Switched-Mode Power Supply Controller Using a Single Pin for Both Input Voltage Sensing and Control of Power Supply Charging

Patent metadata

Field	Value
Publication number	US-2018226894-A1
Application number	US-201715426647-A
Country	US
Kind code	A1
Filing date	Feb 7, 2017
Priority date	Feb 7, 2017
Publication date	Aug 9, 2018
Grant date	—

Abstract

Circuits and methods within a switched-mode power supply (SMPS) controller are provided. The SMPS controller includes an SMPS power stage which is integrated within the same package, and which has a first power switch. The first power switch is used to supply current to a power supply for the SMPS controller during a start-up phase of the SMPS, thereby charging this power supply prior to normal operational mode of the SMPS. A lead of the SMPS controller is connected to a control terminal of the first power switch during the start-up phase. After the start-up phase, this same lead is instead routed to an input source voltage monitor, and is used for detecting overvoltage or undervoltage conditions at the SMPS input power source.

First claim

1 . An integrated controller and power stage for a switched-mode power supply (SMPS), the integrated controller and power stage comprising:
a high-voltage supply lead, an input voltage lead, an SMPS controller, a first power switch, a controller power supply and a source voltage monitoring circuit integrated in the same package, wherein the high-voltage supply lead provides a first point of external electrical contact to the package, wherein the input voltage lead provides a second point of external electrical contact to the package, wherein the first power switch comprises a first power switch control terminal, wherein the controller power supply is configured to power the SMPS controller, wherein the SMPS controller is operable to measure a supply voltage of the controller power supply and to couple, based upon the supply voltage, an input voltage at the input voltage lead to at most one of the first power switch control terminal and the source voltage monitoring circuit wherein the first power switch is operable to connect the high-voltage supply lead to the controller power supply in order to charge the controller power supply during a start-up phase of the SMPS controller, during which the SMPS controller couples the input voltage to the first power switch control terminal, wherein the SMPS controller is operable to couple the source voltage monitoring circuit to the input voltage lead during a normal operating phase of the SMPS controller which follows the start-up phase.

2 . The integrated controller and power stage of claim 1 , further comprising:
a first routing switch interposed between the input voltage lead and the first power switch control terminal, wherein the first routing switch is turned on during the start-up phase of the SMPS controller.

3 . The integrated controller and power stage of claim 2 , further comprising:
a first comparator coupled to the controller power supply, the first comparator operable to detect that the supply voltage of the controller power supply is above a first voltage threshold and, responsive to said detection, to generate a first control signal that turns off the first routing switch, thereby turning off the first power switch.

4 . The integrated controller and power stage of claim 2 , further comprising:
a second comparator coupled to the controller power supply, the second comparator operable to detect that the supply voltage of the controller power supply is below a second voltage threshold and, responsive to said detection, to generate a second control signal that turns on the first routing switch.

5 . The integrated controller and power stage of claim 1 , further comprising:
a second routing switch interposed between the input voltage lead and the source voltage monitoring circuit, wherein the second routing switch is turned on during the normal operating phase of the SMPS controller.

6 . The integrated controller and power stage of claim 5 , further comprising:
a comparator coupled to the controller power supply, the comparator operable to detect that a voltage of the controller power supply is above a first voltage threshold; a pulse genera operable to activate a discharge control signal responsive to said detection and to deactivate the discharge control signal a clamp time delay after said detection; and a fast discharge circuit comprising a discharge switch that is coupled to the input voltage lead, the fast discharge circuit being operable to quickly discharge a voltage of the input voltage lead by turning on the discharge switch responsive to receiving the discharge control signal.

7 . The integrated controller and power stage of claim 6 , wherein the pulse generator comprises a digital counter.

8 . The integrated controller and power stage of claim 6 , wherein the pulse generator comprises an analog delay line.

9 . The integrated controller and power stage of claim 1 , wherein the first power switch is part of a power stage of the SMPS.

10 . The integrated controller and power stage of claim 1 , further comprising:
a second power switch that is coupled to the first power switch, and which is turned on during the normal operating phase of the SMPS controller.

11 . The integrated controller and power stage of claim 10 , wherein the second power switch is turned off during the start-up phase of the SMPS controller.

12 . The integrated controller and power stage of claim 1 , wherein the source voltage monitoring circuit further comprises a comparator operable to detect an overvoltage condition of the input voltage lead or an undervoltage condition of the input voltage lead and, responsive to said detection, generate a signal indicating an abnormal condition of an input voltage to the SMPS.

13 . A switched-mode power supply (SMPS), comprising:
integrated controller and power stage, comprising: a high-voltage supply lead, an input voltage lead, an SMPS controller, a first power switch, a controller power supply and a source voltage monitoring circuit integrated in the same package, wherein the high-voltage supply lead provides a first point of external electrical contact to the package, wherein the input voltage lead provides a second point of external electrical contact to the package, wherein the first power switch comprises a first power switch control terminal, wherein the controller power supply is configured to power the SMPS controller, wherein the SMPS controller is operable to measure a supply voltage of the controller power supply and to couple, based upon the supply voltage, an input voltage at the input voltage lead to at most one of the first power switch control terminal and the source voltage monitoring circuit, wherein the first power switch is operable to connect the high-voltage supply lead to the controller power supply in order to charge the controller power supply during a start-up phase of the SMPS controller, during which the SMPS controller couples the input voltage to the first power switch control terminal, wherein the SMPS controller is operable to couple the source voltage monitoring circuit to the input voltage lead during a normal operating phase of the SMPS controller which follows the start-up phase; a sense resistor coupled between the input voltage lead of the integrated controller and power stage, and a high-voltage supply of the SMPS.

14 . The SMPS of claim 13 , further comprising:
a transformer having an auxiliary winding, the auxiliary winding supplying power to the controller power supply during the normal operating phase of the SMPS controller.

15 . The SMPS of claim 13 , further comprising:
a rectification diode coupled to a switch output of the integrated controller and power stage; a smoothing filter coupled to the rectification diode and operable to provide a smoothed output voltage to a load of the SMPS, wherein the smoothed output voltage also supplies power to the controller power supply during the normal operating phase of the SMPS controller.

16 . A method, in an integrated controller and power stage for a switched-mode power supply (SMPS), the integrated controller and power stage comprising a high-voltage supply lead, an input voltage lead, an SMPS controller, a first power switch comprising a first power switch control terminal, a controller power supply and a source voltage monitoring circuit integrated in the same package, for charging the controller power supply, the method comprising:
detecting that an input voltage at the input voltage lead is above a switch turn-on threshold; responsive to said detecting, turning on the first power

Assignees

• Infineon Technologies Austria Ag

Inventors

• Teo Yong Siang
• Gong Xiaowu
• Lim Kok Kee

Classifications

• H02M2001/0009

  Electricity · mapped topic

• H02M1/36

  Means for starting or stopping converters · CPC title

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M3/33523 Primary

  with galvanic isolation between input and output of both the power stage and the feedback loop · CPC title

• H02M1/0006

  Arrangements for supplying an adequate voltage to the control circuit of converters · CPC title