TWI586208B - Dimmable electronic control gears for led light engine and application thereof - Google Patents

Description

Electronic control device for dimmable LED light engine and its application

The invention relates to a dimmable light-emitting diode light engine control device, in particular to adjusting a current intensity through an LED sub-array by using a shared current sense and modulation unit. A dimmable light-emitting diode light engine electronic control device that correspondingly changes the illumination brightness.

Compared to conventional luminaires, LEDs have a high luminous efficacy. Traditional bulbs provide about 15 lumens per watt (15 lumens per watt), while light-emitting diodes have up to 100 lumens per watt (100 lumens per Above watt), the light-emitting diode has the advantages of longer relative life, less interference from outside interference and less damage, and is the first choice for lighting equipment.

Generally speaking, the light-emitting diode needs to be driven by a direct current, and the commercial power is an alternating current, which must be converted into a direct current through a rectifier (full-wave or half-wave rectification) before being supplied to the light-emitting diode for use. After the converted DC pulse signal (DC), near the initial and end sections of each cycle (ie, no-load time), the forward voltage drop of the LED cannot be overcome to drive the illumination. The polar body results in a narrow conduction angle and a low power factor. The dead time is the period during which the LED stops conducting. In contrast, the conduction angle refers to a period during which the LED is turned on. The sum of the conduction angle and the dead time is a rectified DC pulse waveform. The longer the dead time, the narrower the conduction angle and the lower the power factor. Traditional LED drivers typically face the following three problems.

The first problem is that traditional LED drivers must use filters, rectifiers, And a more complicated driver circuit such as a power factor corrector (PFC), which causes the cost of the driver to be high. At the same time, although the life of the light-emitting diode is long, the electrolytic capacitor used in the power factor corrector is easily damaged, so that the overall life is relatively shortened, and the advantages of the light-emitting diode cannot be exhibited.

The second problem is that at no-load time, no current passes through the light-emitting diode, causing the photo The flicker phenomenon of the device. During the DC pulse period, the LED is driven by the forward current and is illuminated by the zero current. When there is no dead time, the LED will cause flicker between lighting and extinction. The frequency of the general city AC power is 60 Hz. After rectification, a DC voltage pulse is formed, the frequency is twice (about 120 Hz), and the flicker phenomenon occurs at a no-load time at a frequency of about 120 Hz. The flickering phenomenon caused by the dead time is not easy to be perceived by the human eye, but it is easy to cause eye fatigue.

The third problem is the low power factor. Low power power factor corrector, The loop current is too weak to be accurately detected, and the AC input current is corrected to a sine wave waveform. The power factor can be calculated by dividing the input power by the product of the input voltage (line voltage) and the input current (line current) (PE=P/(V×I), where PF is the power factor, P is the input power, V And I are the effective values of the line voltage and the line current, respectively, to measure the efficiency of the electricity. When the line voltage and the line current are similar, the power is made. The better the efficiency, the higher the power factor. When the line voltage and the line current waveform are almost identical, at this time, the power factor has a maximum value of approximately 1.

Traditional power factor correctors need to detect the current in the loop to correct The line current waveform is closer to the line voltage waveform. If the current in the loop is too low to be correctly detected by the current detection circuit of the power factor corrector, the power factor corrector will not properly align the waveform and phase of the line current with the line voltage to achieve better power. Factor. Due to the discontinuity of the AC input current waveform and the total harmonic distortion (THD) caused by the jump point, the dead time is related to the dead time. According to the Fourier analysis for the development of the periodic signal, any discontinuity or jump point in the periodic waveform will result in higher-order harmonics on the basic components, resulting in an increase in total harmonic distortion. Therefore, eliminating discontinuities and jumping points will help reduce total harmonic distortion.

The fourth problem is that if the lighting device has a dimming function, it needs to be modulated. The current intensity of the LED. However, the current dimming lighting devices on the market often have a complicated circuit structure. For example, when dimming a multi-segment LED sub-array is required, multiple sets of dimming elements are often required, which not only increases production cost, but also has difficulty in process design or control.

In view of this, how to use a simple circuit structure to efficiently dim and maintain Good power factor and low harmonic distortion are one of the main topics in the development of light-emitting diode sources. Embodiments of the present invention provide a dimmable light-emitting diode light source, which has the advantages of low manufacturing cost, excellent performance, non-damage, and simple circuit, as will be described later.

The electronic control device of the dimmable LED light engine proposed by the invention is only The current flowing through the shared current sensing and modulation unit is controlled by a single shared current sensing and modulation unit, and the current through the LED sub-array is adjusted correspondingly to achieve the effect of adjusting the brightness of the light, which has a simplified circuit, Convenient control and low manufacturing cost.

The invention provides an electronic control device for a dimmable LED light engine, Dimming unit manual dimming (mechanical dimming). Or, dimming through the dimming signal (electronically controlled dimming). The dimming signal is generated, for example, by a built-in signal generator or remotely dimmed by microwave transmission to the electronic control unit of the light engine. The dimming signal is, for example, a Pulse Width Modulation (PWM) signal, and the duty cycle of the pulse width modulation signal is adjusted, and the average driving current of the LED array can be controlled correspondingly. Since the brightness of the light-emitting diode is proportional to the average value of the driving current, the brightness of the light-emitting diode can be controlled according to the average value of the driving current.

Electronic control of dimmable LED light engine proposed by an embodiment of the invention The device includes a current regulator and an array of switching regulators. The electronic control device of the dimmable LED light engine is connected to the LED array to form a dimmable light-emitting diode lighting device.

The current regulator is used to adjust the input current wave to form a sinusoidal (quasi-sinusoidal) A square wave or step wave waveform effectively boosts the power factor.

The switching regulator array of an embodiment of the present invention is disposed in parallel with the LED array. The LED array is formed by connecting a plurality of LED sub-arrays in series. The switching regulator array is formed by connecting a plurality of switching regulators in series. In addition to the last-level LED sub-array, a switch regulator is connected in parallel with an LED sub-array.

In the embodiment of the invention, the switching regulator array comprises a plurality of switching regulators, and any switching regulator comprises a bypass switch and a programmable current sensing circuit. Using a switching regulator with a depleted or enhanced transistor, according to the input AC voltage, when the voltage rises, the LED sub-array is driven step by step, and the line current is increased step by step; when the voltage is lowered, the LED sub-array is extinguished step by step. At the same time, the line current is reduced step by step, simplifying the circuit, improving the luminous efficiency, improving the power factor and reducing the cost.

In an embodiment, the bypass switch can be a normally closed switch, that is, in a normal state (when the source of the gate is not subjected to voltage or the voltage is zero, V _GS =0), the normally closed switch is Short circuit (conducting); when receiving a negative voltage (V _GS <0), the normally closed switch is open (off). For example, an N-channel depletion-mode MOSFET or an N-channel depletion-mode JFET can be used as a bypass switch. When the gate source is not subjected to voltage or positive voltage (V _GS ≧0), the channel is turned ON (ON state), when sufficient negative voltage is applied (V _GS <V _th <0, V _th is the cutoff voltage of the transistor), Channel cutoff.

During the first half of the input voltage, when the input voltage has not overcome the forward voltage drop of the lower LED sub-array, the bypass switch is in an ON state; as the input voltage rises, the forward voltage drop of the lower LED sub-array is overcome. However, the forward voltage drop of the LED sub-array of the current stage has not been overcome, and the switch control circuit turns the bypass switch into a Regulating state; the voltage continues to rise to overcome the forward direction of the LED sub-array. The voltage drop, the switch control circuit turns the bypass switch of the current stage into an OFF state, thus lighting the LED sub-array step by step from bottom to top.

In the second half of the input voltage, the input voltage is gradually reduced, and the input voltage is still sufficient. To overcome the forward voltage drop of the current LED sub-array, when the stage bypass switch is maintained in the OFF state; the input voltage is gradually reduced to overcome the forward voltage of the current LED sub-array, but still overcome the lower LED The forward voltage drop of the sub-array, the switch control circuit switches the bypass switch from the OFF state to the regulated state; the input voltage continues to fall to the inability to overcome the forward voltage drop of the lower LED sub-array, and the switch control circuit bypasses The switch is switched from the regulated state to the conductive state, so that the LED sub-array is extinguished step by step from top to bottom.

In another embodiment, the bypass switch can also be a normally open switch (normally Open switch), for example, an N-channel enhancement-mode junction-mode MOSFET or an N-channel enhancement-mode junction field effect transistor (NEJFET) As a bypass switch, a gate of the N-channel enhancement type MOS field-effect transistor is coupled to a starting resistor.

When the input voltage has not overcome the forward voltage drop of the last stage LED sub-array, The bypass switch string is turned off. Once the input voltage overcomes the forward voltage drop of the last stage LED sub-array, the input capacitance Ciss (not shown) between the gate-source of the N-channel enhancement type MOS field-effect transistor is charged to the threshold voltage via the startup resistor (threshold) Above, the bypass switch string is turned on, causing all of the bypass switches to enter an ON state.

After all bypass switches are turned on, during the first half of the input voltage, with the input power The voltage continues to rise. When the input voltage overcomes the forward voltage drop of the last stage LED sub-array, but has not overcome the forward voltage drop of the penultimate stage LED sub-array, the switch control circuit turns the last stage of the bypass switch into regulation. Regulating state; when the voltage continues to rise to overcome the forward voltage drop of the penultimate LED sub-array, the switch control circuit turns the next-stage bypass switch into an OFF state, and so on. The bottom-up way lights up step by step LED sub-array.

During the second half of the input voltage, the input voltage is gradually reduced, and the input power is still sufficient. To overcome the forward voltage drop of all of the LED sub-arrays of the LED sub-array chain, the first-stage bypass switch remains in the OFF state; the input voltage gradually drops to the inability to overcome the forward direction of all of the LED sub-arrays The voltage, but still overcomes the forward voltage drop of the LED sub-array below the second stage, the switch control circuit switches the first stage bypass switch from the OFF state to the regulated state; when the input voltage continues to fall to the insurmountable The forward voltage drop of the LED sub-array below the second stage, the switch control circuit turns the first-stage bypass switch from the regulated state to the conductive state, and so on, so that the LED sub-array is extinguished step by step from top to bottom.

The programmable current sensing circuit includes a switch control circuit and a shared current sensing Shared current sense and modulation unit. The switch control circuit is configured to compare the voltage across the shared current sensing and modulation unit and a reference voltage to switch the on or off of the bypass switch of the switching regulator array to stabilize the current value through the LED sub-array.

The shared current sensing and modulation unit is, for example, any adjustable variable resistance component. Including a potentiometer, commonly known as a variable resistor, the resistance of the potentiometer is modulated to control the current passing therethrough by virtue of the resistance being inversely proportional to the current. The shared current sensing and modulation unit can also be implemented by a transistor, including a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) and a Junction Field-Effect Transistor (Junction Field-Effect Transistor, JFET) is a voltage-controlled resistor, or a switching element (transistor switch) including a Bipolar Junction Transistor (BJT) and a MOS field-effect transistor.

The transistor switch directly controls the formation of the current loop through the LED sub-array Or not, to adjust the average current through the LED sub-array. Alternatively, the transistor switch can be connected in parallel with a current sensing resistor. When the transistor switch is turned on, the resistor can be bypassed so that the equivalent current sensing resistance value of the current passing through the LED sub-array is low. The current through the LED sub-array is large. When the transistor switch is turned off, the equivalent current sensing resistance value passing through the current of the LED sub-array is relatively high, and the current through the LED sub-array is small, thereby adjusting the brightness of the LED.

In an embodiment, a switch can be included, including a total of contacts and a plurality of Switch contacts. One of the switch contacts is a floating pin. When the common contact is connected to the floating pin, all LED sub-arrays are turned off. The other of the switch contacts is directly coupled to the current regulator. When the common contact is connected to the switch contact, the circuit has the highest resistance, so that the brightness of the LED sub-array is minimized. Except for the floating pin and the switch contact, the other switch contacts are respectively coupled to different transistor switches, and the transistor switches are respectively connected with a series resistor (the series resistor is disposed in the loop of the LED sub-array) The different sections are connected in parallel. When the common contact is coupled to one of the switch contacts, and the transistor switch coupled to the switch contact is turned on, the corresponding resistance section can be bypassed for modulating (lowering) the loop in the LED sub-array The resistance value to adjust the brightness of the LED sub-array.

