WO2010141157A1 - Led power source and dc-dc converter - Google Patents
Led power source and dc-dc converter Download PDFInfo
- Publication number
- WO2010141157A1 WO2010141157A1 PCT/US2010/031968 US2010031968W WO2010141157A1 WO 2010141157 A1 WO2010141157 A1 WO 2010141157A1 US 2010031968 W US2010031968 W US 2010031968W WO 2010141157 A1 WO2010141157 A1 WO 2010141157A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- inverter
- inductance
- operative
- converter
- voltage
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
- H02M1/4225—Arrangements for improving power factor of AC input using a non-isolated boost converter
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Definitions
- LEDs Light emitting diodes
- LED arrays are becoming more and more popular for lighting and signaling applications, in which multiple LEDs are formed into an array and powered to emit light.
- LED arrays are typically supplied with DC current with the amount of supplied power controlling the array brightness.
- An LED power source is provided along with a self oscillating DC-DC converter therefor, which can be employed for operating an LED array.
- the power source includes an input rectifier which receives an input AC voltage signal and produces an initial DC voltage received by the DC-DC converter.
- the power source includes a boost converter operafively coupled between the input rectifier and the DC-DC converter, which may have a power factor correction controller to control a power factor of the power source.
- the DC-DC converter has isolated supply-side and load-side ground connections as well as a self-oscillating inverter and an output rectifier.
- the inverter is coupled with the supply-side ground connection and receives the initial DC voltage directly or indirectly from the input rectifier and produces an intermediate AC signal.
- the output rectifier is coupled with the load-side ground connection and receives the intermediate AC signal from which if produces an output DC voltage to supply power to the LED array.
- the DC-DC converter may further include an inverter controller that modifies the inverter frequency to control the supplied power based at least in pan on sensed output power draw, where the inverter controller is electrically isolated from the inverter in some embodiments.
- the DC-DC converter may be controlled using a control transformer with a primary winding operatively coupled to and controlled by the inverter controller, as well as secondary windings that control the inverter switching frequency.
- the transformer in some embodiments has a core made of a material having a Curie temperature associated with a maximum operating temperature of a component in the power source, where the control transformer reduces the inductance of the secondary windings when the core temperature exceeds the Curie temperature to prevent the power source from
- Fig. 1 is a schematic diagram illustrating an exemplary LED power source having a self-oscillating isolated DC-DC converter for powering an LED array;
- FIG. 2 is a schematic diagram illustrating details of an exemplary self-oscillating isolated DC-DC converter
- Fig. 3 is a side elevation view illustrating an exemplary control transformer with a core having a Curie temperature Tc set for thermal protection of the system and DC- DC converter of Figs. 1 and 2.
- Fig. 1 illustrates an LED power source 102 including a rectifier 110 receiving input power from an AC input 104, where the rectifier can be active or passive or the power source 102 can alternatively be supplied with DC input power with the rectifier omitted.
- the rectifier 110 has an output 112 providing a rectified DC voltage to a switching type DC-DC converter 120, which includes various switching devices operated by suitable control signals (not shown).
- the converter 120 is a boost converter with a power factor control (PFC) component 121 to control the power factor of the ballast 102.
- the initial converter 120 may be omitted, with the rectifier (or external DC supply) providing the DC voltage 122.
- the LED power source 102 further includes a self-oscillating isolated DC-DC converter 200 that is comprised of an inverter 210 receiving the DC voltage 122 and generating an intermediate AC, and a controller 220 that controls the inverter 210.
- the inverter 210 is transformer coupled to provide isolated AC power to an output rectifier 230.
- the output rectifier converts the intermediate AC to provide a DC power output 202 for driving an LED array load 130, which mas include any number of LEDs 132 arranged in any suitable series and/or parallel configuration.
- the exemplary controller 220 senses one or more conditions at the output rectifier 230 and selectively modifies operation of the inverter 210 accordingly.
- the exemplary DC-DC converter 200 of Fig. 2 may be advantageously employed in the LED power source 102 of Fig. 1 above, and may be employed in any system in which isolated DC-DC conversion is required.
- the DC-DC converter 200 includes an inverter 210 having terminals 210a and 210b that receive DC power from the boost converter 120 or other preceding DC supply.
- the inverter 210 moreover, includes a resonant circuit 213 and a pair of resonance controlled switching devices Q1 and 02, in one example, n-type MOSFETs although any suitable switching devices may be employed.
- the inverter receives DC input voltage via the terminals 210a and 210b and this input DC is selectively switching by the switching devices Q1 and Q2 coupled in series between a positive voltage node DC+ and a negative node coupled to a first circuit ground GNDl .
- the selective switching of the switches Q1 and Q2 operates to generate a square wave at an inverter output node 211, which in turn excites the resonant circuit 213 to thereby drive a high frequency bus 212.
- the converter 200 includes transformers for power and control isolation, as well as for self-oscillation. These include a first transformer Tl with a winding Tl A in the resonant circuit 213 and a winding TlB in the output rectifier circuit 230, a second transformer T2 having a first winding T2A in series with the winding Tl A in the resonant circuit 213 and second and third windings T2B and T2C in switch control circuits associated with the first and second switching devices Q1 and Q2, respectively, as well as a third transformer T3 with a first winding T3A in the controller 220 and second and third windings T3B and T3C in the switch control circuits associated with Q1 and Q2.
- the first transformer Tl provides AC power from the high frequency bus 212 to the secondary winding T! B of the output rectifier 230, and the secondary current from T1B is rectified to provide output power at terminals 202a and 202b for driving the LED array 130 with power isolated from the first circuit ground GNDI , where the negative output terminal 202b provides an output ground GND2 that is isolated from the first circuit ground GNDl via the first transformer Tl .
- the first winding T2A of the second transformer operates as a primary- in the resonant circuit 213 and the secondary windings T2B and T2C are connected in the gate drive circuits for Ql and Q2, respectively for oscillators' actuation of the switches according to the resonance of the circuit 213.
- the third transformer T3 is used by the controller 220 to selectively control the inductance of the gate drive circuits for closed loop operation of the converter 200, in one example, to control the LED array output current
- the high frequency bus is generated at the node 212 by the inverter 210 and the resonant circuit 213, which includes a resonant inductance (e.g., the series connected windings TI A and T2A) as well as an equivalent resonant capacitance including the equivalent of capacitors C1 and C2 connected in series between the DC+ and GND1 nodes, with a center node at the high frequency bus 212.
- the inverter 210 also includes a clamping circuit formed by clamping diodes D1 and D2 individually coupled in parallel with the capacitances C1 and C2, respectively.
- the switches Q1 and Q2 are alternately activated to provide a square wave of amplitude VDC/2 at a common inverter output node 211 (e.g., half the DC bus voltage across the terminals 122a and 122b).
- the square wave output of the inverter 210 excites the resonant circuit 213.
- Gate or control lines 214 and 216 include resistances Rl and 112 for providing control signals to the gates of the inverter switches QJ and Q2, respectively.
- the switch gating signals are generated using first and second gate drive circuits 221 and 222, respectively, with the first drive circuit 221 coupled between the inverter output node 211 and a first circuit node 218, and the second drive circuit 222 coupled between the circuit ground GNDl and node 216.
- the drive circuits 221 and 222 respectively include the first and second driving inductors T2B and T2C which are secondary windings mutually coupled to the resonant inductor T2A of the resonant circuit 213 to induce voltage in the driving inductors T2B and T2C proportional to the instantaneous rate of change of current in the resonant circuit 213 for self-oscillatory operation of the inverter 210.
