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US 8,710,804 B2Granted
Discharge circuit and method
AssigneeSemiconductor Components Industries, LLC
InventorsKarel Ptacek, Juan Carlos Pastrana, Jiri Bubla, Jaromir Uherek
Life of this patent
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Abstract
In accordance with an embodiment, a power supply may include a filter stage coupled to an input terminal of a discharge circuit and a supply capacitor coupled to an output terminal of the discharge circuit. In accordance with another embodiment, a method for discharging at least one capacitor includes discharging the at least one capacitor in response to a signal at the input terminal of the discharge circuit being different from a reference signal.
Claims24
A power supply, comprising:
- a first signal detection circuit having an input terminal and an output terminal;
- a logic circuit having first and second input terminals and an output terminal, the first input terminal coupled to the output terminal of the first signal detection circuit;
- a second signal detection circuit having first and second input terminals and an output terminal, the first input terminal coupled for receiving a first reference signal and the output terminal coupled to the second input terminal of the logic circuit;
- a first current control element having first and second current carrying terminals and a control terminal, the second input terminal of the logic circuit coupled to the control terminal of the first current control element, the first current carrying terminal coupled to the input terminal of the first signal detection circuit;
- and
- a second current control element having first and second current carrying terminals and a control terminal, the control terminal coupled to the output terminal of the logic circuit and the first current carrying terminal coupled to the second current carrying terminal of the first current control element.
3 more elements
A power supply comprising:
- a filter stage having at least one input terminal and an output terminal;
- a discharge circuit having an input terminal and an output terminal, the input terminal of the discharge circuit coupled to the output terminal of the filter stage, the discharge circuit comprising:
- a first detection stage having first and second input terminals and an output terminal, first input terminal serving as the input terminal of the discharge circuit;
- a gating element having first and second input terminals and an output terminal, the first input terminal coupled to the output terminal of the first detection stage;
- a second detection stage having first and second input terminals and an output terminal, the output terminal coupled to the second input terminal of the gating element;
- a first current control element having a control terminal and first and second current carrying terminals, the first current control terminal coupled to the output of the gating element and the first current carrying terminal coupled to the first input terminal of the second detection stage;
- and
- a diode having an anode and a cathode, the anode coupled to the first current carrying terminal of the first current control element and the cathode coupled to the first input terminal of the second detection stage.
5 more elements
A power supply comprising:
- a filter stage having at least one input terminal and an output terminal;
- a discharge circuit having an input terminal and an output terminal, the input terminal of the discharge circuit coupled to the output terminal of the filter stage, the discharge circuit comprising:
- a first detection stage having first and second input terminals and an output terminal, first input terminal serving as the input terminal of the discharge circuit, wherein the first detection stage comprises:
- an AC detector having a first input terminal that serves as the input terminal of the first detection stage, a second input terminal, and an output terminal;
- at least one timer having first and second input terminals and first and second output terminals, the first input terminal coupled to the output terminal of the AC detector;
- and
- a latch having a first input terminal coupled to the first output terminal of the at least one timer and the output terminal serving as the output terminal of the first detection stage;
- a gating element having first and second input terminals and an output terminal, the first input terminal coupled to the output terminal of the first detection stage;
- a second detection stage having first and second input terminals and an output terminal, the output terminal coupled to the second input terminal of the gating element;
- a first current control element having a control terminal and first and second current carrying terminals, the first current control terminal coupled to the output of the gating element and the first current carrying terminal directly coupled to the first input terminal of the second detection stage.
7 more elements
A method for operating a power supply, comprising:
- generating a first signal in response to removing a first AC signal from an input to a filter stage, wherein the first signal is greater than or less than a first reference level;
- and
- discharging one or more capacitors coupled to the filter stage in response to the first signal being greater than or less than the first reference level for a predetermined period of time, wherein discharging the one or more capacitors coupled to the filter stage includes:
- starting a first timer in response to the first signal;
- starting a second timer in response to the first signal being delayed by a second predetermined period of time;
- and
- generating a control signal in response to the first signal being delayed by the first predetermined period of time;
- and
- using the control signal to generate a discharge current.
6 more elements
Dependencies are inferred from the claim text.