Way out of balance (WOB) current correction for use with a multi-phase DC-DC converter

1. A way out of balance (WOB) rebalancer for use with a two-phase DC-DC converter that includes

a pulse width modulator adapted to output a first pulse width modulated signal (PWM 1 out) and a second pulse width modulated signal (PWM 2 out) that is substantially 180 degrees out of phase from the first pulse width modulated signal (PWM 1 out),

a first channel including a first driver MOSFET stage (DrMOS 1 ) having an input and an output, and a first inductor (L 1 ) having a terminal that is driven in dependence on the output of the first driver MOSFET stage (DrMOS 1 ),

a second channel including a second driver MOSFET stage (DrMOS 2 ) having an input and an output, and a second inductor (L 2 ) having a terminal that is driven in dependence on the output of the second driver MOSFET stage (DrMOS 2 ),

wherein the WOB rebalancer comprises:

a WOB detector adapted to detect WOB conditions within the two-phase DC-DC converter; and

a pulse path director adapted to adjust a balance between a current through the first channel and a current through the second channel in dependence on feedback from the WOB detector;

wherein the pulse path director is adapted to

provide one or more pulses of the first pulse width modulated signal (PWM 1 out) to the first channel, and provide one or more pulses of the second pulse width modulated signal (PWM 2 out) to the second channel, when the WOB detector does not detect a WOB condition; and

selectively provide one or more pulses of the first pulse width modulated signal (PWM 1 out) to the second channel, or selectively provide one or more pulses of the second pulse width modulated signal (PWM 2 out) to the first channel, in response to the WOB detector detecting a WOB condition, to thereby adjust the balance between the current through the first channel and the current through the second channel in dependence on feedback from the WOB detector.

2. The WOB rebalancer of claim 1 , wherein the WOB detector is adapted to

detect a first WOB condition when a first current (IL 1 ) indicative of the current through the first channel is more than a predetermined offset current greater than the a second current (IL 2 ) indicative of the current through the second channel, and

detect a second WOB condition when the second current (IL 2 ) indicative of the current through the second channel is more than a predetermined offset current greater than the first current (IL 1 ) indicative of the current through the first channel.

3. The WOB rebalancer of claim 2 , wherein the pulse path director is adapted to

receive the first and second pulse width modulated signals (PWM 1 out and PWM 2 out) from the pulse width modulator, and

selectively provide pulses of the first and second pulse width modulated signals (PWM 1 out and PWM 2 out) to the inputs of the first and second driver MOSFET stages (DrMOS 1 and DrMOS 2 ), in dependence on feedback from the WOB detector, to adjust a balance between the current through the first channel and the current through the second channel.

4. The WOB rebalancer of claim 3 , wherein the pulse path director can selectively provide individual pulses of the first pulse width modulation signal (PWMout 1 ) to the input of first driver MOSFET stage (DrMOS 1 ) or the input of the second driver MOSFET stage (DrMOS 2 ), and can selectively provide individual pulses of the second pulse width modulation signal (PWMout 2 ) to the input of first driver MOSFET stage (DrMOS 1 ) or the input of the second driver MOSFET stage (DrMOS 2 ).

5. The WOB rebalancer of claim 1 , wherein each of said driver MOSFET stages includes a driver and a pair of power field-effect transistors (FETs).

6. A way out of balance (WOB) rebalancer for use with a two-phase DC-DC converter that includes

a pulse width modulator adapted to output a first pulse width modulated signal (PWM 1 out) and a second pulse width modulated signal (PWM 2 out) that is substantially 180 degrees out of phase from the first pulse width modulated signal (PWM 1 out),

a first channel including a first driver MOSFET stage (DrMOS 1 ) having an input and an output, and a first inductor (L 1 ) having a terminal that is driven in dependence on the output of the first driver MOSFET stage (DrMOS 1 ),

