Controller for a power supply with transition region regulation

• US 9,680,384 B2
• Filed: 06/30/2016
• Issued: 06/13/2017
• Est. Priority Date: 08/15/2014
• Status: Expired due to Fees

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Power Integrations Incorporated
• Inventors: Matthews, David Michael Hugh
• Primary Examiner(s): Finch, III, Fred E
• Assistant Examiner(s): Gibson, Demetries A
• Application Number:
  US15/199,625
• Publication Number:
  US 20160315542A1
• Time in Patent Office: 348 Days
• CPC Class Codes: H02M 1/0003 Details of control, feedback or regulation circuits
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/1566 with means for compensating against rapid load changes, e.g. with auxiliary current source, with dual mode control or with inductance variation
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33515 with digital control
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop

Abstract

Energy in a power converter is regulated by receiving a first signal representative of an output voltage and a second signal representative of a current of the power converter. An output current of the power converter is determined in response to at least one of the first and second signals. An inner maximum output power point corresponding to a first value of output voltage and a first value of output current is determined. An outer maximum output power point corresponding to a second value of output voltage and a second value of output current is determined. A maximum capability boundary between the inner maximum output power point and the outer maximum output power point is determined. A power switch is switched to regulate the output voltage and the output current of the power converter such that the maximum output power is lower than the maximum capability boundary.

Claims

1. A method of regulating energy in a power converter, comprising:

receiving with a voltage regulation circuit a first signal representative of an output voltage of the power converter;

receiving with a current regulation circuit a second signal representative of a current of the power converter;

determining an output current of the power converter in response to at least one of the first signal received by the voltage regulation circuit and the second signal received by the current regulation circuit,

wherein a first transition point corresponds to a first output transition voltage of the output voltage of the power converter and a first output transition current of the output current of the power converter, wherein the first transition point is between an inner transition point and an outer transition point, wherein the inner transition point corresponds to an inner transition point voltage of the output voltage of the power converter and an inner transition point current of the output current of the power converter, wherein the outer transition point corresponds to an outer transition point voltage of the output voltage of the power converter and an outer transition point current of the output current of the power converter,

wherein a second transition point corresponds to a second output transition voltage of the output voltage of the power converter and a second output transition current of the output current of the power converter, wherein the second transition point is between an upper transition point and a lower transition point, wherein the upper transition point corresponds to an upper transition point voltage of the output voltage of the power converter and an upper transition point current of the output current of the power converter, wherein the lower transition point corresponds to a lower transition point voltage of the output voltage of the power converter and a lower transition point current of the output current of the power converter, and

wherein a third transition point corresponds to a third output transition voltage of the output voltage of the power converter and a third output transition current of the output current of the power converter;

switching a power switch of the power converter to regulate the output voltage and the output current of the power converter between the first transition point and the second transition point;

switching the power switch of the power converter to regulate the output current of the power converter between the second transition point and the third transition point; and

switching the power switch of the power converter to regulate the output current of the power converter between the third transition point and a short circuit current at zero output voltage.

2. The method of claim 1 further comprising:

switching the power switch of the power converter to regulate the output voltage of the power converter at a substantially constant voltage value when the power converter operates in a regulated voltage region between a no-load output voltage at zero output current and the first transition point;

switching the power switch of the power converter to regulate the output current of the power converter at a substantially constant current value when the power converter operates in a regulated current region between the second transition point and the third transition point;

switching the power switch of the power converter to regulate an output power of the power converter to a substantially constant power value when the power converter operates in a regulated transition region between the first transition point and the second transition point; and

switching the power switch of the power converter to regulate the output current of the power converter between the third output transition current and the short circuit current when the power converter operates in a foldback region where a reduction in the output voltage results in a reduction in the output current.