In one embodiment, another switch is included, including at least one common contact, a first switch contact, a second switch contact, a third switch contact, and a fourth switch contact. When the common contact is connected to the first switch contact, the maximum brightness of the main LED array can be provided. When the common contact is connected to the second switch contact, a smaller brightness of the main LED array can be provided. When the common contact is connected to the third switch contact, the LED brightness of the sub-LED array can be provided. When connected When the point is connected to the fourth switch contact (floating pin), all LED arrays can be turned off.

In an embodiment, a valley filling circuit may be further included to The current required to illuminate the LED sub-array. In various embodiments, the valley fill circuit can include a valley fill capacitor that supplies a constant current to the LED sub-array and recharges to a fixed valley voltage to prepare for the next stage of discharge. The valley fill capacitor can also be charged in equal proportions according to the voltage drop caused by the current supplied to the LED sub-array to prepare for the next stage of discharge.

In an embodiment of the invention, a voltage regulator array is further included, including A plurality of voltage regulators are respectively coupled between the input voltage and the switching regulator to stabilize the turn-on voltage of the bypass switch, so that the conduction state of the bypass switch is not affected by the falling edge of the input voltage of the DC pulse influences.

In an embodiment of the invention, a sinusoidal voltage compensator is further coupled to Between the input voltage and the switch control circuit, the input voltage of the DC pulse is taken to compensate the voltage waveform of the light-emitting diode, so that the voltage waveform is modified from the step wave to a waveform closer to the sine wave, further improving Power factor.

The above embodiment may further include an active dummy load and a three-pole AC switch. The dynamic dummy load actively divides the full-wave/half-wave rectifier to keep the line current above the holding current (minimum dimming condition) to avoid flicker. When adjusting the potentiometer/variable resistor, the analog dimming signal, the pulse width modulation signal or the Bluetooth signal usage rate, since the quasi-sinusoidal LED/line current system is proportionally amplified or reduced, there is almost no waveform distortion, so it can be maintained. The same high power factor and the same low total harmonic distortion.

AC‧‧‧AC voltage source

100‧‧‧Rectifier

101‧‧‧ trigger circuit

120‧‧‧current regulator

140, 142, 144‧‧‧ switch control circuit

160, 160a, 160b, 160c, 160d, 160e, 160f, 165‧‧‧ shared current sensing and modulation unit

180, 182, 184‧‧ ‧ voltage regulator

VF, 200a, 200b‧‧‧ Valley Filling Circuit

220a, 220b‧‧‧ judgment circuit

300‧‧‧Active dummy load

C2, C4, C5, C5', C6, C7, C8, Cf, Cv, Cz, C51, C53, C55‧‧‧ capacitors

F‧‧‧Voltage Follower

PWM‧‧‧ pulse width modulation unit

R3, R4, R5, R6, R7 R9, R11, R12, R16, R18, R20, Rv1, Rv2, Rv3, Rv4, Rn, Rp1, Rp2, Rp3, Rp4, Rb1, Rb2, Rb3, r0, r1, r2 , r3, r4, r5, r6, r8, r9, r10, r11, r14, r15, r16, rb, Rx, Ra, Ra1, Ra2, Ra3, Ra4, Ra5, Ra6, Ra9, Ra10, Ra11, Ra20, Ra22 , Rb, Rb1, Rb2, Rb3, Rb4, Rb5, Rb6, Rb22, Rc1, Rc2, Rc3, Rc4, Rc5, Rc6, Rd1, Rd2, Rd3, Re1, Re2, Re3, Rg1, Rg2, Rg3, Rs9, Rs10 , Rs11, R22, R24, R30, R32, R34, R36, R50, R51, R52, R53, R54, R55, R56, R57, R58, R59‧‧‧ resistor

R1, R2‧‧‧ sinusoidal voltage compensator

SW, SW’‧‧‧Toggle switch

Vcom‧‧‧ joints

P1, P2, P3, P4, Y1, Y2, Y3, Y4, Y5‧‧‧ switch contacts

G‧‧‧LED array

G1, G2, Gn, Gn+1, L9, L10, Ln1, Ln2‧‧‧LED subarray

S1, S2, Sn‧‧‧ bypass switch

Z1, Z2, Z3, Z4, Z5, Z6, Z8, Zn, Zb‧‧‧ Zener diode

D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D12, Dx, Dy, Dz, Dp‧‧‧ diode

X2, X4, X5, X6, X‧‧‧ shunt regulator

M1, M2, M3, M18, Mb, Mn, M50, M52, M54, B1, B2 B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14, B15, B16, B18, B20, B22, B50, B52, B54, B, Bb, Bn, Bv1, Bv2‧ ‧‧Optocrystal

T1, T2, T3, T4, 160g, 165g‧‧‧ nodes

Tr‧‧‧ three-pole AC switch

1 is a schematic diagram showing the circuit architecture of a lighting device in accordance with the present invention. The illumination device includes an electronic control unit for the dimmable LED light engine and an external LED array (divided into a plurality of light emitting diode sub-arrays). The electronic control unit of the dimmable LED light engine includes a current regulator and a switching regulator array. The switching regulator includes a bypass switch and a programmable current sensing circuit. The programmable current sensing circuit comprises a switch control circuit and a shared current sensing and modulation unit. The switch control circuit compares the voltage across the current sensing and modulation unit and a reference voltage to switch the bypass switch to be turned on. The state, the regulated state, or the cutoff state, the shared current sensing and modulation unit controls the current through the LED sub-array to adjust the illumination brightness.

The embodiment shown in FIG. 2A is a detailed circuit diagram of an electronic control unit having a dimmable LED light engine in accordance with FIG. The switching regulator array includes a plurality of switching regulators, each including a bypass switch and a programmable current sensing circuit. The bypass switch corresponds to an N-channel depletion-mode metal oxide semiconductor field effect transistor (NDMOSFET). The programmable current sensing circuit comprises a switch control circuit and a shared current sensing and modulation unit. The switch control circuit includes a shunt regulator and a voltage dividing circuit for switching the bypass switch to be turned on or off.

2B is another schematic circuit diagram of the electronic control unit with the dimmable LED light engine of FIG. 1. The difference from FIG. 2A is that the switch control circuit controls the switching regulator to be turned on or off through a dual carrier junction transistor.

Figure 3A shows an electronic control of the dimmable LED light engine in accordance with Figure 1. A specific circuit schematic of the device. The difference from FIG. 2A is that the switch control circuit includes a bi-carrier junction transistor and a voltage dividing circuit for switching the switching regulator to be turned on or off.

FIG. 3B is a schematic diagram showing another specific circuit of the electronic control device with the dimmable LED light engine according to FIG. The difference from FIG. 3A is that the switch control circuit switches the switching regulator to turn on or off through a pair of carrier junction transistors.

4A is a schematic diagram of a specific circuit of an electronic control device with a dimmable LED light engine in accordance with FIG. The difference from FIG. 2A is that the bypass switch of the switching regulator corresponds to an n-channel enhancement-mode metal oxide semiconductor field effect transistor (NEMOSFET).

4B is another detailed circuit diagram of the electronic control unit with the dimmable LED light engine of FIG. 1. The difference from FIG. 4A is that the switch control circuit controls the switching regulator to turn on or off through a pair of carrier junction transistors.

FIG. 5A is a schematic diagram showing a specific circuit of an electronic control device with a dimmable LED light engine according to FIG. The difference from FIG. 4A is that the switch control circuit includes a dual carrier junction transistor and a voltage dividing circuit for switching the switching regulator to be turned on or off.

FIG. 5B is a schematic diagram showing another specific circuit of the electronic control device with the dimmable LED light engine according to FIG. The difference from FIG. 5A is that the switch control circuit controls the on or off of the switching regulator through a pair of carrier junction transistors.

5C-5D are schematic diagrams showing different circuits of the electronic control unit with the dimmable LED light engine according to FIG. In FIGS. 5C-5D, the electronic control device of the dimmable LED light engine includes a switch including a common contact and a plurality of switch contacts. The common contact is coupled to the positive end of the rectifier, wherein one of the switch contacts is a floating pin, when connected When the floating pin is connected, all LED sub-arrays are turned off. The remaining switch contacts correspond to the resistance values of different segments respectively. By using the common contacts to connect different switch contacts, the equivalent current sense resistance value passing through the current of the LED sub-array can be modulated to be used for planning. The magnitude of the current in the LED sub-array, thereby modulating the brightness of the LED sub-array.

Figure 6A shows an electronic control of the dimmable LED light engine in accordance with Figure 1. A schematic diagram of a circuit of the device. FIG. 6A illustrates a specific implementation of a shared current sensing and modulation unit, which may include a low pass filter, a voltage follower, a voltage dividing resistor, and a metal oxide half field effect transistor (MOSFET), using pulse width modulation. (Pulse Width Modulation, PWM) signal, controlling the current through the gold oxide half field effect transistor and the LED sub-array.

Figure 6B shows the electronic control of the dimmable LED light engine according to Figure 1. Another circuit schematic of the device. FIG. 6B illustrates a specific implementation of the shared current sensing and modulation unit, which may include a resistor and a dual-carrier junction transistor (BJT), which is controlled by a pulse width modulation (PWM) signal. The conduction and the turn-off of the sub-junction transistors are used to control the magnitude of the average current through the LED sub-arrays.

Figure 6C shows the electronic control of the dimmable LED light engine according to Figure 1. A further circuit schematic of the device. FIG. 6C illustrates a specific implementation of the shared current sensing and modulation unit, which may include a resistor and a MOS field effect transistor, and the pulse width modulation (PWM) signal is used to control the MOSFET through the MOS field. The turn-on and turn-off, according to which the average current through the LED sub-array is controlled.

6D-6E are schematic diagrams showing different circuits of the electronic control unit with the dimmable LED light engine of FIG. Sharing current sensing and FIG. 6D to 6E Different embodiments of the modulation unit may include a series resistor and a transistor switch, and one end of one of the series resistors is coupled to both ends of a channel of a transistor switch. Whether the resistance of one of the series resistors is bypassed by the transistor switch is determined by whether the transistor switch is turned on or off, thereby controlling the resistance value of the equivalent current sensed by the current through the LED sub-array, and controlling the passing of the LED The size of the current in the array.

Figure 6F shows the electronic control of the dimmable LED light engine according to Figure 1. Another circuit schematic of the device. Another embodiment of a shared current sensing and modulation unit is illustrated in FIG. 6F, with a potentiometer (ie, a variable resistor) implemented as a shared current sensing and modulation unit.

Figure 7 shows the electronic control of the dimmable LED light engine in accordance with Figure 1. A specific circuit diagram of the device. The difference from FIG. 5A is that the electronic control device of the dimmable LED light engine further includes a voltage regulator array including a plurality of voltage regulating circuits for stabilizing the conduction state of the bypass switch. The voltage regulator array is suitable for the circuit structure of any of the foregoing embodiments.

Figure 8A shows the dimming LED light guide with the valley filling circuit shown in Figure 1. A specific circuit diagram of the electronic control device. Except for the last stage LED sub-array, the cathode of each stage of the LED sub-array is connected in series with a diode, and then connected in parallel with the corresponding switching regulator. The valley filling circuit has a first energy storage capacitor and a second energy storage capacitor, and the second energy storage capacitor is connected in series to compensate a light-emitting diode (compensate LED). The input voltage charges the first storage capacitor and the second storage capacitor in a high voltage section of the input voltage. In the low voltage section of the input voltage, the first storage capacitor is discharged, and the current is transmitted to the LED sub-array of the next stage through the respective switching regulators, so that the LED sub-arrays of the respective stages are lit in parallel. At the same time, the second storage capacitor discharges, current The compensated LEDs are connected in series to illuminate the compensation LEDs to improve the condition of the dark areas of the dead time.

FIG. 8B is a schematic diagram showing a specific circuit of an electronic control device with a dimming LED light engine in FIG. In addition to the last stage of the LED sub-array, each stage of the LED sub-array is connected in parallel with the corresponding switching regulator. The valley filling circuit has a storage capacitor. In the high voltage section of the input voltage, the input voltage charges the storage capacitor. At the same time, the charging current is connected to the compensation LED, and the compensation LED is lit to increase the brightness. In the low voltage section of the input voltage, the storage capacitor discharges, and the current is transmitted to the next-level LED sub-array through each switching regulator, so that the LED sub-arrays of each level are lit in parallel to improve the condition of the dark area of the dead time. The above embodiment may further include an active load and a three-pole AC switch. The active load actively divides the full-wave/half-wave rectifier to maintain the line current of the three-pole AC switch at a minimum dimming condition. Avoid flickering.

