Efficient multi-mode dc-dc converter

Patent metadata

Field	Value
Publication number	US-2016294285-A1
Application number	US-201514873406-A
Country	US
Kind code	A1
Filing date	Oct 2, 2015
Priority date	Apr 3, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

In one form, a multi-mode converter includes first, second, third, and fourth transistors having respective control terminals and arranged in a four-switch buck-boost (FSBB) configuration for coupling to an inductor. The multi-mode converter also includes a first driver having an input for receiving a first switching signal and an output, a first charge pump having an output, a second driver having an input for receiving a second switching signal and an output, a second charge pump having an output, and a control circuit. The control circuit alternatively couples an output of the first driver or an output of the first charge pump to the control terminal of the first transistor, and the output of the second driver or the output of the second charge pump to the control terminal of the fourth transistor in response to a mode of operation of the multi-mode power converter.

First claim

What is claimed is:

1 . A multi-mode power converter ( 200 / 300 ) comprising:
first ( 222 ), second ( 224 ), third ( 262 ), and fourth ( 264 ) transistors having respective control terminals and arranged in a four-switch buck-boost (FSBB) configuration for coupling to an inductor ( 240 ); a first driver ( 226 ) having an input for receiving a first switching signal and an output; a first charge pump ( 230 ) having an output; a second driver ( 272 ) having an input for receiving a second switching signal and an output; a second charge pump ( 276 ) having an output; and a control circuit ( 228 / 232 / 274 / 278 / 280 ) for alternatively coupling said output of said first driver ( 226 ) or said output of said first charge pump ( 230 ) to said control terminal of said first transistor ( 222 ), and said output of said second driver ( 272 ) or said output of said second charge pump ( 276 ) to said control terminal of said fourth transistor ( 262 ) in response to a mode of operation of the multi-mode power converter ( 200 ).

2 . The multi-mode power converter ( 200 ) of claim 1 wherein said first ( 222 ) and fourth ( 264 ) transistors comprise P-channel MOS transistors and said second ( 224 ) and third ( 262 ) transistors comprise N-channel MOS transistors.

3 . The multi-mode power converter ( 200 ) of claim 2 wherein said first ( 230 ) and second ( 276 ) charge pumps comprise negative charge pumps.

4 . The multi-mode power converter ( 200 ) of claim 3 wherein said first transistor ( 222 ) has a source for receiving an input voltage, said fourth transistor ( 264 ) has a source for providing an output voltage, said first charge pump ( 230 ) has an input for receiving said input voltage, and said second charge pump ( 276 ) has an input for receiving said output voltage.

5 . The multi-mode power converter ( 300 ) of claim 1 wherein first ( 322 ), second ( 324 ), third ( 362 ), and fourth ( 364 ) transistors comprise N-channel MOS transistors.

6 . The multi-mode power converter ( 300 ) of claim 5 wherein said first ( 330 ) and second ( 376 ) charge pumps comprise positive charge pumps.

7 . The multi-mode power converter ( 300 ) of claim 5 wherein said first transistor ( 322 ) has a drain for receiving an input voltage, said fourth transistor ( 364 ) has a drain for providing an output voltage, said first charge pump ( 330 ) has an input for receiving said input voltage, and said second charge pump ( 376 ) has an input for receiving said output voltage.

8 . The multi-mode power converter ( 200 / 300 ) of claim 1 wherein said control circuit ( 228 / 232 / 274 / 278 / 280 ) comprises:
a first switch ( 228 ) coupled between said output of said first driver ( 226 ) and said control terminal of said first transistor ( 222 ) and conductive in response to a first control signal;
a second switch ( 232 ) coupled between said output of said first charge pump ( 230 ) and said control terminal of said first transistor ( 222 ) and conductive in response to a second control signal;
a third switch ( 274 ) coupled between said output of said second driver ( 272 ) and said control terminal of said fourth transistor ( 264 ) and conductive in response to a third control signal;
a fourth switch ( 278 ) coupled between said output of said second charge pump ( 276 ) and said control terminal of said third transistor ( 264 ) and conductive in response to a fourth control signal; and
a controller ( 280 ) for activating said first control signal in one of a buck mode and a buck-boost mode, said second control signal in a boost mode, said third control signal in one of said boost mode and said buck-boost mode, and said fourth control signal in said buck mode.

