Energy storage circuit for DC-DC converter
AssigneeDelta Electronics, Inc.
InventorsZhongwei Ke, Alpha J. Zhang, Bin Jin
Life of this patent
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Abstract
An energy storage circuit for a wide input voltage range DC-DC converter with holdup time requirement. The energy storage circuit comprises (1) an energy storage capacitor, (2) a charging path including a diode connected in series with a current limiting resistor coupled in series with the energy storage capacitor, (3) a discharging path including a parallel-coupled switch and a diode coupled in series with a filtering inductor which is coupled in series with the energy storage capacitor, and (4) a logic control unit coupled to the switch for turning the switch of the discharge path on and off.
Claims20
An energy storage circuit for use in a DC-DC converter, comprising:
- an energy storage capacitor with one terminal coupled to a ground terminal;
- a charging path including a first diode connected in series with a current limiting resistor coupled in series between a node which serves as a charging source and said energy storage capacitor for providing a path for charging said energy storage capacitor;
- a discharging path including a parallel-coupled switch and a second diode connected in series with a filtering inductor which is coupled in series between said energy storage capacitor and a positive terminal of a DC voltage bus of said DC-DC converter, wherein said switch is configured to turn off during a holdup mode to allow said energy storage capacitor to discharge a current to said DC voltage bus;
- and
- a logic control unit coupled to said switch for turning said switch on and off.
A method of extending a holdup time of a DC-DC converter comprising steps of:
- providing an energy storage capacitor with one terminal coupled to a ground terminal;
- providing a charging path, including a first diode connected in series with a current limiting resister coupled in series between one node of said DC-DC converter as a charging source and said energy storage capacitor, for limiting a current to flow from said charging source to said energy storage capacitor and keeping a voltage of said energy storage capacitor equal to a peak voltage of said charging source when said DC-DC converter is in a normal mode;
- and
- providing a discharging path, including a parallel-coupled switch and a second diode connected in series with a filtering inductor which is coupled in series between said energy storage capacitor and a positive terminal of a DC voltage bus, wherein said switch is configured to turn off during a holdup mode to allow said energy storage capacitor to discharge current to said DC voltage bus through said discharging path.
A DC-DC converter coupled to a DC power source, comprising:
- at least one power switch that turns on alternately to transfer energy from said DC power source to a DC output of said converter;
- a transformer having a primary winding coupled in series with said power switch;
- an energy storage circuit coupled across said DC bus and one node of said converter, comprising:
- an energy storage capacitor with one terminal coupled to a ground terminal;
- a charging path including a first diode connected in series with a current limiting resistor coupled in series between one node of said DC-DC converter as a charging source and said energy storage capacitor for providing a path for charging a current to flow from said DC-DC converter to said storage capacitor;
- a discharging path including a parallel-coupled switch and a second diode connected in series with a filtering inductor which is coupled in series between said energy storage capacitor and a positive terminal of a DC voltage bus, wherein said switch is configured to turn off during a holdup time to allow said energy storage capacitor to discharge a current to said DC voltage bus;
- and
- a logic control unit coupled to said switch for turning said switch on and off.
Dependencies are inferred from the claim text.