Abstract: A fuel cell stack assembly comprises fuel cells disposed in a stacked configuration, each cell substantially parallel to an x-y plane and including a tab extending laterally from an edge of a plate in the cell in the x-direction to form an array of tabs extending along a side face of the fuel cell stack in a z-direction orthogonal to the x-y plane. A connector engages with the tabs of the fuel cell stack. The connector comprises a support region and engagement regions, each engagement region bounded by the support region and configured to receive one of the array of tabs by engagement in the x-direction. The connector has flexible conductors, each of the flexible conductors laterally extending from the support region over at least a portion of one of the engagement regions and configured to be deflected away from the support region by a received tab.

Abstract: A direct drive LED lighting circuit includes a LED current control circuit with a power switching device; a current sensing device, an averaging circuit, and an error amplifier. A LED chain circuit is formed by connecting several LEDs in series with a capacitor connecting in parallel with the series of LEDs, with a current flowing in side as a positive terminal, and a current leaving terminal as a negative terminal. The LED chain circuit and the LED current control circuit are connecting in series and the whole circuit is connected between the positive and negative terminals of a rectified AC power source.

Abstract: A portable lamp, such as a headlamp, comprising wireless bidirectional communication means for exchanging configuration instructions, parameters and/or data with at least one mobile information processing system. This mobile processing system establishes a downlink for the transmission of said configuration instructions, parameters and/or data to the lamp. The lamp can establish an uplink for the transmission of configuration instructions, parameters and/or data from the lamp to said mobile information processing system.

Abstract: An electronic system includes a feedback voltage regulator circuit including input terminals receiving a rectified alternating input voltage signal and a feedback input terminal receiving a feedback voltage that is generated based on a load current through an electric load. A sensing element senses the load current through the electric load and generates sensed voltage based upon the sensed load current. A current transducer receives the sensed voltage and provides the feedback voltage based upon the sensed voltage. A current generator receives the alternating input voltage signal and provides a biasing current signal that is a function of the alternating input voltage signal to modulate the feedback voltage on the feedback input terminal based upon the alternating input voltage signal.

Abstract: A device suppresses flicker and improves compatibility of a lamp including at least one solid state light source, the lamp being operably connected to a control circuit, such as a dimmer circuit. The device includes a connector enabling connection of the solid state light source to a lamp socket configured to receive an incandescent light source, and an adapter circuit connected in parallel with the at least one solid state light source when the solid state light source is connected to the socket via the connector. The adapter circuit provides a resistive path for current to pass through the lamp, during all or part of the AC mains cycle.

Abstract: An electro-optical device includes a first data transfer line that intersects a scan line, a second data transfer line, a first transistor that controls coupling between the first data transfer line and the second transfer line. The two or more second data transfer lines are respectively coupled to the first data transfer line via first capacitors, and when a collection of pixel circuits that are coupled to the same first data transfer line via the second data transfer lines is referred to as a pixel string, the second data transfer lines are provided to pixel circuits less than the pixel circuits included in the pixel string.

Abstract: The AMOLED display device includes a light-emitting source and a display screen provided with a plurality of subpixels. Each subpixel includes a driving transistor, and a capacitor arranged between a gate electrode and a source electrode of the driving transistor and connected to a signal line via a switching element. The shutdown controlling method includes: determining whether or not a shutdown signal has been detected; performing a first control operation when the shutdown signal has been detected, so as to control a voltage on the signal line to be in a first voltage state; and performing a second control operation when the shutdown signal has been detected, so as to control the switching element to be in an on state, thereby to enable the capacitor to be discharged completely toward the signal line in the first voltage state via the switching element.

Abstract: There was a problem that it was difficult for a semiconductor device in the related art to increase the switching frequency of a step-up circuit, and it was difficult to stabilize an output current and an output voltage. A semiconductor device controls a step-up circuit including an inductor and a drive transistor to drive the inductor. The semiconductor device calculates upper and lower limits which determine the variable range of an input current, based on an output current and an input voltage, controls the switch timing of the drive transistor based on the relation between the upper and lower limits and the magnitude of the input current, and at the same time, corrects the upper and lower limits to be calculated, based on the magnitude of the difference between the output current and a target output current value as an ideal value of the output current.

Abstract: A power management method includes generating a power related value; notifying a power management controller if the power related value has passed a threshold; and performing a power control operation by the power management controller. The power control operation prevents an over current event.

