Chiu Hung-Wei, Lu Chien-Chi, Chuang Jia-min, Lin Wei-Tso, Lin Chii-Wann, Kao Ming-Chien, Lin Mu-Lien
Department of Electronic Engineering and Graduate Institute of Computer and Communication Engineering, National Taipei University of Technology, Taipei 10608, Taiwan.
IEEE Trans Biomed Circuits Syst. 2013 Jun;7(3):243-55. doi: 10.1109/TBCAS.2012.2205245.
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.
本文介绍了用于植入式电刺激系统的两款高效E类放大器的设计流程。植入式刺激器是一种高Q值E类驱动器，可提供正弦波脉冲射频（PRF）刺激，经证实其在缓解疼痛方面比方波具有更高的疗效。所提出的采用高Q因子设计的占空比控制E类PRF驱动器有两种工作模式，能够实现100%的直流-交流转换，且仅涉及一个开关串联电感和一个不变的并联电容。在22%占空比的低压（LV）模式下测得的输出幅度为0.98 V，效率为91%；在47%占空比的高压（HV）模式下测得的输出幅度为2.95 V，效率为92%。这些模式由占空比检测器进行电感控制，该检测器可检测从外部互补低Q值E类功率放大器（PA）产生的占空比调制信号。本文还介绍了非50%占空比的低Q值电感接口的设计方法。实验结果表明，消耗14.21 mW直流功率的1.5 V PA能够向500 Ω负载提供2.9 V的正弦波。在10 mm的耦合距离下，系统从PA到负载的最佳漏极效率为60%。
