Method and apparatus for a control circuit responsive to an impedance coupled to a control circuit terminal
AssigneePower Integrations, Inc.
InventorsZhao-Jun Wang, Stefan Bäurle, David Michael Hugh Matthews
Life of this patent
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Abstract
An example power supply controller includes a regulation circuit, a current sense circuit, and a response circuit. The regulation circuit is coupled to regulate a sense terminal to a voltage level. The current sense circuit is coupled to the sense terminal to sense a current through the sense terminal a measurement delay period after a magnitude of the current through the sense terminal reaches a first threshold current level. The response circuit is coupled to the sense circuit and is responsive to the current through the sense terminal only after the measurement delay period.
Claims20
A power supply controller, comprising:
- a regulation circuit coupled to regulate a sense terminal to a voltage level;
- a current sense circuit coupled to the sense terminal to sense a current through the sense terminal a measurement delay period after a magnitude of the current through the sense terminal reaches a first threshold current level;
- and
- a response circuit coupled to the sense circuit and responsive to the current through the sense terminal only after the measurement delay period.
A power supply, comprising:
- a controller including a sense terminal coupled to receive a sense terminal current representative of an input voltage of the power supply during normal operation;
- and
- an impedance block external to the controller and coupled to the sense terminal, the impedance block including a Zener diode coupled to conduct a current to adjust the sense terminal current during a fault condition, wherein during the fault condition the controller is responsive to a measured impedance of the impedance block which is determined in response to the sense terminal current.
Dependencies are inferred from the claim text.