9 . A multi-mode power converter ( 200 / 300 ) adapted to be coupled to an inductor ( 240 ) having a first terminal and a second terminal, comprising:
a buck portion ( 220 ) having a first high side switch ( 222 ) and a first low side switch ( 224 ) for selectively switching the first terminal of the inductor ( 240 ) between an input voltage terminal and a reference voltage terminal; a boost portion ( 260 ) having a second high side switch ( 264 ) and a second low side switch ( 262 ) for selectively switching the second terminal of the inductor ( 240 ) between said reference voltage terminal and an output voltage terminal; and a controller ( 280 ) coupled to said buck portion ( 220 ) and said boost portion ( 260 ), wherein in a buck mode, said controller ( 280 ) causes said buck portion ( 220 ) alternatively to drive said first high side switch ( 222 ) and said first low side switch ( 224 ) while causing said boost portion ( 260 ) to provide a first charge pumped voltage on a control electrode of said second high side switch ( 264 ), and in a boost mode, said controller ( 280 ) causes said boost portion ( 260 ) alternatively to drive said second high side switch ( 264 ) and said second low side switch ( 262 ) while causing said buck portion ( 220 ) to provide a second charge pumped voltage on a control electrode of said first high side switch ( 222 ).

10 . The multi-mode power converter ( 200 ) of claim 9 wherein said controller ( 280 ) is in said buck mode when said input voltage on said input voltage terminal is greater than said output voltage on said output voltage terminal, and is in said boost mode when said input voltage is less than said output voltage.

11 . The multi-mode power converter ( 200 ) of claim 10 wherein said controller ( 280 ) is in a buck-boost mode when said input voltage is approximately equal to said output voltage, and in said buck-boost mode, said controller ( 280 ) causes said buck portion ( 220 ) alternatively to drive said first high side switch ( 222 ) and said first low side switch ( 224 ) and causes said boost portion ( 260 ) using duty cycles that are based on a feedback signal.

12 . The multi-mode power converter ( 200 ) of claim 9 wherein in said buck mode said controller ( 280 ) further causes said boost portion ( 260 ) to keep said second low side switch ( 262 ) nonconductive, and in said boost mode said controller ( 280 ) further causes said buck portion ( 220 ) to keep said first low side switch ( 222 ) nonconductive.

13 . The multi-mode power converter ( 200 ) of claim 9 wherein said first ( 222 ) and second ( 264 ) high side switches comprise P-channel MOS transistors and said first and second charge pumped voltages comprise negative voltages.

14 . The multi-mode power converter ( 200 ) of claim 9 wherein said first ( 322 ) and second ( 364 ) high side switches comprise N-channel MOS transistors and said first and second charge pumped voltages comprise positive voltages.

15 . A method of operating a four-switch buck-boost (FSBB) power converter ( 200 ) comprising:
coupling a first transistor ( 222 ) as a high-side switch of a first terminal of an inductor ( 240 ) and a second transistor ( 224 ) as a low-side switch of the first terminal of the inductor ( 240 ); coupling a third transistor ( 262 ) as a low-side switch of a second terminal of the inductor ( 240 ) and a fourth transistor ( 264 ) as a high-side switch of the second terminal of the inductor ( 240 ); receiving an input voltage on a first terminal of the first transistor ( 222 ); providing an output voltage on a first terminal of the fourth transistor ( 264 ); in a buck mode:
disabling the third transistor ( 262 );
driving the first ( 222 ) and second ( 224 ) transistors at a first variable duty cycle responsive to a feedback signal;
charge pumping a first predetermined voltage to provide a first charge-pumped voltage; and
biasing a gate of

Assignees

• Semiconductor Components Ind Llc

Inventors

• Le Men Berengere
• Ramond Stephane

Classifications

• H02M1/08

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

• H03K2217/0081

  Power supply means, e.g. to the switch driver · CPC title

• H02M3/1582 Primary

  Buck-boost converters (H02M3/1584 takes precedence) · CPC title

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title