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US 7,023,289 B2Granted
Programmable oscillator
AssigneeSTMicroelectronics S.r.l.
InventorsAlbino Pidutti, Stefano Beria
Life of this patent
Estimating the term…
Abstract
A programmable oscillator comprises a capacitor; a current generator couplable to said capacitor that generates a charging current of said capacitor; further comprising at least one resistance coupled to said capacitor; a comparator coupled to said capacitor for comparing a voltage at the terminals of said capacitor with a prefixed reference voltage and for generating an output signal; a first switch, controlled by said output signal, coupled to said capacitor that creates a current path able to facilitate the discharging of said capacitor.
Claims20
A programmable oscillator comprising:
- a capacitor;
- a current generator couplable to said capacitor and that generates a charging current for said capacitor;
- at least one resistor coupled to said capacitor and operable to discharge the capacitor during a first time period;
- a comparator coupled to said capacitor for comparing a voltage at a terminal of said capacitor with a prefixed reference voltage and for generating an output signal;
- and
- a first switch, controlled by said output signal, coupled to said capacitor, and operable to discharge said capacitor during a second time period that is different than said first time period.
3 more elements
A controller circuit for lamps of the ballast type comprising:
- a half bridge that drives a lamp, said half bridge being controlled by an oscillator that comprises a capacitor;
- a current generator couplable to said capacitor and that generates a charging current for said capacitor;
- at least one resistance coupled to said capacitor and operable to discharge the capacitor during a first time period;
- a comparator coupled to said capacitor for comparing a voltage at a terminal of said capacitor with a prefixed reference voltage and for generating an output signal;
- and
- a first switch, controlled by said output signal, coupled to said capacitor, and operable to discharge said capacitor during a second time period that is different than the first time period.
3 more elements
An oscillator, comprising:
- a capacitor having first and second nodes;
- a current source operable to be coupled to the first node of the capacitor and to charge the capacitor during a charge portion of an oscillating period;
- a resistor coupled to the first node of the capacitor and operable to discharge the capacitor during a discharge portion of the oscillating period;
- and
- a discharge switch coupled to the first node of the capacitor and operable to discharge the capacitor during only a part of the discharge portion of the oscillating period.
2 more elements
An oscillator, comprising:
- a capacitor having first and second nodes;
- a current source operable to be coupled to the first node of the capacitor and to charge the capacitor during a charge portion of an oscillating period;
- a resistor coupled to the first node of the capacitor and operable to discharge the capacitor during a first part of a discharge portion of the oscillating period;
- a discharge switch having a drive node coupled to the first node of the capacitor and having a control node, the discharge switch operable to discharge the capacitor during a second part of the discharge portion;
- and
- an oscillator switch operable to couple the current source to the first node of the capacitor during the charge portion of the oscillating period and operable to couple the control node of the discharge switch to the first node of the capacitor during the discharge portion of the oscillating period.
3 more elements
An integrated circuit, comprising:
- a first terminal operable to be coupled to an external capacitor and to a first external resistor that is operable to discharge the capacitor during a discharge portion of an oscillating period;
- a current source operable to be coupled to the first terminal and to charge the capacitor with a charge current during a charge portion of the oscillating period;
- and
- a second terminal coupled to the current source and operable to be coupled to a second external resistor that is operable to set a value of the charge current without conducting the charge current.
1 more element
A lamp control circuit, comprising:
- a first terminal operable to be coupled to an external capacitor and to a first external resistor that is operable to discharge the capacitor during a discharge portion of an oscillating period;
- a current source operable to be coupled to the first terminal and to charge the capacitor with a charge current during a charge portion of the oscillating period;
- a second terminal coupled to the current source and operable to be coupled to a second external resistor that is operable to set a value of the charge current;
- a third terminal operable to provide a drive signal to the lamp;
- and
- a generator coupled to the first and third terminals and operable to generate the drive signal in response to a voltage across the capacitor.
3 more elements
A method, comprising:
- charging a capacitor with a current source during a charge portion of an oscillating period;
- discharging the capacitor through a resistor during a first part of a discharge portion of the oscillating period;
- and
- discharging the capacitor through a switch during a second part of the discharge portion of the oscillating period, the second part being different than the first part.
1 more element
Dependencies are inferred from the claim text.