- the drive circuits 221 and 222 include the secondary inductors T3B and T3C serially connected to the respective first and second driving inductors T2B and T2C and the gate control lines 214 and 216, where the controller 220 can change the oscillatory frequency of the inverter 210 by varying the inductance of the windings T3B and T3C through control of the current through the primary winding T3A.
- the gate drive circuits 221 and 222 maintain Ql in an "ON" state for a first half of a cycle and the switch Q2 "ON" for a second half of the cycle to generate a generally square wave at the output node 211 for excitation of the resonant circuit 213.
- the gate to source voltages Vgs of the switching devices Ql and Q2 in one embodiment are limited by bi-directional voltage clamps Z1, Z2 and Z3.
- ZA e.g., back-to-back Zener diodes
- the individual bi-directional voltage clamp Zl , Z2 and Z3, Z4 cooperate with the respective inductor T3B and T3C to control the phase angle between the fundamental frequency component of voltage across the resonant circuit 213 and the AC current in the resonant inductor T2A.
- series coupled resistors R3 and R4 across the input terminals 122a and 122b cooperate with a resistor R6 (coupled between the inverter output node 211 and the circuit GND1) to initiate regenerative operation of the gate drive circuits 221 and 222.
- the inverter switch control circuitry includes capacitors C3 and C4 coupled in series with the windings T3B and T3C, respectively, upon application of DC power, C3 is charged from the positive DC input via R3, R.4 and R6.
- a resistor R5 shunts the capacitor CA to prevent C4 from charging and thereby prevents concurrent activation of Ql and Q2.
- This current biases Ql in a common drain, C1ass A amplifier configuration having sufficient gain to allow the combination of the resonant circuit 213 and the gate control circuit 221 to produce a regenerative action to begin oscillation of the inverter 210 at or near the resonant frequency of the network including C3 T3B and T2B, which is above the natural resonant frequency of the resonant circuit 213.
- the resonant voltage seen at the high frequency bus node 212 lags the fundamental of the inverter output voltage at node 211, thereby- facilitating soil-switching operation of the inverter 210.
- the inverter 210 therefore begins operation in a linear mode at startup and transitions into switching C1ass D mode.
- the square wave voltage at the inverter output node 211 has an amplitude of approximately one-half of the voltage of the positive terminal 122a (e.g.. Vdc/2), and the initial bias voltage across C3 drops.
- a first network 224 including the capacitor C3 and inductor T3B and a second network 226 including the capacitor C4 and inductor T3C are equivalently inductive with an operating frequency above the resonant frequency of the first and second networks 224, 226.
- the output voltage of the inverter 210 in one embodiment is clamped by serially connected clamping diodes D1, D2 to limit high voltage seen by the capacitors C1 and C2. As the inverter output voltage at node 211 increases, the clamping diodes Dl, D2 start to clamp, preventing the voltage across the capacitors C1 and C2 from changing sign and limiting the output voltage to a value that prevents thermal damage Io components of the inverter 210.
- the inverter 210 provides ahigh frequency bus at the common node 211 while maintaining the soft switching condition for Ql and Q2.
- the high frequency current flowing through the primary winding TI A of the resonant circuit 213 is transformer coupled to the secondary winding TI B that drives a passive full wave rectifier bridge which includes diodes D7, D8, D9, and Dl 0 in the output rectifier 230.
- Other forms of output rectifiers can be used, including active or passive, full or half-wave rectifiers, with or without filtering components.
- the exemplary output rectifier 230 includes an output filter capacitance CS operative to smooth the rectified DC voltage from the diodes bridge D7-D10.
- the output rectifier 230 also includes a sense resistance Rl 1 coupled between the lower leg of the rectifier D7-D10 and the negative output terminal 202b, where the voltage across Rl 1 is proportional to the DC current provided to the LED array 130 (or to other load) connected to the output terminals 202.
- the controller circuit 220 senses this load current signal and operates to vary/control the inductance of the inverter windings T3B and T3C, and hence the operating frequency of the inverter 210, by changing the loading seen by the tertiary winding T3A.
- the output current provided to the LED sensed via resistor Rl i
- the inverter frequency moreover, decreases with decreased loading of T3A.
- the exemplary controller 220 of Fig. 2 operates to increase or decrease the loading on T3 A to reduce or raise the LED current respectively.
- the controller 220 includes an operational amplifier (OP-AMP) U1 with a non-inverting input coupled to the output ground GND2 and an inverting input receiving the LED current sensing signal from the output rectifier 230 via a resistor R10.
- Resistors R9 and R 10 provide a reference to the non-inverting input based on the level set by a stabilized shunt regulator formed using zener Z8 and capacitance C6, and the stabilized reference node at R9 is connected via a resistor R8 to an upper terminal of a full bridge rectifier D3-D6 coupled to the tertiary winding T3A.
- a zener Z6 is coupled across the bridge D3-D6, and the loading of the bridge is controlled by a MOSFET Q3 series connected with a zener Z7 across the bridge output
- the amplifier UI drives the gate of Q3 to perform proportional integral (Pl) control via integrator feedback capacitance C7 and resistor R7 connected between the amplifier output and inverting input to reduce any difference between the established reference level and the LED current sense signal from the output rectifier 230.
- Ihe closed loop controller 220 thus increases the loading (increasing the gate signal to Q3) to decrease the inductance of the transformer windings T3B and T3C to thereby increase the inverter frequency and thus decrease the LED output current when the sensed LED current level is above the reference level, and vice versa when the sensed LED current level is below the reference level.
- the illustrated embodiment shows one exemplary controller 220, but other embodiments are possible in which the loading of a tertiary winding T3A is modified to control the output of the rectifier 230.
- the DC-DC converter 200 thus provides electrically isolated inverter input and rectifier output circuits 210 and 230 using the transformer Tl for isolated power transfer to the output load, together with isolated control via the transformer windings of T3, and self- osciliating operation using the resonant circuit 213 and the gate drive circuit coupling viaT2.
- the inverter 210 is provided with an input DC bus level of about 450 volts at the terminals 122 and drives an LBD array at a nominal voltage of around 63 volts with the inverter frequency being controlled in a range of around 120- 160 kHz.
- the installed LED array can have its negative terminal connected Io earth ground if desired, and this is fully isolated from the supply main and the circuit ground of the inverter 210 without requiring a separate power supply for isolation.
- the self-oscillating features of the inverter 210 allows for robust startup and steady-state operation without requiring pulse width modulation (PWM) or frequency controller.
- the DC-DC converter may further include integral thermal protection incorporated into the isolated control configuration as described above.
- the transformer T3 has a ferromagnetic core 3(K) with a Curie temperature Tc set at a temperature threshold level corresponding to a desired thermal shutdown safety level for the DC-DC converter 200.
- the threshold level may be set to 100 degrees C or 125 degrees C or other level corresponding to a limit above which one or more components of the converter 200 may be subject to thermal failure or degradation.
- the core material becomes paramagnetic and the inductance of the inverter gate control circuit windings T3B and T3C decreases due to the Curie effect, thereby increasing the inverter frequency.
- the DC-DC converter 200 in this embodiment provides thermal self- protection.
Abstract
Isolated LEED power sources and DC-DC converters therefor are presented in which the DC-DC converter includes a seif-osciilating inverter driving an output rectifier for operating an LED array of one or more LEDs. where the ins erter uses a control transformer with core having a Curie temperature set to a maximum operating temperature of one or more power supply components to reduce inductances of secondary windings in the inverter oscillation circuitry to lower the power supplied to the load so as to prevent the inverter from overheating.
