Patent Publication Number: US-11051374-B2

Title: Identifiable LED lamp and self-adaptive dimming driving system thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a light-emitting diode (LED) lamp and a dimming driving system thereof. More particularly, the invention relates to an identifiable LED lamp and a self-adaptive dimming driving system. 
     2. Description of Related Art 
     With the advancement of technology, the breakthroughs in white LEDs have resulted in the gradual replacement of the conventional lightbulbs and mercury-based light tubes by LEDs, which advantageously feature not only lower power consumption, but also longer service lives, higher efficiency, and less susceptibility to breakage than the traditional light sources. LED lamps, e.g., LED light tubes, are different from their conventional counterparts, e.g., fluorescent light tubes, in that, while a fluorescent light tube requires a stabilizer mounted in the lamp base in order to convert mains electricity into high-frequency alternating current (AC) for driving the fluorescent light tube, an LED light tube is designed to be driven by a direct-current (DC) power source instead and hence requires a power converter for converting mains electricity into DC power for driving the LED light tube, wherein the power converter may be built into the LED light tube or provided in the lamp base of the LED light tube. An LED lamp, therefore, allows its output power, and consequently brightness, to be freely adjusted (i.e., to be dimmed as desired), which is an obvious advantage over the traditional lightbulbs, mercury-based light tubes, and other fixed-power lighting devices in general lighting applications. 
     Current LED lamp standards cater only for the requirements of mains electricity, and this explains why most of the LED lamps (e.g., LED lightbulbs) come with an adapter and a driver. When such an LED lamp is damaged or reaches the end of its service life, the adapter and the driver of the LED lamp cannot but be discarded along with the LED lamp, which constitutes a wasteful use of resources. In view of this, some LED lamp base manufacturers have integrated the adapter and driver of an LED lamp into the lamp base so that, when the service life of the lightbulb or light plate mounted on the lamp base expires, all that needs to be replaced is the lightbulb or light plate. Nevertheless, the lack of an established limitation on the number or driving power of the LED light bulbs or light beads that can be mounted on a lamp base hinders interchangeability between the light bulbs or light plates of different brands, or even of different models of the same brand, causing inconvenience in use. 
     BRIEF SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide an identifiable light-emitting diode (LED) lamp, comprising: a lamp body, at least one LED unit, and an identification resistor. The LED unit is provided on the lamp body and electrically connected to a power input port. The identification resistor is provided on the lamp body and connected in parallel to the LED unit, wherein the identification resistor has a resistance value corresponding to a model number or type of the LED lamp. 
     Another objective of the present invention is to provide a self-adaptive dimming driving system, comprising: a lamp base, a driving circuit, a lamp identification circuit, and a controller. The lamp base, where the aforementioned LED lamp is able to be mounted, comprises an LED power port configured to be electrically connected to the power input port of the LED lamp. The driving circuit is connected or coupled to the LED power port and configured to modulate power to be output to the LED lamp and output the modulated power to the LED lamp. The lamp identification circuit comprises a test current output module and a voltage feedback module, wherein the test current output module is connected to a circuit of the LED power port, and the voltage feedback module is connected to one end or two ends of the LED power port in order to receive a voltage parameter as feedback and output a detection signal according to the voltage parameter. The controller receives the detection signal, obtains a correlation parameter of the resistance value of the identification resistor according to the detection signal, and switches a power output mode of the driving circuit according to the correlation parameter. 
     Comparing to the conventional techniques, the present invention has the following advantages: 
     The present invention enables an LED lamp driving system to switch its output power automatically in adaptation to the LED lamp in use (e.g., an LED lightbulb or light plate). The invention contributes to the universal usability of LED lamps, is effective in reducing wasteful use of resources, and enhances convenience of use. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a block diagram of a self-adaptive dimming driving system according to the present invention. 
         FIG. 2  is a circuit diagram of a self-adaptive dimming driving system according to the present invention. 
