A Q-Modulation Technique for Efficient Inductive Power Transmission

Mehdi Kiani, Byunghun Lee, Pyungwoo Yeon, Maysam Ghovanloo

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


A fully integrated power management ASIC for efficient inductive power transmission has been presented capable of automatic load transformation using a method, called Q-modulation. Q-modulation is an adaptive scheme that offers load matching against a wide range of loading (R{L}) and coupling distance (d{23}) variations in inductive links to maintain high power transfer efficiency (PTE). It is suitable for inductive powering implantable microelectronic devices (IMDs), recharging mobile electronics, and electric vehicles. In Q-modulation, the zero-crossings of the induced current in the receiver (Rx) LC-Tank are detected and a low-loss switch chops the Rx LC-Tank for part of the power carrier cycle to form a high-Q LC-Tank and store the maximum energy, which is then transferred to RL by opening the switch. By adjusting the duty cycle (D), the loaded-Q of the Rx LC-Tank can be dynamically modulated to compensate for variations in RL. A Q-modulation power management (QMPM) prototype chip was fabricated in a 0.35 μm standard CMOS process, occupying 4.8 mm2. In a 1.45 W wireless power transfer setup, using a class-E power amplifier (PA) operating at 2 MHz, the QMPM successfully increased the inductive link PTE and the overall power efficiency by 98.5% and 120.7% at d{23} = 8 cm, respectively, by compensating for 150 Ω variation in RL at D = 45%.

Original languageEnglish (US)
Article number7169628
Pages (from-to)2839-2848
Number of pages10
JournalIEEE Journal of Solid-State Circuits
Issue number12
StatePublished - Dec 2015

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


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