dimming level reference. ### Claim 17 (depends on 16) The dimming control method according to claim 16, wherein the error is a difference between the sensed signal and the dimming level reference. ### Claim 18 (depends on 15) The dimming control method according to claim 15, wherein generating the timing signal comprises the step of: comparing the sensed signal with a second reference signal, and outputting the timing signal when the sensed signal is less than the second reference signal. ### Claim 19 (depends on 15) The dimming control method according to claim 15, wherein generating the timing signal comprises the step of: comparing the rectified DC output voltage with a second reference signal, and outputting the timing signal when the sensed signal is less than the second reference signal.