Relaxation oscillator of reduced complexity using CMOS equivalent of a four-layer diode
AssigneeEricsson Inc.
InventorPaul W. Dent
Life of this patent
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Abstract
A relaxation oscillator of reduced complexity is described which can be constructed as part of a silicon integrated circuit. The current controlled oscillator includes complementary field effect transistors operating in enhancement mode. The drain of one FET is connected to the gate of the other FET and vice versa. The resulting CMOS circuit functions as a four-layer diode. A resistor is connected between the drains of both transistors. A storage capacitor is connected between the sources of both transistors. A current source is connected to charge the storage capacitor such that the frequency of an oscillator output signal is determined by the current generated by the current source.
Claims14
An electrical oscillator, comprising:
- an P-channel field effect transistor (FET) operating in an enhancement mode including source, drain, and gate electrodes;
- an N-channel field effect transistor (FET) operating in enhancement mode including source, drain, and gate electrodes, wherein the drain electrode of the P-channel FET is connected to the gate electrode of the N-channel FET and the drain electrode of the N-channel FET is connected to the gate electrode of the P-channel FET;
- an impedance connected between the drain electrodes of the P-channel and N-channel FETs;
- a first capacitor connected between the source electrodes of the P-channel and N-channel FETs;
- and
- a current source connected to charge the capacitor.
A radio for conducting communications over a radio channel, comprising:
- a microphone for detecting an acoustic signal and generating a corresponding electrical current;
- a current-controlled oscillator of reduced complexity responsive to the electrical current for generating an oscillator output signal representing the acoustic signal;
- and
- a transmitter for transmitting over an antenna a radio output signal based on the oscillator output signal,
- wherein the oscillator includes:
- a complementary metal oxide silicon (CMOS) circuit with a P-channel field effect transistor (FET) operating in an enhancement mode connected to an N-channel field effect transistor (FET) operating in enhancement mode so that the drain electrode of the P-channel FET is connected to a gate of the N-channel FET and a drain of the N-channel FET is connected to a gate of the P-channel FET, and
- a first capacitor connecting the P-channel and N-channel FETs such that the oscillator is repetitively charged and discharged through the CMOS circuit in response to the detected acoustic signal.
A current-controlled, relaxation oscillator, comprising:
- a voltage supply having positive and negative terminals;
- a complementary metal-oxide-silicon (CMOS) circuit having a pair of terminals and a shunt capacitor across said terminals;
- and
- a current source having a pair of terminals through which a controlled current may flow;
- wherein the voltage supply, CMOS circuit, and current source are connected in series in a loop such that current flow through the current source charges and discharges the shunt capacitor at controlled intervals that depend on the controlled current source current such that a Voltage output of the oscillator oscillates between a striking voltage and a quenching voltage at a controlled frequency.
Dependencies are inferred from the claim text.