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US 7,453,298 B1Granted
PWM controller and method therefor
AssigneeSemiconductor Components Industries, LLC
InventorsRadim Mlcousek, Pavel Latal
Life of this patent
Estimating the term…
Abstract
In one embodiment, a PWM controller is configured to form a control signal that has reduced noise. The control signal is used to adjust a frequency of a clock signal of the PWM controller.
Claims16
A PWM controller comprising:
- an input;
- a first PWM control channel configured to form a first PWM drive signal to control a first switch and form a first output voltage;
- the first PWM control channel including a first clock circuit configured to form a first clock signal that is used to form the first PWM drive signal wherein the first clock circuit is configured to adjust a frequency of the first clock signal responsively to a clock control signal;
- a second PWM control channel configured to form a second PWM drive signal to control a second switch and form a second output voltage;
- the second PWM control channel including a second clock circuit configured to form a second clock signal that is used to form the second PWM drive signal wherein the second clock circuit is configured to adjust a frequency of the second clock signal responsively to the clock control signal;
- a voltage to current converter circuit coupled to the input to supply a current to the input and form a control voltage;
- a capacitor coupled to selectively receive the control voltage to form the clock control signal;
- a first timing circuit configured to decouple the capacitor from receiving the control voltage responsively to the second clock signal;
- a second timing circuit configured to decouple the capacitor from receiving the control voltage responsively to the second PWM drive signal;
- and
- a control circuit configured to decouple the capacitor from receiving the control voltage responsively to the first drive PWM signal.
8 more elements
A method of forming a PWM controller comprising:
- configuring the PWM controller with a first PWM channel that includes a first clock circuit that forms a first clock signal that is used to establish one of a beginning or an end of a first PWM drive signal of the PWM controller, wherein the first PWM drive signal is used to regulate a first output voltage;
- coupling a sense circuit of the PWM controller to form a sense voltage on an input of the PWM controller and to form a control voltage responsively to a current that results from the sense voltage;
- configuring a signal conditioning circuit to couple the control voltage to a sense capacitor to form a control signal on the sense capacitor and to decouple the sense capacitor from the control voltage responsively to the first PWM drive signal;
- and
- configuring the first clock circuit to receive the control signal and responsively control a frequency of the first clock signal.
2 more elements
Dependencies are inferred from the claim text.