Lossless synchronous rectification power supply circuit and design method
AssigneeNavitas Semiconductor Limited
InventorsXiucheng Huang, Yingchuan Lei, Yun Zhou, Weijing Du
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Abstract
A low power-loss supply circuit minimizes the losses in a synchronous rectifier power conversion circuit by regulating the voltage supply (Vcc) of a synchronous rectifier controller. The low power-loss supply circuit uses two regulating capacitors to regulate the value of the voltage supplied to the controller. A first regulating capacitor supplies the input voltage which powers the synchronous rectifier controller. A second regulating capacitor is used to cyclically charge the first regulating capacitor.
Claims20
A circuit comprising:
- a transformer winding extending between a first lead and a second lead, wherein the second lead is connected to a first output terminal;
- a solid-state switch electrically connected between the first lead and a second output terminal;
- a first capacitor coupled in series with a second capacitor forming a capacitor circuit that is coupled in parallel with the solid-state switch, wherein the first capacitor is coupled directly to the second output terminal;
- and
- a controller circuit arranged to control operation of the solid-state switch to be in an off state during a first time period and in an on state during a second time period such that:
- during the first time period the second capacitor is charged through the first capacitor, wherein the first capacitor limits the charge of the second capacitor;
- and
- during the second time period the first capacitor discharges to the second output terminal and the second capacitor supplies power to the controller circuit.
A method of operating a circuit, the method comprising:
- operating the circuit sequentially in a first time period then in a second time period, the circuit comprising:
- a transformer winding extending between a first lead and a second lead, wherein the second lead is connected to a first output terminal;
- a solid-state switch electrically connected between the first lead and a second output terminal;
- a first capacitor coupled in series with a second capacitor forming a capacitor circuit that is coupled in parallel with the solid-state switch, wherein the first capacitor is coupled directly to the second output terminal;
- and
- a controller arranged to control operation of the solid-state switch such that the solid-state switch is:
- in an off state during the first time period causing the second capacitor to charge through the first capacitor;
- and
- in an on state during the second time period.
A circuit comprising:
- a primary winding of a transformer arranged to be coupled to a power source;
- a secondary winding of the transformer extending between a first lead and a second lead, the second lead connected to a first load terminal;
- a solid-state switch having a source connected to the first lead and a drain connected to a second load terminal;
- a first capacitor coupled in series with a second capacitor forming a capacitor circuit that is coupled in parallel with the solid-state switch, wherein the first capacitor is coupled directly to the second load terminal;
- and
- a controller circuit that turns the solid-state switch off during a first time period and turns the solid-state switch on during a second time period, wherein during the first time period the first capacitor supplies power to the second capacitor and to the controller circuit, and wherein during the second time period the first capacitor discharges to the second load terminal and the second capacitor supplies power to the controller circuit.
Dependencies are inferred from the claim text.