INDUCTORLESS LED DRIVER DETAILS:
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INDUCTORLESS LED DRIVER
Inductorless multi-mode mA LED charge pump LEDs Magazine
Furthermore, FIG. The power converter comprises a plurality of switches S1S2SaSbSca plurality of diodes or switches S4S3as well as the capacitors C1 inductorless led C2 The power converter and the current source are typically comprised within the driver circuit 8 of the SSL device The power converter is configured to convert the rectified input voltage such that the constant voltage Vled is provided at the SSL device and such that the voltage drop Vsrc across the current source is maintained below or at a maximum voltage, thereby ensuring that the power loss at the current source is kept below a maximum inductorless led level.
For this purpose, the plurality of switches of the power converter may switched according to different modes, wherein each mode allows for a different conversion ratio between the input voltage Vin being the rectified input voltage waveform from the mains power supply and the 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 sourcei. Table 1 shows example modes of the power converter of FIG. The switches listed in the first and second phase of Table 1 indicate the switches which are in the on-state. The other switches are typically in the off-state. Each mode comprises a first phase phase 1 typically used for charging the capacitorsand a second phase phase 2 typically used for discharging the capacitors Mode 1 provides a conversion ratio 1 i.
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. In case of Mode 1, the first phase and the second phase are equal, thereby providing a fixed on of the switches S1 and S2.
During the first phase of mode 2, only the switches S1Sa and Inductorless led are closed and the other switches are openthereby charging the capacitors C1 and C2 in parallel. In the second phase of mode 2, only the switch S2 and Sb are closed and the other switches are openthereby discharging the capacitors C1 and C2 in series.
As outlined above, the sequence of a first phase and a second phase is typically referred to as a commutation cycle. The power converter of FIG. The MCPX50 has selectable outputs of either 3. Mode 1 comprises a first and second phase, where the switches S1 and S2 are continuously closed and the other inductorless led are openthereby providing the input voltage Vin directly to the output.
In case of Mode 1, the first phase and the second phase are equal, thereby providing a fixed on of the switches S1 and S2. During the first phase of mode 2, only the switches S1Sa and Sc are closed and the other switches are openthereby charging the capacitors C1 and C2 in parallel. In the second phase of mode 2, only the switch S2 and Sb are closed and the other switches are openinductorless led discharging the capacitors C1 and C2 in series. As outlined above, the sequence of a first phase and a second phase is typically referred to as a commutation cycle.
The power converter of FIG. In particular, the control unit may select an appropriate operation mode for the power converter based on the value of the input voltage Vin. Even more particularly, the appropriate operational mode i.
HV - Display and LED Drivers - EL Backlight Driver ICs
Hence, the output voltage Vout can be controlled such that the voltage drop Vsrc across the inductorless led source remains below a pre-determined maximum value. For this purpose, the control unit may operate the power converter in one of the modes listed in Table 1, depending on the present inductorless led of the continuously charging input voltage Vin.
This is illustrated in the voltage diagram of FIG. Furthermore, the voltage diagram shows the voltage drop Vsrc across the current source inductorless led As soon as the input voltage Vin goes below V, the power converter switches back to the mode 3, at time instant back to mode 2 and at time instant back to mode 1. It must be noted that the above voltage values are only examples and the present disclosure is not limited to these values and may be applied to other values. For example, the constant voltage drop Vled at the SSL device may only be 50V and the voltage drop Vsrc across the current source may be limited to 10V. 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 inductorless led, 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.
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- Product Description
Heat dissipation is an important factor particularly for air-conditioned buildings when overall energy efficiency is considered. T5 fluorescent lamps perform better than some existing LEDs in terms of luminous efficacy and heat generation in this study. Mar Sachin Rao. The only way to eliminates such problematic, and potentially dangerous situation, is to add an external low Vth Schottky diode on Vx. This diode will be activated before switches body diodes and will eliminate the substrate current injection. It will however add up inductorless led the BOM which is already the most important disadvantage of the inductor-based SRs.
On the other hand, the noise injected in the substrate by inductorless SRs comes exclusively from parasitic capacitance coupling. Therefore, an inductorless SR do not generate more substrate inductorless led then any digital circuit of the same size clocked at the same frequency. On inductorless led substrate noise perspective, it is then not more hazardous to integrate an inductorless SR then to integrate a CMOS logic bloc.
MPL Active. Engine Management. Pump Systems. Safety and ADAS. As long as the regulator has a sufficient bandwidth and open-loop gain, inductor-based and inductorless SR can both achieve great PSRR. However, the switching nature of these regulators makes intrinsic noise noise generated by the regulator itself dominant compared to any other noise sources.Analog Devices has a very broad line of LED drivers for backlighting applications. They are configured as either inductorless white LED drivers (for LEDs inductorless led parallel) or inductor-based white LED drivers (for LEDs in series).
Topologies include boost regulator LED drivers, buck. ROHM offers a broad lineup of LED drivers, such as AC/DC, DC/AC, and constant current types optimized for a variety of applications, including lighting, backlighting, camera inductorless led, displays, and automotive systems. Output Current (Max.)[mA] LED Configuration.