A receiver circuit for detecting and waking up a wakeup impulse sequence is provided. Herein, a transmitter circuit is configured to transmit a wakeup impulse sequence to wake up a receiver circuit. The receiver circuit includes a main receiver circuit and a wakeup receiver circuit. The main receiver circuit, which consumes far more energy than the wakeup receiver circuit, will remain in sleep mode as much as possible to conserve power. While the main receiver circuit is asleep, the wakeup receiver circuit is configured to detect the wakeup impulse sequence and wake up the main receiver circuit if the wakeup impulse sequence is intended for the receiver circuit. By keeping the main receiver circuit asleep as much as possible, it is possible to reduce power consumption, thus making the receiver circuit an ideal receiver option for an Internet-of-Things (IoT) device(s).