a second channel including a second driver MOSFET stage (DrMOS 2 ) having an input and an output, and a second inductor (L 2 ) having a terminal that is driven in dependence on the output of the second driver MOSFET stage (DrMOS 2 ),

wherein the WOB rebalancer comprises:

a WOB detector adapted to detect WOB conditions within the two-phase DC-DC converter; and

a pulse path director adapted to adjust a balance between a current through the first channel and a current through the second channel in dependence on feedback from the WOB detector;

wherein the pulse path director is adapted to

not swap phases of the first and second pulse width modulated signals (PWM 1 out and PWM 2 out), output by the pulse width modulator, before the first and second pulse width modulated signals (PWM 1 out and PWM 2 out) are provided to the first and second driver MOSFET stages (DrMOS 1 and DrMOS 2 ), when the WOB detector does not detect a WOB condition; and

selectively swap phases of the first and second pulse width modulated signals (PWM 1 out and PWM 2 out), output by the pulse width modulator, before the first and second pulse width modulated signals (PWM 1 out and PWM 2 out) are provided to the first and second driver MOSFET stages (DrMOS 1 and DrMOS 2 ), in response to the WOB detector detecting a WOB condition, to adjust a balance between the currents through the first and second channels.

7. A method for use with a two-phase DC-DC converter that includes

a pulse width modulator adapted to output a first pulse width modulated signal (PWMlout) and a second pulse width modulated signal (PWM 2 out) that is substantially 180 degrees out of phase from the first pulse width modulated signal (PWM 1 out),

a first channel including a first driver MOSFET stage (DrMOS 1 ) having an input and an output, and a first inductor (L 1 ) having a terminal that is driven in dependence on the output of the first driver MOSFET stage (DrMOS 1 ),

a second channel including a second driver MOSFET stage (DrMOS 2 ) having an input and an output, and a second inductor (L 2 ) having a terminal that is driven in dependence on the output of the second driver MOSFET stage (DrMOS 2 ),

wherein the method comprises:

(a) monitoring for WOB conditions within the two-phase DC-DC converter;

(b) providing pulses of the first pulse width modulated signal (PWM 1 out) to the first channel, and providing pulses of the second pulse width modulated signal (PWM 2 out) to the second channel, when a WOB condition is not detected; and

(c) selectively providing one or more pulses of the first pulse width modulated signal (PWM 1 out) to the second channel, or selectively providing one or more pulses of the second pulse width modulated signal (PWM 2 out) to the first channel, in response to a WOB condition being detected, to thereby adjust a balance between a current through the first channel and a current through the second channel.

8. The method of claim 7 , wherein step (a) comprises:

(a.1) detecting a first WOB condition when a first current (IL 1 ) indicative of the current through the first channel is more than a predetermined offset current greater than the a second current (IL 2 ) indicative of the current through the second channel, and

(a.2) detecting a second WOB condition when the second current (IL 2 ) indicative of the current through the second channel is more than a predetermined offset current greater than the first current (IL 1 ) indicative of the current through the first channel.

9. The method of claim 8 , wherein step (c) comprises selectively providing pulses of the first and second pulse width modulated signals (PWM 1 out and PWM 2 out) to the inputs of the first and second driver MOSFET stages (DrMOS 1 and DrMOS 2 ), in dependence on the WOB conditions detected at step (a), to adjust a balance between the current through the first channel and the current through the second channel.

10. The method of claim 9 , wherein step (c) can include selectively providing individual pulses of the first pulse width modulation signal (PWMout 1 ) to the input of the first driver MOSFET stage (DrMOS 1 ) or the input of the second driver MOSFET stage (DrMOS 2 ), and selectively providing individual pulses of the second pulse width modulation signal (PWMout 2 ) to the input of first driver MOSFET stage (DrMOS 1 ) or the input of the second driver MOSFET stage (DrMOS 2 ).