Generally, the output voltage of the AC power source is a sinusoidal waveform, and after being rectified by the rectifier, the pulse voltage of the pulsed DC waveform of the first half of the sine wave is applied to the LED lighting device.

At the beginning of the first half of each cycle and the low voltage section at the end of the second half, the input voltage cannot overcome the forward voltage drop of the LED, and no current flows, forming a dead time. In addition, LED lighting devices are typically constructed from LED sub-arrays. When the number of LEDs connected in series is large, the forward voltage drop is increased, so that the dead time becomes larger, the conduction angle becomes narrower, and the power factor is lowered.

For the problem of narrow conduction angle, the traditional solution is to use the power factor corrector to push the rectified AC voltage above the sum of the forward voltage drops of all LED sub-arrays. The constant current voltage value. However, the electrolytic capacitor used in the power factor corrector is easily damaged, so that the light-emitting diode cannot perform the intended effect.

The lighting strategy of the present invention is to cut the LED array into several LED sub-arrays. (subarray). The electronic control device of the LED light engine formed by the switching regulator string, in the first half cycle of the cycle, as the input voltage rises, the LED sub-array is illuminated step by step from bottom to top, and the line current is gradually increased; In the second half cycle of a cycle, as the input voltage decreases, the LED sub-array is extinguished step by step from top to bottom, thereby increasing the conduction angle and modifying the current mode.

In addition, the brightness of the LED can be adjusted by adjusting the current through the LED. That is, when there are multiple segments of the LED sub-array that need to be dimmed, the resistance values of the segments of the LED sub-arrays can be adjusted in stages, thereby changing the current through each segment of the LED sub-array to adjust the brightness of each segment of the LED. However, such a dimming mechanism is not easy to implement on a circuit structure, and requires high manufacturing cost and manufacturing difficulty. In particular, the more the number of segments of the LED sub-array, the higher the manufacturing cost and difficulty of the circuit. Therefore, the dimming strategy of the present invention, that is, an electronic control device for providing a dimmable LED light engine that simplifies the dimming mechanism, can achieve equal proportion segmentation by using only one shared current sensing and modulation unit. The effect of dimming.

Referring to Figure 1, the electronic control unit of the dimmable LED light engine includes current a regulator (current regulator) 120 and a switching regulator array, the switching regulator array has a plurality of switching regulators, each of the switching regulators respectively including a bypass switch and a programmable current sensing circuit (programmable current sensing circuit) The planning current sensing circuit includes a switch control circuit and a shared current sensing and modulation unit.

For example, the first set of switching regulators includes a bypass switch S1 and programmable power Influenza measuring circuit (including switch control circuit 140 and shared current sensing and modulation unit 160), the second group of switching regulators includes a bypass switch S2 and a programmable current sensing circuit (including switch control circuit 142 and shared current sensing) And the modulation unit 160), the nth group of switching regulators includes a bypass switch Sn and a programmable current sensing circuit (including the switch control circuit 144 and the shared current sensing and modulation unit 160).

Switch control circuits 140, 142, and 144 compare shared current sensing and modulation units The voltage at both ends and a reference voltage respectively switch the operating states (on, off, or off) of the bypass switches S1, S2, and Sn. The shared current sensing and modulation unit 160 is, for example, a potentiometer (also known as a variable resistor) or a voltage controlled resistor containing a transistor, and adjusts the impedance of the resistor to adjust the sharing to the light emitting diode. Body current. The shared current sensing and modulation unit 160 may also include a transistor switch to adjust the average current through the light emitting diodes by utilizing the turn-on and turn-off of the transistor switches. The voltage control resistor is, for example, a gold oxide half field effect transistor (MOSFET) or a junction field effect transistor (JFET).

During the first half of the input voltage, the input voltage gradually increases from zero. When the input voltage has not overcome the forward voltage drop (V _Gn+1 ) of the last stage LED sub-array, no current passes through the last stage LED sub-array (G _i+1 ), and the switch control circuit 144 fails to generate a voltage control signal, bypassing The switches (S1, S2, Sn) maintain an ON state. As the input voltage rises to overcome the forward voltage drop (V _Gn+1 ) of the last stage LED sub-array Gi+1, but has not overcome the forward voltage drop of the second-order second LED sub-array Gn (V _Gn+1) +V _Gn ), the bypass switch S2 is originally in an on state, and the current passes through the bypass switch S2 to the lower LED sub-array Gn+1, and then the switch control circuit 144 detects that the last-level LED sub-array Gn+1 is turned on, generating voltage control. The signal is turned off the bypass switch S2, so that the bypass switch S2 quickly switches between the on and off states during this phase, which is called a regulatory state. The voltage continues to rise to overcome the forward voltage drop of the penultimate LED sub-array Gn (V _Gn+1 +V _Gn ), and the current passes through the last-stage LED sub-array Gn through the last-level LED sub-array (Gn+1), The switch control circuit 142 generates a voltage control signal to keep the bypass switch S2 off. This phase is called an OFF state, and the switch control circuit 140 detects the voltage across the shared current sensing and modulation unit 160 (along with The voltage rises from the current stage to the upper switch control circuit for detection. The switch control circuit 140 causes the third-order bypass switch S1 to start to transition, so that the LED sub-array is illuminated step by step from the bottom up.

During the second half of the input voltage, the input voltage gradually decreases. When the input voltage still overcomes the forward voltage drop of the first-stage LED sub-array G1 (V _Gn+1 +V _Gn +...+V _G2 +V _G1 ), the bypass switch S1 is maintained in the OFF state, the current The first stage LED sub-array G1 passes through each stage of the LED sub-array to the last stage of the LED sub-array (Gn+1). The input voltage continues to drop to the inability to overcome the forward voltage below the first-level LED sub-array G1 (V _Gn+1 +V _Gn +...+V _G2 +V _G1 ), but still overcomes the second-level LED sub-array G2 When the forward voltage (V _Gn+1 +V _Gn +...+V _G2 ), the switch control circuit 140 switches the bypass switch S1 from off to on, and then switches from on to off. In this phase, the bypass switch S1 continuously switches the cut-off and conduction states to enter the Regulating state. When the input voltage continues to drop to overcome the forward voltage drop of the second stage LED sub-array G2 (V _Gn+1 +V _Gn +...+V _G2 ), the switch control circuit switches the bypass switch S1 from the regulated state to the conducting state. (ON state), at the same time, the switch control circuit 142 detects the voltage across the shared current sensing and modulation unit (as the voltage drops, the current level moves to the lower switch control circuit for detection), and is extinguished step by step from top to bottom. The LED sub-array is cycled until the end of the cycle, then re-cycled.

It is worth noting that the number of LED sub-arrays shown in the figure is only indicative. For convenience of explanation, a fourth-order LED sub-array (third-order bypass switch) is taken as an example, and the number or form of the LED sub-array embodying the present invention is not limited.

Referring to FIG. 2A, the embodiment shown is a specific circuit diagram of the electronic control device with the dimmable LED light engine according to FIG. The switching regulator array includes a plurality of switching regulators, each including a bypass switch S1, S2 or Sn and a programmable current sensing circuit. The bypass switch S1, S2 or Sn is a normally closed switch, for example, an N-channel depletion-mode metal oxide semiconductor field effect transistor (NDMOSFET), which is in the gate When the potential difference between the sources is zero or is not subjected to voltage (V _GS ≧0), the potential difference between the gate and the source is a sufficiently negative voltage (V _GS <V _th <0, V _th indicates the cutoff of the transistor) When the voltage is applied, the channel is turned off. Each of the programmable current sensing circuits includes a switch control circuit 140, 142 or 144, and a shared current sensing and modulation unit 160.

Switch control circuits 140, 142, ... or 144 include shunt regulators, respectively (shunt regulator) X2, X4 or X6 and voltage dividing circuit (voltage dividing resistor r0 and r2, voltage dividing resistor r4 and r6 or voltage dividing resistor r8 and r10) for switching bypass switch S1, S2, ... or Sn Turn on or off.

The voltage dividing node voltage of the voltage dividing circuit shares the current sensing and the voltage across the voltage modulation unit through the voltage dividing circuit. When the last LED sub-array Gn+1 is turned on, the voltage of the voltage dividing node T3 is made. The shunt regulator X6 is turned on, and the current is grounded by the anode of the last stage LED sub-array Gn+1 via the resistor r5 and the resistor r11, through the shunt regulator X6 to the resistor R2. Therefore, the potential difference between the gate and the source of the bypass switch Sn can be approximated by the forward voltage drop (V _Gn+1 ) of the last stage LED sub-array Gn+1 through the voltage division of the resistor r11 and the resistor r5, and the voltage division provides The gate of the bypass switch Sn receives a sufficiently negative voltage to turn off the bypass switch Sn. However, the input voltage at this time cannot overcome the forward voltage of the first and second LED sub-arrays Gn+1 and Gn ( V _Gn+1 +V _Gn ), so that the bypass switch Sn is quickly switched on and off during this phase, which is called an adjustment state.

As the input voltage overcomes the forward voltage (V _Gn+1 +V _Gn ) of the first and second LED sub-arrays Gn+1 and Gn, the inverse first, second and third LED sub-arrays Gn+1 have not been overcome. , the forward voltage drop of Gn and G2 (V _Gn+1 +V _Gn +V _G2 ), the current flows from the bypass switch S1 and S2 through the source of the bypass switch S2 to the LED sub-arrays Gn and Gn+1, The current flows through the resistor r9 and the resistor r3, and is grounded through the parallel regulator X4 to the resistor R2. Therefore, the potential difference between the gate and the source of the bypass switch Sn can be approximated by the forward voltage drop (V _Gn+1 +V _Gn ) of the last two-level LED sub-array Gn+1 and Gn through the resistor r9 and the resistor r3. Pressing, this divided voltage provides a gate voltage source of the bypass switch S2 to receive a sufficiently negative voltage, so that the bypass switch S2 is turned off, which is called an off state. At this time, current flows to the LED sub-arrays G2, Gn, and Gn+1 through the bypass switch S1.

When the input voltage is between the forward three-level LED sub-arrays Gn+1, Gn and G2, the forward voltage drop (V _Gn+1 +V _Gn +V _G2 ) and the last four LED sub-arrays Gn+1, Gn, G2 and When the forward voltage drop of G1 (V _Gn+1 +V _Gn +V _G2 +V _G1 ) is between, the bypass switch S1 enters the regulation state. Until the input voltage overcomes the forward voltage drop of the four LED sub-arrays Gn+1, Gn, G2, and G1 (V _Gn+1 +V _Gn +V _G2 +V _G1 ), the bypass switch S1 is subjected to the shunt regulator X2. Control and cut off. The current passes directly through and illuminates the LED sub-arrays G1, G2, Gn, and Gn+1. The control method of the bypass switch by the switch control circuit has been described above, and will not be described herein.

During the second half of the input voltage, the input voltage gradually decreases. Controlled by switches The parallel regulator X2, X4 or X6 of the circuit 140, 142 or 144 detects the voltage across the shared current sensing and modulation unit and is turned on or off, and controls the resistor r1 and the resistor r7, the resistor r3 and the resistor r9, the resistor r5 or the resistor. The loop of r11 is formed or not. When the loop is formed, a negative voltage is generated between the gates of the bypass switch S1, S2 or S3, and the operating state of the bypass switch S1, S2 or S3 can be controlled, and the LED sub-arrays G1, G2, Gn and the LED sub-arrays are extinguished step by step. Gn+1.

In the embodiment, the gate and the source of the bypass switch S1, S2 or S3 are further arranged. With the Zener diodes Z1, Z2 and Z3, the gate voltage of the bypass switch S1, S2 or S3 can be controlled to the breakdown voltage Vz of the Zener diode to protect the bypass switch S1, S2 or S3. The insulation between the gate and source is not broken down.

The following describes the dimming mechanism. In the case of node 160g, it is assumed that the flow is ignored. By controlling the currents of circuits 140, 142, and 144, the current flowing through shared current sensing and modulation unit 160 can approximate the current flowing to the illuminated LED sub-array. Therefore, the brightness of the illuminated LED sub-array can be controlled by the current through the shared current sensing and modulation unit 160.

