AC/DC converter with galvanic insulation and signal corrector
View Patent ↗An AC/DC converter comprising an input rectifier circuit connected in series with a primary winding ( 5 ) of an isolating transformer ( 6 ) and to a chopper switch (T 1 ) driven by a control circuit ( 10 ) using pulse width modulation on the basis of a signal representative of a primary current, the isolating transformer having a first secondary winding ( 7 ) that is wound in the same direction as the primary winding and that is connected to an output line ( 8 ) of the converter via a diode (D 4 ) and a filter coil (L 1 ), and a second secondary winding ( 9 ) that is wound in the opposite direction to the primary winding and that is connected directly to the output line via a diode (D 2 ), the output line being connected to an output capacitor (Cout). The converter includes an analog correction circuit for correcting the primary current, which circuit is connected to the control circuit and to a measurement element ( 30 ) delivering a signal representative of the primary current, and is arranged to transform said signal into a triangular signal suitable for driving the control circuit.
1. An AC/DC converter comprising:
an input rectifier circuit connected in series with a primary winding of an isolating transformer and to a chopper switch driven by a control circuit using pulse width modulation on the basis of a signal representative of a primary current,
wherein the isolating transformer comprises:
a first secondary winding that is wound in a same direction as the primary winding and that is connected to an output line of the converter via a first diode and a filter coil; and
a second secondary winding that is wound in an opposite direction to the primary winding and that is connected directly to the output line via a second diode, the output line being connected to an output capacitor (Cout), and
wherein the converter comprises an analog correction circuit for correcting the primary current, which circuit is connected to the control circuit and to a measurement element delivering a signal representative of the primary current, and is arranged to transform said signal into a triangular signal suitable for driving the control circuit,
wherein the analog correction circuit comprises a main having connected in series therein, in succession:
a first resistor;
a first switch;
a second resistor and the control circuit;
there being a first capacitor connected firstly to the main line between the first resistor and the first switch and secondly to ground;
a second switch connected firstly to the main line between the second resistor and the control circuit, and secondly to a third resistor that is also connected to ground; and
a second capacitor connected firstly to the main line between the connection between the second switch and the control circuit, and secondly to ground.