11. A method for use with a two-phase DC-DC converter that includes

a pulse width modulator adapted to output a first pulse width modulated signal (PWM 1 out) and a second pulse width modulated signal (PWM 2 out) that is substantially 180 degrees out of phase from the first pulse width modulated signal (PWM 1 out),

a first channel including a first driver MOSFET stage (DrMOS 1 ) having an input and an output, and a first inductor (L 1 ) having a terminal that is driven in dependence on the output of the first driver MOSFET stage (DrMOS 1 ),

a second channel including a second driver MOSFET stage (DrMOS 2 ) having an input and an output, and a second inductor (L 2 ) having a terminal that is driven in dependence on the output of the second driver MOSFET stage (DrMOS 2 ),

wherein the method comprises:

(a) monitoring for WOB conditions within the two-phase DC-DC converter;

(b) not swapping phases of the first and second pulse width modulated signals (PWM 1 out and PWM 2 out), output by the pulse width modulator, before the first and second pulse width modulated signals (PWM 1 out and PWM 2 out) are provided to the first and second driver MOSFET stages (DrMOS 1 and DrMOS 2 ), when a WOB condition is not detected; and

(c) selectively swapping phases of the first and second pulse width modulated signals (PWM 1 out and PWM 2 out), output by the pulse width modulator, before the first and second pulse width modulated signals (PWM 1 out and PWM 2 out) are provided to the first and second driver MOSFET stages (DrMOS 1 and DrMOS 2 ), when a WOB condition is detected, to adjust a balance between the currents through the first and second channels.

12. A two-phase DC-DC converter adapted to correct way out of balance (WOB) conditions, the two-phase DC-DC converter comprising:

a pulse width modulator adapted to output a first pulse width modulated signal (PWM 1 out) and a second pulse width modulated signal (PWM 2 out) that is substantially 180 degrees out of phase from the first pulse width modulated signal (PWM 1 out);

a first channel including a first driver MOSFET stage (DrMOS 1 ) having an input and an output, and a first inductor (L 1 ) having a terminal that is driven in dependence on the output of the first driver MOSFET stage (DrMOS 1 );

a second channel including a second driver MOSFET stage (DrMOS 2 ) having an input and an output, and a second inductor (L 2 ) having a terminal that is driven in dependence on the output of the second driver MOSFET stage (DrMOS 2 );

a WOB rebalancer comprising a WOB detector and a pulse path director;

wherein the WOB detector is adapted to detect WOB conditions within the two-phase DC-DC converter; and

wherein the pulse path director is adapted to

selectively move one or more pulses of the first pulse width modulated signal (PWM 1 out) to the second channel, in response to the WOB detector detecting a first WOB condition, and

selectively move one or more pulses of the second pulse width modulated signal (PWM 1 out) to the first channel, in response to the WOB detector detecting a second WOB condition,

to thereby adjust a balance between a current through the first channel and a current through the second channel in dependence on feedback from the WOB detector.

13. The DC-DC converter of claim 12 , wherein the WOB detector is adapted to

detect the first WOB condition when a first current (IL 1 ) indicative of the current through the first channel is more than a predetermined offset current greater than the a second current (IL 2 ) indicative of the current through the second channel, and

detect the second WOB condition when the second current (IL 2 ) indicative of the current through the second channel is more than a predetermined offset current greater than the first current (IL 1 ) indicative of the current through the first channel.

14. The DC-DC converter of claim 13 , wherein the pulse path director is adapted to

receive the first and second pulse width modulated signals (PWM 1 out and PWM 2 out) from the pulse width modulator, and

selectively provide pulses of the first and second pulse width modulated signals (PWM 1 out and PWM 2 out) to the inputs of the first and second driver MOSFET stages (DrMOS 1 and DrMOS 2 ), in dependence on feedback from the WOB detector, to adjust a balance between the current through the first channel and the current through the second channel.

