Indicator using existing power supply controller terminals
AssigneeSemiconductor Components Industries, LLC
InventorsChristophe BASSO, Stephanie CANNENTERRE
Life of this patent
Estimating the term…
Abstract
A power conversion circuit has a controller with an input terminal and a circuit configured to drive an electric current out of the input terminal in response to a condition of the controller. An indicator is coupled to the input terminal of the controller. The controller includes a clock signal controlling the electric current out of the input terminal. The input terminal is a voltage sensing terminal or feedback input terminal in some embodiments.
Claims20
A power conversion circuit for converting comprising:
- a primary side defining an input voltage, a primary winding of a transformer coupled to the input voltage, and a primary switch coupled to the primary winding;
- a secondary side defining an output voltage, and a secondary winding coupled to the output voltage;
- a controller comprising:
- a brownout terminal coupled to the input voltage;
- a feedback terminal coupled to the output voltage;
- a first circuit having a first input coupled to the feedback terminal and a second input coupled to the brownout terminal, the first circuit configured to:
- sense a voltage on the brownout terminal;
- sense a voltage on the feedback terminal indicative of output voltage of the power conversion circuit while refraining from driving the alarm current to the feedback terminal;
- assert an internal signal if the voltage sensed on the brownout terminal during the refraining falls outside a predetermined range;
- and
- drive the alarm current to the feedback terminal responsive to the assertion of the internal signal;
- an external indicator coupled feedback terminal, the external indicator configured to activate responsive to the alarm current.
A controller for a power conversion circuit, comprising:
- a brownout terminal, the controller configured to receive an input signal on the brownout terminal, the input signal proportional to an input voltage to the power conversion circuit;
- a gate terminal, the controller configured to drive a gate signal for a primary field effect transistor (FET) on the gate terminal;
- a feedback terminal, the controller configured to receive a feedback signal indicative of an output voltage on the feedback terminal;
- a first circuit having a first input coupled to the feedback terminal and a second input coupled to the brownout terminal, the first circuit configured to:
- sense the input signal on the brownout terminal;
- sense the feedback signal on the feedback terminal;
- assert an internal signal if the input signal sensed on the brownout terminal falls outside a predetermined range;
- and
- drive an alarm current to the feedback terminal responsive to the assertion of the internal signal.
A method of operating a switch mode-power supply, comprising:
- driving, by a controller, a gate signal to a field effect transistor (FET) on a primary side of the switch-mode power supply;
- sensing, by the controller, a value indicative of input voltage on a first input terminal of the controller;
- sensing, by the controller, a value indicative of output voltage on a second input terminal of the controller;
- asserting an internal signal of the controller if the value indicative of input voltage sensed on the input terminal falls outside a predetermined range;
- and
- driving, by the controller, an alarm current to an external indicator connected to the second input terminal of the controller in response to the assertion of the internal signal of the controller.
Dependencies are inferred from the claim text.