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US 5,687,065 AGranted
Pre-regulator with light switch to limit voltage ringing on turn-off
AssigneePhilips Electronics North America Corporation
InventorNaveed Majid
Life of this patent
Estimating the term…
Abstract
A power integrated circuit pre-regulator AC/DC converter circuit which employs a slow turn-off lateral insulated gate bipolar transistor (LIGBT) device as the switching transistor so as to reduce the decay time of a current generated by the parasitic inductance in the circuit upon turn-off of the LIGBT device, thereby to substantially reduce the level of a ringing voltage produced at the drain of the LIGBT device.
Claims12
An AC/DC converter circuit comprising:
- a pair of input terminals for connection to a source of AC supply voltage for the converter circuit,
- a pair of DC output terminals for supplying a load adapted to be coupled to said output terminals,
- a rectifier circuit coupled between the input terminals and the output terminals,
- a load capacitor coupled to said output terminals,
- a slow turn-off switching transistor connected in series circuit with the load capacitor to output terminals of the rectifier circuit, and
- a control circuit having an output coupled to a control electrode of the switching transistor to supply a control signal that will turn off the switching transistor at a predetermined level of the output voltage.
3 more elements
A switching power supply circuit comprising:
- a pair of input terminals for connection to a source of supply voltage for the converter circuit,
- a pair of output terminals for supplying a load adapted to be coupled to said output terminals,
- a load capacitor coupled between said output terminals,
- a slow turn-off switching transistor,
- means coupling said switching transistor to the load capacitor so that the switching transistor controls the flow of current in said load capacitor, and
- a control circuit having an input coupled to said load capacitor and an output coupled to a control electrode of the switching transistor to supply a control signal that will turn off the switching transistor at a predetermined level of the output voltage, said slow turn-off transistor being responsive to said control signal to slow the decay of current therein so as to reduce the level of a ringing voltage at one main electrode of the switching transistor on turn-off thereof.
3 more elements
Dependencies are inferred from the claim text.