Description
LED POWER SOURCE AND DC-DC CONVERTER
BACKGROUND OF THE DISCLOSURE
[0001] Light emitting diodes (LEDs) are becoming more and more popular for lighting and signaling applications, in which multiple LEDs are formed into an array and powered to emit light. LED arrays are typically supplied with DC current with the amount of supplied power controlling the array brightness. In many applications, it is desirable to maintain electrical isolation between the LED array and the input power supply, such as where installers may ground the LED array to earth ground. Moreover, it is desirable to avoid thermal excesses in the LED power source. A need therefore exists for improved LED power sources and DC-DC converters that provide isolation and self-protection against overheating.
SUMMARY OF THE DISCLOSURE
[0001] An LED power source is provided along with a self oscillating DC-DC converter therefor, which can be employed for operating an LED array. The power source includes an input rectifier which receives an input AC voltage signal and produces an initial DC voltage received by the DC-DC converter. In one embodiment the power source includes a boost converter operafively coupled between the input rectifier and the DC-DC converter, which may have a power factor correction controller to control a power factor of the power source. The DC-DC converter has isolated supply-side and load-side ground connections as well as a self-oscillating inverter and an output rectifier. The inverter is coupled with the supply-side ground connection and receives the initial DC voltage directly or indirectly from the input rectifier and produces an intermediate AC signal. The output rectifier is coupled with the load-side ground connection and receives the intermediate AC signal from which if produces an output DC voltage to supply power to the LED array. The DC-DC converter may further include an inverter controller that modifies the inverter frequency to control the supplied power based at least in pan on sensed output power draw, where the inverter controller is electrically isolated from the inverter in some embodiments. The DC-DC converter
may be controlled using a control transformer with a primary winding operatively coupled to and controlled by the inverter controller, as well as secondary windings that control the inverter switching frequency. The transformer in some embodiments has a core made of a material having a Curie temperature associated with a maximum operating temperature of a component in the power source, where the control transformer reduces the inductance of the secondary windings when the core temperature exceeds the Curie temperature to prevent the power source from
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] One or more exemplary embodiments are set forth in the following detailed description and the drawings, in which:
[0003] Fig. 1 is a schematic diagram illustrating an exemplary LED power source having a self-oscillating isolated DC-DC converter for powering an LED array;
[0004] Fig. 2 is a schematic diagram illustrating details of an exemplary self-oscillating isolated DC-DC converter; and
[0005] Fig. 3 is a side elevation view illustrating an exemplary control transformer with a core having a Curie temperature Tc set for thermal protection of the system and DC- DC converter of Figs. 1 and 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0006] Referring now to the drawings, where like reference numerals are used to refer to like elements throughout, and wherein the various features are not necessarily drawn to scale. Fig. 1 illustrates an LED power source 102 including a rectifier 110 receiving input power from an AC input 104, where the rectifier can be active or passive or the power source 102 can alternatively be supplied with DC input power with the rectifier omitted. The rectifier 110 has an output 112 providing a rectified DC voltage to a switching type DC-DC converter 120, which includes various switching devices operated by suitable control signals (not shown). In one embodiment, the converter 120
is a boost converter with a power factor control (PFC) component 121 to control the power factor of the ballast 102. In certain embodiments, the initial converter 120 may be omitted, with the rectifier (or external DC supply) providing the DC voltage 122.
[0007] The LED power source 102 further includes a self-oscillating isolated DC-DC converter 200 that is comprised of an inverter 210 receiving the DC voltage 122 and generating an intermediate AC, and a controller 220 that controls the inverter 210. The inverter 210 is transformer coupled to provide isolated AC power to an output rectifier 230. The output rectifier converts the intermediate AC to provide a DC power output 202 for driving an LED array load 130, which mas include any number of LEDs 132 arranged in any suitable series and/or parallel configuration. The exemplary controller 220 senses one or more conditions at the output rectifier 230 and selectively modifies operation of the inverter 210 accordingly.
[0008] Referring also to Fig. 2, further details of an embodiment of a self-oscillating isolated DC-DC converter 210 are illustrated. The exemplary DC-DC converter 200 of Fig. 2 may be advantageously employed in the LED power source 102 of Fig. 1 above, and may be employed in any system in which isolated DC-DC conversion is required. As shown in Fig. 2, the DC-DC converter 200 includes an inverter 210 having terminals 210a and 210b that receive DC power from the boost converter 120 or other preceding DC supply. The inverter 210, moreover, includes a resonant circuit 213 and a pair of resonance controlled switching devices Q1 and 02, in one example, n-type MOSFETs although any suitable switching devices may be employed. The inverter receives DC input voltage via the terminals 210a and 210b and this input DC is selectively switching by the switching devices Q1 and Q2 coupled in series between a positive voltage node DC+ and a negative node coupled to a first circuit ground GNDl . In operation, the selective switching of the switches Q1 and Q2 operates to generate a square wave at an inverter output node 211, which in turn excites the resonant circuit 213 to thereby drive a high frequency bus 212.
[0009] The converter 200 includes transformers for power and control isolation, as well as for self-oscillation. These include a first transformer Tl with a winding Tl A in the resonant circuit 213 and a winding TlB in the output rectifier circuit 230, a second
transformer T2 having a first winding T2A in series with the winding Tl A in the resonant circuit 213 and second and third windings T2B and T2C in switch control circuits associated with the first and second switching devices Q1 and Q2, respectively, as well as a third transformer T3 with a first winding T3A in the controller 220 and second and third windings T3B and T3C in the switch control circuits associated with Q1 and Q2. In operation, the first transformer Tl provides AC power from the high frequency bus 212 to the secondary winding T! B of the output rectifier 230, and the secondary current from T1B is rectified to provide output power at terminals 202a and 202b for driving the LED array 130 with power isolated from the first circuit ground GNDI , where the negative output terminal 202b provides an output ground GND2 that is isolated from the first circuit ground GNDl via the first transformer Tl . The first winding T2A of the second transformer operates as a primary- in the resonant circuit 213 and the secondary windings T2B and T2C are connected in the gate drive circuits for Ql and Q2, respectively for oscillators' actuation of the switches according to the resonance of the circuit 213. The third transformer T3 is used by the controller 220 to selectively control the inductance of the gate drive circuits for closed loop operation of the converter 200, in one example, to control the LED array output current
[0010] The high frequency bus is generated at the node 212 by the inverter 210 and the resonant circuit 213, which includes a resonant inductance (e.g., the series connected windings TI A and T2A) as well as an equivalent resonant capacitance including the equivalent of capacitors C1 and C2 connected in series between the DC+ and GND1 nodes, with a center node at the high frequency bus 212. The inverter 210 also includes a clamping circuit formed by clamping diodes D1 and D2 individually coupled in parallel with the capacitances C1 and C2, respectively. The switches Q1 and Q2 are alternately activated to provide a square wave of amplitude VDC/2 at a common inverter output node 211 (e.g., half the DC bus voltage across the terminals 122a and 122b). The square wave output of the inverter 210 excites the resonant circuit 213. Gate or control lines 214 and 216 include resistances Rl and 112 for providing control signals to the gates of the inverter switches QJ and Q2, respectively.
[ 0011] The switch gating signals are generated using first and second gate drive circuits 221 and 222, respectively, with the first drive circuit 221 coupled between the inverter output node 211 and a first circuit node 218, and the second drive circuit 222 coupled between the circuit ground GNDl and node 216. The drive circuits 221 and 222 respectively include the first and second driving inductors T2B and T2C which are secondary windings mutually coupled to the resonant inductor T2A of the resonant circuit 213 to induce voltage in the driving inductors T2B and T2C proportional to the instantaneous rate of change of current in the resonant circuit 213 for self-oscillatory operation of the inverter 210. In addition, the drive circuits 221 and 222 include the secondary inductors T3B and T3C serially connected to the respective first and second driving inductors T2B and T2C and the gate control lines 214 and 216, where the controller 220 can change the oscillatory frequency of the inverter 210 by varying the inductance of the windings T3B and T3C through control of the current through the primary winding T3A.
