Power converter having primary and secondary side switches
First Claim
1. A power converter comprising:
- an input terminal;
an output terminal;
a transformer having a primary side and a secondary side, said transformer further comprising a primary side winding connected to said input terminal and a secondary side winding connected to said output terminal;
a primary side switch;
a secondary side switch;
a slave control unit controlling switching of said secondary side switch;
a master control unit controlling switching of said primary side switch; and
a secondary current sense detecting said secondary current in said secondary side switch, said primary side switch and said secondary side switch being configured to be switched on and off alternately;
wherein said switching of said secondary side switch is accomplished depending on a secondary current detected in said secondary side switch, and wherein said primary side switch and said secondary side switch are switched on during a zero voltage switching condition;
wherein said slave control unit further comprises a comparator and a set/reset flip flop, wherein said secondary current sense conveys an output signal into said comparator when said secondary current becomes negative, wherein said comparator compares said output signal of said secondary current sense to a current reference level and outputs a switching signal to said set/reset flip flop when said output signal of said secondary current sense exceeds said current reference level, wherein said set/reset flip flop switches said secondary side switch when said switching signal is received and wherein said current reference level is given by the following equation;
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Accused Products
Abstract
A power converter having a transformer with a primary side winding and a secondary side winding, each having a switch. When the primary master switch is switched on, the transformer charges. When it is switched off, the intrinsic capacitance of the secondary slave switch discharges generating the zero voltage switching condition for the secondary slave switch. The secondary slave switch is switched on at a time determined in accordance with the waveform generated by the transformer. When the secondary slave switch is switched on, the transformer discharges and ultimately the charge from an output capacitor flows into the transformer as a backflow which charges the transformer. The secondary slave switch is switched off at a time determined in accordance with a current flowing through said secondary switch. The intrinsic capacitance of primary master switch discharges generating the zero voltage switching condition for primary master switch which is then switched on.
79 Citations
21 Claims
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1. A power converter comprising:
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an input terminal;
an output terminal;
a transformer having a primary side and a secondary side, said transformer further comprising a primary side winding connected to said input terminal and a secondary side winding connected to said output terminal;
a primary side switch;
a secondary side switch;
a slave control unit controlling switching of said secondary side switch;
a master control unit controlling switching of said primary side switch; and
a secondary current sense detecting said secondary current in said secondary side switch, said primary side switch and said secondary side switch being configured to be switched on and off alternately;
wherein said switching of said secondary side switch is accomplished depending on a secondary current detected in said secondary side switch, and wherein said primary side switch and said secondary side switch are switched on during a zero voltage switching condition;
wherein said slave control unit further comprises a comparator and a set/reset flip flop, wherein said secondary current sense conveys an output signal into said comparator when said secondary current becomes negative, wherein said comparator compares said output signal of said secondary current sense to a current reference level and outputs a switching signal to said set/reset flip flop when said output signal of said secondary current sense exceeds said current reference level, wherein said set/reset flip flop switches said secondary side switch when said switching signal is received and wherein said current reference level is given by the following equation;
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A power converter comprising:
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a transformer having a primary side and a secondary side;
a primary side switch;
a secondary side switch;
a slave control unit controlling switching of said secondary side switch;
a master control unit controlling switching of said primary side switch; and
a secondary current sense detecting a secondary current in said secondary side switch;
wherein said switching of said secondary side switch is accomplished depending on said secondary current detected in said secondary side switch, wherein said primary side switch and said secondary side switch are switched on during a zero voltage switching condition;
wherein said slave control unit further comprises a comparator and a set/reset flip flop, wherein said secondary current sense conveys an output signal into said comparator when said secondary current becomes negative, wherein said comparator compares said output signal of said secondary current sense to a current reference level and outputs a switching signal to said set/reset flip flop when said output signal of said secondary current sense exceeds said current reference level;
wherein said set/reset flip flop switches said secondary side switch when said switching signal is received;
wherein said current reference level is given by the following equation;
- View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification