Radio-frequency circuit

Abstract

The present disclosure discloses a radio frequency (RF) circuit. In one example, the RF circuit includes an RF oscillator and a power amplifier. The RF oscillator is configured to generate an RF signal. The power amplifier is configured to generate an amplified RF signal based on the RF signal. The power amplifier includes a transformer including a primary winding and a secondary winding, and a feedback capacitor electrically coupled to the primary winding and the secondary winding.

Description

technical field [0001] The present disclosure relates to a radio frequency circuit. Background technique [0002] Ultra-low power (ULP) radios enhance short-range communications for the wireless Internet of Things (IoT). However, the lifetime of IoT systems is still often severely limited by transmitter power consumption and available battery technology. Radio Frequency (RF) transmitters, such as ULP transmitters, typically include a phase locked loop (PLL) that produces an output signal that is correlated with a phase of the input signal. [0003] A PLL such as an all-digital PLL may employ a digitally controlled oscillator (DCO) with a digital power amplifier (DPA) to switch current sources to reduce supply voltage and power without sacrificing its start-up margin. When the DPA has harmonic distortion at a similar frequency to the DCO's operating frequency, injection pulling occurs at the DCO to pull its operating frequency to have harmonic distortion. As such, the effi...

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Problems solved by technology

As such, the efficiency of RF transmitters including DCOs and DPAs will be affected by harmonic distortion and injection pulling

[0004] Therefore, conventional transmitter circuits are not entirely satisfactory

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