A 93.3% peak-efficiency self-resonant hybrid-switched-capacitor LED driver in 0.18-μm CMOS technology

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)

Abstract

This paper presents an integrated light-emitting diode (LED) driver based on a self-resonant hybrid-switched-capacitor converter (H-SCC) operating in the megahertz range. An integrated zero-current detection (ZCD) circuit is designed to enable self-resonant operation and zero-current switching. A self-resonant timer is proposed to set the switching frequency to resonance automatically, accommodating for variations in the LED voltage, output current, inductor value, and/or parasitic components, and improving the converter efficiency at light loads without the need for an accurate clock with variable frequency. A ZCD threshold control is also proposed to enable continuous conduction mode and improve efficiency at large currents. The design of high-speed integrated current sensors to measure the inductor current in the H-SCC is also presented. Capacitors, power switches, ZCD, current monitors, and the control circuitry of the LED driver are integrated on-chip in a low-cost, 5-V, 0.18-μm bulk CMOS technology. The proposed driver was measured using inductor values between 36 and 470 nH. It achieves a peak efficiency of 93.3% and an efficiency of 83.1% at the nominal current. The LED driver is able to control a 700-mA LED down to less than 10% of its nominal current. The effective chip area is 7.5 mm², and the maximum power density is 373 mW/mm². To our knowledge, this LED driver can achieve efficiencies comparable to prior art LED drivers using a 6.6x smaller inductor. IEEE
LanguageEnglish
Article number8353793
Pages1924-1935
JournalIEEE Journal of Solid-State Circuits
Volume53
Issue number7
DOIs
StatePublished - 1 Jul 2018

Fingerprint

Light emitting diodes
Capacitors
Switching frequency
Clocks
Switches
Networks (circuits)
Sensors
Electric potential
Costs

Keywords

  • CMOS integrated circuit
  • light-emitting diode (LED) drivers
  • power integrated circuits
  • switching converters
  • zero-current switching (ZCD)

Cite this

@article{2fc658971f334d82a3676533d4d0f029,
title = "A 93.3{\%} peak-efficiency self-resonant hybrid-switched-capacitor LED driver in 0.18-μm CMOS technology",
abstract = "This paper presents an integrated light-emitting diode (LED) driver based on a self-resonant hybrid-switched-capacitor converter (H-SCC) operating in the megahertz range. An integrated zero-current detection (ZCD) circuit is designed to enable self-resonant operation and zero-current switching. A self-resonant timer is proposed to set the switching frequency to resonance automatically, accommodating for variations in the LED voltage, output current, inductor value, and/or parasitic components, and improving the converter efficiency at light loads without the need for an accurate clock with variable frequency. A ZCD threshold control is also proposed to enable continuous conduction mode and improve efficiency at large currents. The design of high-speed integrated current sensors to measure the inductor current in the H-SCC is also presented. Capacitors, power switches, ZCD, current monitors, and the control circuitry of the LED driver are integrated on-chip in a low-cost, 5-V, 0.18-μm bulk CMOS technology. The proposed driver was measured using inductor values between 36 and 470 nH. It achieves a peak efficiency of 93.3{\%} and an efficiency of 83.1{\%} at the nominal current. The LED driver is able to control a 700-mA LED down to less than 10{\%} of its nominal current. The effective chip area is 7.5 mm², and the maximum power density is 373 mW/mm². To our knowledge, this LED driver can achieve efficiencies comparable to prior art LED drivers using a 6.6x smaller inductor. IEEE",
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author = "Castellanos, {Juan C.} and Mert Turhan and Eugenio Cantatore",
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A 93.3% peak-efficiency self-resonant hybrid-switched-capacitor LED driver in 0.18-μm CMOS technology. / Castellanos, Juan C.; Turhan, Mert; Cantatore, Eugenio.

In: IEEE Journal of Solid-State Circuits, Vol. 53, No. 7, 8353793, 01.07.2018, p. 1924-1935.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - A 93.3% peak-efficiency self-resonant hybrid-switched-capacitor LED driver in 0.18-μm CMOS technology

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AU - Cantatore,Eugenio

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N2 - This paper presents an integrated light-emitting diode (LED) driver based on a self-resonant hybrid-switched-capacitor converter (H-SCC) operating in the megahertz range. An integrated zero-current detection (ZCD) circuit is designed to enable self-resonant operation and zero-current switching. A self-resonant timer is proposed to set the switching frequency to resonance automatically, accommodating for variations in the LED voltage, output current, inductor value, and/or parasitic components, and improving the converter efficiency at light loads without the need for an accurate clock with variable frequency. A ZCD threshold control is also proposed to enable continuous conduction mode and improve efficiency at large currents. The design of high-speed integrated current sensors to measure the inductor current in the H-SCC is also presented. Capacitors, power switches, ZCD, current monitors, and the control circuitry of the LED driver are integrated on-chip in a low-cost, 5-V, 0.18-μm bulk CMOS technology. The proposed driver was measured using inductor values between 36 and 470 nH. It achieves a peak efficiency of 93.3% and an efficiency of 83.1% at the nominal current. The LED driver is able to control a 700-mA LED down to less than 10% of its nominal current. The effective chip area is 7.5 mm², and the maximum power density is 373 mW/mm². To our knowledge, this LED driver can achieve efficiencies comparable to prior art LED drivers using a 6.6x smaller inductor. IEEE

AB - This paper presents an integrated light-emitting diode (LED) driver based on a self-resonant hybrid-switched-capacitor converter (H-SCC) operating in the megahertz range. An integrated zero-current detection (ZCD) circuit is designed to enable self-resonant operation and zero-current switching. A self-resonant timer is proposed to set the switching frequency to resonance automatically, accommodating for variations in the LED voltage, output current, inductor value, and/or parasitic components, and improving the converter efficiency at light loads without the need for an accurate clock with variable frequency. A ZCD threshold control is also proposed to enable continuous conduction mode and improve efficiency at large currents. The design of high-speed integrated current sensors to measure the inductor current in the H-SCC is also presented. Capacitors, power switches, ZCD, current monitors, and the control circuitry of the LED driver are integrated on-chip in a low-cost, 5-V, 0.18-μm bulk CMOS technology. The proposed driver was measured using inductor values between 36 and 470 nH. It achieves a peak efficiency of 93.3% and an efficiency of 83.1% at the nominal current. The LED driver is able to control a 700-mA LED down to less than 10% of its nominal current. The effective chip area is 7.5 mm², and the maximum power density is 373 mW/mm². To our knowledge, this LED driver can achieve efficiencies comparable to prior art LED drivers using a 6.6x smaller inductor. IEEE

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KW - light-emitting diode (LED) drivers

KW - power integrated circuits

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JF - IEEE Journal of Solid-State Circuits

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