SWITCHING REGULATOR WITH BOOSTED AUXILIARY WINDING SUPPLY
First Claim
1. A switched-power circuit, comprising:
- an inductive storage element for coupling an input of the switched-power circuit to an output of the switched-power circuit and having a primary winding and an auxiliary winding;
a switching circuit for controlling charging of the inductive storage element from an input voltage source connected to the input of the switched-power circuit to the primary winding of the inductive storage element;
a control circuit coupled to the switching circuit for generating control signals for operating the switching circuit in response to a feedback signal provided from the output of the switched-power circuit; and
a boost circuit having a boost input coupled to the auxiliary winding of the inductive storage element for supplying power to the control circuit from a boost output at least during start-up of the switched-power circuit, wherein the boost circuit provides a voltage at the boost output that is substantially greater than a voltage of the boost input during start-up of the switched-power circuit.
1 Assignment
0 Petitions
Accused Products
Abstract
A boosted auxiliary winding power supply for a switched-power converter circuit provides operating voltage for control and other circuits early in the start-up phase of converter operation. A boost circuit has an input coupled to the auxiliary winding to boost the voltage available from the auxiliary winding at least during start-up of the switched-power converter. The boost thereby provides a voltage that is greater than the voltage across the auxiliary winding during start-up of the switched-power converter. The boost circuit may be actively switched at a rate higher than a switching rate of the switched-power converter, to increase a rate of rise of the operating voltage. Polarity information, which may be provided from the switched-power converter control circuit, can be used to actively rectify the output of the auxiliary winding.
119 Citations
24 Claims
-
1. A switched-power circuit, comprising:
-
an inductive storage element for coupling an input of the switched-power circuit to an output of the switched-power circuit and having a primary winding and an auxiliary winding; a switching circuit for controlling charging of the inductive storage element from an input voltage source connected to the input of the switched-power circuit to the primary winding of the inductive storage element; a control circuit coupled to the switching circuit for generating control signals for operating the switching circuit in response to a feedback signal provided from the output of the switched-power circuit; and a boost circuit having a boost input coupled to the auxiliary winding of the inductive storage element for supplying power to the control circuit from a boost output at least during start-up of the switched-power circuit, wherein the boost circuit provides a voltage at the boost output that is substantially greater than a voltage of the boost input during start-up of the switched-power circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method of controlling a switched-power circuit, comprising:
-
switching an input voltage source across a primary winding of an inductive storage element to transfer power to an output of the switched-power circuit, wherein the inductive storage element has the primary winding and an auxiliary winding; controlling a period of the switching in conformity with a feedback signal provided from the output of the switched-power circuit; and boosting a voltage of the auxiliary winding of the inductive storage element for supplying power to a control circuit that performs the controlling at least during start-up of the switched-power circuit, wherein the boosting provides a boost output voltage that is substantially greater than a voltage across the auxiliary winding during start-up of the switched-power circuit. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. An integrated circuit, comprising:
-
a switching control circuit for controlling a switch for charging an external inductive storage element through a primary winding in response to a feedback signal provided to the integrated circuit; and a boost circuit having an input coupled to a boost input terminal for coupling the integrated circuit to an auxiliary winding of the external inductive storage element, wherein the boost circuit supplies power to the switching control circuit from a boost output at least during start-up of the integrated circuit, wherein the boost circuit provides a voltage at the boost output that is substantially greater than a voltage of the boost input during start-up of the integrated circuit, wherein the boost circuit includes an active switch for providing a low-impedance path across the auxiliary winding in response to a boost pulse signal. - View Dependent Claims (20, 21, 22, 23, 24)
-
Specification