         FIG. 3  is a control flowchart of a self-adaptive dimming driving system according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The details and technical solution of the present invention are hereunder described with reference to accompanying drawings. For illustrative sake, the accompanying drawings are not drawn to scale. The accompanying drawings and the scale thereof are not restrictive of the present invention. 
     Please refer to  FIG. 1  for a block diagram of a self-adaptive dimming driving system according to the present invention. 
     As shown in  FIG. 1 , the present invention essentially includes a driving system  100  designed for self-adaptive dimming and an LED lamp  200  for use with the driving system  100 . While implementing the invention, the driving system  100  and the LED lamp  200  can be configured to work with or use any type of LED light sources. The invention is applicable to indoor lighting, outdoor lighting, portable lamps, medical lamps, industrial lamps, and so forth. 
     The LED lamp  200  essentially includes a lamp body N 1 , an LED unit N 2 , and an identification resistor N 3 . The lamp body N 1  serves as a carrier for the LED unit N 2 , the identification resistor N 3 , and other circuits or mechanisms (e.g., a circuit board, a heat dissipation plate, and so on) and has a power input port N 4  electrically connected to the LED unit N 2  and the identification resistor N 3 . The resistance value of the identification resistor N 3  corresponds to the model number or type of the LED lamp  200  in order for the driving circuit of the lamp base of the driving system  100  to be able to self-adapt to the type of the LED lamp  200  and switch to a proper output power accordingly. In terms of circuit configuration, the identification resistor N 3  in this embodiment is provided on the lamp body N 1  and is connected in parallel to the LED unit N 2 . In another preferred embodiment, the identification resistor N 3  is provided in a separate circuit and has a separate connection port instead; the present invention has no limitation in this regard. 
     The driving system  100  has a lamp base M 1  on which the LED lamp  200  can be fixedly mounted. The lamp base M 1  includes an LED power port M 2  configured for electrical connection to the power input port N 4  of the LED lamp  200 . 
     A preferred embodiment of the present invention is described below with reference to  FIG. 1  and  FIG. 2 , which are respectively a block diagram and a circuit diagram of the self-adaptive dimming driving system according to the preferred embodiment. 
     The driving system  100  shown in  FIG. 1  and  FIG. 2  is configured for self-adaptive dimming and can automatically adapt to the LED lamp  200  by identifying the type and required operating voltage of the LED lamp  200  and switching to a power output mode suitable for the LED lamp  200 . The self-adaptive dimming driving system  100  essentially includes a driving circuit  10 , a lamp identification circuit  20 , and a controller  30 . 
     The driving circuit  10  is connected to the LED power port M 2  in order to provide the LED power port M 2  with the required operating power. In one embodiment, the driving circuit  10  includes a rectifier  11 , an electromagnetic interference (EMI) filter  12  provided at the rear end of the rectifier  11 , and a power modulator  13  connected to the output of the EMI filter  12 . The rectifier  11  is configured to convert the input power from AC to DC. The EMI filter  12  is configured to suppress electromagnetic interference, transmit DC power to the rear-end device without power attenuation, and protect the rear-end device by minimizing the EMI signal transmitted to the rear-end device along with the DC power. The power modulator  13  is connected to the controller  30  and is configured to change its own power output mode according to the output signal of the controller  30 . The power modulator  13  includes a pulse width modulation (PWM) module  131  connected to the controller  30  and a field-effect transistor  132  provided at the rear end of the PWM module  131 . The field-effect transistor  132  is connected to the output of the EMI filter  12  and is turned on or off according to the output of the PWM module  131  in order for the output power of the EMI filter  12  to be controlled by the duty cycle of the output of the PWM module  131 . 