In an embodiment, the resistor R1 and the resistor R2 are selectively disposed. First, test The value of the resistor R1 is approximately infinite, and the value of the resistor R2 is approximately zero, that is, the case where the resistor R1 is open and the resistor R2 is short-circuited. During the first half of the input voltage, as the input voltage (line voltage) rises, the number of stages of the lit LED sub-array increases. It can be designed that when only the last stage LED sub-array Gn+1 is lit, the current through the LED sub-array Gn+1 is I1, and the countdown two-level LED sub-arrays Gn+1 and Gn are all lit, through the LED The currents of the sub-arrays Gn+1 and Gn are I2, and the latter three-level LED sub-arrays Gn+1, Gn and G2 When all are lit, the current through the LED sub-arrays Gn+1, Gn, and G2 is I3 (current I3 > current I2 > current I1), and the current is regulated by the current regulator 100 and the switching regulator array to be a fixed current output. The current I1, the current I2, and the current I3 exhibit a sinusoidal (Vasi-sinusoidal wave) step waveform.

When the input voltage overcomes only the last stage LED sub-array Gn+1, the current flowing through the shared current sensing and modulation unit 160 (approx. current I1) and the shared current sensing and the resistance of the modulation unit 160 ( That is, the potential of the node 160g reaches the reference voltage of the shunt regulator X6, so that the shunt regulator X6 is turned on, and the reference voltage (V _ref ) of the shunt regulator X6 is approximately set as the voltage divider of the resistor r8 and the resistor r10 (I ₁ ×R ₁₆₀ × = V _ref ). At this time, the gate potential of the bypass switch Sn is pulled low by the loop formed by the resistor r11 and the resistor r5 via the shunt regulator X6. As a result, the gate of the bypass switch Sn is applied with a sufficient negative voltage to turn off the LED sub-array.

When the input voltage only overcomes the countdown secondary LED sub-arrays Gn and Gn+1, the current flowing through the shared current sensing and modulation unit 160 (approx. current I2) and the shared current sensing and modulation unit 160 are blocked. The product of the value reaches the reference voltage of the shunt regulator X4, so that the shunt regulator X4 is turned on, and the reference voltage (V _ref ) of the shunt regulator X4 is approximately set to the voltage division of the resistor r4 and the resistor r6 (I ₂ × R ₁₆₀ × = V _ref ). At this time, the gate potential of the bypass switch S2 is pulled low by the loop formed by the resistor r3 and the resistor r9 via the shunt regulator X4. As a result, the gate of the bypass switch S2 is applied with a sufficient negative voltage to turn off the LED sub-array.

Similarly, when the input voltage overcomes only the inverse three-level LED sub-arrays G2, Gn, and Gn+1, the current flowing through the shared current sensing and modulation unit 160 (approx. current I3) and the shared current sensing and modulation The product of the resistance of the variable unit 160 reaches the reference voltage of the shunt regulator X2, so that the shunt regulator X2 is turned on, and the reference voltage (V _ref ) of the shunt regulator X2 is about the voltage division of the resistor r0 and the resistor r2 (I ₃ × R ₁₆₀ × = V _ref ). At this time, the gate potential of the bypass switch S1 is pulled low by the loop formed by the resistor r1 and the resistor r7 via the parallel regulator X2. As a result, the gate of the bypass switch S1 is applied with a sufficient negative voltage to turn off the LED sub-array.

The mechanism for stabilizing current illuminating the LED sub-array is explained below. When the input voltage overcomes the forward voltage drop of the last stage LED sub-array Gn+1, but is insufficient to overcome the forward voltage drop of the inverse two-stage LED sub-arrays Gn and Gn+1, the current I1 is sensed and modulated by the shared current. The voltage of the unit 160 at the node 160g (for example, V ₁₆₁ ), the voltage division of the resistors r8 and r10 at the node T3 causes the shunt regulator X6 to rapidly switch between the on and off states, so that the bypass switch Sn is subjected to the shunt regulator The control of X6 is rapidly switched between the off-state and the on-state, and the bypass switch Sn is now operated in the regulation state to maintain the current through the last-stage LED sub-array Gn+1 at the current I1.

When the input voltage overcomes the forward voltage drop of the last two LED sub-arrays Gn and Gn+1, but is insufficient to overcome the forward voltage drop of the last three LED sub-arrays G2, Gn, and Gn+1, the current I2 is shared. The voltage of the sensing and modulation unit 160 at the node 160g (for example, V ₁₆₂ ) is divided by the voltages of the resistors r4 and r6 at the node T2, so that the shunt regulator X4 is rapidly switched between the on and off states, so that The bypass switch S2 is rapidly switched between the off-state and the on-state by the control of the shunt regulator X4, and the bypass switch S2 is defined to operate in the regulation state to pass the last two-level LED sub-arrays Gn and Gn+1. The current is maintained at current I2. At the same time, since the voltage (V ₁₆₂ ) is greater than the voltage (V ₁₆₁ ), the voltage (V ₁₆₂ ) is divided by the voltages of the resistors r8 and r10 at the node T3, which inevitably causes the shunt regulator X6 to be turned on and the bypass switch Sn to be turned off. , to operate in the cutoff state.

By analogy, when the input voltage overcomes the forward voltage drop of all LED sub-arrays, current I3 is shared by current sensing and modulation unit 160 at node 160g (V ₁₆₃ ), via resistors r0 and r2 at node T1. The partial pressure causes the shunt regulator X2 to rapidly switch between on and off, so that the bypass switch S1 is controlled by the shunt regulator X2 to operate in an adjusted state to maintain the current through the last stage LED sub-array Gn+1 at the current I3. . At this time, the voltage (V ₁₆₃ ) is divided by the voltages of the nodes T2 and T3, and the parallel regulators X4 and X6 are inevitably turned on, and the bypass switches S2 and Sn are operated in the off state.

Next, consider that the resistor R1 and the resistor R2 are between 0 and infinity (0 < R1 < ∞ and 0 < R2 < ∞). When only the last stage LED sub-array Gn+1 is illuminated, the current passing through is I1. The reference voltage (V _ref ) of the shunt regulator X6 is equal to the product of the current I1 and the resistance of the shared current sensing and modulation unit 160 (ie, the voltage value of the node 160g), minus the input voltage through the resistor R1 and the resistor R2. After the partial pressure, the partial pressure of the resistor r8 and the resistor r10, that is, =V _ref . In other words, the value of the reference voltage of the shunt regulator X6 is compensated by the input voltage via the sinusoidal voltage compensator (resistor R1 and resistor R2), and the compensation value is the DC pulse after the input voltage is rectified by the rectifier 100. a part of. Therefore, a sinusoidal step waveform such as a line current sharing the current sensing and modulation unit 160 is compensated to be closer to the waveform of the sine wave, and thus closer to the waveform of the line voltage. In this way, the power factor and the harmonic distortion can be further improved. Similarly, the values of the reference voltages of the shunt regulators X2 and X4 are also compensated by the voltage division of the input voltage, which further improves the power factor and reduces harmonic distortion.

In summary, the electronic control of the dimmable LED light engine depicted in Figure 2A The device controls the source gate voltage of the stage bypass switch by using a forward voltage drop including the LED sub-array of the current stage and the LED sub-array below the stage, thereby adjusting the operating state of the stage bypass switch (conduction, regulation) Or the off state), thereby correspondingly controlling the lighting or extinguishing state of the LED sub-array, and stabilizing the current through the LED sub-array.

With the rising edge of the voltage waveform in the first half of the cycle, the line current rises, LED The sub-array lights up step by step, and the current that illuminates the LED sub-array rises. As the voltage mode of the second half of the cycle falls, the line current decreases, the LED sub-array is extinguished step by step, and the current that illuminates the LED sub-array decreases. Since the current through the shared current sensing and modulation unit 160 is similar to the current through the LED sub-array, by adjusting the current through the single shared current sensing and modulation unit 160, the LED sub-array can be correspondingly adjusted. The current, proportionally scales the current that illuminates the LED sub-arrays of each stage.

2B is an electronic control of the dimmable LED light engine according to FIG. Another specific circuit schematic of the device. The difference from FIG. 2A is that each switch control circuit controls the switching regulator to be turned on or off through a pair of carrier junction transistors. The collectors of the dual-carrier junction transistors are respectively coupled to the cathodes of the LED sub-arrays, such that the source gates of the bypass switches S1, S2, and Sn are applied with a driving voltage, and the driving voltages are respectively The forward voltage drop of the LED sub-array is divided by resistor r1 and resistor r7, resistor r3 and resistor r9, resistor r5 and resistor r11.

When the input voltage overcomes the forward voltage drop of the last stage LED sub-array Gn+1, but is insufficient to overcome the forward voltage drop of the inverse two-stage LED sub-arrays Gn and Gn+1, the current I1 is sensed and modulated by the shared current. The voltage of the unit 160 at the node 160g, the voltage division at the node T3 causes the shunt regulator X6 to rapidly switch between the on and off states, so that the pnp bipolar junction transistor (BJT) B3 is switched on. Between the off-state and the off-state, the bypass switch Sn is rapidly switched between the off-state and the on-state, so that the source gate voltage of the bypass switch Sn is pulled down by the pnp bipolar junction transistor B3 through the resistor r5 and the resistor r11. (pull low), the gate of the bypass switch Sn is applied with a sufficient negative voltage, and the negative voltage is approximated by the forward voltage of the LED sub-array Gn+1 of the last stage falling to the voltage divider of the resistor r5 and the resistor r11. (V _Gn+1 × At this time, the bypass switch Sn operates in the regulation state to maintain the current through the last stage LED sub-array Gn+1 at the current I1.

When the input voltage overcomes the forward voltage drop of the last two LED sub-arrays Gn and Gn+1, but is insufficient to overcome the forward voltage drop of the last three LED sub-arrays G2, Gn, and Gn+1, the current I2 is shared. The voltage of the sensing and modulation unit 160 at the node 160g is divided by the voltage dividing resistor at the node T2, so that the shunt regulator X4 is rapidly switched between the on and off states, and the pnp bipolar junction transistor B2 is switched. Between the on and off, when the pnp bipolar junction transistor B2 is turned on, the source gate voltage of the bypass switch S2 is pulled down by the pnp bipolar junction transistor B2 through the resistor r3 and the resistor r9. The gate of the switch S2 is turned off by applying a sufficient negative voltage. The negative voltage is similar to the forward voltage of the second-order LED sub-array Gn falling to the voltage divider of the resistor r3 and the resistor r9 (V _Gn × The bypass switch S2 is switched to be turned off and on, at which time the bypass switch S2 is operated in an adjusted state to maintain the current through the last secondary LED sub-arrays Gn and Gn+1 at the current I2. At the same time, the shunt regulator X6 is turned on, and the bypass switch Sn operates in the off state.

By analogy, when the input voltage overcomes the forward voltage drop of all LED sub-arrays, the current I3 is shared by the current sensing and modulation unit 160 at the voltage of node 160g. The partial pressure of point T1 causes the shunt regulator X2 to rapidly switch on and off, causing the bypass switch S1 to operate in an adjusted state to maintain the current through all of the LED sub-arrays G1, G2, Gn, and Gn+1 at current I3. . At this time, the shunt regulators X2 and X3 are kept on, and the bypass switches S2 and Sn are kept off.

In summary, the electronic control of the dimmable LED light engine depicted in Figure 2B The device utilizes the forward voltage drop of the next-level LED sub-array to control the source gate voltage of the current-stage bypass switch, thereby adjusting the operating state (conduction, regulation or cut-off state) of the stage bypass switch, thereby correspondingly controlling The LED sub-array is lit or extinguished and stabilizes the current through the LED sub-array. The lighting mechanism and the dimming mechanism of the LED sub-array are the same as those of FIG. 2A, and are not described herein again.

Figure 3A shows an electronic control of the dimmable LED light engine in accordance with Figure 1. Another specific circuit schematic of the device. The difference from FIG. 2A is that the shunt regulators X2, X4 and X6 of the switch control circuits 140, 142 and 144 are replaced by bipolar junction transistors B4, B5 and B6. The base and the emitter of the bipolar junction transistor B4 are respectively coupled to the two ends of the resistor r2 of the voltage dividing resistor, and the base and the emitter of the bipolar junction transistor B5 are respectively coupled. Connected to the two ends of the resistor r6 of the voltage dividing resistor, the base and the emitter of the bipolar junction transistor B6 are respectively coupled to the two ends of the resistor r10 of the voltage dividing resistor.

Figure 3A shows the role of the bi-carrier junction transistors B4, B5 and B6 and Figure 2A The shunt regulators X2, X4 and X6 are similar. The main difference is that the action mechanism of the shunt regulator is to compare the voltage received by the reference terminal with its reference voltage to control the conduction or the cut-off of the shunt regulator. The action mechanism of the junction transistor is to control the conduction of the bi-carrier junction transistor by comparing the voltage received between the base and the emitter with its threshold voltage. Pass or cut off.

