DC-DC CONVERTERS
First Claim
1. A DC-DC converter comprising:
- an inductor operably connected between a first node and an output node;
a high side switch operably connected between a high side supply input node and the first node;
a low side switch operably connected between a low side supply input node and the first node;
switch control circuitry for controlling said switches, wherein the switch control circuitry comprises first monitoring circuitry for determining whether a first time period between the high side switch turning off and the inductor current reaching zero is less than a threshold time period,wherein if the first time period in one duty cycle is less than the threshold time period the switch control circuitry inhibits the low side switch from turning on in a subsequent cycle.
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Accused Products
Abstract
Methods and apparatus for control of DC-DC converters. The DC-DC converter is operable so that the low side supply switch may be inhibited from turning on in a cycle following the high side supply switch turning off. Turn on of the low side switch is inhibited if the time between turn off of the high side switch and the inductor (L) current reaching zero is less than a predetermined duration. Inhibiting the low side switch from turning on can prevent the inductor current from going negative, which would reduce the efficiency of the converter. When turn on of the low side switch is inhibited the inductor current flows through a parallel path, such as a parasitic body diode associated with the low side switch, which allows current flow in one direction only.
137 Citations
32 Claims
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1. A DC-DC converter comprising:
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an inductor operably connected between a first node and an output node; a high side switch operably connected between a high side supply input node and the first node; a low side switch operably connected between a low side supply input node and the first node; switch control circuitry for controlling said switches, wherein the switch control circuitry comprises first monitoring circuitry for determining whether a first time period between the high side switch turning off and the inductor current reaching zero is less than a threshold time period, wherein if the first time period in one duty cycle is less than the threshold time period the switch control circuitry inhibits the low side switch from turning on in a subsequent cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 29, 30, 31)
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24. A method of controlling a DC-DC converter comprising an inductor operably connected between a first node and an output node;
- a high side switch operably connected between a high side supply input node and the first node; and
a low side switch operably connected between a low side supply input node and the first node;
the method comprising;monitoring whether a first time period between the high side switch turning off and the inductor current reaching zero is less than a threshold time period, and where the first time period in one duty cycle is less than the threshold time period the switch control circuitry inhibiting the low side switch from turning on in a subsequent cycle.
- a high side switch operably connected between a high side supply input node and the first node; and
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25. (canceled)
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26. A DC-DC converter comprising:
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an inductor operably connected between a first node and an output node; a high side switch operably connected between a high side supply input node and the first node; a low side switch operably connected between a low side supply input node and the first node; switch control circuitry arranged to monitor the time between the high side switch turning off and the voltage at the first node reaching zero and, if said monitored time is less than a first time threshold, preventing the low side switch from subsequently turning on the next time the high side switch is turned on.
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27. A DC-DC converter comprising:
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an inductor operably connected between a first node and an output node; a high side switch operably connected between a high side supply input node and the first node; a low side switch operably connected between a low side supply input node and the first node; and switch control circuitry operable in a first mode where the low side switch is not turned on following the high side switch being turned off.
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28. A DC-DC converter operable in a mode wherein a low side switch is not turned on following activation and deactivation of a high side supply switch.
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32. (canceled)
Specification