Patent ID: 8036002
Filing Date: 2011-10-11
Classification: H02M

Abstract:
1. A wide supply range flyback converter comprising: (a) a storage capacitor having two terminals where one terminal is connected to a common ground of the circuit; (b) an under-voltage lockout circuit with hysteresis having an input, an output, and ground terminal where the ground terminal is connected to the common ground of the circuit; (c) the other terminal of said storage capacitor connected to the input terminal of a said under-voltage lockout circuit with hysteresis and a terminal of a startup resistor; (d) a output terminal of said under-voltage lockout circuit with hysteresis connected to one terminal of a first voltage controlled current source, one terminal of a voltage controlled current source with gated threshold, a cathode of a bias rectifier, and an output terminal of a first switching element; (e) said first voltage controlled current source and voltage controlled current source with gated threshold controlled by a feedback signal of the circuit; (f) the other terminal of said first voltage controlled current source connected to a negative input of a current sense comparator, a terminal of a second voltage controlled current source, and a terminal of a current sample feed resistor; (g) a positive input of said current sense comparator forming a voltage reference point of the converter; (h) the output of said current sense comparator connected to a input of said first switching element; (i) the other output of said first switching element connected to a terminal of a switched current source; (j) an other terminal of said switched current source connected to an input of an inverted Schmitt trigger, a terminal of a timing capacitor, a terminal of a voltage controlled current sink, a terminal of a feed forward current source, and a remaining terminal of said voltage controlled current source with gated threshold; (k) the other terminal of said voltage controlled current sink connected to an output of said inverted Schmitt trigger and an input of a second switching element, such as a MOSFET; (l) an output terminal of said second switching element connected to an other terminal of said current sample feed resistor and a terminal of a sensing resistor; (m) the other terminal of said sensing resistor connected to common ground; (n) an other output terminal of said second switching element connected to a dotted terminal of a primary winding of a transformer; (o) said transformer comprised of primary, secondary, and bias windings; (p) the other terminal of the primary winding of said transformer connected to a positive terminal of a DC supply, a remaining terminal of said second voltage controlled current source, a remaining terminal of said feed forward current source, and a remaining terminal of said startup resistor; (q) said second voltage controlled current source and said feed forward current source controlled by said DC supply; (r) a negative terminal of said DC supply connected to common ground; (s) a dotted terminal of the bias winding of said transformer connected to a terminal of a bias resistor; (t) an other terminal of said bias resistor connected to the anode of said bias rectifier; (u) an other terminal of the bias winding of said transformer connected to common ground; (v) an dotted terminal of the secondary winding of said transformer connected to the anode of an output rectifier; (w) the cathode of said output rectifier connected to a terminal of an output capacitor and a terminal of a load forming a positive output of the converter; (x) an other terminal of the secondary winding of said transformer connected to an other terminal of said output capacitor and an other terminal of said load forming a negative output of the converter.