3. The method of claim 1 wherein the power converter is a flyback converter.

4. A regulator circuit for use in a power converter, comprising:

a voltage regulation circuit coupled to receive a first signal representative of an output voltage at an output of the power converter, wherein the voltage regulation circuit is coupled to generate a first regulation signal;

a current regulation circuit coupled to receive a second signal representative of a current of the power converter, wherein the current regulation circuit is coupled to generate a second regulation signal;

a transition region regulation circuit coupled to receive the first signal, the second signal, and an adjustment signal, wherein the transition region regulation circuit is coupled to generate a third regulation signal in response to the first signal, the second signal, and the adjustment signal; and

a controller coupled to receive a feedback signal responsive to the first, second and third regulation signals, wherein the controller is coupled to generate a drive signal in response to the feedback signal to control a switching of a power switch of the power converter,

wherein a first transition point corresponds to a first output transition voltage of the output voltage of the power converter and a first output transition current of an output current of the power converter, wherein the first transition point is between an inner transition point and an outer transition point, wherein the inner transition point corresponds to an inner transition point voltage of the output voltage of the power converter and an inner transition point current of the output current of the power converter, wherein the outer transition point corresponds to an outer transition point voltage of the output voltage of the power converter and an outer transition point current of the output current of the power converter,

wherein a second transition point corresponds to a second output transition voltage of the output voltage of the power converter and a second output transition current of the output current of the power converter, wherein the second transition point is between an upper transition point and a lower transition point, wherein the upper transition point corresponds to an upper transition point voltage of the output voltage of the power converter and an upper transition point current of the output current of the power converter, wherein the lower transition point corresponds to a lower transition point voltage of the output voltage of the power converter and a lower transition point current of the output current of the power converter,

wherein a third transition point corresponds to a third output transition voltage of the output voltage of the power converter and a third output transition current of the output current of the power converter,

wherein the controller is coupled to generate the drive signal to regulate the output voltage of the power converter at a substantially constant output voltage value when the power converter operates in a voltage regulation region between a no-load output voltage at zero output current and the first transition point, wherein the controller is further coupled to generate the drive signal to regulate the output current at a substantially constant output current value when the power converter operates in a current regulation region between the second transition point and the third transition point, and wherein the controller is further coupled to generate the drive signal to regulate the output power at a substantially constant output power when the power converter operates in a regulated transition region between the first transition point and the second transition point.

5. The regulator circuit of claim 4 wherein the power converter is a flyback converter.

6. A regulator circuit for use in a power converter, comprising:

a power switch; and

a controller coupled to the power switch, and coupled to receive a first signal representative of an output voltage of the power converter, a second signal representative of a current of the power converter, and an adjustment signal received at a terminal of the controller, wherein the regulator circuit is coupled to determine the output voltage and an output current of the power converter in response to at least the first and second signals and the adjustment signal,

wherein a first transition point corresponds to a first output transition voltage of the output voltage and a first output transition current of the output current, wherein the first transition point is between an inner transition point and an outer transition point, wherein the inner transition point corresponds to an inner transition point voltage of the output voltage and an inner transition point current of the output current, wherein the outer transition point corresponds to an outer transition point voltage of the output voltage and an outer transition point current of the output current,

wherein a second transition point corresponds to a second output transition voltage of the output voltage and a second output transition current of the output current, wherein the second transition point is between an upper transition point and a lower transition point, wherein the upper transition point corresponds to an upper transition point voltage of the output voltage and an upper transition point current of the output current, wherein the lower transition point corresponds to a lower transition point voltage of the output voltage and a lower transition point current of the output current,

wherein a third transition point corresponds to a third output transition voltage of the output voltage and a third output transition current of the output current,

wherein the controller is coupled to control a switching of the power switch to regulate the output voltage of the power converter at a substantially constant output voltage value when the power converter operates in a voltage regulation region between a no-load output voltage at zero output current and the first transition point, wherein the controller is further coupled to control the switching of the power switch to regulate the output current at a substantially constant output current value when the power converter operates in a current regulation region between the second transition point and the third transition point, and wherein the controller is further coupled to control the switching of the power switch to regulate the output power at a substantially constant output power when the power converter operates in a regulated transition region between the first transition point and the second transition point.

7. The regulator circuit of claim 6 wherein the first and second signals are generated on a primary side of the power converter.