     To isolate the front-end power circuit from the rear-end LED circuit, the driving circuit  10  further includes an isolation transformer module  14  provided at the rear end of the EMI filter  12 , lest electric current be input directly from the power supply end (e.g., mains electricity) to the LED power port M 2 . In addition, the rear end of the isolation transformer module  14  is provided with a rectifier unit  15  and a filter unit  16  at the rear end of the rectifier unit  15 , in order to rectify and filter the voltage to be output to the LED power port M 2 . The filter unit  16  serves mainly to filter the rectified DC power and thereby remove noise (e.g., ripples) from the DC power. The driving circuit  10  in the present invention may include any selected ones or combination of the foregoing devices, and the invention has no limitation on such selection or combination. 
     The lamp identification circuit  20 , whose two ends are connected to the LED power port M 2  and the controller  30  respectively, is configured to output a test current, obtain the voltage fed back from the LED power port M 2 , convert the voltage obtained into a detection signal, and provide the detection signal to the controller  30 . The lamp identification circuit  20  includes a test current output module  21  and a voltage feedback module  22 . In a feasible embodiment, the test current output module  21  is connected to the circuit of the LED power port M 2  in order to output the test current to the LED power port M 2  and thus form a testing circuit together with the LED power port M 2 . In an embodiment in which the identification resistor N 3  has its own circuit and connection port, the test current output module  21  is connected to the independent circuit of the identification resistor N 3  through the independent connection port of the identification resistor N 3 . The voltage feedback module  22  is configured to output the detection signal to the controller  30  according to a voltage parameter of the LED power port M 2  (or of the independent connection port). The test current must be smaller than the minimum turn-on current of the LED lamp  200  connected to the LED power port M 2 , lest the LED unit N 2  be turned on and result in a detection error. 
     In a feasible embodiment, the test current output module  21  includes a test current circuit  211  and a bypass circuit  212 . The bypass circuit  212  includes a switch unit  213  connected to the controller  30 . The switch unit  213  is turned on or off according to the instruction output from the controller  30 , and the controller  30 &#39;s decision to turn on or off the switch unit  213  is based on the voltage parameter received from the voltage feedback module  22 . When the test current supplied to the LED unit N 2  is smaller than the turn-on current of the LED unit N 2 , the LED unit N 2  is in a state equivalent to an open circuit, so all the test current flows through the identification resistor N 3 , where a voltage drop takes place. It is worth noting that a detection signal associated with the resistance value of the identification resistor N 3  can be derived from a single-end feedback (e.g., a high- or low-voltage-end feedback through the corresponding voltage division node) or a two-end feedback (i.e., from two ends of the electrical component of interest). Although the test current circuit  211  and the bypass circuit  212  in this embodiment are controlled by two separate switches respectively (which two switches work in two opposite directions respectively), the test current value is so small that it is feasible to have only the switch unit  213  in the bypass circuit  212  while neglecting the test current. 
     In this embodiment, the voltage feedback module  22  includes a subtractor  221 , a comparator array  222 , and a PWM driver  223 . The subtractor  221  is connected to both ends of the LED power port M 2  in order to obtain the voltage across the two ends of the LED power port M 2  and then calculate the voltage difference between the two ends by subtracting the voltage at one end from the voltage at the other end. The comparator array  222  includes a plurality of comparators that are preset with different voltage values respectively. The comparator array  222  compares the voltage across the two ends of the LED power port M 2  with the preset voltage values and outputs the comparison result to the PWM driver  223 . The PWM driver  223 , in turn, outputs a detection signal to the controller  30  according to the comparison result. In a feasible embodiment in which the controller  30  is configured to obtain a correlation parameter from a lookup table, the comparator array  222  may be dispensed with. 
     The controller  30  is connected to the driving circuit  10  and the lamp identification circuit  20 . For example, the controller  30  may be a central processing unit, a programmable general-purpose or application-specific microprocessor, a digital signal processor (DSP), a programmable controller, an application-specific integrated circuit (ASIC), a radio-frequency system-on-chip (RF-SoC), other similar devices, or a combination of the above; the present invention has no limitation in this regard. The controller  30  may be configured to work with a storage unit, wherein the storage unit stores, for example, parameters, lookup tables, failure records, and so on. The storage unit may be, but is not limited to, an electrically erasable programmable read-only memory (EEPROM). 
