Capacitor and EMI considerations for new high frequency switching regulators

Nelson, Carl Vern; Essaff, Bob

doi:10.1016/b978-0-12-800001-4.00026-0

Cited by 2 publications

(3 citation statements)

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“…As depicted in Figure 2.1, a typical automotive LED lighting system also embodies various interior lights, including the dome light and the console light. Because of their low power rating, the interior lights typically employ linear LED drivers shown in Figure 2.3, vis-à -vis aforesaid switched-mode counterparts, for sake of smaller form factor and lower cost [67]. The benefits of the linear LED driver include high accuracy, small form factor, and low cost, whilst its main shortcoming is low power-efficiency and low power handling capability.…”

Section: Interior Lightsmentioning

confidence: 99%

“…Conducted EMI arises from high-frequency noise conducted from the LED driver to the input leads of the power supply [67]. For example, the input capacitor CIN in Figure 2.13 plays a critical role in supplying high-frequency currents to the LED driver.…”

Section: Conducted Emimentioning

confidence: 99%

“…The output is the sum of the two phase currents, i.e., iLED=iL1+iL2, where iL1 and iL2 are the inductor currents in the Phase 1 and Phase 2, respectively. It can be seen that consequent to the dual-phase modality, the current ripples in the large input and output currents are small.The proposed design features enhanced reliability by means of small input/output current ripples and embodying monolithic integration of controllers, current sensors, and power transistors[67].…”

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Design and realization of high-performance LED drivers for automotive lighting applications

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This Ph.D. program pertains to the design and monolithic realization of Light Emitting Diode (LED) drivers for automotive lighting where the imperative parameters are high power-efficiency and high reliability. The grand objectives thereto are substantial improved specifications over the state-of-the-art, including power-efficiency, reliability, current driving capability, and dimming range. To achieve the said grand objectives, the specific objectives are to decouple, and hence mitigate the following two major design trade-offs that limit the performance of contemporary automotive LED drivers. The first trade-off is between high reliability and high current driving capability, and applies to both single-phase and multi-phase LED drivers. Specifically, to achieve high current driving capability, the contemporary single-phase LED driver typically suffers from low reliability arising from large current ripples. On the other hand, the multi-phase LED driver is highly advantageous to provide high current driving capability, but suffers from low reliability because of the ensuing subharmonic oscillation. To decouple this limiting trade-off, we propose the design and monolithic realization of a novel Pulse-Width-Modulation (PWM)-based dual-phase LED driver in Global Foundries (GF) 130nm BCDLite process. To achieve high current driving capability, we adopt a dual-phase power stage. To achieve high reliability, we propose an Average Current Control to eliminate the subharmonic oscillation by considering the complete inductor-current profile vis-à-vis peak current adopted/reported elsewhere. To further improve the reliability, we propose an accuracy-enhanced current sensor to ascertain good current balance in the adopted dual-phase power stage. With measurements on our prototype LED driver ICs embodying our aforesaid adoption and vi proposed circuits, we demonstrate, to the best of our knowledge, for the first time that the trade-off between high reliability and high current driving capability is decoupled, i.e., an LED driver uniquely featuring high reliability, yet high current driving capability. The second trade-off is between high power-efficiency and wide dimming range. Specifically, a wide dimming range is derived by means of high switching frequency, hence the ensuing reduced settling time of the LED current. This, however, in turn leads to a degradation of the power-efficiency due to increased switching losses. To decouple this limiting trade-off, we propose the design and monolithic realization of a novel fully soft-switched LED driver in GF 130nm BCDLite process. We achieve wide dimming range by operating at high switching frequencies, but the high switching does not compromise the power-efficiency. Using a fully soft-switching approach, the ensuing switching losses are negligible. This is achieved by a proposed Hysteretic Soft-Switching Controller (HSSC) and proposed circuitries, i.e., a voltage detector, current sensor, and a level shifter. The HSSC enables complete soft-switching, including zerovoltage switc...

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Section: Interior Lightsmentioning

confidence: 99%

Section: Conducted Emimentioning

confidence: 99%

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