Current controlled synchronous rectifying drive circuit
A current controlled synchronous rectifying drive circuit including a current transducer ST having a primary winding connected in series with a synchronous rectifier SR and having a secondary winding to detect a current signal of a synchronous rectifier SR, a signal shaping and reset circuit connected to the secondary winding of the current transducer ST to convert the synchronous rectifier SR's current signal into a voltage signal and shapes it into a pulse signal, a push-pull power amplifying circuit having an input end connected to the signal shaping and reset circuit and an output end connected to a gate of the synchronous rectifier SR to amplify a drive signal generated by the signal shaping and reset circuit to drive the synchronous rectifier SR, and a drive self-bias drive circuit having an input end connected to the secondary winding of the current transducer ST and an output end connected to the push-pull power amplifying circuit to store energy from the current transducer ST to generate a voltage source.
1. A current controlled synchronous rectifying drive circuit, comprising:
a current transducer ST having a primary winding connected in series with a synchronous rectifier SR and having a secondary winding to detect a current signal of a synchronous rectifier SR;
a signal shaping and reset circuit connected to the secondary winding of the current transducer ST to convert the synchronous rectifier SR's current signal into a voltage signal and shapes it into a pulse signal;
a push-pull power amplifying circuit having an input end connected to the signal shaping and reset circuit and an output end connected to a gate of the synchronous rectifier SR to amplify a drive signal generated by the signal shaping and reset circuit to drive the synchronous rectifier SR; and
a drive self-bias drive circuit having an input end connected to the secondary winding of the current transducer ST and an output end connected to the push-pull power amplifying circuit to store energy from the current transducer ST to generate a voltage source.
2. The current controlled synchronous rectifying drive circuit of claim 1 , wherein the signal shaping and reset circuit comprises diodes SD 1 , SD 2 , SD 3 , resistors SR 1 , SR 2 , SR 3 and transistor SQ 1 ;
wherein a cathode of diode SD 1 is connected to a non-dotted terminal of the secondary winding of a current transducer ST, and to a collector of transistor SR 1 and one node of resistor SR 3 , while an anode of diode SD 1 is connected to resistor SR 1 , and another node of resistor SR 1 is connected to the anode of diode SD 2 ;
wherein one node of resistor SR 2 is connected to a base of transistor SQ 1 ;
wherein a cathode of diode SD 2 is connected to the dotted terminal of the secondary winding of current transducer ST, and to another node of resistor SR 2 and a cathode of diode SD 3 ; and,
wherein an anode of diode SD 3 is connected to an emitter of transistor SQ 1 , and to another node of resistance SR 3 and a ground.
3. The current controlled synchronous rectifying drive circuit of claim 1 , wherein the push-pull power amplifying circuit comprises a NPN transistor SQ 2 , a PNP transistor SQ 3 , a drive synchronous rectifier SR with a power amplified drive voltage signal, wherein a base of NPN transistor SQ 2 is connected to a base of PNP transistor SQ 3 , and to a non-dotted terminal of the secondary winding of current transducer ST and an emitter of NPN transistor SQ 2 is connected to an emitter of PNP transistor SQ 3 , and to a control pole of synchronous rectifier SR, while an emitter of PNP transistor SQ 3 is connected to a ground.
4. The current controlled synchronous rectifying drive circuit of claim 1 , further comprising a diode SD 4 , a capacitor SC 1 , and a Zener diode VR 1 .
5. The current controlled synchronous rectifying drive circuit of claim 4 , wherein an anode of diode SD 4 is connected to a non-dotted terminal of the secondary winding of current transducer ST while a cathode of diode SD 4 is connected to a collector of a transistor SQ 2 , to one node of capacitor SC 1 and to a cathode of Zener diode, and another node of capacitor SC 1 is connected to an anode of the Zener diode VR 1 and a ground.
6. The current controlled synchronous rectifying drive circuit of claim 5 , further comprising a driving self-powered circuit comprising a diode SD 5 , wherein an anode of diode SD 5 is connected to a cathode of diode SD 4 and a cathode of diode SD 5 is connected to a positive pole of the output.
7. The current controlled synchronous rectifying drive circuit of claim 4 , wherein an anode of diode SD 4 is connected to the non-dotted terminal of the secondary winding of the current transducer ST while a cathode of diode SD 4 is connected to a collector of transistor SQ 2 , to one node of capacitor SC 1 and to the cathode of Zener diode, and another node of capacitor SC 1 is connected to the anode of the Zener diode VR 1 and the positive pole of the output.
8. The current controlled synchronous rectifying drive circuit of claim 1 , wherein the signal shaping and reset circuit enables the current transducer ST to reset when the current of the synchronous rectifier SR is zero.
9. The current controlled synchronous rectifying drive circuit of claim 1 , wherein the current signal of the synchronous rectifier SR is detected by the current transducer ST.
10. The current controlled synchronous rectifying drive circuit of claim 1 , wherein the drive self-bias drive circuit further comprises a capacitor SC 1 to store energy from the current transducer ST.
11. The current controlled synchronous rectifying drive circuit of claim 1 , wherein the voltage source generated from the energy stored is provided to regulate with a change of current in the synchronous rectifier SR and to power the whole drive circuit.
12. A current controlled synchronous rectifying drive circuit, comprising:
a current transducer ST having a primary winding connected in series with a synchronous rectifier SR and having a secondary winding;
a signal shaping and reset circuit connected to the secondary winding of the current transducer ST;
a push-pull power amplifying circuit having an input end connected to the signal shaping and reset circuit and an output end connected to a gate of the synchronous rectifier SR; and
a drive self-bias drive circuit having an input end connected to the secondary winding of the current transducer ST and an output end connected to the push-pull power amplifying circuit;
wherein the drive self-bias drive circuit stores energy from the current transducer ST to generate a voltage source.
13. A current controlled synchronous rectifying drive circuit, comprising:
a current transducer ST having a primary winding connected in series with a synchronous rectifier SR and having a secondary winding;
a signal shaping and reset circuit connected to the secondary winding of the current transducer ST;
a push-pull power amplifying circuit having an input end connected to the signal shaping and reset circuit and an output end connected to a gate of the synchronous rectifier SR; and
a drive self-bias drive circuit having an input end connected to the secondary winding of the current transducer ST and an output end connected to the push-pull power amplifying circuit;
wherein the drive self-bias drive circuit further comprises a capacitor SC 1 to store energy from the current transducer ST.
14. The current controlled synchronous rectifying drive circuit of claim 12 , wherein the voltage source generated from the energy stored is provided to regulate with a change of current in the synchronous rectifier SR and to power the whole drive circuit.