Patent ID: 11959995
Assignee: STMICROELECTRONICS S.R.L.
Field: Basic communication processes (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 7:
8. A radar sensor, comprising:
a circuit comprising:
a tunable resonant circuit having a first node and a second node, and comprising:
an inductance coupled between said first node and said second node;
a variable capacitance coupled between said first node and said second node;
a set of capacitances selectively coupleable between said first node and said second node; and
a control node coupled to said variable capacitance, the control node configured to receive a control signal, wherein said tunable resonant circuit is tunable as a function of said control signal;

a biasing circuit coupled to said tunable resonant circuit and configured to bias the tunable resonant circuit to generate a variable-frequency output signal between said first node and said second node;
a phase-frequency detector circuit sensitive to an input reference signal and to said variable-frequency output signal, and configured to generate a first digital control signal and a second digital control signal as a function of a timing offset of said variable-frequency output signal with respect to said input reference signal, wherein assertion of said first digital control signal is indicative of a first operational state where said timing offset has a first sign, and wherein assertion of said second digital control signal is indicative of a second operational state where said timing offset has a second sign opposite said first sign;
a charge pump circuit and a filter circuit configured to generate said control signal to the control node as a function of said first digital control signal and said second digital control signal;
a timer circuit sensitive to a reset signal and configured to generate a timing signal, wherein said timing signal is asserted in response to a pulse sensed in said reset signal and said timing signal is de-asserted after a time interval from said sensed pulse; and
a calibration circuit configured to selectively couple, between said first node and said second node, selected capacitances from said set of capacitances, said selected capacitances being selected as a function of said second digital control signal, said calibration circuit performing the selective coupling in response to said timing signal being asserted; and

a transmitter circuit coupled to an antenna;
wherein the circuit is further configured to receive said input reference signal from a microcontroller unit and provide said variable-frequency output signal to said transmitter circuit.