[0012 ] In operation, the gate drive circuits 221 and 222 maintain Ql in an "ON" state for a first half of a cycle and the switch Q2 "ON" for a second half of the cycle to generate a generally square wave at the output node 211 for excitation of the resonant circuit 213. The gate to source voltages Vgs of the switching devices Ql and Q2 in one embodiment are limited by bi-directional voltage clamps Z1, Z2 and Z3. ZA (e.g., back-to-back Zener diodes) coupled between the respective switch sources and the gate control lines 214 and 216. In this embodiment, the individual bi-directional voltage clamp Zl , Z2 and Z3, Z4 cooperate with the respective inductor T3B and T3C to control the phase angle between the fundamental frequency component of voltage across the resonant circuit 213 and the AC current in the resonant inductor T2A.
[ 0013] To start the converter 200, series coupled resistors R3 and R4 across the input terminals 122a and 122b cooperate with a resistor R6 (coupled between the inverter output node 211 and the circuit GND1) to initiate regenerative operation of the gate drive circuits 221 and 222. In addition, the inverter switch control circuitry includes capacitors C3 and C4 coupled in series with the windings T3B and T3C, respectively, upon application of DC power, C3 is charged from the positive DC input via R3, R.4
and R6. During this time, a resistor R5 shunts the capacitor CA to prevent C4 from charging and thereby prevents concurrent activation of Ql and Q2. Since the voltage across C3 is initially zero, the series connected inductors T2B and T3B act as a short circuit due to a relatively long time constant for charging of the capacitor C3. Once C3 charges up to the threshold voltage of the Vgs of Ql , (e.g..2-3 volts in one embodiment), Ql turns ON and a small bias current flows through Ql . This current biases Ql in a common drain, C1ass A amplifier configuration having sufficient gain to allow the combination of the resonant circuit 213 and the gate control circuit 221 to produce a regenerative action to begin oscillation of the inverter 210 at or near the resonant frequency of the network including C3 T3B and T2B, which is above the natural resonant frequency of the resonant circuit 213. As a result, the resonant voltage seen at the high frequency bus node 212 lags the fundamental of the inverter output voltage at node 211, thereby- facilitating soil-switching operation of the inverter 210. The inverter 210 therefore begins operation in a linear mode at startup and transitions into switching C1ass D mode.
[0014] In steady state operation of the LED power source 102 circuit, the square wave voltage at the inverter output node 211 has an amplitude of approximately one-half of the voltage of the positive terminal 122a (e.g.. Vdc/2), and the initial bias voltage across C3 drops. In the illustrated inverter a first network 224 including the capacitor C3 and inductor T3B and a second network 226 including the capacitor C4 and inductor T3C are equivalently inductive with an operating frequency above the resonant frequency of the first and second networks 224, 226. In steady state oscillatory operation, this results in a phase shift of the gale circuit to allow the current flowing through the inductor T2A to lag the fundamental frequency of the voltage produced at the inverter output node 21 L thus facilitating soft-switching of the inverter 210 during the steady-state operation. The output voltage of the inverter 210 in one embodiment is clamped by serially connected clamping diodes D1, D2 to limit high voltage seen by the capacitors C1 and C2. As the inverter output voltage at node 211 increases, the clamping diodes Dl, D2 start to clamp, preventing the voltage across the capacitors C1 and C2 from changing sign and limiting the output voltage to a value that prevents thermal damage Io components of the inverter 210.
[0015] In steady state operation, therefore, the inverter 210 provides ahigh frequency bus at the common node 211 while maintaining the soft switching condition for Ql and Q2. The high frequency current flowing through the primary winding TI A of the resonant circuit 213 is transformer coupled to the secondary winding TI B that drives a passive full wave rectifier bridge which includes diodes D7, D8, D9, and Dl 0 in the output rectifier 230. Other forms of output rectifiers can be used, including active or passive, full or half-wave rectifiers, with or without filtering components. The exemplary output rectifier 230 includes an output filter capacitance CS operative to smooth the rectified DC voltage from the diodes bridge D7-D10. and the resulting DC output voltage is provided at rectifier output terminals 202a and 202b, with the negative output terminal 202b forming an output ground GND2 as shown in Fig. 2. The output rectifier 230 also includes a sense resistance Rl 1 coupled between the lower leg of the rectifier D7-D10 and the negative output terminal 202b, where the voltage across Rl 1 is proportional to the DC current provided to the LED array 130 (or to other load) connected to the output terminals 202.
[0016] The controller circuit 220 senses this load current signal and operates to vary/control the inductance of the inverter windings T3B and T3C, and hence the operating frequency of the inverter 210, by changing the loading seen by the tertiary winding T3A. In particular, as the frequency of the inverter 210 is decreased, the output current provided to the LED (sensed via resistor Rl i) will increase, and vice versa. The inverter frequency, moreover, decreases with decreased loading of T3A. Thus, the exemplary controller 220 of Fig. 2 operates to increase or decrease the loading on T3 A to reduce or raise the LED current respectively. The controller 220 includes an operational amplifier (OP-AMP) U1 with a non-inverting input coupled to the output ground GND2 and an inverting input receiving the LED current sensing signal from the output rectifier 230 via a resistor R10. Resistors R9 and R 10 provide a reference to the non-inverting input based on the level set by a stabilized shunt regulator formed using zener Z8 and capacitance C6, and the stabilized reference node at R9 is connected via a resistor R8 to an upper terminal of a full bridge rectifier D3-D6 coupled to the tertiary winding T3A. A zener Z6 is coupled across the bridge D3-D6, and the loading of the
bridge is controlled by a MOSFET Q3 series connected with a zener Z7 across the bridge output
[0017] The amplifier UI drives the gate of Q3 to perform proportional integral (Pl) control via integrator feedback capacitance C7 and resistor R7 connected between the amplifier output and inverting input to reduce any difference between the established reference level and the LED current sense signal from the output rectifier 230. In general, Ihe closed loop controller 220 thus increases the loading (increasing the gate signal to Q3) to decrease the inductance of the transformer windings T3B and T3C to thereby increase the inverter frequency and thus decrease the LED output current when the sensed LED current level is above the reference level, and vice versa when the sensed LED current level is below the reference level. The illustrated embodiment shows one exemplary controller 220, but other embodiments are possible in which the loading of a tertiary winding T3A is modified to control the output of the rectifier 230. The DC-DC converter 200 thus provides electrically isolated inverter input and rectifier output circuits 210 and 230 using the transformer Tl for isolated power transfer to the output load, together with isolated control via the transformer windings of T3, and self- osciliating operation using the resonant circuit 213 and the gate drive circuit coupling viaT2.
[0018] In one embodiment, the inverter 210 is provided with an input DC bus level of about 450 volts at the terminals 122 and drives an LBD array at a nominal voltage of around 63 volts with the inverter frequency being controlled in a range of around 120- 160 kHz. In this example, the following exemplary components and values may be used: Rl and R2 10 Ω; R3 and R4 2MΩ; R5 100kΩ; R6 1MΩ; R7 100 Q; R8 10kΩ; R9 143 kΩ; R10 20 kΩ; Rl 0.1 Ω; C1 and C26.8 nF; C3 and C4 3.3 nF; C5 I nF; C6 and C7 i μF; C82x47μF; TiA 2 mH; TlB 320 μH; T2A 150 μH; T2B and T2C 1.0 μH; T3A 1 mH; T3B and T3C 500 μH; DI and D2 EDlF; D3-D6 1N4148; Z1 and Z3TZM52399.1 V: Z2 and Z4 TZM525020V; Z6 TZM526251V; Z7 TZM5231 5.1V; Z82.5V; Ql and Q2 BSS165; Q3 BSS138; and Ul LMV931. By using the isolation transformers Tl and T3, the installed LED array can have its negative terminal connected Io earth ground if desired, and this is fully isolated from the supply main and
the circuit ground of the inverter 210 without requiring a separate power supply for isolation. Moreover, the self-oscillating features of the inverter 210 allows for robust startup and steady-state operation without requiring pulse width modulation (PWM) or frequency controller.