For example, when the input voltage overcomes the forward voltage drop of the last stage LED sub-array Gn+1, but is insufficient to overcome the forward voltage drop of the inverse two-stage LED sub-arrays Gn and Gn+1, the current I1 shares a sense of current. The voltage of the measuring and modulating unit 160 at the node 160g (V ₁₆₁ ), the voltage division at the node T3 after the resistors r8 and r10 causes the bipolar junction transistor B6 to rapidly switch between the on and off states, so that the side The switch Sn is rapidly switched between the off-state and the on-state by the control of the bipolar junction transistor B6, and the bypass switch Sn is operated in the regulation state to pass the last-level LED sub-array Gn+1. The current is maintained at current I1.

By analogy, when the input voltage overcomes the forward voltage drop of all the LED sub-arrays, the current I3 is shared by the current sensing and modulation unit 160 at the voltage of the node 160g (V ₁₆₃ ), after the resistors r0 and r2, at the node T1. The partial pressure causes the bipolar junction transistor B4 to rapidly switch between on and off, so that the bypass switch S1 is controlled by the bipolar junction transistor B4 to operate in an adjusted state to pass through the LED sub-array G2. The current of Gn and Gn+1 is maintained at current I3. At this time, the voltage (V ₁₆₃ ) is divided by the voltages of the nodes T2 and T3, and the bipolar junction transistors B5 and B6 are inevitably turned on, and the bypass switches S2 and Sn are operated in the off state. Conversely, at the falling edge of the half cycle of the input voltage, as the voltage drops, the bypass switches S1, S2, and Sn are controlled by the bipolar junction transistors B4, B5, and B6, respectively, and are turned on step by step, so that the LEDs are turned on. The arrays G1, G2, Gn, and Gn+1 are extinguished step by step.

The mechanism of dimming the shared current sensing and modulation unit 160 and the waveform of the line voltage of the input power source by using the sinusoidal voltage compensator (resistor R1 and resistor R2), the principle of modifying the line current waveform has been explained before. And will not repeat them.

Figure 3B shows the electronic control of the dimmable LED light engine according to Figure 1. Another specific circuit schematic of the device. The difference from FIG. 2B is that the shunt regulators X2, X4 and X6 of the switch control circuits 140, 142 and 144 are replaced by bipolar junction transistors B4, B5 and B6. The roles of the bi-carrier junction transistors B4, B5, and B6 are similar to those of FIG. 3A, and the mechanism of action thereof has been described in FIG. 3A, and details are not described herein again.

4A is an electronic control of the dimmable LED light engine according to FIG. Another specific circuit schematic of the device. The difference from FIG. 2A is that the Metal-Oxide-Semiconductor FET (MOSFET) of the bypass switches S1, S2 and Sn of this embodiment is enhanced, that is, the bypass switches S1 and S2. And Sn is normally open switches. When no voltage is applied to the gate source or the applied voltage is less than the threshold voltage, the bypass switch is turned off, and when the voltage applied to the gate source is greater than or equal to the threshold voltage When the bypass switch is turned on.

Since the bypass switches S1, S2, and Sn are normally open switches, an initial state needs to be established. The bypass switches S1, S2, and Sn are turned on. In the embodiment, the starting resistors Ra1 to Ra3 are respectively disposed between the gates and the drains of the bypass switches S1, S2, and Sn. In the first half of the cycle of the input voltage (rising edge), when the input voltage overcomes the forward voltage drop of the last stage LED sub-array, the first stage of the starting resistor Ra1 can draw the input voltage to the gate of the bypass switch S1, The capacitor (not shown) between the gate and the source of the bypass switch S1 is charged, so that the bypass switch S1 is turned on, and the current flows to the drain of the bypass switch S2 through the source of the bypass switch S1, and the second stage The starting resistor Ra2 connected to the drain of the bypass switch S2 then charges the capacitance between the gate and the source of the bypass switch S2, so that the bypass switch S2 is turned on. In this way, until the last stage of the bypass switch Sn is turned on to enter the regulation state to regulate the current at the current I1, the current flows to the last-stage LED sub-array Gn+1 through the bypass switches S1, S2, and Sn, and finally flows to the shared Current sensing and modulation unit 160. The detailed mechanism for illuminating the LED sub-array has been described above and will not be described again.

In the second half of the cycle of the input voltage (falling edge), when the forward voltage drop (V _Gn+1 ) of the last LED sub-array Gn+1 is divided by the resistor r8 and the resistor r10, the shunt regulator X6 is turned on. The source voltage of the bypass switch Sn is pulled low through the loop of the diode D3 and the resistor Rd3, so that the bypass switch Sn is turned off. When the forward voltage drop (V _Gn+1 +V _Gn ) of the last two-level LED sub-arrays Gn and Gn+1 is divided by the resistor r4 and the resistor r6, the shunt regulator X4 is turned on, and the source of the bypass switch S2 is turned on. The voltage is pulled low through the loop of diode D2 and resistor Rd2, causing bypass switch S2 to be turned off, and so on, to extinguish the LED sub-array step by step. The mechanism for extinguishing the LED sub-array has been described before and will not be described again.

Since the current flowing through the LED sub-array is similar to the flow through the shared current sensing and modulation The current of the variable cell 160 (the current flowing to the switch control circuit is small and negligible), so the brightness of the LED sub-array can be adjusted by regulating the current flowing to the shared current sensing and modulation unit 160.

4B is another detailed circuit diagram of the electronic control unit with the dimmable LED light engine of FIG. 1. This embodiment is not described in detail in the same manner as in FIG. 4A. The difference is that the operating states of the enhanced bypass switches S1, S2, and Sn are controlled by the conduction of the bipolar junction transistors B7, B8, and B9. . In FIG. 4B, when the normally open switches of the bypass switches S1, S2, and Sn are charged by the input voltage through the start resistors Ra1 to Ra3 between the gates and the drains of the bypass switches S1, S2, and Sn, and are established. After the initial state, the bypass switch S1 is in an on state, the bypass switch S2 is in an on state, and the bypass switch Sn is in an adjusted state. This is the lighting mode of the last-level LED sub-array Gn+1, in this way, with the input voltage The rise of the LED sub-array can be illuminated step by step.

In the second half of the cycle of the input voltage (falling edge), when the forward voltage drop (V _Gn+1 ) of the last LED sub-array Gn+1 is divided by the resistor r8 and the resistor r10, the shunt regulator X6 is turned on. The bipolar junction transistor B9 is turned on, and the gate voltage of the bypass switch Sn is pulled low, so that the bypass switch Sn is turned off. When the forward voltage drop (V _Gn+1 +V _Gn ) of the last two-level LED sub-arrays Gn and Gn+1 is divided by the resistor r4 and the resistor r6, the parallel regulator X4 is turned on, and the double-carrier junction transistor is turned on. B8 is turned on, the gate voltage of the bypass switch S2 is pulled low, the bypass switch S2 is turned off, and so on, to extinguish the LED sub-array step by step.

5A and 5B show the LED light engine with dimming according to FIG. A schematic diagram of a different embodiment of an electronic control unit. 5A and 5B are similar to FIGS. 4A and 4B, respectively, except that the bipolar junction transistors B4, B5 and B6 are used, and the voltage dividing resistors r0 and r2, r4 and r6, and r8 and r10 are used as the switch control. Circuits 140, 142, and 144. In FIG. 5A, the circuit of the diode D1 and the resistor Rg1, the circuit of the diode D2 and the resistor Rg2, and the diode D3 are respectively controlled by the on or off of the bipolar junction transistors B4, B5 and B6. Whether the loop of the resistor Rg3 is formed or not, thereby controlling the cut-off or conduction of the bypass switch. In FIG. 5B, the on or off of the bipolar junction transistors B1, B5, and B6 are controlled to turn on or off the bipolar junction transistors B1, B2, and B3, respectively, thereby controlling the cutoff of the bypass switch or Turn on.

5C~5D show the electric power of the dimmable LED light engine according to FIG. A schematic diagram of the different circuits of the sub-controller. In FIG. 5C, the electronic control device of the dimmable LED light engine includes a switch SW' including a common contact Vcom and a plurality of switch contacts Y1, Y2, Y3, Y4 and Y5. The shared current sensing and modulation unit 165 includes a series connection Resistor R50, R52, R54 and R56, the voltage at node 165g is V165g. The common contact Vcom is coupled to the positive terminal of the rectifier 100, the switch contact Y1 is a floating pin, and the switch contact Y2 is coupled to the current regulator 120, except for the switch contacts Y1 and Y2. The switch contacts Y3~Y5 are respectively coupled to the transistor switches B54, B52 and B50, and the transistor switches B50, B52 and B54 are respectively connected in parallel with different sections of a series resistor, and the series resistors include resistors R50, R52 and R54. And R56, the series resistor is disposed in the loop of the LED sub-array.

Zener diodes D51, D53 and D55 are used to protect the transistor switches B50, B52 Or B54. When the common contact Vcom is coupled to the switch contact Y5, Y4 or Y3, the input voltage charges the capacitor C51, C53 or C55 to the breakdown voltage Vz of the Zener diode. When the common contact Vcom is not coupled to the switch contact Y5, Y4 or Y3, the capacitor C51, C53 or C55 is discharged to 0 volts (V). Thus, when the common contact Vcom is coupled or uncoupled to the switch contact Y3, Y4 or Y5, the transistor switch B50, B52 or B54 corresponding to the switch contact Y5, Y4 or Y3 is turned on or off normally. Operating status.

LED subarray when the common contact Vcom is connected to the switch contact Y1 (floating pin) There is no current in the loops of columns G1~Gn+1, and all LED sub-arrays G1~Gn+1 are turned off (for example, providing 0% brightness). When the common contact Vcom is connected to the switch contact Y2, the function of the electronic control device of the dimmable LED light engine is similar to that shown in FIG. 5A. The positive terminal of the rectifier 100 is directly coupled to the current regulator 120, and through the LED sub-array. The current is planned by series resistors R50, R52, R54 and R56. At this time, the resistance value in the loop is large, the current through the LED sub-array is small, and the brightness of the LED sub-array is also small (for example, providing 25% brightness). .

When the common contact Vcom is connected to the switch contact Y3, the input voltage is transmitted to the Dx to The current regulator 120 is supplied to the LED sub-array. At the same time, the input voltage charges the capacitor C55 via the resistor R58, and the bipolar junction transistor B54 is turned on through the resistors R58 and R59 to bypass the resistor R56 in the series resistor. The current through the LED sub-array is planned by the series resistors R50, R52 and R54. At this time, the resistance value in the loop is slightly lowered, the current through the LED sub-array is slightly increased, and the brightness of the LED sub-array is also increased (for example, 50% is provided). brightness).

When the common contact Vcom is connected to the switch contact Y4, the input voltage is transmitted to the current regulator 120 via Dy for supply to the LED sub-array, and the input voltage is charged to the capacitor C53 via the resistor R55, and the dual-load is conducted through the resistors R55 and R57. The sub-junction transistor B52 is used to bypass the resistors R54 and R56 in the series resistor, so that the current through the LED sub-array is planned by the series resistors R50 and R52, and the resistance value in the loop is further reduced. The current in the array is increased and the brightness of the LED sub-array is again increased (for example, providing 75% brightness).

When the common contact Vcom is connected to the switch contact Y5, the input voltage is transmitted to the current regulator 120 via Dz to be supplied to the LED sub-array, and the input voltage is charged to the capacitor C51 via the resistor R51, and the dual-load is conducted through the resistors R51 and R53. Sub-junction transistor B50 is used to bypass resistors R52, R54 and R56 in the series resistor, so that the current through the LED sub-array is planned by resistor R50, and the resistance value in the loop is minimized, through the LED sub-array The current rises to the highest and the brightness of the LED sub-array is the brightest (for example providing 100% brightness).

In summary, when the common contact Vcom is coupled to one of the switch contacts, and the transistor switch coupled to the switch contact is turned on, the corresponding resistance section can be bypassed for adjustment. Varying the equivalent current sense resistance value of the current through the LED sub-array to adjust the current through the LED sub-array and the brightness of the LED sub-array, wherein the brightness ratios exemplified in the above embodiments are a relative ratio to It is convenient to explain the brightness relationship when the common contacts are connected to different switch contacts, and is not intended to limit the present invention.

