Pulsed feedback switching converter

Patent metadata

Field	Value
Publication number	US-2016252918-A1
Application number	US-201514632774-A
Country	US
Kind code	A1
Filing date	Feb 26, 2015
Priority date	Feb 26, 2015
Publication date	Sep 1, 2016
Grant date	—

Abstract

The present disclosure is directed to a switching power converter having a regulated output voltage or output current. The power converter uses a control unit having a signal conditioning circuit to produce a control voltage signal, which is used to drive a power stage of the converter. The signal conditioning circuit includes a comparator that compares a measured electrical quantity to a reference value representative of a desired regulated output quantity, and produces a digital detection signal based on the comparison. A control actuator uses the digital detection signal to produce a correction signal, which is received by an averaging circuit. The averaging circuit then produces the control voltage signal based on an average of the correction signal.

First claim

1 . A device, comprising:
a comparator configured to receive a reference signal and a measured value signal representative of an output electrical quantity of a power stage of a switching converter, the comparator being configured to produce a digital detection signal based on a comparison of the measured value signal and the reference signal; a control actuator configured to produce a correction signal based on the digital detection signal; an averaging circuit configured to produce a control signal by averaging the correction signal; and a power stage driver configured to drive the power stage of the switching converter based on the control signal, to regulate the output electrical quantity.

2 . The device of claim 1 , wherein the control actuator includes a monostable oscillator configured to produce the correction signal.

3 . The device of claim 2 , wherein the control actuator further includes a counter coupled to the monostable oscillator and configured to reduce a frequency of the correction signal.

4 . The device of claim 2 , wherein the control actuator further includes a logic gate configured to receive the digital detection signal and a clock signal, and to produce a logic signal to the monostable oscillator.

5 . The device of claim 1 , wherein the control actuator further includes:
a clock configured to produce a clock signal; a set-reset flip-flop having a set input configured to receive the digital detection signal and a reset input configured to receive the clock signal.

6 . The device of claim 5 , wherein the control actuator further includes a counter configured to reduce a frequency of the correction signal.

7 . The device of claim 5 , wherein the control actuator further includes:
a time delay circuit coupled between the clock and the reset input of the flip-flop and configured to delay the clock signal; a logic gate configured to receive the clock signal and an output of the flip-flop, and to produce a logic signal to the monostable oscillator, the monostable oscillator being configured to produce the correction signal based on the logic signal.

8 . The device of claim 1 , wherein the control actuator includes:
an oscillator configured to produce the correction signal based on the digital detection signal.

9 . The device of claim 1 , wherein the measured value signal is representative of an output voltage of the switching converter.

10 . The device of claim 1 , wherein the averaging circuit further comprises:
a first resistor coupled to a reference voltage terminal; a second resistor coupled to the first resistor; and a capacitor coupled to the first resistor and configured to discharge based on the correction signal.

11 . A method, comprising:
comparing a measured value signal representative of a an output electrical quantity of a power stage of a switching converter to a reference value; producing a digital detection signal based on the comparison of the measured value signal and the reference value; performing a corrective action at a control actuator when the measured value signal has a value greater than the reference value, performing the corrective action including:
receiving the digital detection signal at an input of the control actuator;
producing a correction signal based on the digital detection signal;
averaging the correction signal to produce a control voltage signal; and driving the power stage of the switching convert based on the control voltage signal to regulate the output voltage.

12 . The method of claim 11 , performing the corrective action further including:
receiving the digital detection signal and a clock signal at a logic gate; receiving an output signal of the logic gate at a monostable oscillator; producing the correction signal from the monostable oscillator based on the output signal of the logic gate.

13 . The method of claim 11 , performing the corrective action further including:
receiving the digital detection signal at a set input of a set-reset flip-flop; receiving a clock signal at a reset input of the set-reset flip-flop; producing the correction signal from the set-reset flip-flop based on the digital detection signal and the clock signal.

14 . The method of claim 11 , performing the corrective action further including:
receiving the digital detection signal at a monostable oscillator; producing the correction signal from the monostable oscillator.

15 . The method of claim 11 , performing the corrective action further including:
receiving the digital detection signal at a set input of a set-reset flip-flop; producing a clock signal; delaying the clock signal; receiving the delayed clock signal at a reset input of the set-reset flip-flop; producing an output signal from the set-reset flip-flop; receiving the clock signal and the output signal of the set-reset flip-flop at a logic gate; receiving an output signal of the logic gate at a monostable oscillator; producing the correction signal from the monostable oscillator based on the output signal of the logic gate.

16 . A switching converter, comprising:
a power stage, including:
a transformer coupled to an input voltage and configured to produce an output electrical quantity;
a first switch coupled to the transformer;
a sensing circuit configured to produce a measured value signal representative of the output voltage of the transformer; a signal conditioning circuit, including:
a comparator configured to receive a reference signal and the measured value signal, and to produce a digital detection signal based on a comparison of the measured value signal and the reference signal;
a control actuator configured to produce a correction signal based on the digital detection signal;
an averaging circuit configured to produce a control voltage signal by averaging the correction signal over time;
a modulator coupled to the signal conditioning circuit and configured to produce a pulsed signal based on the control voltage signal; and a driver coupled to the modulator and configured to provide a driving signal to the switch of the power stage based on the pulsed signal to regulate the output voltage of the transformer.

17 . The switching converter of claim 16 , wherein the control actuator includes an oscillator configured to produce the correction signal.

18 . The switching converter of claim 17 , wherein the control actuator further includes a logic gate configured to receive the digital detection signal and a clock signal, and to provide a logic signal to the oscillator.

19 . The switching converter of claim 16 , wherein the control actuator includes:
a clock configured to produce a clock signal; and a set-reset flip-flop having a set input configured to receive the digital detection signal and a reset input configured to receive the clock signal, the flip-flop being configured to produce the correction signal.

20 . The switching converter of claim 16 , wherein the power stage further comprises a second switch coupled to the transformer.

Assignees

• St Microelectronics Srl

Inventors

• Adragna Claudio

Classifications

• G05F1/56 Primary

  using semiconductor devices in series with the load as final control devices (G05F1/461 takes precedence) · CPC title

• H02M3/33571

  Half-bridge at primary side of an isolation transformer · CPC title

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title