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US 7,679,874 B2Granted
Power overload detection method and structure therefor
AssigneeSemiconductor Components Industries, LLC
InventorsGeorge H. Barbehenn, John D. Stone
Life of this patent
Estimating the term…
Abstract
In one embodiment, the bulk input voltage is used to form a reference signal that is used for controlling a switching power supply system to operate in a power overload operating mode.
Claims20
A method of forming a power overload detection circuit of a switching power supply system comprising:
- configuring the power overload detection circuit to use a reference signal derived from and representative of a bulk voltage wherein the bulk voltage is used to form an output voltage of the switching power supply system and wherein variations of the reference signal are representative of variations of the bulk voltage;
- configuring the switching power supply system to receive a feedback signal that is representative of the output voltage and to use the feedback signal to regulate a value of the output voltage;
- and
- configuring the power overload detection circuit to compare the feedback signal to the reference signal to detect power delivered to a load exceeding a predetermined rated maximum value as a result of an increase in the bulk voltage and responsively reduce power supplied to the load.
1 more element
A method of forming a skip cycle comparator of a power supply system comprising:
- configuring the skip cycle comparator to receive a reference signal derived from a bulk voltage used to form an output voltage of the power supply system wherein the reference signal is representative of the bulk voltage and varies responsively to variations in the bulk voltage;
- configuring a switching control circuit of a power supply controller of the power supply system to receive a feedback signal that is representative of the output voltage and to use the feedback signal to regulate a value of the output voltage;
- and
- configuring the skip cycle comparator to compare the feedback signal to the reference signal and responsively initiate entering a skip cycle mode and to decrease a threshold value for entering the skip cycle mode as the bulk voltage decreases.
1 more element
A switching power supply controller configured to form a drive signal operable to control a power switch to use a bulk voltage and form a regulated output voltage comprising:
- a skip cycle comparator coupled to receive a first reference signal derived from the bulk voltage and to receive a feedback signal that is representative of the regulated output voltage wherein the skip cycle comparator is configured to compare the feedback signal to the first reference signal and responsively initiate entering a skip cycle mode and to decrease a threshold value for entering the skip cycle mode as the bulk voltage decreases wherein the first reference signal varies responsively to variations in the bulk voltage;
- and
- a power overload detection circuit configured to compare the feedback signal to a second reference signal that is derived from and is representative of the bulk voltage to detect power delivered to the load exceeding a predetermined rated maximum value as a result of an increase in the bulk voltage and responsively reduce power supplied to the load.
Dependencies are inferred from the claim text.