THIRD QUARTER 2022 IEEE CIRCUITS AND SYSTEMS MAGAZINE 27 Cabled Charge Management Unit Battery Charger/ Power Management IC Rechargeable Battery 3.7 V LDO 3.3 V Data Telemetry Bluetooth Tx/Rx WER Headset EEG Recorder Recording Electrodes Stimulating Electrodes Vagus Nerve Extension Leads IVNS DFAICL Transmitter Recording Electrodes Handset Multi-Channel Pre-Amplifier WER Modified Class-E Power Amplifier 2 MHz Colpitts Oscillator Distance-Frequency Adaptive ICL (DFAICL) Transmitter Distance-Frequency Adaptive ICL (DFAICL) Receiver Impedance Matching/Resonating/ Rectifying/Filtering Controller Data Telemetry Bluetooth Tx/Rx LDO 5 V Charge Management IC Rechargeable Battery 3.7 V ADC Microprocessor (MCU) UART Thresholding Epileptic Seizure Detector BoostConverter 8 V Step-Down LDO 3.3 V Ultra-Low Power Microprocessor (MCU) Communication and Control Stimulating Electrodes Switched Resistor Array Pulse Generator IVNS Figure 2. Architecture of the HybridVNS. ETI Impedance Extractor Temperature Sensor