Abstract: A switching converter, including an input interface for providing an input voltage, an output interface for providing at least one output voltage, a voltage conversion device for converting the provided input voltage into one of the at least one output voltage, and a clock generator for providing a working clock, the clock generator being configured in such a way that the clock generator provides a modulated basic clock as the working clock. A control unit including such a switching converter, and a method for operating such a switching converter, are also described.

Abstract: An LED lamp arrangement adapted for fitting in a luminaire. The luminaire is adapted for a fluorescent lamp and having a ballast. The LED lamp arrangement has a plurality of LEDs, and two or more electrodes for releasably connecting to the luminaire and for conducting current from the ballast for supply to the LEDs. The LED lamp arrangement further has a sensor circuit and a protection circuit. The sensor circuit and the protection circuit are adapted to increase the total load impedance of the LED lamp arrangement if the ballast is a constant power electronic ballast.

Abstract: The present invention relates to a lighting lamp system and a power distributor used for the lighting lamp system. The lighting lamp system comprising: a plurality of lighting lamps; a main converter for converting external alternating-current power into direct-current power; a distributor provided to be isolated from the lighting lamps and supplying power for lighting to the plurality of lighting lamps by converting the direct-current power from the main converter; and a controller for controlling the operations of the lighting lamps by controlling the distributor.

Abstract: A solid-state lighting system includes a light-emitting device connected in series with a variable dim setting resistor, an adjustable regulator, and a current sensor disposed in a feedback loop between an adjust input of the adjustable regulator and the variable dim setting resistor. The voltage dropped across the variable dim setting resistor is forced to remain constant irrespective of the resistance setting of the dim setting resistor. The current sensor measures or senses the current flowing through the variable dim setting resistor and causes the adjustable regulator to adjust its output voltage and the forward voltage drop across the light-emitting device so that the current flowing through the light-emitting device matches the current set by the variable dim setting resistor. Controlling the current in this manner allows dimming to be performed over an extremely wide dimming range, to very low light levels, and without producing light flicker at any dim level.

Abstract: An antenna arrangement for a solid-state lamp is disclosed. Embodiments of the invention provide for improved performance by positioning the antenna for radio frequency (RF) control of the lamp non-parallel to the main driver board and/or the LED board. This positioning can provide distance from the main board circuitry and a ground plane for the antenna. An RF daughter card can be used for the antenna and also possibly for other RF components. In some embodiments, the antenna is substantially perpendicular to the main board. In some embodiments, the lamp is dimensioned as a replacement for a standard incandescent bulb, such as an A, BR, or PAR bulb. In some embodiments, an optically transmissive enclosure and/or a base define the interior cavity of the lamp. A plurality of LEDs can be disposed within the optically transmissive enclosure.

Abstract: Systems, devices, and methods for dimming of solid state lighting reduce ripple and flicker at low load dimming levels (low LED current, lower light levels) yet provide full power to the load at high load dimming levels (high LED current, higher light levels) thereby reducing power loss compared to conventional dimming techniques. When dimming to lower light levels a flicker resisting metal oxide semiconductor field effect transistor (MOSFET) connected to the LED operates in linear mode such that the relationship of its drain-source voltage to the LED current is resistive to provide flicker reduction. Conversely, at higher light levels the flicker resisting MOSFET is operated in saturation mode such that full power is supplied to the LED as flicker reduction is less needed. The disclosed techniques also reduce undershoot and overshoot of the LED voltage during transitions in dimming control from high to low and low to high respectively.

Abstract: An LED luminaire comprises a rechargeable battery, LED array(s), multiple drivers, and a control circuit. The LED luminaire may be used to replace a fluorescent or a conventional LED lamp connected to AC mains. The multiple drivers comprise a first driver configured to charge the rechargeable battery, a second driver configured to convert a DC voltage from the rechargeable battery to light up the LED array(s) when a line voltage from the AC mains is unavailable, and a third driver configured to operate the LED array(s) when the line voltage from the AC mains is available. The control circuit is configured to manage the multiple drivers in a way that the second driver is disabled when the line voltage from the AC mains is available and that the first driver and the third driver are disabled when a rechargeable battery test is performed, without ambiguity and safety issues.