The embodiment of Figure 5D is similar to Figure 5C, with the difference being shared current sensing and modulation. In the variable unit 165', the transistor switches M50, M52 and M54 to which the switch contacts Y3~Y5 are respectively coupled are, for example, a gold oxide half field effect transistor, and the transistor switches M54, M52 and M50 are respectively connected to a series resistor. Different sections are connected in parallel to selectively bypass different sections of the series resistor.

Zener diodes D51, D53 and D55 are used to protect the transistor switch M50, The insulating layer between the gate and source of M52 or M54 is not broken down. When the common contact Vcom is coupled to the switch contact Y5, Y4 or Y3, the input voltage charges the capacitor C51, C53 or C55 to the breakdown voltage Vz of the Zener diode. When the common contact Vcom is not coupled to the switch contact Y5, Y4 or Y3, the capacitor C51, C53 or C55 is discharged to 0 volts (V). Thus, when the common contact Vcom is coupled or uncoupled to the switch contact Y3, Y4 or Y5, the transistor switch M50, M52 or M54 corresponding to the switch contact Y5, Y4 or Y3 is turned on or off normally. Operating status.

6A, 6B, 6C, 6D, 6E and 6F are adjustable according to Fig. 1 The electronic control device of the light LED light engine is respectively implemented in different forms of shared current sensing and modulation unit. Referring to FIG. 6A, in this embodiment, the shared current sensing and modulation unit 160a includes a voltage controlled resistance of the transistor, including a Pulse Width Modulation (PWM) unit PWM and a resistor. R16, resistor R20, voltage dividing resistors Rm1 and Rm2, capacitor Cf, gold oxide half field effect transistor (MOSFET) M16, and voltage follower F (Voltage Follower) F.

The pulse width modulation unit PWM can provide a pulse width modulation signal through the remote The Bluetooth function of the control device (such as a mobile phone, a remote controller, etc.) is transmitted by microwave, for example, a transmitter (Transmitter) provided with an antenna in the remote control device, and a receiver (Receiver) provided with an antenna in the circuit structure of the illumination device, pulse wave The signal is transmitted by the transmission of the remote control device and the reception of the illumination device. Alternatively, the pulse width modulation can also be generated by a built-in signal generator.

In the state where the frequency is constant, the working week of the pulse width modulation signal is adjusted. Period, the overall average voltage value of the adjustable signal rises or falls. Then, through the antenna transmission or built-in pulse width modulation signal, through the low-pass filter composed of the resistor R20 and the capacitor Cf, the analog signal is outputted to the voltage follower F, and the analog signal is turned by the voltage follower F. And passed to the gold oxide half field effect transistor M16. The voltage follower F can ensure that the analog signal transmission is not distorted, does not draw current itself, and can supply enough current to drive the metal oxide half field effect transistor M16 without causing a load effect on the circuit.

The gold-oxygen half-field effect transistor M16 acts as a voltage-controlled resistor with its gate and source indirect The analog signal provided by the voltage dividing resistors Rm1 and Rm2 forms a channel between the drain and the source, and generates a corresponding amplified current. The amplified current is inversely proportional to the resistance of the metal oxide half field effect transistor M16. That is to say, the resistance of the gold-oxygen half-field effect transistor M16 can be regulated, and the gold-oxygen half-field effect transistor M16 (voltage-controlled resistor) is connected in series with the resistor R16, and the resistor R16 and the gold-oxygen half-field effect are connected in series. The current of transistor M16 is the current through the LED sub-array.

In other words, by adjusting the duty cycle of the pulse width modulation signal, the overall average voltage value of the signal can be adjusted, thereby controlling the resistance of the gold-oxygen half-field effect transistor M16, and the modulation is passed through the resistor R16 and the gold-oxygen half-field effect transistor. The current of M16, because the current through the resistor R16 and the MOSFET half-effect transistor M16 approximates the current through the LED sub-array, so that the current through the LED sub-array can be controlled to adjust the illumination brightness.

In the above embodiments, other voltage-controlled resistors such as a junction field effect transistor (JFET) may be used instead of the gold-oxygen half-field effect transistor, and the working principle is similar, so it is not described here.

Referring to FIG. 6B, the shared current sensing and modulation unit 160b includes a transistor as a switch, including a pulse width modulation (PWM) unit PWM, a resistor Rp, a resistor R16, and a bipolar junction transistor (BJT) B16. . In this embodiment, the pulse width modulation (PWM) unit PWM signal is supplied to the base of the bi-carrier junction transistor (BJT) B16 as a current signal through the resistor Rp, thereby modulating the double-carrier junction surface. The turn-on or turn-off of the crystal (BJT) B16 controls the formation of a loop through the current of the LED sub-array to control the average current through the LED sub-array. In this way, the brightness of each segment of the LED sub-array can be adjusted.

Referring to FIG. 6C, the shared current sensing and modulation unit 160c includes a transistor as a switch, including a pulse width modulation (PWM) unit PWM, voltage dividing resistors Rm1 and Rm2, a resistor R16, and a gold oxide half field effect transistor ( MOSFET) M16. In this embodiment, the pulse width modulation (PWM) unit PWM signal is provided as a voltage signal through the voltage dividing resistors Rm1 and Rm2 to provide a gate electrode of the metal oxide half field effect transistor M16, thereby modulating the gold oxide half field effect power. The turn-on or turn-off of crystal M16 controls the formation of a loop through the current of the LED sub-array to control the average current through the LED sub-array. In this way, you can regulate The brightness of each segment of the LED sub-array.

Please refer to FIG. 6D, where a specific circuit structure of the current regulator 120 is provided. The transistor switch M1 (for example, a gold oxide half field effect transistor), a starting resistor Ra, a bipolar transistor B, and a detecting resistor Rb are included. In this embodiment, a valley filling circuit VF and a switch SW are further included. The switch SW includes a common contact Vcom, a switch contact P1, a switch contact P2, a switch contact P3, and a switch contact P4. The Vcom is connected to the positive end of the rectifier 100 for selectively coupling to the switch contact P1, the switch contact P2, the switch contact P3 or the switch contact P4, and the switch contact P4 is a floating pin. . The switching mode of the switch SW can be manual switching or automatic switching, and by switching to different switch contacts, different brightness or illumination modes of the lighting device can be provided.

The valley filling circuit VF is coupled to the source of the transistor switch M1 of the current regulator 120 The pole and the switch contact P1 of the switch SW. The valley filling circuit VF includes a valley filling capacitor Cv, a gold oxide half field effect transistor Mv, a starting resistor Rv1, a bipolar junction transistor Bv1, a series resistor Rv2, and a Rv3 bridged across the bipolar junction transistor Bv1. The collector of the other bi-carrier junction transistor Bv2 is coupled to the node between the series resistors Rv2 and Rv3, and the base of the bi-carrier junction transistor Bv2 is transmitted through the sub-portion. The voltage resistors Rv4 and Rb3 are coupled to the anode of the last stage LED sub-array, and the voltage dividing nodes of the voltage dividing resistors Rv4 and Rb3 are coupled to the shared current sensing and modulation unit 160d.

The shared current sensing and modulation unit 160d includes a transistor as a switch, and a package Including resistors R16 and R18 and a metal oxide half field effect transistor (MOSFET) Mb. In this embodiment, the drain of the gold-oxygen half-field effect transistor M18 is coupled to the gate of the gold-oxygen half-field transistor Mb and the voltage dividing node of the voltage dividing resistors Rv4 and Rb3 for controlling the gold-oxygen half field effect transistor. Mb Turn on or off. In addition, the gate of the metal oxide half field effect transistor M18 is coupled to the switch contact P2 through the voltage dividing resistors Rb1 and Rb2, and the gate of the gold oxide half field effect transistor M18 is coupled to a Zener diode Zb and a capacitor. Cz.

The switching principle of different brightness or illumination modes is explained below. When the common contact Vcom is coupled to the switch contact P1, the input voltage charges the valley filling capacitor Cv. At this time, the current through the current regulator 120 passes through the bypass switch S1, the bypass switch S2, and the bypass switch Sn to the minute. The voltage resistors Rb3 and Rv4 are supplied to the base of the bipolar junction transistor Bv2 to be turned on, the bipolar junction transistor Bv2 bypasses the resistor Rv3, and the charging current (I _Cv ) is planned by the resistor Rv2. Let the charging current of the valley filling capacitor Cv be (I _Cv = ). At the same time, the gate of the gold-oxygen half-field effect transistor M18 has no voltage, the gold-oxygen half-field effect transistor M18 is turned off, the gold-oxygen half-field effect transistor Mb is turned on, the resistor R18 is bypassed, and the current through the LED sub-array G1~Gn+1 It is planned by the resistor R16 (the resistance of the resistor R16 in the loop is less than the resistance of the series resistors R16 and R18, and the equivalent current sensing resistance value through the current of the LED sub-array is reduced), the current is (I _d = ), providing a greater brightness of the main LED array (LED sub-arrays G1~Gn+1).

When the common contact Vcom is coupled to the switch contact P2, the voltage division of the voltage dividing resistors Rb1 and Rb2 turns on the metal oxide half field effect transistor M18, the gold oxide half field effect transistor Mb is turned off, and the double carrier junction transistor Bv2 is cut off. . At this time, the input voltage charges the valley filling capacitor Cv, the charging current (I _Cv ) is planned by the series resistors Rv2 and Rv3, and the charging current of the valley filling capacitor Cv is (I _Cv = ). At the same time, the input voltage is transmitted to the LED sub-array through the diode Dp via the current regulator 120, and the current through the LED sub-array Gn+1 is planned by the series resistors R16 and R18, and the current is (I _Cv = ), providing a smaller brightness of the main LED array (LED sub-arrays G1~Gn+1).

In this way, the conduction resistor Rv3 and the resistor R18 can be bypassed by the conduction or the off of the bipolar junction transistor Bv2 and the gold oxide half field effect transistor Mb, respectively, so that the charging current and the passage of the valley filling capacitor Cv are passed. The currents of the LED sub-arrays G1 to Gn+1 are correspondingly equal.

Referring to FIG. 6D, the load NL includes series resistors Rp1 and Rp3 and another series resistors Rp2 and Rp4. A MOSFET of the MOS half-field effect transistor is coupled to the resistor Rp3, and the gate and the source of the Mn-half field effect transistor Mn are respectively coupled to the collector and the base of the bipolar junction transistor Bn, A resistor Rn is connected across the base and the emitter of the carrier junction transistor Bn, and a Zener diode Zn is bridged between the collector and the emitter of the bipolar junction transistor Bn. The emitter of the bipolar junction transistor Bn is coupled to the sub-LED sub-arrays Ln1 and Ln2.

In one embodiment, the sub-LED sub-arrays Ln1 and Ln2 are, for example, nightlights. When the common contact is connected to the switch contact P3, the positive terminal of the rectifier 100 is coupled to the load NL, and the input voltage is transmitted through the series resistors Rp2 and Rp4 to the capacitance between the gate and the source of the MOS half-effect transistor Mn ( Charging is not shown, so that the MOS half-field effect transistor Mn is turned on, illuminating the LED sub-arrays Ln1 and Ln2, and the currents that illuminate the LED sub-arrays Ln1 and Ln2 are planned by the resistor Rn, and the current is (I _L = ).

When the common contact is connected to the switch contact P4 (floating pin), all LED arrays (including the main LED sub-array and the sub-LED sub-array) can be turned off.

Please refer to FIG. 6E , which is similar to the electronic control device of the dimmable LED light engine illustrated in FIG. 6D . The difference is that the shared current sensing and modulation unit 160e is replaced by a dual carrier junction transistor Bb. Shared current sensing and modulation unit 160d Transistor Mb. Moreover, the gold-oxygen half field effect transistor M18 is replaced by a bipolar junction transistor B18. In another embodiment, the gold oxide half field effect transistor M18 or the bipolar junction transistor B18 may also be a parallel regulator. (not shown) is used to control the conduction of the gold-oxygen half field effect transistor Mb or the bi-carrier junction transistor Bb.

In summary, the transistor switch can directly control the current through the LED sub-array. The formation of the loop is used to adjust the average current through the LED sub-array. Alternatively, the transistor switch can be connected in parallel with a current sensing resistor. When the transistor switch is turned on, the resistor can be bypassed so that the equivalent current sensing resistance value of the current passing through the LED sub-array is low. The current through the LED sub-array is large. When the transistor switch is turned off, the equivalent current sensing resistance value passing through the current of the LED sub-array is relatively high, and the current through the LED sub-array is small, thereby adjusting the brightness of the LED.

