ADAPTIVE DEAD-TIME CONTROL

• US 20130147458A1
• Filed: 11/19/2012
• Published: 06/13/2013
• Est. Priority Date: 12/07/2011
• Status: Active Grant

• Current Assignee: Maxim Integrated Products, Inc. (Analog Devices, Inc.)
• Original Assignee: Maxim Integrated Products, Inc. (Analog Devices, Inc.)
• Inventors: Miwa, Brett A., Zhak, Serhii M.
• Granted Patent: US 8,933,679 B2
• Time in Patent Office: Days
• US Class Current: 323/311
• CPC Class Codes: G05F 3/08 wherein the variable is dc
• CPC Class Codes: H02M 1/38 Means for preventing simultaneous conduction of switches
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A DC-to-DC converter includes first and second transistors that are connected in series between a supply voltage and ground and that are driven by PWM pulses. A junction of the transistors is connected to an inductance that is connected in series to a load. A first timing module determines a first time difference between a first edge of a first signal at the junction and a first edge of a second signal at a control terminal of the first transistor. A second timing module determines a second time difference between a second edge of the first signal and a second edge of the second signal. The first and second edges of the second signal respectively correspond to first and second edges of one of the PWM pulses. A delay module delays the first and second edges of the second signal respectively based on the first and second time differences.

Claims

1. A DC-to-DC converter comprising:

first and second transistors each driven by pulse-width modulated (PWM) pulses and each having first and second terminals and a control terminal, wherein the first terminal of the first transistor is connected to a supply voltage, the second terminal of the first transistor and the first terminal of the second transistor are connected to a node, the second terminal of the second transistor is connected to ground, and the node is connected to an inductance that is connected in series to a load;

a first timing module that determines a first time difference between a first edge of a first signal at the node and a first edge of a second signal at the control terminal of the first transistor, wherein the first edge of the second signal corresponds to a first edge of one of the PWM pulses;

a second timing module that determines a second time difference between a second edge of the first signal at the node and a second edge of the second signal at the control terminal of the first transistor, wherein the second edge of the second signal corresponds to a second edge of the one of the PWM pulses; and

a delay module that delays the first edge of the second signal at the control terminal of the first transistor based on the first time difference and that delays the second edge of the second signal at the control terminal of the first transistor based on the second time difference.

2. The DC-to-DC converter of claim 1, wherein:

the first and second transistors are PMOS and NMOS transistors, respectively;

the first and second edges of the first signal at the node are falling and rising edges, respectively;

the first and second edges of the second signal at the control terminal of the first transistor are rising and falling edges, respectively; and

the first and second edges of the one of the PWM pulses are falling and rising edges, respectively.

3. The DC-to-DC converter of claim 1 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the first edge of the second signal at the control terminal of the first transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the delay module delays the first edge of the one of the PWM pulses based on the amount of increase in the voltage.

4. The DC-to-DC converter of claim 1 further comprising:

a charge pump that outputs a voltage,

wherein the voltage decreases when the first edge of the second signal at the control terminal of the first transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage decreases by an amount that is proportional to a difference between the first and second times, and

wherein the delay module delays the first edge of the one of the PWM pulses based on the amount of decrease in the voltage.

5. The DC-to-DC converter of claim 1 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the second edge of the second signal at the control terminal of the first transistor occurs at a first time and the second edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the delay module delays the second edge of the one of the PWM pulses based on the amount of increase in the voltage.

6. The DC-to-DC converter of claim 1 further comprising:

a charge pump that outputs a voltage,

wherein the voltage decreases when the second edge of the second signal at the control terminal of the first transistor occurs at a first time and the second edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage decreases by an amount that is proportional to a difference between the first and second times, and

wherein the delay module delays the second edge of the one of the PWM pulses based on the amount of decrease in the voltage.

7. A DC-to-DC converter comprising:

first and second transistors each driven by pulse-width modulated (PWM) pulses and each having first and second terminals and a control terminal, wherein the first terminal of the first transistor is connected to a supply voltage, the second terminal of the first transistor and the first terminal of the second transistor are connected to a node, the second terminal of the second transistor is connected to ground, and the node is connected to an inductance that is connected in series to a load;

a first timing module that determines a first time difference between a first edge of a first signal at the node and a first edge of a second signal at the control terminal of the second transistor, wherein the first edge of the second signal corresponds to a first edge of one of the PWM pulses;

a second timing module that determines a second time difference between a second edge of the first signal at the node and a second edge of the second signal at the control terminal of the second transistor, wherein the second edge of the second signal corresponds to a second edge of the one of the PWM pulses; and

a delay module that delays the first edge of the second signal at the control terminal of the second transistor based on the first time difference and that delays the second edge of the second signal at the control terminal of the second transistor based on the second time difference.