     The controller  30  receives the detection signal, obtains a correlation parameter of the resistance value of the identification resistor N 3  according to the detection signal, and switches the power output mode of the driving circuit  10  according to the correlation parameter. 
     In a feasible embodiment, a signal isolator  50  is provided between the feedback output end of the lamp identification circuit  20  and the controller  30  to prevent noise that may otherwise result from interference between the controller  30  and the LED power port M 2 . In one embodiment, the signal isolator  50  is an optical coupler in which the light emitter and the corresponding light receiver relay the detection signal from the lamp identification circuit  20  to the controller  30  and thereby isolate the controller  30  from the circuit where the LED power port M 2  is provided. 
     To supply the controller  30  with the necessary electricity, an adapter  60  is provided between the driving circuit  10  and the controller  30  to convert the output of the driving circuit  10  into the driving voltage and power needed by the controller  30 . The adapter  60  includes a voltage reduction unit  61 , a rectifier unit  62  provided at the rear end of the voltage reduction unit  61 , and a filter unit  63  provided at the rear end of the rectifier unit  62 . 
     The operation process of the disclosed self-adaptive dimming driving system is described below with reference to  FIG. 3 , which is a control flowchart of the driving system. 
     To begin with, an activation instruction for activating the controller  30  is triggered by mounting the LED lamp  200  to the LED power port M 2  (step S 01 ). The activation instruction may be triggered through a micro switch mounted on the lamp base M 1  or be controlled by a program in the controller  30 . For example, the activation instruction may be triggered by a change in the voltage across the two ends of the LED power port M 2  or by communication with a chip built in the LED lamp  200 ; the present invention has no limitation in this regard. 
     Once activated, the controller  30  outputs a first switching instruction to the switch unit  213  to turn off the switch unit  213  (i.e., to turn the switch unit  213  into an open circuit). As a result, the main load current flows through the test current circuit  211  in order for the test current circuit  211  to provide a fixed test current through the LED power port M 2  (or an independent connection port) to the identification resistor N 3 . The voltage drop caused by the identification resistor N 3  changes the voltage value at each node as well as the voltage value across the two ends of the identification resistor N 3  (step S 02 ). 
     After the completion of step S 02 , the comparator array  222  of the lamp identification circuit  20  performs a comparison operation with reference to the preset voltage of each comparator in the comparator array  222  and outputs the comparison result to the PWM driver  223  (step S 03 ). Thus, the interval to which the voltage across the two ends of the identification resistor N 3  belongs is determined. Following that, the PWM driver  223  outputs a detection signal to the controller  30  according to the comparison result (step S 04 ). It should be pointed out that the detection signal is not necessarily a precise voltage value; it may be any parameter that is highly positively correlated to the barrier potential. 
     After obtaining the detection signal, the controller  30  finds the correlation parameter corresponding to the detection signal in a lookup table in order to switch the driving circuit  10  to the corresponding power output mode (step S 05 ). The correlation parameter refers to the model number, code, or other related index of the LED lamp  200  and dictates the driving mode by which to control the output power of the driving circuit  10 . 
     Once the appropriate power output mode is determined, the controller  30  turns on the LED lamp  200  by sending a second switching instruction to the switch unit  213  to switch the main load current to the bypass circuit  212 , and by controlling the driving circuit  10  according to the power output mode determined (step S 06 ). 
     In summary of the above, the present invention enables an LED lamp driving system to switch its output power automatically in adaptation to the LED lamp in use (e.g., an LED lightbulb or light plate). The invention contributes to the universal usability of LED lamps, is effective in reducing wasteful use of resources, and enhances convenience of use. 
     The above is the detailed description of the present invention. However, the above is merely the preferred embodiment of the present invention and cannot be the limitation to the implement scope of the invention, which means the variation and modification according to the present invention may still fall into the scope of the invention.