title: A dual-mode highly efficient class-E stimulator controlled by a low-Q class-E power amplifier through duty cycle.
abstract: This paper presents the design flow of two high-efficiency class-E amplifiers for the implantable electrical stimulation system. The implantable stimulator is a high-Q class-E driver that delivers a sine-wave pulsed radiofrequency (PRF) stimulation, which was verified to have a superior efficacy in pain relief to a square wave. The proposed duty-cycle-controlled class-E PRF driver designed with a high-Q factor has two operational modes that are able to achieve 100% DC-AC conversion, and involves only one switched series inductor and an unchanged parallel capacitor. The measured output amplitude under low-voltage (LV) mode using a 22% duty cycle was 0.98 V with 91% efficiency, and under high-voltage (HV) mode using a 47% duty cycle was 2.95 V with 92% efficiency. These modes were inductively controlled by a duty-cycle detector, which can detect the duty-cycle modulated signal generated from the external complementary low-Q class-E power amplifier (PA). The design methodology of the low-Q inductive interface for a non-50% duty cycle is presented. The experimental results exhibits that the 1.5-V PA that consumes DC power of 14.21 mW was able to deliver a 2.9-V sine wave to a 500 Ω load. The optimal 60% drain efficiency of the system from the PA to the load was obtained at a 10-mm coupling distance.
authors.affiliation: Department of Electronic Engineering and Graduate Institute of Computer and Communication Engineering, National Taipei University of Technology, Taipei 10608, Taiwan. hwchiu@ntut.edu.tw
authors.forename: Hung-Wei
authors.initials: HW
authors.lastname: Chiu
authors.forename: Chien-Chi
authors.initials: CC
authors.lastname: Lu
authors.forename: Jia-min
authors.initials: JM
authors.lastname: Chuang
authors.forename: Wei-Tso
authors.initials: WT
authors.lastname: Lin
authors.forename: Chii-Wann
authors.initials: CW
authors.lastname: Lin
authors.forename: Ming-Chien
authors.initials: MC
authors.lastname: Kao
authors.forename: Mu-Lien
authors.initials: ML
authors.lastname: Lin
mesh_terms: D000669:Amplifiers, Electronic; D000818:Animals; D025802:Electric Capacitance; D011211:Electric Power Supplies; D004599:Electric Stimulation Therapy / Q000295:instrumentation*; D004567:Electrodes, Implanted; D004867:Equipment Design; D006930:Hyperalgesia; D009186:Myelin Sheath / Q000473:pathology; D009474:Neurons / Q000473:pathology; D059408:Pain Management; D010147:Pain Measurement; D011846:Radio Waves; D051381:Rats; D012815:Signal Processing, Computer-Assisted; D013696:Temperature; D059015:Wireless Technology