[0019] Referring also to Fig. 3, the DC-DC converter may further include integral thermal protection incorporated into the isolated control configuration as described above. In certain embodiments, the transformer T3 has a ferromagnetic core 3(K) with a Curie temperature Tc set at a temperature threshold level corresponding to a desired thermal shutdown safety level for the DC-DC converter 200. For example, the threshold level may be set to 100 degrees C or 125 degrees C or other level corresponding to a limit above which one or more components of the converter 200 may be subject to thermal failure or degradation. In this embodiment, once the temperature of the core of T3 exceeds the threshold Tc, the core material becomes paramagnetic and the inductance of the inverter gate control circuit windings T3B and T3C decreases due to the Curie effect, thereby increasing the inverter frequency. This lowers the output power level, in turn reducing the temperature of T3, and the closed-loop control will stabilize at a lowered power operating point sufficient to prevent thermal degradation of the DC-DC converter 200. Thus, even in high ambient temperature operating conditions, the DC-DC converter 200 in this embodiment provides thermal self- protection.
[0020] The above examples are merely illustrative of several possible embodiments of various aspects of the present disclosure, wherein equivalent alterations and/or modifications will occur to others skilled in the art upon reading and understanding this specification and the annexed drawings, in particular regard to the various functions performed by the above described components (assemblies, devices, systems, circuits, and the like), the terms (including a reference to a "means") used to describe such components are intended to correspond, unless otherwise indicated, to any component, such as hardware, software, or combinations thereof, which performs the specified function of the described component (i.e., mat is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the
illustrated implementations of the disclosure. In addition, although a particular feature of the disclosure may have been illustrated and/or described with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, references to singular components or items are intended, unless otherwise specified, to encompass two or more such components or items. Also, to the extent that the terms "including", "includes", "having", "has", "with", or variants thereof are used in the detailed description and/or in the claims, such terms are intended to be inclusive in a manner similar to the term "comprising". The invention has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. ϊt is intended that the invention be construed as including all such modifications and alterations.
Claims
1. An LED power source for operating an LED array of one or more LEDs, the power source comprising: an input rectifier operative to receive an input AC voltage signal and to produce an initial DC voltage; and a DC -DC converter which is operatively coupled to the input rectifier to receive the initial DC voltage, the DC-DC converter comprising: a supply-side ground connection, a load-side ground connection electrically isolated from the supply side ground,. a self-oscillating inverter operatively coupled to the supply-side ground connection and receiving the initial DC voltage, the inverter operative to produce an intermediate AC signal, and an output rectifier operatively coupled to receive the intermediate AC signal from the inverter and being coupled with the load-side ground connection, the output rectifier operative to produce an output DC voltage to supply power to the LED array.
2. The LED power source of claim 1. further comprising a boost converter operatively coupled between the input rectifier and the DC-DC converter, the boost converter receiving the initial DC voltage from the input rectifier and amplifying the initial DC voltage to provide an intermediate DC voltage, the inverter converting the intermediate DC voltage to produce the intermediate AC signal.
3. The LED power source of claim 2, wherein the boost converter further comprises a power factor correction controller Io control a power factor of the power source.
4. The LED power source of claim 1 , wherein the DC-DC converter further comprises an inverter controller operatively coupled to the inverter, to modify a switching frequency of the inverter, to control a frequency of the intermediate AC signal to control power supplied to the LED array based at least in part on a sensed power drawn by the LED array.
5. The LED power source of claim 4, wherein the inverter controller is electrically isolated from the inverter.
6. The LED power source of claim 4, wherein the DC-DC converter further comprises a control transformer comprising: a primary winding operali veJy coupled to and controlled by the inverter controller; a secondary winding operative to control the switching frequency of the inverter: and a core operativeiy coupled to the primary winding and the secondary- windings, the core comprising a core materia! having a Curie temperature associated with a maximum operating junction temperature of a component in the power source, operative to become paramagnetic when the temperature of the core exceeds the Curie temperature of the core; the control transformer being operative to reduce the inductance of the secondary windings to lower the power supplied to the LED array to prevent the component of the power source from overheating.
7. The LED power source of claim 4, wherein the inverter further comprises: a resonant circuit which generates an oscillation signal, including a resonant inductance and a resonant capacitance; first and second switches operativeiy connected together at a common node to receive the oscillation signal determining the switching rate of the first and second switches; a first gate control circuit controlling the first switch, the first gate control circuit comprising an inductance operativeiy connected between the junction of the first and second switches and the gate of the first switch and being coupled to the resonant inductance; and a second gate control circuit controlling the second switch, the second gate control circuit comprising an inductance operatively connected between the supply-side ground connection and the gate of the second switch and being coupled to the resonant inductance; wherein the first and second switches induce an AC current in the resonant circuit.
8. The LED power source of claim 1 , wherein the inverter further comprises: a feedback transformer comprising: a primary winding, and a first and second secondary winding operative!}- connected to the primary- winding of the feedback transformer; a resonant circuit comprising: a signal-to-center capacitance operative!}' connected to the positive rail of the initial DC voltage, a center-to-ground capacitance operatively connected between the signal- to-center capacitance and the supply-side ground connection, and an inductance comprising the primary winding of the feedback transformer operatively connected to the junction of the signal-to-center capacitance and the center-to-ground capacitance; a first gate control circuit comprising: an inductance comprising the first secondary winding of the feedback transformer operatively connected to the inductance of the resonant circuit, a capacitance operatively connected to the inductance of the first gate control circuit, and a resistance operative!}- connected to the capacitance of the first gate drive circuit; a second gate control circuit comprising: an inductance comprising the second secondary winding of the feedback transformer operative!}- connected to the supply-side ground connection, a capacitance and resistance in parallel operatively connected to the inductance of the second gate control circuit, and a resistance operatively connected to the parallel capacitance-resistance of the second gate drive circuit; and first and second switches operatively connected in series between the positive rail of the DC voltage and the supply-side ground connection, and the junction of the first and second switches is connected to the inductance of the resonant circuit, the first and second switches being controlled by the first and second gate control circuits respectively; wherein the primary winding of the feedback transformer induces a voltage in the inductance of the first and second gate control circuits proportional to the instantaneous rate of change of current in the resonant circuit, the first and second gate control circuits alternatively switching the first and second switches operating to excite the resonant circuit.
9. An isolated, self-oscillating DC-DC converter comprising: a supply-side ground connection; a load-side ground connection electrically isolated from the supply side ground connection; a self-oscillating inverter operatively coupled to the supply-side ground connection and receiving the initial DC voltage, the inverter operative to produce an intermediate AC signal; and an output rectifier operatively coupled to receive the intermediate AC signal from the inverter and being coupled with the load-side ground connection, the output rectifier operative to produce an output DC voltage to supply power to a load.
10. The DC-DC converter of claim 9, further comprising an inverter controller operatively coupled to the inverter, to modify a switching frequency of the inverter, to control a frequency of the intermediate AC signal to control power supplied to a load based at least in part on a sensed power drawn by the load.