Abstract: A signal-adjusting module applied to a light emitting diode driving apparatus includes an input terminal, an output terminal, a switch-control unit, and a switch. The switch-control unit is electrically connected to the input terminal for receiving an illuminant-control signal, and the switch is electrically connected to the input terminal, the output terminal, and the switch-control unit. The switch-control unit is configured to turn on the switch when a level of the illuminant-control signal reaches a first threshold level and turn off the switch when the level of the illuminant-control signal reaches a second threshold level, thus a transition time of the illuminant-control signal transits from an upper limit level to a lower limit level is decreased.

Abstract: An electro-optical device includes a first data transfer line that intersects a scan line, a second data transfer line, a first transistor that controls coupling between the first data transfer line and the second transfer line. The two or more second data transfer lines are respectively coupled to the first data transfer line via first capacitors, and when a collection of pixel circuits that are coupled to the same first data transfer line via the second data transfer lines is referred to as a pixel string, the second data transfer lines are provided to pixel circuits less than the pixel circuits included in the pixel string.

Abstract: Smart USB plug detection is disclosed. In some embodiments, a battery charger identification chip includes circuitry configured to determine whether an external USB device has been plugged into a USB port of an associated system while the system is in a sleep mode and includes a pin configured to output a control signal indicating whether an external USB device is plugged into the system, wherein when an external USB device is plugged into the system the control signal facilitates powering on a current limit switch that is otherwise powered off during the sleep mode and wherein the current limit switch facilitates regulated delivery of current to the plugged in external USB device.

Abstract: A voltage regulator includes a control circuit, a switch circuit, a first over-current protection circuit, and a second over-current protection circuit. The control circuit generates a pulse-width modulation (PWM) signal having a duty cycle proportional to an output voltage of the voltage regulator. The first over-current protection circuit blocks the PWM signal when an over-current condition exists during an off time of the PWM signal until a low-side switch current-sense level in the switch circuit drops below a set current limit level, while the second over-current protection circuit turns off the PWM signal when an over-current condition occurs during an on time of the PWM signal when a ramp adjusted voltage level added to the low-side switch current-sense level exceeds a summed level of the set current limit level and a set threshold.

Abstract: Provided is a lighting apparatus. The lighting apparatus may provide an output voltage to lighting loads, and include: a converter configured to generate the output voltage using a driving signal; and a driving circuit configured to provide the driving signal, and spread the frequency of the driving signal by performing frequency dithering on the driving signal while changing the shape of an oscillation signal.

Abstract: An illumination device includes an optical component and a light-emitting module. The optical component includes a light-transmitting body, a first optical unit, and a second optical unit. The first optical unit has a light input surface and a plurality of surrounding structures surrounding the light input surface and arranged in a pattern of concentric circles, and each surrounding structure has a first surrounding surface and a second surrounding surface. The second optical unit has a spiral structure surrounding the light output surface of the light-transmitting body and a surrounding frame surrounding the light output surface of the light-transmitting body and the spiral structure, and a relative height from a topmost surface of the spiral structure to the light output surface of the light-transmitting body is increased gradually from inner to outer. The light-emitting module is disposed under the light input surface of the first optical unit.

Abstract: A pseudo-resonant element (130) is disposed in series with respect to an inductive load (180) on the inductive load (180) side rather than an output end of an inverter unit (120) constituted of a magnetic energy recovery switch.

Abstract: A semiconductor apparatus includes: a switch circuit connected between a first power supply terminal and an output terminal; a switching element connected between the output terminal and a second power supply terminal; and a control circuit that, when a predetermined period has elapsed since the entry of the switch circuit into an ON state in response to an enable signal, causes the switching element to start a switching operation to increase a power supply voltage supplied between the first power supply terminal and the second power supply terminal.

Abstract: The invention describes a linear post-regulator (1) realized for use in an LED lighting arrangement (2), which linear post-regulator (1) comprises a control loop cascade (L1, L2, L3) realized for connection between a terminal of an LED lighting load (20) and a power converter (21) of the LED lighting arrangement (2); a transistor (Q) realized to regulate an LED current (ILED) through the LED lighting load (20); a first input (11) for connection to a reference current input (Iref); a second input (12) for connection to a performance parameter input (Vref, ?lref); and an output for connecting a power control output (Pctr) of the linear post-regulator (1) to the power converter (21); wherein the control loop cascade (L1, L2, L3) comprises at least two interconnected control loops (L1, L2, L3) to regulate the LED current (ILED) on the basis of the reference current input (Iref) and to regulate a further performance parameter of the LED lighting arrangement (2) on the basis of the performance parameter input (Vref

Abstract: A replacement light tube for replacing a fluorescent light tube includes a bulb portion extending between a first end and a second end, the bulb portion comprising a support structure, a plurality of white light emitting diodes (LEDs) and an elongate light-transmissive cover. The support structure has a first surface extending between the first end and the second end. The plurality of LEDs are supported by the first surface and arranged between the first end and the second end. The elongate light-transmissive cover extends between the first end and the second end and over the first surface of the support structure. A first end cap and a second end cap are disposed on the first end and the second end, respectively, each configured to fit with a socket for a fluorescent light tube. A power supply circuit is configured to provide power to the plurality of LEDs.