Figure 6F shows the electronic control of the dimmable LED light engine according to Figure 1. Another circuit schematic of the device. The difference from FIG. 6A is that the shared current sensing and modulation unit 160f of FIG. 6F is a potentiometer (ie, a variable resistor). By modulating the resistance of the potentiometer, the current through the potentiometer can be controlled to control the current through the LED sub-array to adjust the illumination brightness.

Figure 7 shows the electronic control of the dimmable LED light engine in accordance with Figure 1. A specific circuit diagram of the device. The difference from FIG. 5A is that the electronic control device of the dimmable LED light engine further includes a voltage regulator array suitable for the circuit structure of any of the foregoing embodiments, including a plurality of voltage regulating circuits 180, 182 and 184. They are used to stabilize the conduction states of the bypass switches S1, S2, and Sn, respectively.

The voltage regulator 180 is taken as an example, and includes a resistor Rc1, a Zener diode Z4, a bipolar junction transistor B10, and a capacitor C2. When the input voltage is rectified by the rectifier 100, it is output through the current regulator 120, supplied to the collector of the bipolar junction transistor B10, and passed through the resistor Rc1 to the Zener diode Z4 to maintain the voltage at the Zener voltage V. _Z4 , at this time, the voltage V _C coupled across the capacitor C2 of the emitter of the bipolar junction transistor B10 is equal to the potential difference between the Zener voltage V _Z4 and the base emitter of the bipolar junction transistor B10. The difference between _{BE, 10} (ie V _C = V _Z4 - V _BE ). The voltage regulator 182 and the voltage regulator 184 are similar to the voltage regulator 180 and will not be described again. By means of the voltage regulators 180, 182 and 184, a constant voltage V _C can be supplied to the gates of the enhanced bypass switches S1, S2 and Sn via the resistors Re1 to Re3 to charge the capacitance between the gate and the source to establish a bypass. The initial state of the channel formed by the switch S1, the bypass switch S2, and the bypass switch Sn. In this way, the bypass switches S1, S2, and Sn can be stably maintained even at the falling edge of the period of the input voltage.

8A and 8B show the LED light engine with dimming according to FIG. Other embodiments of electronic control devices. 8A and 8B, the problem that the low-voltage section cannot illuminate the illumination brightness of the plurality of LED sub-arrays can be solved, and the brightness of the illumination device in the low-voltage section is improved. Referring first to FIG. 8A, in this embodiment, the LED array includes a plurality of LED sub-arrays L1, L2, L3, L4, L5, L6, L7, and L8. The switching regulator array is coupled to the current regulator 120 and includes a plurality of bypass switches S4, S5 and S6, such as an enhanced MOS field effect transistor. The input voltage determination circuit 220a includes a voltage dividing circuit (a series resistor R3 and a resistor R5), a Zener diode Z5, a capacitor C4, and a shunt regulator X4.

At the beginning of a cycle, the rising edge of the input voltage, when the input voltage is utilized The dynamic resistances Ra4 to Ra6 establish an initial state for the bypass switches S4, S5, and S6. The bypass switches S4 and S5 enter the conduction state, and the switching regulator S6 enters the regulation state. At the same time, the input voltage is judged The voltage division of the voltage dividing node T4 of the voltage dividing circuit (resistor R3 and the resistor R5) of the breaking circuit 220a is insufficient for the parallel regulator X4 to be turned on, and the diodes D7, D8 and D9 are not grounded and cannot be turned on, and the switch The gates of the bypass switches S9, S10 and S11 of the regulator array are charged by the starting resistors Ra9 to Ra11 to the capacitance between the gate and the source, so that the gate is maintained at a high level and turned on.

The input voltage is coupled to the bi-carrier via a voltage dividing node of the resistor R11 and the resistor R12. The base of the junction transistor B12. Since the bypass switch S9 is turned on, the voltage of the base of the bipolar junction transistor B12 is pulled low by the bypass switch S9 and the resistor Rs9, so that the bipolar junction transistor B12 is turned on, so the double load The base of the sub-junction transistor B11 is turned on by the high-level input voltage through the bipolar junction transistor B12. When the input voltage rises enough to make a single group of LED sub-arrays forward, the current passes through the MOSFET half-effect transistor M1, the bi-carrier junction transistor B11 to the first group of LED sub-arrays L1 and L2, via the bypass switch S9 And the resistor Rs9 to the ground.

At the same time, the input power supply current flows through the current regulator 120 to the bypass switches S4, S5 and S6, respectively, to the second group of LED sub-arrays L3 and L4, the third group of LED sub-arrays L5 and L6, and the fourth group of LEDs. Sub-arrays L7 and L8. Then, the current through the LED sub-array is again transmitted through the bypass switches S10 and S11 through the resistors Rs10 and Rs11. In this way, all of the LED sub-arrays can be turned on in parallel in the low-voltage input section to improve brightness.

In the embodiment of FIG. 8A, a valley filling circuit 200a is further included. The valley filling circuit 200a includes a gold oxide half field effect transistor M2, a bipolar junction transistor B20, a capacitor C5, a diode D20, and a diode D21. Capacitor C7, light-emitting diode L9 and shunt regulator X5.

In the high voltage section of the input voltage, the high input voltage is in the valley filling circuit 200a The voltage division of the resistors R22 and R24 causes the shunt regulator X5 to be turned on, so that the gate voltage of the metal oxide half field effect transistor M3 is pulled off (pull l0w) and turned off. On the other hand, the input voltage is transmitted through the start-up resistor Ra20 to turn on the gold-oxygen half-effect transistor M2 to charge the capacitor C5 and the capacitor C7.

In the low voltage section of the input voltage, the input voltage is in the valley filling circuit 200a Resisting the voltage division of R22 and R24 causes the shunt regulator X5 to be turned off, and the gate of the MOS field-effect transistor M3 is turned on by the previous start-up resistor Ra22 to charge the capacitor between the gate and the source to maintain a high level. At this time, the diode D20 is biased and discharged through the capacitor C5 connected in series to supply the current of the switching regulator and the LED sub-array. At the same time, the diode D21 is reverse biased, the capacitor C7 is discharged, and the discharge current illuminates the light-emitting diode L9, and passes through the gold-oxygen half-field effect transistor M3 to the resistor Rb22 to the ground. In this way, the illuminated LED L9 can compensate for the brightness of the low voltage section.

In addition, a high voltage section of the input voltage, the input voltage is in the determination circuit 220a The voltage divider circuit (series resistors R3 and R5) is divided at node T4, so that the shunt regulator X4 is turned on, the diodes D7, D8, and D9 are turned on, and the gates of the bypass switches S9, S10, and S11 are pulled. Low (pull low) and cut off, the bi-carrier junction transistor B12 is turned off, the bi-carrier junction transistor B11 is turned off, and the bypass switches S4, S5 and S6 control the LED sub-arrays L1, L2, L3, L4, L5, Turn-on and turn-off of L6, L7, and L8. The LED sub-arrays L1, L2, L3, L4, L5, L6, L7 and L8 described herein may be any form of LED sub-array or light-emitting diode unit, and are not limited.

On the rising edge of a cycle, when the input voltage rises to overcome the last set of two lights In the forward voltage drop of the polar body, as described above, four sets of LED sub-arrays L1 and L2, L3 and L4, L5 and L6, L7 and L8 are connected in parallel. As the input voltage continues to rise to overcome the forward voltage drop of the last two sets of light-emitting diodes, the voltage of the cathode of the LED sub-array L8 is divided by the resistor Rb6 and the resistor r16 to turn on the bi-carrier junction transistor B6. The gate voltage of the bypass switch S6 is pulled low and turned off. Current flows through the bypass switches S4 and S5 to the LED sub-arrays L5 and L6, the diode D12, and the LED sub-arrays L7 and L8. In this way, the brightness of the low voltage section can be compensated. And, and so on, as the input voltage changes, the LED sub-array is turned on or off step by step.

Referring to FIG. 8B, the main difference between this embodiment and FIG. 8a is that the filling valley electricity The design of the road 200b. The valley filling circuit 200b is used as a compensation circuit, including a gold oxide half field effect transistor M2, a bipolar junction transistor B22, a capacitor C5', a diode D20, a diode D22, and a light emitting diode L10.

In the high voltage section of the input voltage, a high input voltage charges capacitor C5', And through the starting resistor Ra22, the gold-oxide half-field effect transistor M2 is turned on, the diode D20 is reverse biased, the diode D22 is biased, the light-emitting diode L10 is lit, and the current and capacitance C5' of the light-emitting diode L10 are passed. The charging current is the same, and this current is grounded via the diode D22.

In the low voltage section of the input voltage, the diode D20 is biased so that the capacitor in series The C5' discharge, the current flows from the anode of the diode D20 to the cathode, supplying the current of the switching regulator and the light emitting diode sub-array. At the same time, the diode D22 is reverse biased, the light-emitting diode L10 is reverse biased, and the gold-oxygen half-field effect transistor M2 has no loop and is cut off.

Please continue to refer to FIG. 8B, the multi-level LED sub-arrays L1, L2, L3 of the LED array, L4, L5, L6, L7, and L8, the plurality of bypass switches S4, S5, and S6 included in the switching regulator array, and the input voltage judging circuit 220b are the same as those in FIG. 8A, and details are not described herein again.

In the low input section, the light-emitting diodes can be turned on in parallel, and the conduction mode is Similar to the embodiment of Figure 8A. The input power supply current flows through the current regulator 120 to the bypass switches S4, S5, and S6, respectively, through the first group of LED sub-arrays L1 and L2, the second group of LED sub-arrays L3 and L4, and the third group of LED sub-arrays L5. And L6, and the fourth group of LED sub-arrays L7 and L8. Then, the current through the LED sub-array is again grounded through the bypass switches S9, S10, and S11 through the resistors Rs9, Rs10, and Rs11. All of the LED sub-arrays can be turned on in parallel at the beginning of the input voltage to improve brightness.

In addition, the present invention provides an electronic control device for a dimmable LED light engine, The active dummy load 300 is coupled between the positive terminal and the negative terminal of the rectifier 100 for drawing current in a low voltage region of the DC pulse voltage waveform. The active dummy load 300 includes a load resistor R30, a resistor R32, a voltage dividing circuit R34 and R36, a shunt regulator X6, a Zener diode Z6, and a MOS field effect transistor M3, a gold oxide half field effect transistor M3, The shunt regulator X6, and the voltage dividing circuits R34 and R36 are connected as a controlled switching circuit to the load resistor R30. The active dummy load 300 is used to draw current in the low voltage region of the DC pulse voltage waveform.

As shown in FIG. 8B, the rectifier 100 is, for example, a full-wave rectifier, and has a live terminal (L) or a neutral (N) terminal, and can be provided with a three-pole AC switch (TRI-ELECTRODE AC SWITCH, TRIAC) Tr, three-pole. The gate of the AC switch Tr is coupled to a trigger circuit 101 for triggering the three-pole AC switch Tr. After the three-pole AC switch Tr is triggered, the phase of the AC signal provided by the AC voltage source AC is subjected to the three-pole AC switch Tr. The interception changes and is passed to the rectifier 100 for supply to the LED sub-array. Accordingly, the three-pole AC switch Tr can be used to modulate the AC input signal to achieve the dimming effect.

Since the three-pole AC switch Tr is triggered, it is necessary to have sufficient line current (need to satisfy the line current I _line > the holding current I _holding ) to maintain the conduction condition of the three-pole AC switch Tr. Conventionally, the three-pole AC switch Tr is in the low voltage section, because the line current is lower than the sustain current, which will make the three-pole AC switch Tr unsustainable. Conventionally, during the low voltage period, it is impossible to dim the light using the three-pole AC switch Tr.

In the embodiment, the three-pole AC switch Tr and the active dummy load 300 can be simultaneously set. Since the active dummy load 300 can draw the line current in the low voltage section, as the line current for maintaining the three-pole AC switch Tr, it can be utilized. The three-pole AC switch Tr is dimmed in the low voltage section.

The electronic control device of the dimmable LED light engine of the present invention can be implemented on an integrated circuit, or can be implemented as a plurality of integrated circuits by modules, and then integrated on a circuit board.

The electronic control device of the dimmable LED light engine of the present invention can be integrated with an LED array, wherein the LED array is arranged in parallel with the electronic control device of the LED light engine as a dimming LED sub-array illumination device.

