Zero-voltage switching quasi-resonant converters
First Claim
1. A quasi-resonant converter comprising:
- (a) a power source;
(b) a load;
(c) a low pass filter formed from at least an inductor and a capacitor for filtering a signal applied to said load; and
(d) a resonant switch means including;
(1) a switch for connecting said power source to said load and for disconnecting said power source from said load, said switch operative in an on state and in an off state, and(2) a resonant capacitor and a resonant inductor coupled together at a common node to form a resonant circuit said common node being operatively connected to said switch, said resonant circuit for imposing a voltage waveform across said switch, said resonant circuit coupled to said switch, and said resonant capacitor and said resonant inductor having respective impedances selected to shape said voltage waveform such that a zero-voltage condition is imposed upon said switch when said switch is disposed to its on state.
3 Assignments
0 Petitions
Accused Products
Abstract
A quasi-resonant converter is disclosed as comprising a power source, a load and a resonant switch circuit for periodically connecting the power source to the load. The resonant switch circuit includes a switch for connecting the power source to the load and for disconnecting the power source from the load, and a resonant circuit comprised of a resonant capacitor and a resonant inductor. The switch is operated at a switching frequency in excess of 1 MHz and in the order of 10 to 20 MHz or greater. The resonant circuit is connected to the switch to impose thereon a voltage waveform as developed across the resonant capacitor. The resonant capacitor and the resonant inductor have respective impedances selected to shape the voltage waveform such that a zero-voltage condition is imposed upon the switch when it is disposed to its on state, whereby the parasitic capacitive losses associated with the switch are eliminated.
268 Citations
41 Claims
-
1. A quasi-resonant converter comprising:
-
(a) a power source; (b) a load; (c) a low pass filter formed from at least an inductor and a capacitor for filtering a signal applied to said load; and (d) a resonant switch means including; (1) a switch for connecting said power source to said load and for disconnecting said power source from said load, said switch operative in an on state and in an off state, and (2) a resonant capacitor and a resonant inductor coupled together at a common node to form a resonant circuit said common node being operatively connected to said switch, said resonant circuit for imposing a voltage waveform across said switch, said resonant circuit coupled to said switch, and said resonant capacitor and said resonant inductor having respective impedances selected to shape said voltage waveform such that a zero-voltage condition is imposed upon said switch when said switch is disposed to its on state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 39)
-
-
34. A quasi-resonant converter comprising:
-
(a) a power source; (b) a load; (c) a low pass filter formed from at least an indicator and a capacitor for filtering said load; and (d) a resonant switch means comprising; (1) switch for connecting said power source to said load and for disconnecting said power source from said load, said switch operative in an on state and in an off state, (2) a resonant capacitor and a resonant inductor coupled together to form a resonant circuit for imposing a voltage waveform across said switch, said resonant circuit coupled to said switch, and said resonant capacitor and said resonant inductor having respective impedances selected to shape said voltage waveform such that a zero-voltage condition is imposed upon said switch when said switch is disposed to its on state, and wherein said resonant capacitor is coupled to said switch and said resonant indicator to shape said voltage waveform such that a zero-voltage condition is imposed upon said switch when said switch is disosed in its off state; and (3) means for disposing said switch to its on state and then to its off state in periodic cycles at a switching frequency Fs in excess of 1 MHz.
-
-
35. A quasi-resonant converter comprising:
-
(a) a power source; (b) a load; (c) a low pass filter formed from at least an inductor and a capacitor for filtering a signal applied to said load; and (d) a resonant switch circuit including; (1) a switch for connecting said power source to said load and for disconnecting said power source from said load, said switch operative in an on state and in an off state, in periodic cycles at a selected switching frequency Fs, and (2) a resonant capacitor and a resonant inductor coupled together to form a resonant circuit for imposing a voltage waveform across said switch, said resonant circuit coupled to said switch, and said resonant capacitor and said resonant inductor having respective impedances selected to shape said voltage waveform such that a zero-voltage condition is imposed upon said switch when said switch is disposed to its on state and wherein said switch is disposed to its off state to simultaneously impose said voltage waveform across said switch, said impedances of said resonant capacitor and resonant inductor reing selected to form said voltage waveform such that said voltage waveform is at substantially zero volts when said switch is next disposed to its on state. - View Dependent Claims (36, 37, 38)
-
-
40. A quasi-resonant converter comprising:
-
(a) a power source; (b) a load; (c) a low pass filter formed from at least an inductor and a capacitor for filtering a signal applied to said load; and (d) a resonant switch means including; (1) a switch for connecting said power source to said load and for disconnecting said power source from said load, said switch operative in an on state and in an off state, and (2) a resonant capacitor and a resonant inductor coupled together to form a resonant circuit for imposing a voltage waveform across said switch, said resonant circuit coupled to said switch, and said resonant capacitor and said resonant inductor having respective impedances selected to shape said voltage waveform such that a zero-voltage condition is imposed upon said switch when said switch is disposed to its on state, said voltage waveform including a DC component and an AC component, wherein said AC component is greater than said DC component such that said voltage waveform imposes said zero-voltage condition upon said switch, when said switch is disposed to its on state.
-
-
41. A quasi-resonant converter comprising:
-
(a) a power source; (b) a load; (c) a low pass filter formed from at least an inductor and a capacitor for filtering a signal applied to said load; and (d) a resonant switch means including;
a switch for connecting said power source to said load, said resonant capacitor being coupled in series with said power source to form a series circuit, said series circuit being coupled in parallel with said switch to form a parallel circuit, said parallel circuit being connected in series with said resonant inductor, coupled together to form a resonant circuit for imposing a voltage waveform across said switch and said resonant capacitor and said resonant inductor having respective impedances selected to shape said voltage waveform such that a zero-voltage condition is imposed upon said switch when said switch is disposed to its on state.
-
Specification