Abstract: A power conversion circuit is provided. An input of the power conversion circuit is coupled to a first voltage potential. A switching frequency of the power conversion circuit is set based on a magnitude of the first voltage potential.

Abstract: An LED dimmer can be connected between a basic LED driver and an LED arrangement. The dimmer is able at least to receive a constant current from a constant current LED driver, and it then uses a boost converter to provide voltage boosting dependent on a required dimming level.

Abstract: The invention relates to a controlling system (4) for controlling loads (2), especially lighting units, of a power/data-communication system like a PoE system, wherein a command is provided, which defines desired power levels of loads of the power/data-communication system. An overall power change amount is determined, which will be caused by the provided command, and the loads are controlled such that the slope of the overall power consumption of the loads, when being set to the desired power levels, is reduced, if the determined overall power change amount is larger than a predefined power change threshold. Thus, if the provided command may lead to an overall power change amount causing problems like blown fuses, the loads are controlled such that the slope of the overall power consumption of the loads, when being set to the desired power levels, and hence the likelihood of, for instance, blown fuses is reduced.

Abstract: A method and an apparatus for detecting a vector shift in an AC power system, the apparatus comprising frequency measuring means adapted to determine a frequency of the AC power system, derivation means adapted to determine a time derivative of the frequency, filtering means adapted to filter the time derivative of the frequency, and detection means adapted to calculate time derivatives for the filtered time derivatives of the frequency over a time period having the length of the fundamental period of the AC power system, to determine a number of positive and negative time derivatives among the calculated time derivatives, and to detect a vector shift in the AC power system in response to an absolute value of a difference between the determined number of positive time derivatives and negative time derivatives exceeding a predetermined threshold value.

Abstract: A power supply detection system and method for determining the AC mains voltage range when a device (e.g., LED based bulbs) is indirectly connected to the AC mains and the device does not receive the complete sinusoidal AC mains signal. The power supply detection system and method receive an input signal having a first portion that is a sinusoidal signal that generally corresponds to a first portion of the voltage source signal and a second portion that is not a sinusoidal signal that generally corresponds to a second portion of the voltage source signal. A selected reference signal is received, wherein the selected reference signal is synchronized with the input signal. The first portion of the input signal is compared with a corresponding portion of the selected reference signal, and the voltage range of the voltage source is determined based on the comparison.

Abstract: A solid state spark device that operates as a two terminal spark gap in a CDI exciter of an aircraft ignition system. The device includes a triggering transformer, a triggering circuit, and a control circuit. The triggering circuit is electrically connected to a first coil of the transformer and includes circuit elements connected to supply current to the first coil upon charging of the triggering circuit up to a triggering voltage. This current through the first coil of the triggering transformer induces an output in a second coil of the transformer. The control circuit is electrically connected to the second coil and includes a switch controlled by the output from the second coil. The switch, when activated by the triggering circuit, discharges energy from the exciter into an igniter of the aircraft ignition system.

Abstract: A switching mode constant current led driver including an energy transmission unit, an LED module, a power transistor, a resistor and a control unit, the control unit including a driving unit for generating a driving voltage signal, and a duty cycle determining unit for determining a duty cycle of the driving voltage signal, wherein, the duty cycle determining unit determines a charging time for a reference current to charge an external capacitor according to a present time length, and determines a discharging time for a discharging current to discharge the external capacitor according to an inductor discharging time, the discharging current being proportional to an average value of an inductor charging status signal, and a comparing voltage is thereby generated on the external capacitor; and compares the comparing voltage with a saw-tooth voltage to generate a next time length of the duty cycle.