11. The DC-DC converter of claim 9, wherein the inverter controller is electrically isolated from the inverter.
12. The DC-DC converter of claim 9, further comprising a control transformer comprising: a primary winding operatively coupled to and controlled by the inverter controller; a secondary winding operative to control the switching frequency of the inverter;
a core operatively coupled to the primary winding and the secondary windings, the core comprising a core materia! having a Curie temperature associated with a maximum operating junction temperature of at least one component in the power source the core being operative to become paramagnetic when a temperature of the core exceeds the Curie temperature of the core; the control transformer being operative to reduce the inductance of the secondary windings to lower the power supplied to the LED array to prevent the component of the power source from overheating.
13. The DC-DC converter of claim 9, further comprising: a resonant circuit which generates an oscillation signal, including a resonant inductance and a resonant capacitance; first and second switches operatively connected together at a common node to receive the oscillation signal determining the switching rate of the first and second switches; a first gate control circuit controlling the first switch, the first gale control circuit comprising: an inductance operatively connected between the junction of the first and second switches and the gate of the first switch and being coupled to the resonant inductance: and a second gate control circuit controlling the second switch, the second gale control circuit comprising: an inductance operatively connected between the supply-side ground connection and the gate of the second switch and being coupled to the resonant inductance; wherein the first and second switches induce an AC current in the resonant circuit.
14. A self-oscillating DC-DC converter comprising: a self-oscillating inverter receiving the initial DC voltage, the inverter operative to produce an intermediate AC signal; an output rectifier operatively coupled to receive the intermediate AC signal from the inverter, the output rectifier operative to produce an output DC voltage to supply power to a load; and a control transformer comprising: a primary winding operatively coupled to and controlled by the inverter controller; a secondary winding operative to control the switching frequency of the inverter; and a core operatively coupled to the primary winding and the secondary windings, the core comprising a core material having a Curie temperature associated with a maximum operating junction temperature of at least one component in the inverter and operative to become paramagnetic when a temperature of the core exceeds the Curie temperature of the core: the control transformer being operative to reduce the inductance of the secondary windings to lower the power supplied to the LED array to prevent the component of the power source from overheating.
15. The self-oscillating DC-DC converter of claim 14, further comprising an inverter controller operatively coupled to the inverter, to modify a switching frequency of the inverter, to control a frequency of the intermediate AC signal to control power supplied to the LED array based at least in part on a sensed power drawn by the LED array.
16. The sell-oscillating DC-DC converter of claim 14, wherein the inverter
a resonant circuit which generates an oscillation signal, including a resonant inductance and a resonant capacitance: first and second switches operative!} connected together at a common node to receive the oscillation signal determining the switching rate of the first and second switches; a first gate control circuit controlling the first switch, the first gate control circuit comprising an inductance operatively connected between the junction of the first and second switches and the gate of the first switch and being coupled to the resonant inductance; and a second gate control circuit controlling the second switch, the second gate control circuit comprising an inductance operatively connected between the supply-side ground connection and the gate of the second switch and being coupled to the resonant inductance; wherein the first and second switches induce an AC current in the resonant circuit.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP10719473A EP2438670A1 (en) | 2009-06-05 | 2010-04-22 | Led power source and dc-dc converter |
CN201080025850.7A CN102460920B (en) | 2009-06-05 | 2010-04-22 | Led power source and dc-dc converter |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/479,312 US7990070B2 (en) | 2009-06-05 | 2009-06-05 | LED power source and DC-DC converter |
US12/479,312 | 2009-06-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2010141157A1 true WO2010141157A1 (en) | 2010-12-09 |
Family
ID=42288621
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2010/031968 WO2010141157A1 (en) | 2009-06-05 | 2010-04-22 | Led power source and dc-dc converter |
Country Status (4)
Country | Link |
---|---|
US (1) | US7990070B2 (en) |
EP (1) | EP2438670A1 (en) |
CN (1) | CN102460920B (en) |
WO (1) | WO2010141157A1 (en) |
Families Citing this family (65)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8118447B2 (en) | 2007-12-20 | 2012-02-21 | Altair Engineering, Inc. | LED lighting apparatus with swivel connection |
US8058820B2 (en) * | 2008-01-14 | 2011-11-15 | Tai-Her Yang | Uni-directional light emitting diode drive circuit in pulsed power parallel resonance |
US8212541B2 (en) | 2008-05-08 | 2012-07-03 | Massachusetts Institute Of Technology | Power converter with capacitive energy transfer and fast dynamic response |
US8360599B2 (en) | 2008-05-23 | 2013-01-29 | Ilumisys, Inc. | Electric shock resistant L.E.D. based light |
JP2010086943A (en) * | 2008-09-04 | 2010-04-15 | Toshiba Lighting & Technology Corp | Led lighting device and illumination fixture |
US8324817B2 (en) | 2008-10-24 | 2012-12-04 | Ilumisys, Inc. | Light and light sensor |
US8653984B2 (en) | 2008-10-24 | 2014-02-18 | Ilumisys, Inc. | Integration of LED lighting control with emergency notification systems |
US8214084B2 (en) | 2008-10-24 | 2012-07-03 | Ilumisys, Inc. | Integration of LED lighting with building controls |
US7938562B2 (en) | 2008-10-24 | 2011-05-10 | Altair Engineering, Inc. | Lighting including integral communication apparatus |
US8901823B2 (en) | 2008-10-24 | 2014-12-02 | Ilumisys, Inc. | Light and light sensor |
TWI489903B (en) * | 2009-07-09 | 2015-06-21 | Light emitting diode lighting device and its current control method | |
US9232590B2 (en) | 2009-08-14 | 2016-01-05 | Once Innovations, Inc. | Driving circuitry for LED lighting with reduced total harmonic distortion |
US8643308B2 (en) * | 2009-08-14 | 2014-02-04 | Once Innovations, Inc. | Spectral shift control for dimmable AC LED lighting |
US9380665B2 (en) | 2009-08-14 | 2016-06-28 | Once Innovations, Inc. | Spectral shift control for dimmable AC LED lighting |
US8373363B2 (en) | 2009-08-14 | 2013-02-12 | Once Innovations, Inc. | Reduction of harmonic distortion for LED loads |
US9433046B2 (en) | 2011-01-21 | 2016-08-30 | Once Innovations, Inc. | Driving circuitry for LED lighting with reduced total harmonic distortion |