8. The DC-to-DC converter of claim 7, wherein:

the first and second transistors are PMOS and NMOS transistors, respectively;

the first and second edges of the first signal at the node are rising and falling edges, respectively;

the first and second edges of the second signal at the control terminal of the second transistor are falling and rising edges, respectively; and

the first and second edges of the one of the PWM pulses are rising and falling edges, respectively.

9. The DC-to-DC converter of claim 7 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the first edge of the second signal at the control terminal of the second transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the delay module delays the first edge of the one of the PWM pulses based on the amount of increase in the voltage.

10. The DC-to-DC converter of claim 7 further comprising:

a charge pump that outputs a voltage,

wherein the voltage decreases when the first edge of the second signal at the control terminal of the second transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage decreases by an amount that is proportional to a difference between the first and second times, and

wherein the delay module delays the first edge of the one of the PWM pulses based on the amount of decrease in the voltage.

11. The DC-to-DC converter of claim 7 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the second edge of the second signal at the control terminal of the second transistor occurs at a first time and the second edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the delay module delays the second edge of the one of the PWM pulses based on the amount of increase in the voltage.

12. The DC-to-DC converter of claim 7 further comprising:

a charge pump that outputs a voltage,

wherein the voltage decreases when the second edge of the second signal at the control terminal of the second transistor occurs at a first time and the second edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage decreases by an amount that is proportional to a difference between the first and second times, and

wherein the delay module delays the second edge of the one of the PWM pulses based on the amount of decrease in the voltage.

13. A DC-to-DC converter comprising:

first and second transistors each driven by pulse-width modulated (PWM) pulses and each having first and second terminals and a control terminal, wherein the first terminal of the first transistor is connected to a supply voltage, the second terminal of the first transistor and the first terminal of the second transistor are connected to a node, the second terminal of the second transistor is connected to ground, and the node is connected to an inductance that is connected in series to a load;

a first timing module that determines a first time difference between a first edge of a first signal at the node and a first edge of a second signal at the control terminal of the first transistor, wherein the first edge of the second signal corresponds to a first edge of one of the PWM pulses;

a second timing module that determines a second time difference between a second edge of the first signal at the node and a second edge of the second signal at the control terminal of the first transistor, wherein the second edge of the second signal corresponds to a second edge of the one of the PWM pulses;

a third timing module that determines a third time difference between the first edge of the first signal at the node and a first edge of a third signal at the control terminal of the second transistor, wherein the first edge of the third signal corresponds to the first edge of the one of the PWM pulses;

a first delay module that delays the first edge of the second signal at the control terminal of the first transistor based on the first time difference and that delays the second edge of the second signal at the control terminal of the first transistor based on the second time difference; and

a second delay module that delays the first edge of the third signal at the control terminal of the second transistor based on the third time difference and that does not delay a second edge of the third signal at the control terminal of the second transistor, wherein the second edge of the third signal corresponds to the second edge of the one of the PWM pulses.

14. The DC-to-DC converter of claim 13, wherein:

the first and second transistors are PMOS and NMOS transistors, respectively;

the first and second edges of the first signal at the node are falling and rising edges, respectively;

the first and second edges of the second signal at the control terminal of the first transistor are rising and falling edges, respectively;

the first and second edges of the third signal at the control terminal of the second transistor are rising and falling edges, respectively; and

the first and second edges of the one of the PWM pulses are falling and rising edges, respectively.

15. The DC-to-DC converter of claim 13 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the first edge of the second signal at the control terminal of the first transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the first delay module delays the first edge of the one of the PWM pulses based on the amount of increase in the voltage.

16. The DC-to-DC converter of claim 13 further comprising:

a charge pump that outputs a voltage,

wherein the voltage decreases when the first edge of the second signal at the control terminal of the first transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage decreases by an amount that is proportional to a difference between the first and second times, and

wherein the first delay module delays the first edge of the one of the PWM pulses based on the amount of decrease in the voltage.

17. The DC-to-DC converter of claim 13 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the second edge of the second signal at the control terminal of the first transistor occurs at a first time and the second edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the first delay module delays the second edge of the one of the PWM pulses based on the amount of increase in the voltage.