Abstract: An AC-DC converter, power supply board and display apparatus is disclosed. The AC-DC converter comprises: an AC-DC converting circuit; a transformer, whose primary coil has a first terminal coupled to a positive output terminal of the AC-DC converting circuit, and second terminal connected to a load; a voltage monitoring circuit, whose input terminal is coupled to the first terminal of the secondary coil, and second terminal of the secondary coil connected to a ground; and a control circuit, whose input terminal is coupled to an output terminal of the voltage monitoring circuit, and output terminal coupled to the AC-DC converting circuit; wherein the voltage monitoring circuit outputs a control voltage when a voltage outputted by the first terminal of the secondary coil of the transformer exceeds a first threshold; the control circuit controls the AC-DC converting circuit to stop providing power supply when the control voltage exceeds a second threshold.

Abstract: A digital control module that is used to power LED light fixtures connected thereto, the digital control module allowing for the continued control and powering of some or all of the connected LED light fixtures even in the event that one of the DC power supplies in the digital control module fails.

Abstract: A LED structure with wireless power driver and display thereof is provided. The LED structure receives outside electric and magnetic field to transform into operation power for LED. The LED structure has a driver IC, a receiving element, and a light-emitting element to dispose and pack into a LED carrier directly. The receiving element is utilized to receive the electric and/or magnetic field, and a wireless control signal. The driver IC has a transformation mechanism and a driver mechanism to control the light-emitting element. With the arrangement of the elements to form a high density LED without wired powers. Therefore, the occupied space is reduced and the pins are omitted to save costs.

Abstract: A power supply and a method for operating the power supply in which a transformer connected to an excitation circuit which is adapted to be connected to a power source, which secondary winding is connected to at least one first power supply. From prior art. switch mode power supply based on fly back technology is well known. Here a power supply with a power inlet is provided with a plurality of separated power outlets. One of the lines connected to the primary winding is further connected to a discharge control circuit, which discharge control circuit is further connected to at least one second power supply and the primary winding is further connected to a discharge circuit where at least one further power supply is connected.

Abstract: A lighting device includes: a variable voltage source; a transistor which controls a current flowing through a light-emitting element; and a control circuit which causes the transistor to pass a current corresponding to a received instruction for a dimming level through the light-emitting element. When the received instruction instructs at least a predetermined dimming level, the control circuit causes a voltage drop in the transistor to become a first voltage by controlling the variable voltage source, and when the received instruction instructs a dimming level less than the predetermined dimming level, the control circuit causes the voltage drop to become a second voltage higher than the first voltage, by controlling the variable voltage source.

Abstract: A lighting circuit is configured to supply a driving current to a first light source and a second light source. The light circuit includes a conversion unit which receives a first voltage for the first light source and a second voltage for the second light source via a common input terminal, performs voltage conversion on the first voltage or the second voltage and supplies the driving current, a control unit which controls a current value of the driving current output from the conversion unit, a first switch which selects whether to supply the driving current to the first light source by a first signal based on the first voltage, a signal generation unit which receives the first voltage and the second voltage and generates a second signal, and a second switch which selects whether to supply the driving current to the second light source by the second signal.

Abstract: According to some embodiments, a system and housing provide a lamp including a heat sink including: an annular tube including a first end and a second end, a plurality of fins extending radially from an exterior surface of the annular tube, wherein a length of each fin extends from the first end of the annular tube to the second end of the annular tube; a plurality of light sources in thermal contact with the heat sink; a driver circuit operative to provide the input voltage and current for the plurality of light sources; and a capper positioned at the second end of the annular tube, wherein the capper is operative to be received in a socket. Numerous other aspects are provided.

Abstract: The present invention provides a correlation-evading commutated-element direct-current current transformer (DCCT) that offers freedom from errors caused by correlation between its commutation frequency and its input current waveform. Its commutated element, comprising a commutating switch and a current transformer generates, responsive to a commutating signal, a current in a burden, which burden generates a signal representing the DCCT input current. A drive generator generates a commutation signal that can be switched between plural frequencies. Correlation detection circuitry detects correlation between the DCCT input current waveform and its commutation frequency and issues a signal for causing the drive generator to switch commutation frequency to evade correlation.

Abstract: A power supply has a first stage for performing AC-DC voltage conversion and power factor correction and a second stage for isolated DC-DC voltage conversion. The power supply includes a feed forward mechanism for transmitting phase information corresponding to AC ripple. The phase information is transmitted from the first stage to a secondary side of the second stage as a digital signal using a low speed optical coupler, where the phase information is utilized by a DC-DC digital controller to implement AC ripple suppression using both phase compensation and amplitude compensation.

