Amplification circuit, human body channel-based communication system including the same, and operation method thereof

A human body channel-based wireless communication system comprising

• an amplification circuit which receives an external signal;
• and
• a control circuit configured to receive the external signal and to generate a control signal for controlling the amplification circuit based on a frequency band of the external signal,
• wherein the amplification circuit includes:
• a first amplifier of two or more amplifiers configured to receive an external signal, and to perform first band pass filtering on the external signal to output a first filter signal;
• and
• a second amplifier of two or more amplifiers configured to receive the first filter signal, and to perform second band pass filtering on the first filter signal to output a second filter signal, and
• wherein a frequency pass bandwidth of the second band pass filtering is narrower than a frequency pass bandwidth of the first band pass filtering.

A method of operating a human body channel-based wireless communication system including an amplification circuit which includes a first amplifier of two or more amplifiers configured to receive an external signal and to perform first band pass filtering on the external signal to output a first filter signal and a second amplifier of two or more amplifiers configured to receive the first filter signal and to perform second band pass filtering on the first filter signal to output a second filter signal, the method comprising:

• receiving the external signal;
• determining a frequency band of the external signal;
• adjusting a frequency pass bandwidth of the first band pass filtering and a frequency pass bandwidth of the second band pass filtering by adjusting resistance values of variable resistors and capacitance values of variable capacitors included in each of the first amplifier and the second amplifier based on the frequency band of the external signal;
• and
• generating, an amplified signal based on the first filter signal, the second filter signal and the external signal, and
• wherein the first amplifier and the second amplifier do not include an inductor element, and the frequency pass bandwidth of the second band pass filtering is narrower than the frequency pass bandwidth of the first band pass filtering.