18. The DC-to-DC converter of claim 13 further comprising:

a charge pump that outputs a voltage,

wherein the voltage decreases when the second edge of the second signal at the control terminal of the first transistor occurs at a first time and the second edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage decreases by an amount that is proportional to a difference between the first and second times, and

wherein the first delay module delays the second edge of the one of the PWM pulses based on the amount of decrease in the voltage.

19. The DC-to-DC converter of claim 13 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the first edge of the third signal at the control terminal of the second transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the second delay module delays the first edge of the one of the PWM pulses based on the amount of increase in the voltage.

20. The DC-to-DC converter of claim 13 further comprising:

a charge pump that outputs a voltage,

wherein the voltage decreases when the first edge of the third signal at the control terminal of the second transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage decreases by an amount that is proportional to a difference between the first and second times, and

wherein the second delay module delays the first edge of the one of the PWM pulses based on the amount of decrease in the voltage.

21. A DC-to-DC converter comprising:

first and second transistors each driven by pulse-width modulated (PWM) pulses and each having first and second terminals and a control terminal, wherein the first terminal of the first transistor is connected to a supply voltage, the second terminal of the first transistor and the first terminal of the second transistor are connected to a node, the second terminal of the second transistor is connected to ground, and the node is connected to an inductance that is connected in series to a load;

a first timing module that determines a first time difference between a first edge of a first signal at the node and a first edge of a second signal at the control terminal of the first transistor, wherein the first edge of the second signal corresponds to a first edge of the one of the PWM pulses;

a second timing module that determines a second time difference between the first edge of the first signal at the node and a first edge of a third signal at the control terminal of the second transistor, wherein the first edge of the third signal corresponds to the first edge of the one of the PWM pulses;

a third timing module that determines a third time difference between a second edge of the first signal at the node and a second edge of the third signal at the control terminal of the second transistor, wherein the second edge of the third signal corresponds to a second edge of the one of the PWM pulses;

a first delay module that delays the first edge of the second signal at the control terminal of the first transistor based on the first time difference and that does not delay a second edge of the second signal at the control terminal of the first transistor, wherein the second edge of the second signal corresponds to the second edge of the one of the PWM pulses; and

a second delay module that delays the first edge of the third signal at the control terminal of the second transistor based on the second time difference and that delays the second edge of the third signal at the control terminal of the second transistor based on the third time difference.

22. The DC-to-DC converter of claim 21, wherein:

the first and second transistors are PMOS and NMOS transistors, respectively;

the first and second edges of the first signal at the node are falling and rising edges, respectively;

the first and second edges of the second signal at the control terminal of the first transistor are falling and rising edges, respectively;

the first and second edges of the third signal at the control terminal of the second transistor are falling and rising edges, respectively; and

the first and second edges of the one of the PWM pulses are rising and falling edges, respectively.

23. The DC-to-DC converter of claim 21 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the first edge of the second signal at the control terminal of the first transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the first delay module delays the first edge of the one of the PWM pulses based on the amount of increase in the voltage.

24. The DC-to-DC converter of claim 21 further comprising:

a charge pump that outputs a voltage,

wherein the voltage decreases when the first edge of the second signal at the control terminal of the first transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage decreases by an amount that is proportional to a difference between the first and second times, and

wherein the first delay module delays the first edge of the one of the PWM pulses based on the amount of decrease in the voltage.

25. The DC-to-DC converter of claim 21 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the first edge of the third signal at the control terminal of the second transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the second delay module delays the first edge of the one of the PWM pulses based on the amount of increase in the voltage.

26. The DC-to-DC converter of claim 21 further comprising:

a charge pump that outputs a voltage,

wherein the voltage decreases when the first edge of the third signal at the control terminal of the second transistor occurs at a first time and the first edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage decreases by an amount that is proportional to a difference between the first and second times, and

wherein the second delay module delays the first edge of the one of the PWM pulses based on the amount of decrease in the voltage.

27. The DC-to-DC converter of claim 21 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the second edge of the third signal at the control terminal of the second transistor occurs at a first time and the second edge of the first signal at the node occurs at a second time that is later than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the second delay module delays the second edge of the one of the PWM pulses based on the amount of increase in the voltage.