Abstract: A clocked electronic energy converter may include an electronic switching element, at least two electrical energy storage devices, connections for connecting an electrical energy source and for connecting an electrical energy sink, a clock generator for controlling the electronic switching element and a switch-on time unit for generating a first signal for the clock generator, which switch-on time unit sets the power of the energy converter to be transmitted in a first power range by the first signal. The switch-on time unit generates a first signal representing a switch-on time for the clock generator in a second power range in which the power lower can be set than in the first power range, and the clocked electronic energy converter has a switch-off time unit generating in the second power range a second signal for the clock generator, which signal represents a switch-off time depending upon the power to be transmitted.

Abstract: A projection device includes a semiconductor light-emitting element, a rotary wheel configured to emit lights of a plurality of colors in a time-division manner by using light which the semiconductor light-emitting element emits, and a controller configured to start, at a time of activating the device, rotation of the rotary wheel and output of a signal, which instructs a turn-on timing, to the semiconductor light-emitting element, in a state in which supply of power to the semiconductor light-emitting element is stopped, and to start, thereafter, the supply of the power to the semiconductor light-emitting element, based on a predetermined condition relating to an activation state.

Abstract: A metering circuit includes a comparator including a first input to receive an input signal, and including a second input and an output. The metering circuit further includes a reference source to provide a time-varying reference signal to the second input during a peak counting operation.

Abstract: A current control apparatus for controlling current of a lamp in a vehicle includes: a plurality of output pins to output currents of different values; an output signal feedback part connected to each of the plurality of output pins, and to generate one of a plurality of output feedback signals; a reference signal generation part to generate one of a plurality of reference signals; a signal selection part configured to select one of the plurality of output feedback signals, and to select one of the plurality of reference signals; a comparator to compare the received output feedback signal to the received reference signal, and to output a signal difference between the receive output feedback signal and the received reference signal; and a constant current driver configured to constantly adjust a current output through one of the plurality of output pins based on the signal difference.

Abstract: A power efficient method and system for ensuring a reliable operation of dimmers in conjunction with solid state lighting devices such as LED or OLED assemblies is presented. A controller for a driver circuit of a solid state light bulb assembly is described. The solid state light bulb assembly comprises a solid state light source. The driver circuit comprises a switched-mode power converter. The controller is configured to receive an input voltage indicative of a mains electricity supply submitted to a dimmer; to determine that the dimmer is in an off-phase, based on the input voltage; and, if it is determined that the dimmer is in an off-phase, to generate a control signal for the switched-mode power converter to operate the switched-mode power converter in a switched mode for discharging one or more capacitances at an input of the switched-mode power converter.

Abstract: A method of driving a number of high-power light-emitting diodes (LEDs) which are divided into two or more groups, each group being separately energizable by a corresponding one of the power supplies, includes: a) energizing or deenergizing a supply current from the corresponding one of the power supplies into a first one of the groups; b) waiting for a predetermined wait time period; and c) repeating step a) and b) for a second one of the groups. Besides, a supply unit for performing the method comprises a control input, a control unit, and at least two power supplies for correspondingly feeding the two or more LEDs groups.

Abstract: A device and method of using a device for photon-induced endodontic and periodontic applications includes a power source, a trigger coupled to the power source and circuit elements initiated by the trigger. The circuit elements include a timing circuit and a driver. A light source is coupled to the circuitry elements wherein and driver controls the period, cycle, and pulse generation of the light source to create photon induced acoustic waves. The optical assembly includes a fiber optic cable and an output tip and is coupled to the light source. This optical assembly refracts light from the light source and photon induced acoustic waves exit the output tip in a pre-determined pattern.

Abstract: A dimming circuit for digital control includes two output terminals, a voltage sampling unit, an error amplifier unit, and an impedance transforming unit. The MCU voltage generating unit configured for setting the output voltage of the dimming circuit. The error amplifier unit is configured for comparing the voltage value between the two output terminals with the output voltage set by the MCU voltage generating unit. The impedance transforming is configured for adjusting the resistance value thereof according to the output of the error amplifier unit so as that the output voltage value of the dimming circuit for digital control is equal to the output voltage value set by the MCU voltage generating unit. While using the MCU voltage generating unit under programming of the user, the dimming circuit 100 can automatically perform the output of the LED lamp required by the user.