By way of example, an operational mode may comprise a first phase with a first capacitor configuration, a succeeding second phase with a second capacitor configuration and a succeeding third phase with a third capacitor configuration. The light bulb assembly of claim 21 wherein the plurality of switches of the power converter is switched according to different modes, wherein each mode allows for a different conversion ratio between the rectified input voltage Vin and an output voltage Vout, with the output voltage Vout being the sum of the voltage Vled across the SSL device and the voltage Vsrc across the current source. EP EPB1 en The maximum peak current is further inherently limited by the capacitor C 1 which has the effect of substantially preventing runaway operation and associated damage to the LEDs. In the present document, it is proposed to use switched capacitor technology within the driver circuit 8. In particular, the control unit may be configured to alternate between the first phase and the second phase of the first operational mode, such that an average charge across the one or more capacitors is maintained constant. Referring generally to FIGS.
|Date Added:||13 November 2014|
|File Size:||13.45 Mb|
|Operating Systems:||Windows NT/2000/XP/2003/2003/7/8/10 MacOS 10/X|
|Price:||Free* [*Free Regsitration Required]|
Furthermore, the frequency f may be varied or modulated. The driver circuit of claim 24wherein the plurality of switches are MOS transistors.
The load current source controls the current through the constant voltage load i. By combining the switched capacitor technology with appropriate signal processing, a new class of SSL device e.
Systems and methods for low-power lamp compatibility with a trailing-edge dimmer and an electronic transformer. The DC input voltage may e. The controller further adjusts switch states for leed bi-directional switching circuit in response to a dimming control iinductorless corresponding to a desired lighting output level.
Mode 1 comprises a first and second phase, where the switches S1 and S2 are continuously closed and the other switches are openthereby providing the input voltage Vin directly to the output.
Furthermore the power converter comprises said first diode, wherein a cathode is connected to the first output port, said second diode wherein an anode is connected to a second output port, and said second capacitor, wherein a second terminal is connected to ground. If the frequency of the light intensity fluctuations is high enough e.
Inductorless (Charge Pump) LED Drivers
The operational mode of the driver circuit 8 may be set such that the conversion losses of the driver circuit 8 are reduced or minimized, while at the same time providing an appropriate output voltage towards the load The light bulb assembly of claim 1 wherein the current source is deployed in series with the SSL device. SSL devices which are operated at high voltage levels e. The controller may generally be configured to provide control signals directly or otherwise indirectly via one or more switch driving circuits for turning the bi-directional switching circuit on and off to enable or disable conduction of power from the AC power source.
The lighting device of claim 1further comprising a resistance coupled on a first end to ineuctorless node between the controllable switch module and the capacitor, and on a second end to the first AC power source input terminal, wherein the capacitor is configured upon disabling of power conduction from the controllable switch module to discharge power through the resistance and the rectifier outputs.
Table 1 shows example modes of the power converter of FIG. The copyright owner has no objection to the reproduction of the patent document or the patent disclosure, as it appears in the U. Subsequently, in step an operational mode of the power converter is selected based on the measured input voltage Vin.
Lisong Li – Google Scholar Citations
The current source may lled configured to supply a constant current to the SSL device, when the SSL device is coupled to the output of the power converter. Inductroless the method comprises the steps of: US USB1 en The plurality of operational modes may comprise one or more operational modes which make use of switched capacitor power conversion.
The current flow through the load can be controlled using the current source As before, the power drawn from the mains is substantially constant, reducing the requirements to the EMI filter, possibly even eliminating the EMI filter. The method of claim 15further comprising: Furthermore the power converter comprises: The light bulb assembly of claim 9wherein the control unit is configured to alternate between the first phase and the second phase of the first operational mode, such that an average inductorles across the one or more capacitors is maintained constant.
Inductorless (Charge Pump) LED Drivers | ROHM Product Search Results
The constant voltage load is coupled to a load current source e. Furthermore, it has already been outlined that the operational modes of the power converter typically comprise a first phase and a second phase.
Inductorlwss method of claim 40wherein the method is executed at a certain executing rate wherein the execution rate is dependent on a mains frequency. For this purpose, the control unit may operate the power converter in one of the modes listed in Table 1, depending on the niductorless level of the continuously charging input voltage Vin.
A further object of the disclosure is to reduce sensitivity of SSL devices to mains voltage changes. Typically, the input voltage is derived from a rectified version of the mains supply voltage alternating at the mains frequency.
The above mentioned process of switching the power converter between different modes, in order to maintain the voltage drop Vsrc across the current source at a minimum level, while ensuring that the output voltage Vout is at or above the constant load voltage Vled at the SSL device may be repeated in sync with the mains frequency e.
The lighting device of claim 4wherein the controllable switch module comprises a controller and a bi-directional switching circuit, le the controller is configured to provide control signals for turning the bi-directional switching circuit on and off to enable or disable conduction of power from the AC power source. The method firstly comprises the following process ineuctorless Finally the power converter comprises said second capacitor wherein a second terminal is connected to an anode of a first diode and to a cathode of a second diode, said first diode, wherein a cathode is connected to the output port, said second diode wherein an anode is connected to ground, and said output port wherein a load is connected between the output port and ground.