In summary, the electronic control device of the dimmable LED light engine proposed by the present invention can be manually dimmed (mechanical dimming) via a dimming unit by a single shared current sensing and modulation unit. Or dimming through the dimming signal (electrically controlled dimming), controlling the current flowing through the shared current sensing and modulating unit, correspondingly adjusting the current through the LED sub-array to achieve the effect of adjusting the illuminating brightness, and having a simplified circuit The advantages of convenient control and low manufacturing cost. An electronic control device for a dimmable LED light engine according to an embodiment of the invention includes a current regulator and a switching regulator array. Will be adjustable The electronic control unit of the light LED light engine is connected to the LED array to form a dimmable light-emitting diode lighting device. The current regulator can be used to adjust the input current wave to form a sinusoidal wave or a waveform of the step wave, effectively increasing the power factor.

The principles, preferred embodiments, and modes of operation of the invention have been described in the foregoing. However, the invention should not be construed as being limited to the specific embodiments discussed. Rather, the above-described embodiments are to be considered as illustrative and not restrictive, and the scope of the invention as defined by the following claims Changes are made to these embodiments.

AC‧‧‧AC voltage source

100‧‧‧Rectifier

120‧‧‧current regulator (current regulator)

140, 142, 144‧‧‧ switch control circuits

160‧‧‧Shared current sense and modulation unit

G‧‧‧LED array (light-emitting diode array)

G1, G2, Gn, Gn+1‧‧‧light-emitting diode subarrays

S1, S2, Sn‧‧‧ Bypass switches

R1, R2‧‧‧ sinusoidal voltage compensator

Claims (19)

An electronic control device for a dimmable LED light engine, comprising: a rectifier for connecting an external AC voltage source and a ground terminal for providing a DC pulse voltage; a current regulator connected to the rectifier; and a switching regulator array Coupling the current regulator and being disposed in parallel with an external LED array, the external LED array comprising a plurality of LED sub-arrays connected in series, the switching regulator array comprising a plurality of bypass switches connected in series and a programmable current sensing circuit The bypass switch is configured to illuminate the LED sub-arrays in sections according to the DC pulse voltage, and the programmable current sensing circuit comprises: a shared current sensing and modulation unit coupled to the external LED An array for proportionally adjusting or decreasing the current of the lit LED sub-array to adjust the brightness of the lit LED sub-array; and a plurality of switch control circuits coupled to the shared current sensing and modulation a unit, any of the switch control circuits comparing the voltage across the shared current sensing and modulation unit and a reference voltage to switch the on or off of the stage bypass switch, wherein the shared power The sensing and modulation unit includes a potentiometer, a voltage-controlled resistor, or a transistor switch and a current sensing resistor, wherein one end of the current sensing resistor is coupled to the channel of the transistor switch, and the shared current A sensing and modulation unit is used to control the current through the LED sub-array. The electronic control device of the dimmable IED light engine of claim 1, wherein the shared current sensing and modulation unit further comprises a pulse width modulation unit and a low pass. At least one of a filter and a voltage follower. The electronic control device for the dimmable LED light engine of claim 1, wherein each of the bypass switches is connected in parallel with the corresponding LED sub-array except for the last-level LED sub-array, and any one of the The bypass switch includes a transistor. An electronic control device for a dimmable LED light engine according to claim 3, wherein any one of the bypass switches is an N-channel MOS field effect transistor or an N-channel junction field effect transistor. An electronic control device for a dimmable LED light engine according to claim 1, wherein the switch control circuit comprises a voltage dividing resistor, and a parallel regulator or a first dual carrier junction a first end of the voltage dividing resistor is coupled to the shared current sensing and modulation unit, and the second end of the voltage dividing resistor is coupled to the anode of the parallel regulator or the first dual carrier junction transistor The emitter, the voltage dividing node of the voltage dividing resistor is coupled to the reference pole of the parallel regulator or the base of the first bipolar junction transistor. The electronic control device of the dimmable LED light engine of claim 5, further comprising a sinusoidal voltage compensator, the first end of the sinusoidal voltage compensator being coupled to the rectifier, the sinusoidal voltage compensator The second end is grounded, and the voltage dividing node of the sinusoidal voltage compensator is coupled to the switch control circuit, and the DC pulse voltage has a further voltage division at the voltage dividing node of the sinusoidal voltage compensator, wherein the reference voltage is subjected to the Another partial voltage compensation, and the voltage across the shared current sensing and modulation unit is related to the current through the shared current sensing and modulation unit. The electronic control device of the dimmable LED light engine of claim 1, wherein each of the bypass switches comprises a depleted MOS field effect transistor, a Zener diode, and a a first resistor and a second resistor, wherein an anode of the Zener diode is coupled to a gate of the depleted metal oxide half field effect transistor, and a cathode of the Zener diode is coupled to the depleted gold oxide half field effect transistor a source of the crystal, the first resistor is coupled in parallel with the Zener diode, and the second resistor is coupled to the gate of the MOSFET and the corresponding switch control circuit. The electronic control device for the dimmable LED light engine of claim 7, further comprising a second dual carrier junction transistor, wherein the second resistor is electrically connected to the second dual carrier interface The crystal is coupled to the switch control circuit. The electronic control device of the dimmable LED light engine of claim 1, wherein each of the bypass switches comprises an enhanced MOS field effect transistor, a diode, a first resistor and a a second resistor, the anode of the diode is coupled to the source of the enhanced MOS field effect transistor, and the cathode of the diode is coupled to the gate of the reinforced MOS field effect transistor, the first resistor As a starting resistor coupled between the gate and the drain of the enhanced MOS field transistor, the capacitance between the gate and the source of the ED field transistor is charged through the starting resistor. The second resistor is coupled to the gate of the MOS field transistor and the corresponding switch control circuit. The electronic control device for the dimmable LED light engine of claim 9, further comprising a third dual carrier junction transistor, wherein the second resistance is transmitted through the third dual carrier junction The transistor is connected to the gate of the MOS field effect transistor. The electronic control device of the dimmable LED light engine of claim 9, further comprising a voltage regulator, wherein the voltage regulator comprises a fourth dual carrier junction transistor, a capacitor, and a capacitor a Zener diode and a third resistor, the capacitor is coupled to the emitter of the bipolar junction transistor and the anode of the other Zener diode, and the first resistor is transmitted through the first The four-double carrier junction transistor is coupled to the rectifier, and the third resistor is connected between the base and the collector of the fourth dual-carrier junction transistor. The electronic control device of the dimmable LED light engine of claim 1, further comprising a valley filling circuit coupled between the rectifier and the ground end, the valley filling circuit is in a no-load time Provides a voltage sufficient to overcome the forward voltage drop of the last stage LED sub-array. The electronic control device of the dimmable LED light engine of claim 12, wherein the valley filling circuit comprises: a first storage capacitor coupled to the rectifier; and a first valley filling a first crystal-filled bipolar junction transistor coupled to the first valley-filled gold-oxygen half field effect transistor; a first valley-filling resistor connected across the first Between the base and the emitter of the valley-filled bipolar junction transistor; a second valley-filling resistor coupled to the collector of the rectifier and the valley-filled bipolar junction transistor; a valley-filled diode coupled to the first a valley-filling resistor; a second storage capacitor coupled to the valley-filled diode and the ground; a valley-filled LED, connected between the valley-filled diode and the second storage capacitor; a second valley-filled gold-oxygen half-field effect transistor coupled to the cathode of the valley-filled light-emitting diode; a third valley-filling resistor coupled to the anode of the valley-filled light-emitting diode and the second valley-filled gold oxide a gate of a half field effect transistor; a second valley-filled dual-carrier junction transistor coupled to the second valley-filled gold-oxygen half field effect transistor The valley fill third resistor; a fourth group valley fill resistor coupled across the valley-fill the second bipolar junction transistor and the emitter of the a valley-filled parallel regulator coupled to the gate of the second valley-filled metal oxide half-effect transistor and the emitter of the second valley-filled bipolar junction transistor; and a valley-filling voltage dividing circuit The rectifier is coupled to the valley shunt regulator, wherein the DC pulse voltage charges the first storage capacitor and the second storage capacitor during a non-idling time, and the charging current is generated by the first energy storage The capacitor passes through the first valley-filled metal oxide half field effect transistor, the first valley-filling resistor, the valley-filled diode to the second storage capacitor, and the first storage capacitor discharges during the idle time. The discharge current is supplied to the LED sub-array through the switching regulator array, and the second storage capacitor is discharged to provide a discharge current to illuminate the valley-filled LED. The electronic control device of the dimmable LED light engine of claim 9, further comprising a compensation circuit coupled between the rectifier and the ground, comprising: a storage capacitor; a compensation gold An oxygen half field effect transistor coupled to the storage capacitor; a first compensation diode connected between the storage capacitor and the MOS field effect transistor; a compensation double carrier junction transistor coupled The compensation metal oxide half field effect transistor; a first compensation resistor is connected between the base and the emitter of the compensation bipolar junction transistor; a second compensation resistor coupled to the rectifier and the compensation pair a collector of the carrier-connected transistor; a light-emitting diode coupled to the first compensation resistor; and a second compensation diode coupled to the light-emitting diode, wherein, during the non-idling time, The DC pulse voltage charges the storage capacitor, and the charging current is compensated by the storage capacitor The gold oxide half field effect transistor and the first compensation resistor illuminate the light emitting diode. The electronic control device for the dimmable LED light engine of claim 1, further comprising an active dummy load and a three-pole AC switch coupled to the positive end of the rectifier The negative terminal is configured to draw current in a low voltage region of the DC pulse voltage waveform, and the three-pole AC switch is coupled to the live terminal or the neutral terminal of the rectifier. The electronic control device for a dimmable LED light engine according to claim 15, wherein the active dummy load comprises: a load resistor; and a controlled switch circuit connected to the load resistor, the controlled switch The circuit includes a transistor, a shunt regulator, and a voltage divider circuit. The electronic control device of the dimmable LED light engine of claim 1, further comprising a judging circuit and an array of another switching regulator, the judging circuit being coupled between the rectifier and the ground end The determining circuit includes: a voltage dividing circuit coupled to the rectifier; a Zener diode coupled to the voltage dividing node of the voltage dividing circuit; a capacitor connected in parallel with the Zener diode; and a parallel adjustment The parallel regulator is coupled to the voltage dividing node of the voltage dividing circuit, and the other switching regulator array is coupled between the external LED array, the determining circuit and the ground end, and includes: a plurality of other sides a switching switch, and a plurality of control diodes respectively coupled between each of the other bypass switches and the shunt regulator, and when the shunt regulator is turned on, the control diodes are turned on to cut off the other One Bypass switch. The electronic control device of the dimmable LED light engine of claim 1, further comprising a valley filling circuit and a switch, the switching switch coupled between the rectifier and the ground end, including a total The junction is connected to the plurality of switch contacts, and the valley-filling circuit is coupled between the external LED array and the ground end, and includes: a valley filling capacitor coupled to the rectifier and one of the switch contacts; The valley field effect transistor is coupled to the valley filling capacitor; a valley-filled dual-carrier junction transistor coupled to the valley-filling effect transistor; and a series resistor connected across the base of the valley-filled dual-carrier junction transistor Between the emitter and the emitter; and a further valley-filled bipolar junction transistor, the two ends of the channel of the other valley-filled bipolar junction transistor are coupled to one of the resistors of the series resistor. A dimmable LED sub-array illumination device comprising: an electronic control device for a dimmable LED light engine, comprising: a rectifier for connecting an external AC voltage source and a ground terminal for providing a DC pulse voltage a current regulator connected to the rectifier; a switching regulator array coupled to the current regulator, the switching regulator array comprising a plurality of bypass switches connected in series and a programmable current sensing circuit; an LED array, and The switching regulator array is arranged in parallel, the LED array includes a plurality of LED sub-arrays connected in series, wherein the bypass switches are configured to segment the IED sub-arrays according to the DC pulse voltage, and the programmable current The sensing circuit includes: a shared current sensing and modulation unit coupled to the LED array for proportionally adjusting or decreasing the current of the lit LED sub-array to adjust the brightness of the lit LED sub-array; and a plurality of The switch control circuit is coupled to the shared current sensing and modulation unit, and the switch control circuit compares the voltage across the shared current sensing and modulation unit and a reference voltage to switch the on/off of the step bypass switch The shared current sensing and modulation unit includes a potentiometer, a voltage controlled resistor, or a transistor switch and a current sensing resistor, wherein one end of the current sensing resistor is coupled to the channel of the transistor switch The shared current sensing and modulation unit is configured to control the current through the LED sub-array.