US9482397B2 (en) | 2010-03-17 | 2016-11-01 | Once Innovations, Inc. | Light sources adapted to spectral sensitivity of diurnal avians and humans |
WO2011119958A1 (en) | 2010-03-26 | 2011-09-29 | Altair Engineering, Inc. | Inside-out led bulb |
US8541958B2 (en) | 2010-03-26 | 2013-09-24 | Ilumisys, Inc. | LED light with thermoelectric generator |
US8294377B2 (en) | 2010-06-25 | 2012-10-23 | Power Integrations, Inc. | Power converter with compensation circuit for adjusting output current provided to a constant load |
EP2593714A2 (en) | 2010-07-12 | 2013-05-22 | iLumisys, Inc. | Circuit board mount for led light tube |
TWI420970B (en) * | 2010-07-16 | 2013-12-21 | Delta Electronics Inc | Lighting devices |
US8258710B2 (en) * | 2010-09-02 | 2012-09-04 | Osram Sylvania Inc. | Solid state light source driving and dimming using an AC voltage source |
WO2012058556A2 (en) | 2010-10-29 | 2012-05-03 | Altair Engineering, Inc. | Mechanisms for reducing risk of shock during installation of light tube |
CN102006703A (en) * | 2010-12-03 | 2011-04-06 | 何志雄 | Light-emitting diode (LED) lamp driving power supply |
US8870415B2 (en) | 2010-12-09 | 2014-10-28 | Ilumisys, Inc. | LED fluorescent tube replacement light with reduced shock hazard |
US10389235B2 (en) | 2011-05-05 | 2019-08-20 | Psemi Corporation | Power converter |
US8461774B2 (en) * | 2011-03-15 | 2013-06-11 | General Electric Company | Lighting power circuit with peak current limiter for EMI filter |
CN103650313B (en) | 2011-05-05 | 2018-09-21 | 北极砂技术有限公司 | DC-DC converter with modular grade |
US9882471B2 (en) | 2011-05-05 | 2018-01-30 | Peregrine Semiconductor Corporation | DC-DC converter with modular stages |
US10680515B2 (en) | 2011-05-05 | 2020-06-09 | Psemi Corporation | Power converters with modular stages |
US8575849B2 (en) * | 2011-07-15 | 2013-11-05 | Osram Sylvania Inc. | Resonate driver for solid state light sources |
US9072171B2 (en) | 2011-08-24 | 2015-06-30 | Ilumisys, Inc. | Circuit board mount for LED light |
US9178354B2 (en) * | 2011-08-24 | 2015-11-03 | 3Dfs L.L.C. | Multipurpose, universal converter with battery control and real-time power factor correction |
TWI599265B (en) * | 2011-11-15 | 2017-09-11 | Hep Tech Co Ltd | Light supply module |
US9374985B2 (en) | 2011-12-14 | 2016-06-28 | Once Innovations, Inc. | Method of manufacturing of a light emitting system with adjustable watt equivalence |
WO2013131002A1 (en) | 2012-03-02 | 2013-09-06 | Ilumisys, Inc. | Electrical connector header for an led-based light |
US10098202B1 (en) * | 2012-03-19 | 2018-10-09 | Universal Lighting Technologies | Constant current source with output voltage range and self-clamping output voltage |
WO2014008463A1 (en) | 2012-07-06 | 2014-01-09 | Ilumisys, Inc. | Power supply assembly for led-based light tube |
US9271367B2 (en) | 2012-07-09 | 2016-02-23 | Ilumisys, Inc. | System and method for controlling operation of an LED-based light |
US9255674B2 (en) | 2012-10-04 | 2016-02-09 | Once Innovations, Inc. | Method of manufacturing a light emitting diode lighting assembly |
US9210758B2 (en) | 2012-10-16 | 2015-12-08 | General Electric Company | Boost converter of driver circuit with thermal compensation |
CN104756385B (en) * | 2012-10-31 | 2018-07-06 | 麻省理工学院 | For the system and method for variable frequency multiplier power converter |
US9285084B2 (en) | 2013-03-14 | 2016-03-15 | Ilumisys, Inc. | Diffusers for LED-based lights |
US8619445B1 (en) | 2013-03-15 | 2013-12-31 | Arctic Sand Technologies, Inc. | Protection of switched capacitor power converter |
WO2014168911A1 (en) | 2013-04-09 | 2014-10-16 | Massachusetts Institute Of Technology | Power conservation with high power factor |
KR20140141907A (en) * | 2013-06-03 | 2014-12-11 | 주식회사 포스코엘이디 | Led luminaire having a high power led driving circuit |
CN109600884B (en) | 2013-08-02 | 2021-02-12 | 昕诺飞北美公司 | System and method for illuminating livestock |
KR20150021838A (en) * | 2013-08-21 | 2015-03-03 | 삼성전자주식회사 | Led driving apparatus and lighting apparatus |
US9267650B2 (en) | 2013-10-09 | 2016-02-23 | Ilumisys, Inc. | Lens for an LED-based light |
WO2015069516A1 (en) | 2013-10-29 | 2015-05-14 | Massachusetts Institute Of Technology | Switched-capacitor split drive transformer power conversion circuit |
DE102013224749A1 (en) * | 2013-12-03 | 2015-06-03 | Tridonic Gmbh & Co Kg | Driver circuit for lamps, in particular LEDs |
CN106061244A (en) | 2014-01-07 | 2016-10-26 | 万斯创新公司 | System and method of enhancing swine reproduction |
JP2017504166A (en) | 2014-01-22 | 2017-02-02 | イルミシス, インコーポレイテッドiLumisys, Inc. | LED-based lamp with LED addressed |
US9247603B2 (en) | 2014-02-11 | 2016-01-26 | Once Innovations, Inc. | Shunt regulator for spectral shift controlled light source |
US9510400B2 (en) | 2014-05-13 | 2016-11-29 | Ilumisys, Inc. | User input systems for an LED-based light |
WO2016004427A1 (en) | 2014-07-03 | 2016-01-07 | Massachusetts Institute Of Technology | High-frequency, high-density power factor correction conversion for universal input grid interface |
USD780348S1 (en) | 2015-06-01 | 2017-02-28 | Ilumisys, Inc. | LED-based light tube |
US10161568B2 (en) | 2015-06-01 | 2018-12-25 | Ilumisys, Inc. | LED-based light with canted outer walls |
USD781469S1 (en) | 2015-07-07 | 2017-03-14 | Ilumisys, Inc. | LED light tube |
USD815763S1 (en) | 2015-07-07 | 2018-04-17 | Ilumisys, Inc. | LED-based light tube |
BR112018069831A2 (en) | 2016-03-29 | 2019-01-29 | Once Innovations Inc | pig lighting control system and method of stimulating a biological response in pigs |
US10314125B2 (en) | 2016-09-30 | 2019-06-04 | Once Innovations, Inc. | Dimmable analog AC circuit |
US11064588B1 (en) | 2019-10-07 | 2021-07-13 | Universal Lighting Technologies, Inc. | Clamped resonant tank with constant soft-switching and startup overshoot prevention |
CN113904305B (en) * | 2021-11-10 | 2024-01-23 | 茂硕电源科技股份有限公司 | Temperature protection circuit of switching power supply |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61221581A (en) * | 1985-03-26 | 1986-10-01 | Toshiba Corp | Inverter |
JPH02216796A (en) * | 1989-02-17 | 1990-08-29 | Tokyo Electric Co Ltd | Discharge lamp lighting device |
WO1995006350A1 (en) * | 1993-08-20 | 1995-03-02 | Powerpaq Technologies Inc. | Thermal shutdown for power converters |
US5475285A (en) * | 1992-07-17 | 1995-12-12 | Motorola, Inc. | Lamp circuit limited to a booster in which the power output decreases with increasing frequency |
US20040183380A1 (en) * | 2003-03-07 | 2004-09-23 | Toko, Inc. | Switching constant-current power supply system |
US20060267513A1 (en) * | 2005-05-31 | 2006-11-30 | Funai Electric Co., Ltd. | Projector |
US20070236159A1 (en) * | 2006-04-10 | 2007-10-11 | Robert Beland | Illumination systems |
EP1868284A1 (en) * | 2006-06-15 | 2007-12-19 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Driver arrangement for LED lamps |
WO2008055545A1 (en) * | 2006-11-09 | 2008-05-15 | Osram Gesellschaft mit beschränkter Haftung | Self-oscillating dc-dc converter and method therefor |
Family Cites Families (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2627342B1 (en) | 1988-02-16 | 1990-07-20 | Applic Util Proprietes Ele | LUMINESCENT TUBE FEEDING DEVICE |
US5172033A (en) | 1990-09-14 | 1992-12-15 | U. S. Philips Corporation | Discharge lamp operating inverter circuit with electric dimmer utilizing frequency control of the inverter |
