Oscillator circuit having an improved capacitor discharge circuit

An oscillator for generating an oscillating signal, comprising:

• a first capacitor;
• a first charging circuit portion for charging the first capacitor to a first high threshold voltage;
• a first discharging circuit portion for discharging the first capacitor;
• a first switching network to alternately connect the first capacitor to the charging circuit portion and the discharging circuit portion to thereby alternately charge and discharge the first capacitor;
• a second capacitor;
• a second charging circuit portion for charging the second capacitor to a low threshold voltage;
• a second switching network to alternately connect the second capacitor to the charging circuit portion and the discharging circuit portion to thereby alternately charge and discharge the second capacitor such that the first capacitor charges while the second capacitor discharges and the first capacitor discharges while the second capacitor charges;
• and
• a set-reset flip flop, having a set input, a reset input, an output, and an inverted output, the set input coupled to the first charging circuit portion, the reset input coupled to the second discharging circuit portion, the output coupled to the first switching network to control the charging of the first capacitor, the output coupled to the second switching network to control the charging and the discharging of the second capacitor, the inverted output coupled to the first switching network to control the discharge of the first capacitor.

A method of generating an oscillating signal, comprising the steps of:

• a. charging a first capacitor to a first supply voltage;
• b. charging a second capacitor to the negative value of a high threshold voltage;
• c. comparing the voltage across the first capacitor with the high threshold voltage;
• d. discharging the first capacitor when the voltage across the first capacitor is greater than or equal to the high threshold voltage by coupling the second capacitor in parallel to the first capacitor;
• e. comparing the voltage across the first capacitor with a low threshold voltage;
• f. charging the first capacitor when the voltage across the first capacitor is less than or equal to the low threshold voltage;
• and
• g. repeating steps a through f.

A method of generating an oscillating signal, comprising the steps of:

• a. charging a first capacitor to a first supply voltage;
• b. discharging a second capacitor to ground;
• c. charging a third capacitor to the negative value of a first high threshold voltage;
• d. comparing the voltage across the first capacitor with a second high threshold voltage;
• e. discharging the first capacitor and the third capacitor when the voltage across the first capacitor is greater than or equal to the second high threshold voltage by coupling the third capacitor in parallel to the first capacitor;
• f. charging the second capacitor to a second supply voltage;
• g. comparing the voltage across the second capacitor with a low threshold voltage;
• and
• h. repeating steps a through g when the voltage across the second capacitor is more than or equal to the low threshold voltage.