15. The DC-DC converter of claim 14 , wherein the pulse path director can selectively provide individual pulses of the first pulse width modulation signal (PWMout 1 ) to the input of first driver MOSFET stage (DrMOS 1 ) or the input of the second driver MOSFET stage (DrMOS 2 ), and can selectively provide individual pulses of the second pulse width modulation signal (PWMout 2 ) to the input of first driver MOSFET stage (DrMOS 1 ) or the input of the second driver MOSFET stage (DrMOS 2 ).

16. The DC-DC converter of claim 12 , wherein the first inductor (L 1 ) includes a further terminal, and the second inductor (L 2 ) includes a further terminal that is connected to the further terminal of the first inductor (L 1 ) to provide a voltage output of the DC-DC converter.

17. A multi-phase DC-DC converter adapted to correct way out of balance (WOB) conditions, the multi-phase DC-DC converter comprising:

a pulse width modulator adapted to output N pulse width modulated signals having different phases from one another, where N≧2;

N channels each including a driver MOSFET stage having an input and an output, and an inductor having a terminal that is driven in dependence on the output of the driver MOSFET stage;

a WOB rebalancer adapted to

detect WOB conditions within the multi-phase DC-DC converter;

provide pulses of each of the N pulse width modulated signals to a corresponding one of the N channels, when a WOB condition is not detected; and

selectively not provide one or more pulses of at least one of the N pulse width modulated signals to the corresponding one of the N channels, in response to a WOB condition being detected, to thereby adjust a balance between currents through the N channels.

18. A way out of balance (WOB) rebalancer for use with a multi-phase DC-DC converter that includes

a pulse width modulator adapted to output N pulse width modulated signals having different phases from one another, where N≧2,

N channels each including a driver MOSFET stage having an input and an output, and an inductor having a terminal that is driven in dependence on the output of the driver MOSFET stage,

wherein the WOB rebalancer is adapted to:

detect WOB conditions within the multi-phase DC-DC converter; and

adjust a balance between currents through the N channels by selectively moving one or more pulses of the N pulse width modulated signals from one channel to another in dependence on feedback from the WOB detector.

19. A method for use with a multi-phase DC-DC converter including N-channels, where N≧2, wherein the method comprises:

(a) monitoring for WOB conditions within the multi-phase DC-DC converter; and

(b) adjusting balance between currents through the N channels by selectively moving one or more pulses of the N pulse width modulated signals from one channel to another in dependence on WOB conditions detected at step (a).

20. A system, comprising:

a multi-phase DC-DC converter adapted to convert a first DC voltage (Vin) to a second DC voltage (Vout), wherein the multi-phase DC-DC converter includes

a pulse width modulator adapted to output N pulse width modulated signals having different phases from one another, where N≧2,

N channels each including a driver MOSFET stage having an input and an output, and an inductor having a terminal that is driven in dependence on the output of the driver MOSFET stage, and

a way out of balance (WOB) rebalancer adapted to detect WOB conditions within the multi-phase DC-DC converter, and adjust a balance between currents through the N channels by selectively moving one or more pulses of the N pulse width modulated signals from one channel to another in dependence on detected WOB conditions;

an AC/DC power supply adapted to produce the first DC voltage (Vin), wherein the first DC voltage (Vin) is used for powering the driver MOSFET stages of the N channels; and

a processing unit adapted to be powered by the second DC voltage (Vout) produced by the multi-phase DC-DC converter.

21. A method for use with multi-phase DC-DC converter that includes

a pulse width modulator adapted to output N pulse width modulated signals having different phases from one another, where N≧2;

N channels each including a driver MOSFET stage having an input and an output, and an inductor having a terminal that is driven in dependence on the output of the driver MOSFET stage;

the method comprising:

detecting WOB conditions within the multi-phase DC-DC converter,

providing pulses of each of the N pulse width modulated signals to a corresponding one of the N channels, when a WOB condition is not detected; and

selectively not providing one or more pulses of at least one of the N pulse width modulated signals to the corresponding one of the N channels, in response to a WOB condition being detected, to thereby adjust a balance between currents through the N channels.