US5162700A (en) * | 1991-05-31 | 1992-11-10 | General Electric Company | Controllable ballast and operating system utilizing same |
SE501046C2 (en) * | 1993-01-25 | 1994-10-24 | Lindmark Electric Ab | Power unit with self-rotating series resonant converter |
CA2124370C (en) * | 1994-05-26 | 1998-09-29 | Ivan Meszlenyi | Self oscillating dc to dc converter |
US5796214A (en) * | 1996-09-06 | 1998-08-18 | General Elecric Company | Ballast circuit for gas discharge lamp |
US5917289A (en) * | 1997-02-04 | 1999-06-29 | General Electric Company | Lamp ballast with triggerless starting circuit |
US6078143A (en) * | 1998-11-16 | 2000-06-20 | General Electric Company | Gas discharge lamp ballast with output voltage clamping circuit |
US6194840B1 (en) * | 1998-12-28 | 2001-02-27 | Philips Electronics North America Corporation | Self-oscillating resonant converter with passive filter regulator |
US6429604B2 (en) * | 2000-01-21 | 2002-08-06 | Koninklijke Philips Electronics N.V. | Power feedback power factor correction scheme for multiple lamp operation |
FI20002493A (en) * | 2000-11-14 | 2002-05-15 | Salcomp Oy | Power Supply Arrangement and Inductively Connected Battery Charger with Wireless Connected Control, and Method for Wirelessly Controlling Power Supply Arrangement and Inductively Connected Battery Charger |
US6417631B1 (en) * | 2001-02-07 | 2002-07-09 | General Electric Company | Integrated bridge inverter circuit for discharge lighting |
US6509696B2 (en) * | 2001-03-22 | 2003-01-21 | Koninklijke Philips Electronics N.V. | Method and system for driving a capacitively coupled fluorescent lamp |
US6525488B2 (en) * | 2001-05-18 | 2003-02-25 | General Electric Company | Self-oscillating synchronous boost converter |
US6836077B2 (en) * | 2001-07-05 | 2004-12-28 | General Electric Company | Electronic elimination of striations in linear lamps |
US6815908B2 (en) * | 2002-12-11 | 2004-11-09 | General Electric | Dimmable self-oscillating electronic ballast for fluorescent lamp |
US6867553B2 (en) * | 2003-04-16 | 2005-03-15 | General Electric Company | Continuous mode voltage fed inverter |
US7372215B2 (en) * | 2004-02-19 | 2008-05-13 | International Rectifier Corporation | Lamp ballast for circuit driving multiple parallel lamps |
US7554822B2 (en) * | 2004-10-01 | 2009-06-30 | Koninklijke Philips Electronics N.V. | Power converter for led large area light source lamp |
US7291987B2 (en) * | 2005-06-17 | 2007-11-06 | Hon Hai Precision Industry Co., Ltd. | Power supply system for flat panel display devices |
DE102005030114A1 (en) * | 2005-06-28 | 2007-01-18 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Circuit arrangement for operating electrical lamp e.g. fluorescent lamp, and light emitting diode, has lamps-supply unit with light emitting diode-supply unit, which is designed to supply light emitting diode with energy |
US7436124B2 (en) * | 2006-01-31 | 2008-10-14 | General Electric Company | Voltage fed inverter for fluorescent lamps |
JP2008187821A (en) * | 2007-01-30 | 2008-08-14 | Matsushita Electric Works Ltd | Insulated ac-dc converter and dc power supply unit for led using it |
CN201114948Y (en) * | 2007-05-21 | 2008-09-10 | 飞利浦(中国)投资有限公司 | Self-activated half-bridge conversion circuit |
CN101222807A (en) * | 2008-01-21 | 2008-07-16 | 昆明挚兴科技发展有限公司 | Auto-excitation type LED driver |
CN101227778B (en) * | 2008-02-19 | 2011-12-14 | 东南大学 | Self-excited oscillation type high power LED constant-current driving circuit |
-
2009
- 2009-06-05 US US12/479,312 patent/US7990070B2/en active Active
-
2010
- 2010-04-22 CN CN201080025850.7A patent/CN102460920B/en not_active Expired - Fee Related
- 2010-04-22 EP EP10719473A patent/EP2438670A1/en not_active Ceased
- 2010-04-22 WO PCT/US2010/031968 patent/WO2010141157A1/en active Application Filing
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61221581A (en) * | 1985-03-26 | 1986-10-01 | Toshiba Corp | Inverter |
JPH02216796A (en) * | 1989-02-17 | 1990-08-29 | Tokyo Electric Co Ltd | Discharge lamp lighting device |
US5475285A (en) * | 1992-07-17 | 1995-12-12 | Motorola, Inc. | Lamp circuit limited to a booster in which the power output decreases with increasing frequency |
WO1995006350A1 (en) * | 1993-08-20 | 1995-03-02 | Powerpaq Technologies Inc. | Thermal shutdown for power converters |
US20040183380A1 (en) * | 2003-03-07 | 2004-09-23 | Toko, Inc. | Switching constant-current power supply system |
US20060267513A1 (en) * | 2005-05-31 | 2006-11-30 | Funai Electric Co., Ltd. | Projector |
US20070236159A1 (en) * | 2006-04-10 | 2007-10-11 | Robert Beland | Illumination systems |
EP1868284A1 (en) * | 2006-06-15 | 2007-12-19 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Driver arrangement for LED lamps |
WO2008055545A1 (en) * | 2006-11-09 | 2008-05-15 | Osram Gesellschaft mit beschränkter Haftung | Self-oscillating dc-dc converter and method therefor |
Non-Patent Citations (1)
Title |
---|
See also references of EP2438670A1 * |
Also Published As
Publication number | Publication date |
---|---|
US20100308751A1 (en) | 2010-12-09 |
US7990070B2 (en) | 2011-08-02 |
EP2438670A1 (en) | 2012-04-11 |
CN102460920B (en) | 2014-12-24 |
CN102460920A (en) | 2012-05-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7990070B2 (en) | LED power source and DC-DC converter | |
US8723428B2 (en) | LED power source with over-voltage protection | |
US8569963B2 (en) | Cascade boost and inverting buck converter with independent control | |
US7375994B2 (en) | Highly efficient isolated AC/DC power conversion technique | |
JP3382012B2 (en) | Self-excited inverter device | |
US8212498B2 (en) | Fluorescent dimming ballast | |
JP5736772B2 (en) | Constant current power supply | |
US20100079085A1 (en) | Supply circuit | |
WO2011111483A1 (en) | Switching power supply device | |
US20090251065A1 (en) | Circuit Arrangement and Method for Operating at Least One LED | |
JP2013529828A (en) | Open voltage clamp for electronic HID ballast | |
US20050152160A1 (en) | Switching-type power converter | |
KR20120034038A (en) | System and method for converting an ac input voltage to a regulated output current | |
JP3821454B2 (en) | Fluorescent lamp lighting device | |
JP2004153948A (en) | Switching power supplying arrangement | |
US7688044B2 (en) | Device for transforming and stabilizing a primary AC voltage for supplying an electric load | |
WO2002025800A1 (en) | Switching mode power supply with high efficiency | |
CN109196767B (en) | Power control circuit | |
CN114362546A (en) | Self-oscillating high-frequency converter with power factor correction | |
KR100356270B1 (en) | Centrally-controlled electronic ballast with enhanced power savings | |
KR200215726Y1 (en) | Centrally-controlled electronic ballast with enhanced power savings | |
KR101700804B1 (en) | The power supply for driving lamp | |
KR20020036166A (en) | Switching mode power supply | |
JP3230560B2 (en) | DC power supply | |
KR101594066B1 (en) | The power supply for driving lamp |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 201080025850.7 Country of ref document: CN |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 10719473 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2010719473 Country of ref document: EP |
|
NENP | Non-entry into the national phase |
Ref country code: DE |