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US 10,666,152 B2Granted
Valley and peak detection for switching power converter
AssigneeDialog Semiconductor GmbH
InventorsHenry Jun, Chuanyang Wang
Life of this patent
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Abstract
A switching power converter is provided with a phase-shifting RC network for phase-shifting a divided version of a drain voltage of a power switch transistor into a phase-shifted voltage. A comparator compares the phase-shifted voltage to a DC bias voltage to detect peaks and valleys during resonant oscillations of the drain voltage of the power switch transistor.
Claims15
A switching power converter, comprising:
- a high-voltage clamping transistor having a first terminal connected to a first terminal of a power switch transistor;
- a capacitor coupled between a second terminal of the high-voltage clamping transistor and ground;
- a first voltage divider for dividing a terminal voltage for the first terminal of the power switch transistor into a divided voltage carried on a divided voltage node, wherein the first terminal of the power switch transistor is connected to a primary winding of a transformer, and wherein a second terminal of the power switch transistor is coupled to ground;
- a second voltage divider for biasing a voltage divider node with a direct current (DC) bias voltage;
- a capacitor coupled between the voltage divider node and the second terminal of the high-voltage clamping transistor, the capacitor being configured to phase-shift the divided voltage by 90 degrees to form a phase-shifted voltage on the voltage divider node that is added with the DC bias voltage to form a composite voltage;
- a first comparator configured to compare the composite voltage to the DC bias voltage to detect peaks and valleys in a resonant oscillation of the terminal voltage of the power switch transistor;
- and
- a controller configured to switch on the power switch transistor at a selected one of the detected valleys in the resonant oscillation of the terminal voltage of the power switch transistor.
5 more elements
A method of operation for a flyback converter, comprising:
- during a valley-switching mode of operation, dividing a drain voltage at a drain of a power switch transistor to form a divided drain voltage while the drain voltage of the power switch transistor is resonantly oscillating, wherein the drain of the power switch transistor is connected to a primary winding of a transformer, and wherein a drain of the power switch transistor is coupled to ground;
- phase-shifting the divided drain voltage by 90 degrees to form a phase-shifted voltage that is added with a DC bias voltage to form a composite voltage;
- comparing the composite voltage to the DC bias voltage to detect valleys in the resonant oscillations of the drain voltage of the power switch transistor;
- and
- switching on the power switch transistor at a selected one of the detected valleys in the resonant oscillations of the drain voltage of the power switch transistor.
2 more elements
Dependencies are inferred from the claim text.