28. The DC-to-DC converter of claim 21 further comprising:

a charge pump that outputs a voltage,

wherein the voltage increases when the second edge of the third signal at the control terminal of the second transistor occurs at a first time and the second edge of the first signal at the node occurs at a second time that is earlier than the first time, and wherein the voltage increases by an amount that is proportional to a difference between the first and second times, and

wherein the second delay module delays the second edge of the one of the PWM pulses based on the amount of increase in the voltage.

29. A DC-to-DC converter comprising:

first and second transistors each driven by pulse-width modulated (PWM) pulses and each having first and second terminals and a control terminal, wherein the first terminal of the first transistor is connected to a supply voltage, the second terminal of the first transistor and the first terminal of the second transistor are connected to a node, the second terminal of the second transistor is connected to ground, and the node is connected to an inductance that is connected in series to a load;

a first timing module that determines a first time difference between a first edge of a first signal at the node and a first edge of a second signal at the control terminal of the first transistor, wherein the first edge of the second signal corresponds to a first edge of one of the PWM pulses;

a second timing module that determines a second time difference between a second edge of the first signal at the node and a second edge of the second signal at the control terminal of the first transistor, wherein the second edge of the second signal corresponds to a second edge of the one of the PWM pulses;

a third timing module that determines a third time difference between the second edge of the first signal at the node and a first edge of a third signal at the control terminal of the second transistor, wherein the first edge of the second signal corresponds to the second edge of the one of the PWM pulses;

a fourth timing module that determines a fourth time difference between the first edge of the first signal at the node and a second edge of the third signal at the control terminal of the second transistor, wherein the second edge of the third signal corresponds to the first edge of the one of the PWM pulses;

a first delay module that delays the first edge of the second signal at the control terminal of the first transistor based on the first time difference and that delays the second edge of the second signal at the control terminal of the first transistor based on the second time difference; and

a second delay module that delays the first edge of the third signal at the control terminal of the second transistor based on the third time difference and that delays the second edge of the third signal at the control terminal of the second transistor based on the fourth time difference.

30. The DC-to-DC converter of claim 29, wherein:

the first and second transistors are PMOS and NMOS transistors, respectively;

the first and second edges of the first signal at the node are falling and rising edges, respectively;

the first and second edges of the second signal at the control terminal of the first transistor are rising and falling edges, respectively;

the first and second edges of the third signal at the control terminal of the second transistor are falling and rising edges, respectively; and

the first and second edges of the one of the PWM pulses are falling and rising edges, respectively.

31. The DC-to-DC converter of claim 29 further comprising:

a first charge pump that outputs a first voltage based on the first time difference, wherein the first delay module delays the first edge of the one of the PMW pulses based on the first time difference;

a second charge pump that outputs a second voltage based on the second time difference, wherein the first delay module delays the second edge of the one of the PMW pulses based on the second time difference;

a third charge pump that outputs a third voltage based on the third time difference, wherein the second delay module delays the second edge of the one of the PMW pulses based on the third time difference; and

a fourth charge pump that outputs a fourth voltage based on the fourth time difference, wherein the second delay module delays the first edge of the one of the PMW pulses based on the fourth time difference.

32. The DC-to-DC converter of claim 31 further comprising:

a first feedback module that senses the second and third voltages, that computes a first average voltage of the second and third voltages, and that injects a first charge into the outputs of the second and third charge pumps, wherein the first charge is based on a difference between the first average voltage and half of the supply voltage; and

a second feedback module that senses the first and fourth voltages, that computes a second average voltage of the first and fourth voltages, and that injects a second charge into the outputs of the first and fourth charge pumps, wherein the second charge is based on a difference between the second average voltage and half of the supply voltage.

33. The DC-to-DC converter of claim 29 further comprising:

a first sensor that senses current through the inductance and that outputs the second signal to the first and second timing modules when a first control voltage at the control terminal of the first transistor is greater than or equal to a first predetermined voltage between a first threshold voltage at which the first transistor turns on and a first plateau voltage of the first transistor; and

a second sensor that senses current through the inductance and that outputs the third signal to the third and fourth timing modules when a second control voltage at the control terminal of the second transistor is greater than or equal to a second predetermined voltage between a second threshold voltage at which the second transistor turns on and a second plateau voltage of the second transistor,

wherein the first and second predetermined voltages are set closer to or farther from the first and second threshold voltages, respectively, based on the load.

34. The DC-to-DC converter of claim 31, wherein each of the first, second, third, and fourth charge pumps includes first and second current sources respectively having first and second gains, wherein the first gain is different than the second gain.